quantum angular momenta: Topics by Science.gov

Sample records for quantum angular momenta

Quantum entanglement of high angular momenta.

PubMed

Fickler, Robert; Lapkiewicz, Radek; Plick, William N; Krenn, Mario; Schaeff, Christoph; Ramelow, Sven; Zeilinger, Anton

2012-11-02

Single photons with helical phase structures may carry a quantized amount of orbital angular momentum (OAM), and their entanglement is important for quantum information science and fundamental tests of quantum theory. Because there is no theoretical upper limit on how many quanta of OAM a single photon can carry, it is possible to create entanglement between two particles with an arbitrarily high difference in quantum number. By transferring polarization entanglement to OAM with an interferometric scheme, we generate and verify entanglement between two photons differing by 600 in quantum number. The only restrictive factors toward higher numbers are current technical limitations. We also experimentally demonstrate that the entanglement of very high OAM can improve the sensitivity of angular resolution in remote sensing.
Quantum orbital angular momentum of elliptically symmetric light

NASA Astrophysics Data System (ADS)

Plick, William N.; Krenn, Mario; Fickler, Robert; Ramelow, Sven; Zeilinger, Anton

2013-03-01

We present a quantum-mechanical analysis of the orbital angular momentum of a class of recently discovered elliptically symmetric stable light fields—the so-called Ince-Gauss modes. We study, in a fully quantum formalism, how the orbital angular momentum of these beams varies with their ellipticity, and we discover several compelling features, including nonmonotonic behavior, stable beams with real continuous (noninteger) orbital angular momenta, and orthogonal modes with the same orbital angular momenta. We explore, and explain in detail, the reasons for this behavior. These features may have applications in quantum key distribution, atom trapping, and quantum informatics in general—as the ellipticity opens up an alternative way of navigating the spatial photonic Hilbert space.
Helicons in uniform fields. II. Poynting vector and angular momenta

NASA Astrophysics Data System (ADS)

Stenzel, R. L.; Urrutia, J. M.

2018-03-01

The orbital and spin angular momenta of helicon modes have been determined quantitatively from laboratory experiments. The current density is obtained unambiguously from three dimensional magnetic field measurements. The only approximation made is to obtain the electric field from Hall Ohm's law which is usually the case for low frequency whistler modes. This allows the evaluation of the Poynting vector from which the angular momentum is obtained. Comparing two helicon modes (m = 0 and m = 1), one can separate the contribution of angular momentum of a rotating and non-rotating wave field. The orbital angular momentum is important to assess the wave-particle interaction by the transverse Doppler shift of rotating waves which has not been considered so far.
Separation of spin and orbital angular coherence momenta in the second-order coherence theory of vector electromagnetic fields.

PubMed

Wang, Wei; Takeda, Mitsuo

2007-09-15

In analogy with the separation of the total optical angular momentum into a spin and an orbital part in electrodynamics, we introduce a new concept of spin and orbital angular coherence momenta into the general coherence theory of vector electromagnetic fields. The properties of the newly introduced spin and orbital angular coherence momenta are investigated through the decomposition of the total coherence angular momentum into the sum of these two components, and their separate conservations have been derived for what is believed to be the first time.
Nuclear scissors modes and hidden angular momenta

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balbutsev, E. B., E-mail: balbuts@theor.jinr.ru; Molodtsova, I. V.; Schuck, P.

The coupled dynamics of low-lying modes and various giant resonances are studied with the help of the Wigner Function Moments method generalized to take into account spin degrees of freedom and pair correlations simultaneously. The method is based on Time-Dependent Hartree–Fock–Bogoliubov equations. The model of the harmonic oscillator including spin–orbit potential plus quadrupole–quadrupole and spin–spin interactions is considered. New low-lying spin-dependent modes are analyzed. Special attention is paid to the scissors modes. A new source of nuclear magnetism, connected with counter-rotation of spins up and down around the symmetry axis (hidden angular momenta), is discovered. Its inclusion into the theorymore » allows one to improve substantially the agreement with experimental data in the description of energies and transition probabilities of scissors modes.« less
Effect of transverse vibrations of fissile nuclei on the angular and spin distributions of low-energy fission fragments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bunakov, V. E.; Kadmensky, S. G., E-mail: kadmensky@phys.vsu.ru; Lyubashevsky, D. E.

2016-05-15

It is shown that A. Bohr’s classic theory of angular distributions of fragments originating from low-energy fission should be supplemented with quantum corrections based on the involvement of a superposition of a very large number of angular momenta L{sub m} in the description of the relative motion of fragments flying apart along the straight line coincidentwith the symmetry axis. It is revealed that quantum zero-point wriggling-type vibrations of the fissile system in the vicinity of its scission point are a source of these angular momenta and of high fragment spins observed experimentally.
Analytical scheme calculations of angular momentum coupling and recoupling coefficients

NASA Astrophysics Data System (ADS)

Deveikis, A.; Kuznecovas, A.

2007-03-01

We investigate the Scheme programming language opportunities to analytically calculate the Clebsch-Gordan coefficients, Wigner 6j and 9j symbols, and general recoupling coefficients that are used in the quantum theory of angular momentum. The considered coefficients are calculated by a direct evaluation of the sum formulas. The calculation results for large values of quantum angular momenta were compared with analogous calculations with FORTRAN and Java programming languages.
A large-alphabet three-party quantum key distribution protocol based on orbital and spin angular momenta hybrid entanglement

NASA Astrophysics Data System (ADS)

Lai, Hong; Luo, Mingxing; Zhang, Jun; Pieprzyk, Josef; Pan, Lei; Orgun, Mehmet A.

2018-07-01

The orthogonality of the orbital angular momentum (OAM) eigenstates enables a single photon carry an arbitrary number of bits. Moreover, additional degrees of freedom (DOFs) of OAM can span a high-dimensional Hilbert space, which could greatly increase information capacity and security. Moreover, the use of the spin angular momentum-OAM hybrid entangled state can increase Shannon dimensionality, because photons can be hybrid entangled in multiple DOFs. Based on these observations, we develop a hybrid entanglement quantum key distribution (QKD) protocol to achieve three-party quantum key distribution without classical message exchanges. In our proposed protocol, a communicating party uses a spatial light modulator (SLM) and a specific phase hologram to modulate photons' OAM state. Similarly, the other communicating parties use their SLMs and the fixed different phase holograms to modulate the OAM entangled photon pairs, producing the shared key among the parties Alice, Bob and Charlie without classical message exchanges. More importantly, when the same operation is repeated for every party, our protocol could be extended to a multiple-party QKD protocol.
Total angular momenta of high-lying odd levels of U I at ∼ 4 eV using resonance ionization laser polarization spectroscopy

NASA Astrophysics Data System (ADS)

Rath, Asawari D.; Kundu, S.; Ray, A. K.

2018-02-01

Laser induced photoionization of atoms shows significant dependence on the choice of polarizations of lasers. In multi-step, multi-photon excitation and subsequent ionization of atoms different polarization combinations of the exciting lasers lead to distinctly different ion yields. This fact is exploited in this work to determine total angular momenta of odd-parity energy levels of U I lying at ∼ 4 eV from its ground level using resonance ionization laser polarization spectroscopy in time of flight mass spectrometer. These levels are populated by two-step resonant excitation using two pulsed dye lasers with preset polarizations of choice followed by nonresonant ionization by third laser. The dependence of ionization yield on specific polarizations of the first two lasers is studied experimentally for each level under consideration. This dependence when compared to simulations makes possible unambiguous assignment of J angular momenta to these levels.
Controlling neutron orbital angular momentum

NASA Astrophysics Data System (ADS)

Clark, Charles W.; Barankov, Roman; Huber, Michael G.; Arif, Muhammad; Cory, David G.; Pushin, Dmitry A.

2015-09-01

The quantized orbital angular momentum (OAM) of photons offers an additional degree of freedom and topological protection from noise. Photonic OAM states have therefore been exploited in various applications ranging from studies of quantum entanglement and quantum information science to imaging. The OAM states of electron beams have been shown to be similarly useful, for example in rotating nanoparticles and determining the chirality of crystals. However, although neutrons--as massive, penetrating and neutral particles--are important in materials characterization, quantum information and studies of the foundations of quantum mechanics, OAM control of neutrons has yet to be achieved. Here, we demonstrate OAM control of neutrons using macroscopic spiral phase plates that apply a `twist' to an input neutron beam. The twisted neutron beams are analysed with neutron interferometry. Our techniques, applied to spatially incoherent beams, demonstrate both the addition of quantum angular momenta along the direction of propagation, effected by multiple spiral phase plates, and the conservation of topological charge with respect to uniform phase fluctuations. Neutron-based studies of quantum information science, the foundations of quantum mechanics, and scattering and imaging of magnetic, superconducting and chiral materials have until now been limited to three degrees of freedom: spin, path and energy. The optimization of OAM control, leading to well defined values of OAM, would provide an additional quantized degree of freedom for such studies.
Quantum entanglement of angular momentum states with quantum numbers up to 10,010

PubMed Central

Fickler, Robert; Campbell, Geoff; Buchler, Ben; Lam, Ping Koy; Zeilinger, Anton

2016-01-01

Photons with a twisted phase front carry a quantized amount of orbital angular momentum (OAM) and have become important in various fields of optics, such as quantum and classical information science or optical tweezers. Because no upper limit on the OAM content per photon is known, they are also interesting systems to experimentally challenge quantum mechanical prediction for high quantum numbers. Here, we take advantage of a recently developed technique to imprint unprecedented high values of OAM, namely spiral phase mirrors, to generate photons with more than 10,000 quanta of OAM. Moreover, we demonstrate quantum entanglement between these large OAM quanta of one photon and the polarization of its partner photon. To our knowledge, this corresponds to entanglement with the largest quantum number that has been demonstrated in an experiment. The results may also open novel ways to couple single photons to massive objects, enhance angular resolution, and highlight OAM as a promising way to increase the information capacity of a single photon. PMID:27856742
Quantum entanglement of angular momentum states with quantum numbers up to 10,010

NASA Astrophysics Data System (ADS)

Fickler, Robert; Campbell, Geoff; Buchler, Ben; Lam, Ping Koy; Zeilinger, Anton

2016-11-01

Photons with a twisted phase front carry a quantized amount of orbital angular momentum (OAM) and have become important in various fields of optics, such as quantum and classical information science or optical tweezers. Because no upper limit on the OAM content per photon is known, they are also interesting systems to experimentally challenge quantum mechanical prediction for high quantum numbers. Here, we take advantage of a recently developed technique to imprint unprecedented high values of OAM, namely spiral phase mirrors, to generate photons with more than 10,000 quanta of OAM. Moreover, we demonstrate quantum entanglement between these large OAM quanta of one photon and the polarization of its partner photon. To our knowledge, this corresponds to entanglement with the largest quantum number that has been demonstrated in an experiment. The results may also open novel ways to couple single photons to massive objects, enhance angular resolution, and highlight OAM as a promising way to increase the information capacity of a single photon.
Quantum entanglement of angular momentum states with quantum numbers up to 10,010.

PubMed

Fickler, Robert; Campbell, Geoff; Buchler, Ben; Lam, Ping Koy; Zeilinger, Anton

2016-11-29

Photons with a twisted phase front carry a quantized amount of orbital angular momentum (OAM) and have become important in various fields of optics, such as quantum and classical information science or optical tweezers. Because no upper limit on the OAM content per photon is known, they are also interesting systems to experimentally challenge quantum mechanical prediction for high quantum numbers. Here, we take advantage of a recently developed technique to imprint unprecedented high values of OAM, namely spiral phase mirrors, to generate photons with more than 10,000 quanta of OAM. Moreover, we demonstrate quantum entanglement between these large OAM quanta of one photon and the polarization of its partner photon. To our knowledge, this corresponds to entanglement with the largest quantum number that has been demonstrated in an experiment. The results may also open novel ways to couple single photons to massive objects, enhance angular resolution, and highlight OAM as a promising way to increase the information capacity of a single photon.
Accompanying coordinate expansion and recurrence relation method using a transfer relation scheme for electron repulsion integrals with high angular momenta and long contractions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayami, Masao; Seino, Junji; Nakai, Hiromi, E-mail: nakai@waseda.jp

An efficient algorithm for the rapid evaluation of electron repulsion integrals is proposed. The present method, denoted by accompanying coordinate expansion and transferred recurrence relation (ACE-TRR), is constructed using a transfer relation scheme based on the accompanying coordinate expansion and recurrence relation method. Furthermore, the ACE-TRR algorithm is extended for the general-contraction basis sets. Numerical assessments clarify the efficiency of the ACE-TRR method for the systems including heavy elements, whose orbitals have long contractions and high angular momenta, such as f- and g-orbitals.
On Angular Momentum

DOE R&D Accomplishments Database

Schwinger, J.

1952-01-26

The commutation relations of an arbitrary angular momentum vector can be reduced to those of the harmonic oscillator. This provides a powerful method for constructing and developing the properties of angular momentum eigenvectors. In this paper many known theorems are derived in this way, and some new results obtained. Among the topics treated are the properties of the rotation matrices; the addition of two, three, and four angular momenta; and the theory of tensor operators.
Control of Rotational Energy and Angular Momentum Orientation with an Optical Centrifuge

NASA Astrophysics Data System (ADS)

Ogden, Hannah M.; Murray, Matthew J.; Mullin, Amy S.

2017-04-01

We use an optical centrifuge to trap and spin molecules to an angular frequency of 30 THz with oriented angular momenta and extremely high rotational energy and then investigate their subsequent collision dynamics with transient high resolution IR spectroscopy. The optical centrifuge is formed by combining oppositely-chirped pulses of 800 nm light, and overlapping them spatially and temporally. Polarization-sensitive Doppler-broadened line profiles characterize the anisotropic kinetic energy release of the super rotor molecules, showing that they behave like molecular gyroscopes. Studies are reported for collisions of CO2 super rotors with CO2, He and Ar. These studies reveal how mass, velocity and rotational adiabaticity impact the angular momentum relaxation and reorientation. Quantum scattering calculations provide insight into the J-specific collision cross sections that control the relaxation. NSF-CHE 105 8721.
Trial wave functions for ring-trapped ions and neutral atoms: Microscopic description of the quantum space-time crystal

NASA Astrophysics Data System (ADS)

Yannouleas, Constantine; Landman, Uzi

2017-10-01

A constructive theoretical platform for the description of quantum space-time crystals uncovers for N interacting and ring-confined rotating particles the existence of low-lying states with proper space-time crystal behavior. The construction of the corresponding many-body trial wave functions proceeds first via symmetry breaking at the mean-field level followed by symmetry restoration using projection techniques. The ensuing correlated many-body wave functions are stationary states and preserve the rotational symmetries, and at the same time they reflect the point-group symmetries of the mean-field crystals. This behavior results in the emergence of sequences of select magic angular momenta Lm. For angular-momenta away from the magic values, the trial functions vanish. Symmetry breaking beyond the mean-field level can be induced by superpositions of such good-Lm many-body stationary states. We show that superposing a pair of adjacent magic angular momenta states leads to formation of special broken-symmetry states exhibiting quantum space-time-crystal behavior. In particular, the corresponding particle densities rotate around the ring, showing undamped and nondispersed periodic crystalline evolution in both space and time. The experimental synthesis of such quantum space-time-crystal wave packets is predicted to be favored in the vicinity of ground-state energy crossings of the Aharonov-Bohm-type spectra accessed via an externally applied, natural or synthetic, magnetic field. These results are illustrated here for Coulomb-repelling fermionic ions and for a lump of contact-interaction attracting bosons.
From rotating atomic rings to quantum Hall states.

PubMed

Roncaglia, M; Rizzi, M; Dalibard, J

2011-01-01

Considerable efforts are currently devoted to the preparation of ultracold neutral atoms in the strongly correlated quantum Hall regime. However, the necessary angular momentum is very large and in experiments with rotating traps this means spinning frequencies extremely near to the deconfinement limit; consequently, the required control on parameters turns out to be too stringent. Here we propose instead to follow a dynamic path starting from the gas initially confined in a rotating ring. The large moment of inertia of the ring-shaped fluid facilitates the access to large angular momenta, corresponding to giant vortex states. The trapping potential is then adiabatically transformed into a harmonic confinement, which brings the interacting atomic gas in the desired quantum-Hall regime. We provide numerical evidence that for a broad range of initial angular frequencies, the giant-vortex state is adiabatically connected to the bosonic ν = 1/2 Laughlin state.
A Universal Angular Momentum Profile for Dark Matter Halos

NASA Astrophysics Data System (ADS)

Liao, Shihong; Chen, Jianxiong; Chu, M.-C.

2017-07-01

The angular momentum distribution in dark matter halos and galaxies is a key ingredient in understanding their formation. Specifically, the internal distribution of angular momenta is closely related to the formation of disk galaxies. In this article, we use halos identified from a high-resolution simulation, the Bolshoi simulation, to study the spatial distribution of specific angular momenta, j(r,θ ). We show that by stacking halos with similar masses to increase the signal-to-noise ratio, the profile can be fitted as a simple function, j{(r,θ )={j}s{\\sin }2{(θ /{θ }s)(r/{r}s)}2/(1+r/{r}s)}4, with three free parameters, {j}s,{r}s, and {θ }s. Specifically, j s correlates with the halo mass M vir as {j}s\\propto {M}{vir}2/3, r s has a weak dependence on the halo mass as {r}s\\propto {M}{vir}0.040, and {θ }s is independent of M vir. This profile agrees with that from a rigid shell model, though its origin is unclear. Our universal specific angular momentum profile j(r,θ ) is useful in modeling the angular momenta of halos. Furthermore, by using an empirical stellar mass-halo mass relation, we can infer the average angular momentum distribution of a dark matter halo. The specific angular momentum-stellar mass relation within a halo computed from our profile is shown to share a similar shape as that from the observed disk galaxies.
Improving Student Understanding of Addition of Angular Momentum in Quantum Mechanics

ERIC Educational Resources Information Center

Zhu, Guangtian; Singh, Chandralekha

2013-01-01

We describe the difficulties advanced undergraduate and graduate students have with concepts related to addition of angular momentum in quantum mechanics. We also describe the development and implementation of a research-based learning tool, Quantum Interactive Learning Tutorial (QuILT), to reduce these difficulties. The preliminary evaluation…

Chirality and angular momentum in optical radiation

NASA Astrophysics Data System (ADS)

Coles, Matt M.; Andrews, David L.

2012-06-01

This paper develops, in precise quantum electrodynamic terms, photonic attributes of the “optical chirality density,” one of several measures long known to be conserved quantities for a vacuum electromagnetic field. The analysis lends insights into some recent interpretations of chiroptical experiments, in which this measure, and an associated chirality flux, have been treated as representing physically distinctive “superchiral” phenomena. In the fully quantized formalism the chirality density is promoted to operator status, whose exploration with reference to an arbitrary polarization basis reveals relationships to optical angular momentum and helicity operators. Analyzing multimode beams with complex wave-front structures, notably Laguerre-Gaussian modes, affords a deeper understanding of the interplay between optical chirality and optical angular momentum. By developing theory with due cognizance of the photonic character of light, it emerges that only the spin-angular momentum of light is engaged in such observations. Furthermore, it is shown that these prominent measures of the helicity of chiral electromagnetic radiation have a common basis in differences between the populations of optical modes associated with angular momenta of opposite sign. Using a calculation of the rate of circular dichroism as an example, with coherent states to model the electromagnetic field, it is discovered that two terms contribute to the differential effect. The primary contribution relates to the difference in left- and right-handed photon populations; the only other contribution, which displays a sinusoidal distance dependence corresponding to the claim of nodal enhancements, is connected with the quantum photon number-phase uncertainty relation. From the full analysis, it appears that the term “superchiral” can be considered redundant.
The cosmic web and the orientation of angular momenta

NASA Astrophysics Data System (ADS)

Libeskind, Noam I.; Hoffman, Yehuda; Knebe, Alexander; Steinmetz, Matthias; Gottlöber, Stefan; Metuki, Ofer; Yepes, Gustavo

2012-03-01

We use a 64 h-1 Mpc dark-matter-only cosmological simulation to examine the large-scale orientation of haloes and substructures with respect to the cosmic web. A web classification scheme based on the velocity shear tensor is used to assign to each halo in the simulation a web type: knot, filament, sheet or void. Using ˜106 haloes that span ˜3 orders of magnitude in mass, the orientation of the halo's spin and the orbital angular momentum of subhaloes with respect to the eigenvectors of the shear tensor is examined. We find that the orbital angular momentum of subhaloes tends to align with the intermediate eigenvector of the velocity shear tensor for all haloes in knots, filaments and sheets. This result indicates that the kinematics of substructures located deep within the virialized regions of a halo is determined by its infall which in turn is determined by the large-scale velocity shear, a surprising result given the virialized nature of haloes. The non-random nature of subhalo accretion is thus imprinted on the angular momentum measured at z= 0. We also find that the haloes' spin axis is aligned with the third eigenvector of the velocity shear tensor in filaments and sheets: the halo spin axis points along filaments and lies in the plane of cosmic sheets.
Angular momentum conservation law in light-front quantum field theory

DOE PAGES

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

2017-03-31

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3, the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED andmore » QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less
Angular momentum conservation law in light-front quantum field theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3, the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QED andmore » QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less
Angular momentum conservation law in light-front quantum field theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chiu, Kelly Yu-Ju; Brodsky, Stanley J.

We prove the Lorentz invariance of the angular momentum conservation law and the helicity sum rule for relativistic composite systems in the light-front formulation. We explicitly show that j 3 , the z -component of the angular momentum remains unchanged under Lorentz transformations generated by the light-front kinematical boost operators. The invariance of j 3 under Lorentz transformations is a feature unique to the front form. Applying the Lorentz invariance of the angular quantum number in the front form, we obtain a selection rule for the orbital angular momentum which can be used to eliminate certain interaction vertices in QEDmore » and QCD. We also generalize the selection rule to any renormalizable theory and show that there exists an upper bound on the change of orbital angular momentum in scattering processes at any fixed order in perturbation theory.« less
Collapse and Nonlinear Instability of AdS Space with Angular Momentum

NASA Astrophysics Data System (ADS)

Choptuik, Matthew W.; Dias, Óscar J. C.; Santos, Jorge E.; Way, Benson

2017-11-01

We present a numerical study of rotational dynamics in AdS5 with equal angular momenta in the presence of a complex doublet scalar field. We determine that the endpoint of gravitational collapse is a Myers-Perry black hole for high energies and a hairy black hole for low energies. We investigate the time scale for collapse at low energies E , keeping the angular momenta J ∝E in anti-de Sitter (AdS) length units. We find that the inclusion of angular momenta delays the collapse time, but retains a t ˜1 /E scaling. We perturb and evolve rotating boson stars, and find that boson stars near AdS space appear stable, but those sufficiently far from AdS space are unstable. We find that the dynamics of the boson star instability depend on the perturbation, resulting either in collapse to a Myers-Perry black hole, or development towards a stable oscillating solution.
Sorting photons of different rotational Doppler shifts (RDS) by orbital angular momentum of single-photon with spin-orbit-RDS entanglement.

PubMed

Chen, Lixiang; She, Weilong

2008-09-15

We demonstrate that single photons from a rotating q-plate exhibit an entanglement in three degrees of freedom of spin, orbital angular momentum, and the rotational Doppler shift (RDS) due to the nonconservation of total spin and orbital angular momenta. We find that the rotational Doppler shift deltaomega = Omega((delta)s + deltal) , where s, l and Omega are quantum numbers of spin, orbital angular momentum, and rotating velocity of the q-plate, respectively. Of interest is that the rotational Doppler shift directly reflects the rotational symmetry of q-plates and can be also expressed as deltaomega = (Omega)n , where n = 2(q-1) denotes the fold number of rotational symmetry. Besides, based on this single-photon spin-orbit-RDS entanglement, we propose an experimental scheme to sort photons of different frequency shifts according to individual orbital angular momentum.
Energy Levels of Hydrogen and Deuterium

National Institute of Standards and Technology Data Gateway

SRD 142 NIST Energy Levels of Hydrogen and Deuterium (Web, free access) This database provides theoretical values of energy levels of hydrogen and deuterium for principle quantum numbers n = 1 to 200 and all allowed orbital angular momenta l and total angular momenta j. The values are based on current knowledge of the revelant theoretical contributions including relativistic, quantum electrodynamic, recoil, and nuclear size effects.
Angular momentum of phonons and its application to single-spin relaxation

NASA Astrophysics Data System (ADS)

Nakane, Jotaro J.; Kohno, Hiroshi

2018-05-01

We reexamine the relaxation process of a single spin embedded in an elastic medium, a problem studied recently by Garanin and Chudnovsky (GC) [Phys. Rev. B 92, 024421 (2015), 10.1103/PhysRevB.92.024421] from the viewpoint of angular-momentum transfer. Using Noether's theorem, we identify two distinct angular momenta of the medium, one Newtonian discussed by GC and the other field-theoretical, both of which consist of an orbital part and a spin part. For both angular momenta, we found that the orbital part is as essential as the spin part in the relaxation process. In particular, the angular-momentum transfer from the (real) spin to the Newtonian orbital part may be considered as an incipient rotation that leads to the Einstein-de Haas effect.
Twisted molecular excitons as mediators for changing the angular momentum of light

NASA Astrophysics Data System (ADS)

Zang, Xiaoning; Lusk, Mark T.

2017-07-01

Molecules with CN or CN h symmetry can absorb quanta of optical angular momentum to generate twisted excitons with well-defined quasiangular momenta of their own. Angular momentum is conserved in such interactions at the level of a paraxial approximation for the light beam. A sequence of absorption events can thus be used to create a range of excitonic angular momenta. Subsequent decay can produce radiation with a single angular momentum equal to that accumulated. Such molecules can thus be viewed as mediators for changing the angular momentum of light. This sidesteps the need to exploit nonlinear light-matter interactions based on higher-order susceptibilities. A tight-binding paradigm is used to verify angular momentum conservation and demonstrate how it can be exploited to change the angular momentum of light. The approach is then extended to a time-dependent density functional theory setting where the key results are shown to hold in a many-body, multilevel setting.
Interface between path and orbital angular momentum entanglement for high-dimensional photonic quantum information.

PubMed

Fickler, Robert; Lapkiewicz, Radek; Huber, Marcus; Lavery, Martin P J; Padgett, Miles J; Zeilinger, Anton

2014-07-30

Photonics has become a mature field of quantum information science, where integrated optical circuits offer a way to scale the complexity of the set-up as well as the dimensionality of the quantum state. On photonic chips, paths are the natural way to encode information. To distribute those high-dimensional quantum states over large distances, transverse spatial modes, like orbital angular momentum possessing Laguerre Gauss modes, are favourable as flying information carriers. Here we demonstrate a quantum interface between these two vibrant photonic fields. We create three-dimensional path entanglement between two photons in a nonlinear crystal and use a mode sorter as the quantum interface to transfer the entanglement to the orbital angular momentum degree of freedom. Thus our results show a flexible way to create high-dimensional spatial mode entanglement. Moreover, they pave the way to implement broad complex quantum networks where high-dimensionally entangled states could be distributed over distant photonic chips.
Combined calculi for photon orbital and spin angular momenta

NASA Astrophysics Data System (ADS)

Elias, N. M.

2014-08-01

Context. Wavelength, photon spin angular momentum (PSAM), and photon orbital angular momentum (POAM), completely describe the state of a photon or an electric field (an ensemble of photons). Wavelength relates directly to energy and linear momentum, the corresponding kinetic quantities. PSAM and POAM, themselves kinetic quantities, are colloquially known as polarization and optical vortices, respectively. Astrophysical sources emit photons that carry this information. Aims: PSAM characteristics of an electric field (intensity) are compactly described by the Jones (Stokes/Mueller) calculus. Similarly, I created calculi to represent POAM characteristics of electric fields and intensities in an astrophysical context. Adding wavelength dependence to all of these calculi is trivial. The next logical steps are to 1) form photon total angular momentum (PTAM = POAM + PSAM) calculi; 2) prove their validity using operators and expectation values; and 3) show that instrumental PSAM can affect measured POAM values for certain types of electric fields. Methods: I derive the PTAM calculi of electric fields and intensities by combining the POAM and PSAM calculi. I show how these quantities propagate from celestial sphere to image plane. I also form the PTAM operator (the sum of the POAM and PSAM operators), with and without instrumental PSAM, and calculate the corresponding expectation values. Results: Apart from the vector, matrix, dot product, and direct product symbols, the PTAM and POAM calculi appear superficially identical. I provide tables with all possible forms of PTAM calculi. I prove that PTAM expectation values are correct for instruments with and without instrumental PSAM. I also show that POAM measurements of "unfactored" PTAM electric fields passing through non-zero instrumental circular PSAM can be biased. Conclusions: The combined PTAM calculi provide insight into mathematically modeling PTAM sources and calibrating POAM- and PSAM-induced measurement errors.
Transfer of Orbital and Spin angular momentum from non-paraxial optical vortex to atomic BEC

NASA Astrophysics Data System (ADS)

Bhowmik, Anal; Mondal, Pradip Kumar; Majumder, Sonjoy; Deb, Bimalendu

2017-04-01

Allen and co-workers first brought up the realization that optical vortex can carry well defined orbital angular momentum (OAM) associated with its spatial mode. Spin angular momentum (SAM) of the light, associated with the polarization, interacts with the internal electronic motion of the atom. The exchange of orbital angular momentum (OAM) between optical vortex and the center-of-mass (CM) motion of an atom or molecule is well known in paraxial approximation. We show that, how the total angular momentum (TAM) of non-paraxial optical vortex is shared with atom, in terms of OAM and SAM. Both the angular momenta are now possible to be transferred to the internal electronic and external CM motion of atom. Here we have studied how the Rabi frequencies of the excitations of two-photon Raman transitions with respect to focusing angles. Also, we investigate the properties of the vortex superposed state for a Bose-Einstein condensate condensate by a single non-paraxial vortex beam. The density distribution of the vortex-antivortex superposed state has a petal structure which is determined by the quantum circulations and proportion of the vortex and antivortex.
Bell’s measure and implementing quantum Fourier transform with orbital angular momentum of classical light

PubMed Central

Song, Xinbing; Sun, Yifan; Li, Pengyun; Qin, Hongwei; Zhang, Xiangdong

2015-01-01

We perform Bell’s measurement for the non-separable correlation between polarization and orbital angular momentum from the same classical vortex beam. The violation of Bell’s inequality for such a non-separable classical correlation has been demonstrated experimentally. Based on the classical vortex beam and non-quantum entanglement between the polarization and the orbital angular momentum, the Hadamard gates and conditional phase gates have been designed. Furthermore, a quantum Fourier transform has been implemented experimentally. PMID:26369424
Quantum and semiclassical spin networks: from atomic and molecular physics to quantum computing and gravity

NASA Astrophysics Data System (ADS)

Aquilanti, Vincenzo; Bitencourt, Ana Carla P.; Ferreira, Cristiane da S.; Marzuoli, Annalisa; Ragni, Mirco

2008-11-01

The mathematical apparatus of quantum-mechanical angular momentum (re)coupling, developed originally to describe spectroscopic phenomena in atomic, molecular, optical and nuclear physics, is embedded in modern algebraic settings which emphasize the underlying combinatorial aspects. SU(2) recoupling theory, involving Wigner's 3nj symbols, as well as the related problems of their calculations, general properties, asymptotic limits for large entries, nowadays plays a prominent role also in quantum gravity and quantum computing applications. We refer to the ingredients of this theory—and of its extension to other Lie and quantum groups—by using the collective term of 'spin networks'. Recent progress is recorded about the already established connections with the mathematical theory of discrete orthogonal polynomials (the so-called Askey scheme), providing powerful tools based on asymptotic expansions, which correspond on the physical side to various levels of semi-classical limits. These results are useful not only in theoretical molecular physics but also in motivating algorithms for the computationally demanding problems of molecular dynamics and chemical reaction theory, where large angular momenta are typically involved. As for quantum chemistry, applications of these techniques include selection and classification of complete orthogonal basis sets in atomic and molecular problems, either in configuration space (Sturmian orbitals) or in momentum space. In this paper, we list and discuss some aspects of these developments—such as for instance the hyperquantization algorithm—as well as a few applications to quantum gravity and topology, thus providing evidence of a unifying background structure.
High-Dimensional Circular Quantum Secret Sharing Using Orbital Angular Momentum

NASA Astrophysics Data System (ADS)

Tang, Dawei; Wang, Tie-jun; Mi, Sichen; Geng, Xiao-Meng; Wang, Chuan

2016-11-01

Quantum secret sharing is to distribute secret message securely between multi-parties. Here exploiting orbital angular momentum (OAM) state of single photons as the information carrier, we propose a high-dimensional circular quantum secret sharing protocol which increases the channel capacity largely. In the proposed protocol, the secret message is split into two parts, and each encoded on the OAM state of single photons. The security of the protocol is guaranteed by the laws of non-cloning theorem. And the secret messages could not be recovered except that the two receivers collaborated with each other. Moreover, the proposed protocol could be extended into high-level quantum systems, and the enhanced security could be achieved.
Angular focusing, squeezing, and rainbow formation in a strongly driven quantum rotor.

PubMed

Averbukh, I S; Arvieu, R

2001-10-15

Semiclassical catastrophes in the dynamics of a quantum rotor (molecule) driven by a strong time-varying field are considered. We show that for strong enough fields, a sharp peak in the rotor angular distribution can be achieved via a time-domain focusing phenomenon, followed by the formation of rainbowlike angular structures. A strategy leading to the enhanced angular squeezing is proposed that uses a specially designed sequence of pulses. The predicted effects can be observed in many processes, ranging from molecular alignment (orientation) by laser fields to heavy-ion collisions, and the trapping of cold atoms by a standing light wave.
On the quantum-channel capacity for orbital angular momentum-based free-space optical communications.

PubMed

Zhang, Yequn; Djordjevic, Ivan B; Gao, Xin

2012-08-01

Inspired by recent demonstrations of orbital angular momentum-(OAM)-based single-photon communications, we propose two quantum-channel models: (i) the multidimensional quantum-key distribution model and (ii) the quantum teleportation model. Both models employ operator-sum representation for Kraus operators derived from OAM eigenkets transition probabilities. These models are highly important for future development of quantum-error correction schemes to extend the transmission distance and improve date rates of OAM quantum communications. By using these models, we calculate corresponding quantum-channel capacities in the presence of atmospheric turbulence.
Timelike Momenta In Quantum Electrodynamics

DOE R&D Accomplishments Database

Brodsky, S. J.; Ting, S. C. C.

1965-12-01

In this note we discuss the possibility of studying the quantum electrodynamics of timelike photon propagators in muon or electron pair production by incident high energy muon or electron beams from presently available proton or electron accelerators.
Quantum storage of orbital angular momentum entanglement in cold atomic ensembles

NASA Astrophysics Data System (ADS)

Shi, Bao-Sen; Ding, Dong-Sheng; Zhang, Wei

2018-02-01

Electromagnetic waves have both spin momentum and orbital angular momentum (OAM). Light carrying OAM has broad applications in micro-particle manipulation, high-precision optical metrology, and potential high-capacity optical communications. In the concept of quantum information, a photon encoded with information in its OAM degree of freedom enables quantum networks to carry much more information and increase their channel capacity greatly compared with those of current technology because of the inherent infinite dimensions for OAM. Quantum memories are indispensable to construct quantum networks. Storing OAM states has attracted considerable attention recently, and many important advances in this direction have been achieved during the past few years. Here we review recent experimental realizations of quantum memories using OAM states, including OAM qubits and qutrits at true single photon level, OAM states entangled in a two-dimensional or a high-dimensional space, hyperentanglement and hybrid entanglement consisting of OAM and other degree of freedom in a physical system. We believe that all achievements described here are very helpful to study quantum information encoded in a high-dimensional space.

Creating fractional quantum Hall states with atomic clusters using light-assisted insertion of angular momentum

NASA Astrophysics Data System (ADS)

Zhang, Junyi; Beugnon, Jerome; Nascimbene, Sylvain

We describe a protocol to prepare clusters of ultracold bosonic atoms in strongly interacting states reminiscent of fractional quantum Hall states. Our scheme consists in injecting a controlled amount of angular momentum to an atomic gas using Raman transitions carrying orbital angular momentum. By injecting one unit of angular momentum per atom, one realizes a single-vortex state, which is well described by mean-field theory for large enough particle numbers. We also present schemes to realize fractional quantum Hall states, namely, the bosonic Laughlin and Moore-Read states. We investigate the requirements for adiabatic nucleation of such topological states, in particular comparing linear Landau-Zener ramps and arbitrary ramps obtained from optimized control methods. We also show that this protocol requires excellent control over the isotropic character of the trapping potential. ERC-Synergy Grant UQUAM, ANR-10-IDEX-0001-02, DIM NanoK Atocirc project.
The azimuthal component of Poynting's vector and the angular momentum of light

NASA Astrophysics Data System (ADS)

Cameron, Robert P.; Speirits, Fiona C.; Gilson, Claire R.; Allen, L.; Barnett, Stephen M.

2015-12-01

The usual description in basic electromagnetic theory of the linear and angular momenta of light is centred upon the identification of Poynting's vector as the linear momentum density and its cross product with position, or azimuthal component, as the angular momentum density. This seemingly reasonable approach brings with it peculiarities, however, in particular with regards to the separation of angular momentum into orbital and spin contributions, which has sometimes been regarded as contrived. In the present paper, we observe that densities are not unique, which leads us to ask whether the usual description is, in fact, the most natural choice. To answer this, we adopt a fundamental rather than heuristic approach by first identifying appropriate symmetries of Maxwell's equations and subsequently applying Noether's theorem to obtain associated conservation laws. We do not arrive at the usual description. Rather, an equally acceptable one in which the relationship between linear and angular momenta is nevertheless more subtle and in which orbital and spin contributions emerge separately and with transparent forms.
Dynamical Quasicondensation of Hard-Core Bosons at Finite Momenta: A Non-equilibrium Condensation Effect

NASA Astrophysics Data System (ADS)

Heidrich-Meisner, Fabian; Vidmar, L.; Ronzheimer, J. P.; Hodgman, S.; Schreiber, M.; Braun, S.; Langer, S.; Bloch, I.; Schneider, U.

2016-05-01

Long-range order in quantum many-body systems is usually associated with equilibrium situations. Here, we experimentally investigate the quasicondensation of strongly interacting bosons at finite momenta in a far-from-equilibrium case. We prepare an inhomogeneous initial state consisting of one-dimensional Mott insulators in the center of otherwise empty one-dimensional chains in an optical lattice with a lattice constant d. After suddenly quenching the trapping potential to zero, we observe the onset of coherence in spontaneously forming quasicondensates in the lattice. Remarkably, the emerging phase order differs from the ground-state order and is characterized by peaks at finite momenta +/-(π / 2)(ℏ / d) in the momentum distribution function. Supported by the DFG via FOR 801.
Quantum X waves with orbital angular momentum in nonlinear dispersive media

NASA Astrophysics Data System (ADS)

Ornigotti, Marco; Conti, Claudio; Szameit, Alexander

2018-06-01

We present a complete and consistent quantum theory of generalised X waves with orbital angular momentum in dispersive media. We show that the resulting quantised light pulses are affected by neither dispersion nor diffraction and are therefore resilient against external perturbations. The nonlinear interaction of quantised X waves in quadratic and Kerr nonlinear media is also presented and studied in detail.
A Very Fast and Angular Momentum Conserving Tree Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marcello, Dominic C., E-mail: dmarce504@gmail.com

There are many methods used to compute the classical gravitational field in astrophysical simulation codes. With the exception of the typically impractical method of direct computation, none ensure conservation of angular momentum to machine precision. Under uniform time-stepping, the Cartesian fast multipole method of Dehnen (also known as the very fast tree code) conserves linear momentum to machine precision. We show that it is possible to modify this method in a way that conserves both angular and linear momenta.
Stimulated scattering of electromagnetic waves carrying orbital angular momentum in quantum plasmas.

PubMed

Shukla, P K; Eliasson, B; Stenflo, L

2012-07-01

We investigate stimulated scattering instabilities of coherent circularly polarized electromagnetic (CPEM) waves carrying orbital angular momentum (OAM) in dense quantum plasmas with degenerate electrons and nondegenerate ions. For this purpose, we employ the coupled equations for the CPEM wave vector potential and the driven (by the ponderomotive force of the CPEM waves) equations for the electron and ion plasma oscillations. The electrons are significantly affected by the quantum forces (viz., the quantum statistical pressure, the quantum Bohm potential, as well as the electron exchange and electron correlations due to electron spin), which are included in the framework of the quantum hydrodynamical description of the electrons. Furthermore, our investigation of the stimulated Brillouin instability of coherent CPEM waves uses the generalized ion momentum equation that includes strong ion coupling effects. The nonlinear equations for the coupled CPEM and quantum plasma waves are then analyzed to obtain nonlinear dispersion relations which exhibit stimulated Raman, stimulated Brillouin, and modulational instabilities of CPEM waves carrying OAM. The present results are useful for understanding the origin of scattered light off low-frequency density fluctuations in high-energy density plasmas where quantum effects are eminent.
Staggering of angular momentum distribution in fission

NASA Astrophysics Data System (ADS)

Tamagno, Pierre; Litaize, Olivier

2018-03-01

We review here the role of angular momentum distributions in the fission process. To do so the algorithm implemented in the FIFRELIN code [?] is detailed with special emphasis on the place of fission fragment angular momenta. The usual Rayleigh distribution used for angular momentum distribution is presented and the related model derivation is recalled. Arguments are given to justify why this distribution should not hold for low excitation energy of the fission fragments. An alternative ad hoc expression taking into account low-lying collectiveness is presented as has been implemented in the FIFRELIN code. Yet on observables currently provided by the code, no dramatic impact has been found. To quantify the magnitude of the impact of the low-lying staggering in the angular momentum distribution, a textbook case is considered for the decay of the 144Ba nucleus with low excitation energy.
Communication: Quantum six-dimensional calculations of the coupled translation-rotation eigenstates of H{sub 2}O@C{sub 60}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Felker, Peter M., E-mail: felker@chem.ucla.edu; Bačić, Zlatko, E-mail: zlatko.bacic@nyu.edu; NYU-ECNU Center for Computational Chemistry at NYU Shanghai, 3663 Zhongshan Road North, Shanghai 200062

2016-05-28

We report rigorous quantum calculations of the translation-rotation (TR) eigenstates of para- and ortho-H{sub 2}O@C{sub 60}. They provide a comprehensive description of the dynamical behavior of H{sub 2}O inside the fullerene having icosahedral (I{sub h}) symmetry. The TR eigenstates are assigned in terms of the irreducible representations of the proper symmetry group of H{sub 2}O@C{sub 60}, as well as the appropriate translational and rotational quantum numbers. The coupling between the orbital and the rotational angular momenta of the caged H{sub 2}O gives rise to the total angular momentum λ, which additionally labels each TR level. The calculated TR levels allowmore » tentative assignments of a number of transitions in the recent experimental INS spectra of H{sub 2}O@C{sub 60} that have not been assigned previously.« less
Unique Properties and Prospects: Quantum Theory of the Orbital Angular Momentum of Ince-Gauss Beams

NASA Astrophysics Data System (ADS)

Plick, William; Krenn, Mario; Fickler, Robert; Ramelow, Sven; Zeilinger, Anton

2012-02-01

The Ince-Gauss modes represent a new addition to the standard solutions to the paraxial wave equation. Parametrized by the ellipticity of the beam, they span the solution space between the Hermite-Gauss and the Laguerre-Gauss modes. These beams may be decomposed in either basis, and single photons in the Ince-Gauss modes exist naturally as superpositions of either Laguerre-Gauss or Hermite-Gauss modes. We present the fully quantum theory of the orbital angular momentum of these beams. Interesting features that arise are: stable beams with fractional orbital angular momentum, non-monotonic behavior of the OAM with respect to ellipticity, and the possibility of orthogonal modes possessing the same OAM. We believe that these modes may open up a fully new parameter space for quantum informatics and communication, and thus are worthy of thorough study.
Optical angular momentum and atoms

PubMed Central

2017-01-01

Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom’s angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light’s OAM, aiding our fundamental understanding of light–matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069766
Quantum Storage of Three-Dimensional Orbital-Angular-Momentum Entanglement in a Crystal.

PubMed

Zhou, Zong-Quan; Hua, Yi-Lin; Liu, Xiao; Chen, Geng; Xu, Jin-Shi; Han, Yong-Jian; Li, Chuan-Feng; Guo, Guang-Can

2015-08-14

Here we present the quantum storage of three-dimensional orbital-angular-momentum photonic entanglement in a rare-earth-ion-doped crystal. The properties of the entanglement and the storage process are confirmed by the violation of the Bell-type inequality generalized to three dimensions after storage (S=2.152±0.033). The fidelity of the memory process is 0.993±0.002, as determined through complete quantum process tomography in three dimensions. An assessment of the visibility of the stored weak coherent pulses in higher-dimensional spaces demonstrates that the memory is highly reliable for 51 spatial modes. These results pave the way towards the construction of high-dimensional and multiplexed quantum repeaters based on solid-state devices. The multimode capacity of rare-earth-based optical processors goes beyond the temporal and the spectral degree of freedom, which might provide a useful tool for photonic information processing.
The issue of gauge choice in the Landau problem and the physics of canonical and mechanical orbital angular momenta

NASA Astrophysics Data System (ADS)

Wakamatsu, M.; Kitadono, Y.; Zhang, P.-M.

2018-05-01

One intriguing issue in the nucleon spin decomposition problem is the existence of two types of decompositions, which are representably characterized by two different orbital angular momenta (OAMs) of quarks. The one is the mechanical OAM, while the other is the so-called gauge-invariant canonical (g.i.c.) OAM, the concept of which was introduced by Chen et al. An especially delicate quantity is the g.i.c. OAM, which must be distinguished from the ordinary (gauge-variant) canonical OAM. We find that, owing to its analytically solvable nature, the famous Landau problem offers an ideal tool to understand the difference and the physical meaning of the above three OAMs, i.e. the standard canonical OAM, g.i.c. OAM, and the mechanical OAM. We analyze these three OAMs in two different formulations of the Landau problem, first in the standard (gauge-fixed) formulation and second in the gauge-invariant (but path-dependent) formulation of DeWitt. Especially interesting is the latter formalism. It is shown that the choice of path has an intimate connection with the choice of gauge, but they are not necessarily equivalent. Then, we answer the question about what is the consequence of a particular choice of path in DeWitt's formalism. This analysis also clarifies the implication of the gauge symmetry hidden in the concept of g.i.c. OAM. Finally, we show that the finding above offers a clear understanding about the uniqueness or non-uniqueness problem of the nucleon spin decomposition, which arises from the arbitrariness in the definition of the so-called physical component of the gauge field.
Maple procedures for the coupling of angular momenta. IX. Wigner D-functions and rotation matrices

NASA Astrophysics Data System (ADS)

Pagaran, J.; Fritzsche, S.; Gaigalas, G.

2006-04-01

The Wigner D-functions, Dpqj(α,β,γ), are known for their frequent use in quantum mechanics. Defined as the matrix elements of the rotation operator Rˆ(α,β,γ) in R and parametrized in terms of the three Euler angles α, β, and γ, these functions arise not only in the transformation of tensor components under the rotation of the coordinates, but also as the eigenfunctions of the spherical top. In practice, however, the use of the Wigner D-functions is not always that simple, in particular, if expressions in terms of these and other functions from the theory of angular momentum need to be simplified before some computations can be carried out in detail. To facilitate the manipulation of such Racah expressions, here we present an extension to the RACAH program [S. Fritzsche, Comput. Phys. Comm. 103 (1997) 51] in which the properties and the algebraic rules of the Wigner D-functions and reduced rotation matrices are implemented. Care has been taken to combine the standard knowledge about the rotation matrices with the previously implemented rules for the Clebsch-Gordan coefficients, Wigner n-j symbols, and the spherical harmonics. Moreover, the application of the program has been illustrated below by means of three examples. Program summaryTitle of program:RACAH Catalogue identifier:ADFv_9_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADFv_9_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Catalogue identifier of previous version: ADFW, ADHW, title RACAH Journal reference of previous version(s): S. Fritzsche, Comput. Phys. Comm. 103 (1997) 51; S. Fritzsche, S. Varga, D. Geschke, B. Fricke, Comput. Phys. Comm. 111 (1998) 167; S. Fritzsche, T. Inghoff, M. Tomaselli, Comput. Phys. Comm. 153 (2003) 424. Does the new version supersede the previous one: Yes, in addition to the spherical harmonics and recoupling coefficients, the program now supports also the occurrence of the Wigner rotation matrices in the algebraic
Realization of optimized quantum controlled-logic gate based on the orbital angular momentum of light.

PubMed

Zeng, Qiang; Li, Tao; Song, Xinbing; Zhang, Xiangdong

2016-04-18

We propose and experimentally demonstrate an optimized setup to implement quantum controlled-NOT operation using polarization and orbital angular momentum qubits. This device is more adaptive to inputs with various polarizations, and can work both in classical and quantum single-photon regime. The logic operations performed by such a setup not only possess high stability and polarization-free character, they can also be easily extended to deal with multi-qubit input states. As an example, the experimental implementation of generalized three-qubit Toffoli gate has been presented.
General equilibrium second-order hydrodynamic coefficients for free quantum fields

NASA Astrophysics Data System (ADS)

Buzzegoli, M.; Grossi, E.; Becattini, F.

2017-10-01

We present a systematic calculation of the corrections of the stress-energy tensor and currents of the free boson and Dirac fields up to second order in thermal vorticity, which is relevant for relativistic hydrodynamics. These corrections are non-dissipative because they survive at general thermodynamic equilibrium with non vanishing mean values of the conserved generators of the Lorentz group, i.e. angular momenta and boosts. Their equilibrium nature makes it possible to express the relevant coefficients by means of correlators of the angular-momentum and boost operators with stress-energy tensor and current, thus making simpler to determine their so-called "Kubo formulae". We show that, at least for free fields, the corrections are of quantum origin and we study several limiting cases and compare our results with previous calculations. We find that the axial current of the free Dirac field receives corrections proportional to the vorticity independently of the anomalous term.
Six-State Quantum Key Distribution Using Photons with Orbital Angular Momentum

NASA Astrophysics Data System (ADS)

Li, Jun-Lin; Wang, Chuan

2010-11-01

A new implementation of high-dimensional quantum key distribution (QKD) protocol is discussed. Using three mutual unbiased bases, we present a d-level six-state QKD protocol that exploits the orbital angular momentum with the spatial mode of the light beam. The protocol shows that the feature of a high capacity since keys are encoded using photon modes in d-level Hilbert space. The devices for state preparation and measurement are also discussed. This protocol has high security and the alignment of shared reference frames is not needed between sender and receiver.
LETTER TO THE EDITOR: Relation between the longitudinal spin polarization of Auger electrons and the anisotropy of their angular distribution

NASA Astrophysics Data System (ADS)

Kabachnik, N. M.; Sazhina, I. P.

2001-09-01

New relations between the intrinsic parameters δk which describe the longitudinal spin polarization of Auger electrons and αk which describe the anisotropy of their angular distribution are found. The relations are valid for arbitrary Auger transitions with initial (Ji) and final (Jf) angular momenta satisfying the condition Ji > Jf.
Large Quantum Probability Backflow and the Azimuthal Angle-Angular Momentum Uncertainty Relation for an Electron in a Constant Magnetic Field

ERIC Educational Resources Information Center

Strange, P.

2012-01-01

In this paper we demonstrate a surprising aspect of quantum mechanics that is accessible to an undergraduate student. We discuss probability backflow for an electron in a constant magnetic field. It is shown that even for a wavepacket composed entirely of states with negative angular momentum the effective angular momentum can take on positive…
Quantum storage of orbital angular momentum entanglement in an atomic ensemble.

PubMed

Ding, Dong-Sheng; Zhang, Wei; Zhou, Zhi-Yuan; Shi, Shuai; Xiang, Guo-Yong; Wang, Xi-Shi; Jiang, Yun-Kun; Shi, Bao-Sen; Guo, Guang-Can

2015-02-06

Constructing a quantum memory for a photonic entanglement is vital for realizing quantum communication and network. Because of the inherent infinite dimension of orbital angular momentum (OAM), the photon's OAM has the potential for encoding a photon in a high-dimensional space, enabling the realization of high channel capacity communication. Photons entangled in orthogonal polarizations or optical paths had been stored in a different system, but there have been no reports on the storage of a photon pair entangled in OAM space. Here, we report the first experimental realization of storing an entangled OAM state through the Raman protocol in a cold atomic ensemble. We reconstruct the density matrix of an OAM entangled state with a fidelity of 90.3%±0.8% and obtain the Clauser-Horne-Shimony-Holt inequality parameter S of 2.41±0.06 after a programed storage time. All results clearly show the preservation of entanglement during the storage.
Primordial random motions and angular momenta of galaxies and galaxy clusters.

NASA Technical Reports Server (NTRS)

Silk, J.; Lea, S.

1973-01-01

We study the decay of primordial random motions of galaxies and galaxy clusters in an expanding universe by solving a kinetic equation for the relaxation of differential energy spectra N(E, t). Systematic dissipative energy losses are included, involving gravitational drag by, and accretion of, intergalactic matter, as well as the effect of collisions with other systems. Formal and numerical solutions are described for two distinct modes of galaxy formation in a turbulent medium, corresponding to formation at a distinct epoch and to continuous formation of galaxies. We show that any primordial random motions of galaxies at the present epoch can amount to at most a few km/sec, and that collisions at early epochs can lead to the acquisition of significant amounts of primordial angular momentum.

Zero-point angular momentum of supersymmetric Penning trap

NASA Astrophysics Data System (ADS)

Zhang, Jian-zu; Xu, Qiang

2000-10-01

The quantum behavior of supersymmetric Penning trap, specially the superpartner of its angular momentum, is investigated in the formulation of multi-dimensional semiunitary transformation of supersymmetric quantum mechanics. In the limit case of vanishing kinetic energy it is found that its lowest angular momentum is 3ℏ/2, which provides a possibility of directly checking the idea of supersymmetric quantum mechanics and thus suggests a possible experimental verification about this prediction.
The Impact of Galactic Winds on the Angular Momentum of Disk Galaxies in the Illustris Simulation

NASA Astrophysics Data System (ADS)

DeFelippis, Daniel; Genel, Shy; Bryan, Greg L.; Fall, S. Michael

2017-05-01

Observed galactic disks have specific angular momenta similar to expectations for typical dark matter halos in ΛCDM. Cosmological hydrodynamical simulations have recently reproduced this similarity in large galaxy samples by including strong galactic winds, but the exact mechanism that achieves this is not yet clear. Here we present an analysis of key aspects contributing to this relation: angular momentum selection and evolution of Lagrangian mass elements as they accrete onto dark matter halos, condense into Milky-Way-scale galaxies, and join the z = 0 stellar phase. We contrast this evolution in the Illustris simulation with that in a simulation without galactic winds, where the z = 0 angular momentum is ≈ 0.6 {dex} lower. We find that winds induce differences between these simulations in several ways: increasing angular momentum, preventing angular momentum loss, and causing z = 0 stars to sample the accretion-time angular momentum distribution of baryons in a biased way. In both simulations, gas loses on average ≈ 0.4 {dex} between accreting onto halos and first accreting onto central galaxies. In Illustris, this is followed by ≈ 0.2 {dex} gains in the “galactic wind fountain” and no further net evolution past the final accretion onto the galaxy. Without feedback, further losses of ≈ 0.2 {dex} occur in the gas phase inside the galaxies. An additional ≈ 0.15 {dex} difference arises from feedback preferentially selecting higher angular momentum gas at accretion by expelling gas that is poorly aligned. These and additional effects of similar magnitude are discussed, suggesting a complex origin of the similarity between the specific angular momenta of galactic disks and typical halos.
Mars: destructive and constructive processes in its crust reflecting tendencies of leveling angular momenta of tropics and extra-tropics

NASA Astrophysics Data System (ADS)

Kochemasov, G. G.

2009-04-01

Mars: destructive and constructive processes in its crust reflecting tendencies of leveling angular momenta of tropics and extra-tropics. G. Kochemasov IGEM of the Russian Academy of Sciences A globular shape of rotating celestial bodies means that their tropical and extra-tropical belts have significantly different angular momenta. But such unevenness in a single body is disturbing because it increases level of tectonic stresses and energetic state what is against natural trends for minimizing these characteristics. To level partly this inequality bodies tend to diminish radius and mass in tropics and increase them in extra-tropics. Traces of these destructive and constructive actions are fixed in planetary geospheres of different classes of celestial bodies: Sun, planets, satellites, and asteroids. The remote geologic mapping of Mars reveals these traces rather obviously. "Mysterious" contact zone of the martian lowlands and highlands with obvious traces of destruction expressed in widespread development of chaotic and fretted terrains is a good evidence that could be considered in comparison with the equatorial and tropical belts of some other planetary bodies [1]. At Earth the wide planetary long tropical zone is marked by its destruction. It is demonstrated by development of numerous islands of the Archipelago between the South-East Asia and Australia. In Africa and South America huge depressions of the Congo and Amazon Rivers develops where the Archean crust is subsided to depths of more than 2 km. In the Pacific along the equator numerous islands of Micronesia occur. Subsidence of the basaltic oceanic crust is followed by an intensive folding and faulting of basalt and sedimentary layers as a larger mass must be held by a smaller space (a planetary radius is diminished). Seismicity of the tropical zone is significantly higher than outside of it that means more intensive destruction in the crust and the upper mantle of tropics. Mantle derived diamonds are
Angular momentum transport with twisted exciton wave packets

NASA Astrophysics Data System (ADS)

Zang, Xiaoning; Lusk, Mark T.

2017-10-01

A chain of cofacial molecules with CN or CN h symmetry supports excitonic states with a screwlike structure. These can be quantified with the combination of an axial wave number and an azimuthal winding number. Combinations of these states can be used to construct excitonic wave packets that spiral down the chain with well-determined linear and angular momenta. These twisted exciton wave packets can be created and annihilated using laser pulses, and their angular momentum can be optically modified during transit. This allows for the creation of optoexcitonic circuits in which information, encoded in the angular momentum of light, is converted into excitonic wave packets that can be manipulated, transported, and then reemitted. A tight-binding paradigm is used to demonstrate the key ideas. The approach is then extended to quantify the evolution of twisted exciton wave packets in a many-body, multilevel time-domain density functional theory setting. In both settings, numerical methods are developed that allow the site-to-site transfer of angular momentum to be quantified.
Generalized optical angular momentum sorter and its application to high-dimensional quantum cryptography.

PubMed

Larocque, Hugo; Gagnon-Bischoff, Jérémie; Mortimer, Dominic; Zhang, Yingwen; Bouchard, Frédéric; Upham, Jeremy; Grillo, Vincenzo; Boyd, Robert W; Karimi, Ebrahim

2017-08-21

The orbital angular momentum (OAM) carried by optical beams is a useful quantity for encoding information. This form of encoding has been incorporated into various works ranging from telecommunications to quantum cryptography, most of which require methods that can rapidly process the OAM content of a beam. Among current state-of-the-art schemes that can readily acquire this information are so-called OAM sorters, which consist of devices that spatially separate the OAM components of a beam. Such devices have found numerous applications in optical communications, a field that is in constant demand for additional degrees of freedom, such as polarization and wavelength, into which information can also be encoded. Here, we report the implementation of a device capable of sorting a beam based on its OAM and polarization content, which could be of use in works employing both of these degrees of freedom as information channels. After characterizing our fabricated device, we demonstrate how it can be used for quantum communications via a quantum key distribution protocol.
Rate coefficients from quantum and quasi-classical cumulative reaction probabilities for the S(1D) + H2 reaction

NASA Astrophysics Data System (ADS)

Jambrina, P. G.; Lara, Manuel; Menéndez, M.; Launay, J.-M.; Aoiz, F. J.

2012-10-01

Cumulative reaction probabilities (CRPs) at various total angular momenta have been calculated for the barrierless reaction S(1D) + H2 → SH + H at total energies up to 1.2 eV using three different theoretical approaches: time-independent quantum mechanics (QM), quasiclassical trajectories (QCT), and statistical quasiclassical trajectories (SQCT). The calculations have been carried out on the widely used potential energy surface (PES) by Ho et al. [J. Chem. Phys. 116, 4124 (2002), 10.1063/1.1431280] as well as on the recent PES developed by Song et al. [J. Phys. Chem. A 113, 9213 (2009), 10.1021/jp903790h]. The results show that the differences between these two PES are relatively minor and mostly related to the different topologies of the well. In addition, the agreement between the three theoretical methodologies is good, even for the highest total angular momenta and energies. In particular, the good accordance between the CRPs obtained with dynamical methods (QM and QCT) and the statistical model (SQCT) indicates that the reaction can be considered statistical in the whole range of energies in contrast with the findings for other prototypical barrierless reactions. In addition, total CRPs and rate coefficients in the range of 20-1000 K have been calculated using the QCT and SQCT methods and have been found somewhat smaller than the experimental total removal rates of S(1D).
u d b \\xAF b \\xAF tetraquark resonances with lattice QCD potentials and the Born-Oppenheimer approximation

NASA Astrophysics Data System (ADS)

Bicudo, Pedro; Cardoso, Marco; Peters, Antje; Pflaumer, Martin; Wagner, Marc

2017-09-01

We study tetraquark resonances with lattice QCD potentials computed for a static b ¯b ¯ pair in the presence of two lighter quarks u d , the Born-Oppenheimer approximation and the emergent wave method. As a proof of concept we focus on the system with isospin I =0 , but consider different relative angular momenta l of the heavy quarks b ¯b ¯. For l =0 a bound state has already been predicted with quantum numbers I (JP)=0 (1+). Exploring various angular momenta we now compute the phase shifts and search for S and T matrix poles in the second Riemann sheet. We predict a tetraquark resonance for l =1 , decaying into two B mesons, with quantum numbers I (JP)=0 (1-) , mass m =10 57 6-4+4 MeV and decay width Γ =11 2-103+90 MeV .
Third Quantization and Quantum Universes

NASA Astrophysics Data System (ADS)

Kim, Sang Pyo

2014-01-01

We study the third quantization of the Friedmann-Robertson-Walker cosmology with N-minimal massless fields. The third quantized Hamiltonian for the Wheeler-DeWitt equation in the minisuperspace consists of infinite number of intrinsic time-dependent, decoupled oscillators. The Hamiltonian has a pair of invariant operators for each universe with conserved momenta of the fields that play a role of the annihilation and the creation operators and that construct various quantum states for the universe. The closed universe exhibits an interesting feature of transitions from stable states to tachyonic states depending on the conserved momenta of the fields. In the classical forbidden unstable regime, the quantum states have googolplex growing position and conjugate momentum dispersions, which defy any measurements of the position of the universe.
A proposed measurement of optical orbital and spin angular momentum and its implications for photon angular momentum

NASA Astrophysics Data System (ADS)

Leader, Elliot

2018-04-01

The expression for the total angular momentum carried by a laser optical vortex beam, splits, in the paraxial approximation, into two terms which seem to represent orbital and spin angular momentum respectively. There are, however, two very different competing versions of the formula for the spin angular momentum, one based on the use of the Poynting vector, as in classical electrodynamics, the other related to the canonical expression for the angular momentum which occurs in Quantum Electrodynamics. I analyze the possibility that a sufficiently sensitive optical measurement could decide which of these corresponds to the actual physical angular momentum carried by the beam.
Energy and angular momentum balance in wall-bounded quantum turbulence at very low temperatures.

PubMed

Hosio, J J; Eltsov, V B; Heikkinen, P J; Hänninen, R; Krusius, M; L'vov, V S

2013-01-01

A superfluid in the absence of a viscous normal component should be the best realization of an ideal inviscid Euler fluid. As expressed by d'Alembert's famous paradox, an ideal fluid does not drag on bodies past which it flows, or in other words it does not exchange momentum with them. In addition, the flow of an ideal fluid does not dissipate kinetic energy. Here we study experimentally whether these properties apply to the flow of superfluid (3)He-B in a rotating cylinder at low temperatures. It is found that ideal behaviour is broken by quantum turbulence, which leads to substantial energy dissipation, as was also observed earlier. Remarkably, the angular momentum exchange between the superfluid and its container approaches nearly ideal behaviour, as the drag almost disappears in the zero-temperature limit. Here the mismatch between energy and angular momentum transfer results in a new physical situation, with severe implications on the flow dynamics.
Induced Angular Momentum

ERIC Educational Resources Information Center

Parker, G. W.

1978-01-01

Discusses, classically and quantum mechanically, the angular momentum induced in the bound motion of an electron by an external magnetic field. Calculates the current density and its magnetic moment, and then uses two methods to solve the first-order perturbation theory equation for the required eigenfunction. (Author/GA)
Photonic polarization gears for ultra-sensitive angular measurements

PubMed Central

D'Ambrosio, Vincenzo; Spagnolo, Nicolò; Del Re, Lorenzo; Slussarenko, Sergei; Li, Ying; Kwek, Leong Chuan; Marrucci, Lorenzo; Walborn, Stephen P.; Aolita, Leandro; Sciarrino, Fabio

2013-01-01

Quantum metrology bears a great promise in enhancing measurement precision, but is unlikely to become practical in the near future. Its concepts can nevertheless inspire classical or hybrid methods of immediate value. Here we demonstrate NOON-like photonic states of m quanta of angular momentum up to m=100, in a setup that acts as a ‘photonic gear’, converting, for each photon, a mechanical rotation of an angle θ into an amplified rotation of the optical polarization by mθ, corresponding to a ‘super-resolving’ Malus’ law. We show that this effect leads to single-photon angular measurements with the same precision of polarization-only quantum strategies with m photons, but robust to photon losses. Moreover, we combine the gear effect with the quantum enhancement due to entanglement, thus exploiting the advantages of both approaches. The high ‘gear ratio’ m boosts the current state of the art of optical non-contact angular measurements by almost two orders of magnitude. PMID:24045270
Superpersistent currents and whispering gallery modes in relativistic quantum chaotic systems

PubMed Central

Xu, Hongya; Huang, Liang; Lai, Ying-Cheng; Grebogi, Celso

2015-01-01

Persistent currents (PCs), one of the most intriguing manifestations of the Aharonov-Bohm (AB) effect, are known to vanish for Schrödinger particles in the presence of random scatterings, e.g., due to classical chaos. But would this still be the case for Dirac fermions? Addressing this question is of significant value due to the tremendous recent interest in two-dimensional Dirac materials. We investigate relativistic quantum AB rings threaded by a magnetic flux and find that PCs are extremely robust. Even for highly asymmetric rings that host fully developed classical chaos, the amplitudes of PCs are of the same order of magnitude as those for integrable rings, henceforth the term superpersistent currents (SPCs). A striking finding is that the SPCs can be attributed to a robust type of relativistic quantum states, i.e., Dirac whispering gallery modes (WGMs) that carry large angular momenta and travel along the boundaries. We propose an experimental scheme using topological insulators to observe and characterize Dirac WGMs and SPCs, and speculate that these features can potentially be the base for a new class of relativistic qubit systems. Our discovery of WGMs in relativistic quantum systems is remarkable because, although WGMs are common in photonic systems, they are relatively rare in electronic systems. PMID:25758591
Superpersistent currents and whispering gallery modes in relativistic quantum chaotic systems.

PubMed

Xu, Hongya; Huang, Liang; Lai, Ying-Cheng; Grebogi, Celso

2015-03-11

Persistent currents (PCs), one of the most intriguing manifestations of the Aharonov-Bohm (AB) effect, are known to vanish for Schrödinger particles in the presence of random scatterings, e.g., due to classical chaos. But would this still be the case for Dirac fermions? Addressing this question is of significant value due to the tremendous recent interest in two-dimensional Dirac materials. We investigate relativistic quantum AB rings threaded by a magnetic flux and find that PCs are extremely robust. Even for highly asymmetric rings that host fully developed classical chaos, the amplitudes of PCs are of the same order of magnitude as those for integrable rings, henceforth the term superpersistent currents (SPCs). A striking finding is that the SPCs can be attributed to a robust type of relativistic quantum states, i.e., Dirac whispering gallery modes (WGMs) that carry large angular momenta and travel along the boundaries. We propose an experimental scheme using topological insulators to observe and characterize Dirac WGMs and SPCs, and speculate that these features can potentially be the base for a new class of relativistic qubit systems. Our discovery of WGMs in relativistic quantum systems is remarkable because, although WGMs are common in photonic systems, they are relatively rare in electronic systems.
Passive measurement-device-independent quantum key distribution with orbital angular momentum and pulse position modulation

NASA Astrophysics Data System (ADS)

Wang, Lian; Zhou, Yuan-yuan; Zhou, Xue-jun; Chen, Xiao

2018-03-01

Based on the orbital angular momentum and pulse position modulation, we present a novel passive measurement-device-independent quantum key distribution (MDI-QKD) scheme with the two-mode source. Combining with the tight bounds of the yield and error rate of single-photon pairs given in our paper, we conduct performance analysis on the scheme with heralded single-photon source. The numerical simulations show that the performance of our scheme is significantly superior to the traditional MDI-QKD in the error rate, key generation rate and secure transmission distance, since the application of orbital angular momentum and pulse position modulation can exclude the basis-dependent flaw and increase the information content for each single photon. Moreover, the performance is improved with the rise of the frame length. Therefore, our scheme, without intensity modulation, avoids the source side channels and enhances the key generation rate. It has greatly utility value in the MDI-QKD setups.
The Elusive Excited Quintet [superscript 5]D of Tb(III): A Source of Luminescence and Resonance Energy Transfer in Terbium Compounds

ERIC Educational Resources Information Center

Klier, Kamil

2010-01-01

The understanding of electronic structure of atomic and molecular term states involved in spectroscopic transitions is aided by projecting combinations of micro-configurations to multi-electron states with "good" quantum numbers of angular momenta. In rare-earth (RE) compounds, atomic term labels are justifiably carried over to compounds, because…
Physical angular momentum separation for QED

NASA Astrophysics Data System (ADS)

Sun, Weimin

2017-04-01

We study the non-uniqueness problem of the gauge-invariant angular momentum separation for the case of QED, which stems from the recent controversy concerning the proper definitions of the orbital angular momentum and spin operator of the individual parts of a gauge field system. For the free quantum electrodynamics without matter, we show that the basic requirement of Euclidean symmetry selects a unique physical angular momentum separation scheme from the multitude of the possible angular momentum separation schemes constructed using the various gauge-invariant extensions (GIEs). Based on these results, we propose a set of natural angular momentum separation schemes for the case of interacting QED by invoking the formalism of asymptotic fields. Some perspectives on such a problem for the case of QCD are briefly discussed.
Angular dependant micro-ESR characterization of a locally doped Gd3+:Al2O3 hybrid system for quantum applications

NASA Astrophysics Data System (ADS)

Wisby, I. S.; de Graaf, S. E.; Gwilliam, R.; Adamyan, A.; Kubatkin, S. E.; Meeson, P. J.; Tzalenchuk, A. Ya.; Lindstrom, T.

Rare-earth doped crystals interfaced with superconducting quantum circuitry are an attractive platform for quantum memory and transducer applications. Here we present a detailed characterization of a locally implanted Gd3+ in Al2O3 system coupled to a superconducting micro-resonator, by performing angular dependent micro-electron-spin-resonance (micro-ESR) measurements at mK temperatures. The device is fabricated using a hard Si3N4 mask to facilitate a local ion-implantation technique for precision control of the dopant location. The technique is found not to degrade the internal quality factor of the resonators which remains above 105 (1). We find the measured angular dependence of the micro-ESR spectra to be in excellent agreement with the modelled Hamiltonian, supporting the conclusion that the dopant ions are successfully integrated into their relevant lattice sites whilst maintaining crystalline symmetries. Furthermore, we observe clear contributions from individual microwave field components of our micro-resonator, emphasising the need for controllable local implantation. 1 Wisby et al. Appl. Phys. Lett. 105, 102601 (2014)
Contact geometry and quantum mechanics

NASA Astrophysics Data System (ADS)

Herczeg, Gabriel; Waldron, Andrew

2018-06-01

We present a generally covariant approach to quantum mechanics in which generalized positions, momenta and time variables are treated as coordinates on a fundamental "phase-spacetime". We show that this covariant starting point makes quantization into a purely geometric flatness condition. This makes quantum mechanics purely geometric, and possibly even topological. Our approach is especially useful for time-dependent problems and systems subject to ambiguities in choices of clock or observer. As a byproduct, we give a derivation and generalization of the Wigner functions of standard quantum mechanics.
Correlated states of a quantum oscillator acted by short pulses

NASA Technical Reports Server (NTRS)

Manko, O. V.

1993-01-01

Correlated squeezed states for a quantum oscillator are constructed based on the method of quantum integrals of motion. The quantum oscillator is acted upon by short duration pulses. Three delta-kickings of frequency are used to model the pulses' dependence upon the time aspects of the frequency of the oscillator. Additionally, the correlation coefficient and quantum variances of operations of coordinates and momenta are written in explicit form.

Electro-optic analyzer of angular momentum hyperentanglement

PubMed Central

Wu, Ziwen; Chen, Lixiang

2016-01-01

Characterizing a high-dimensional entanglement is fundamental in quantum information applications. Here, we propose a theoretical scheme to analyze and characterize the angular momentum hyperentanglement that two photons are entangled simultaneously in spin and orbital angular momentum. Based on the electro-optic sampling with a proposed hyper-entanglement analyzer and the simple matrix operation using Cramer rule, our simulations show that it is possible to retrieve effectively both the information about the degree of polarization entanglement and the spiral spectrum of high-dimensional orbital angular momentum entanglement. PMID:26911530
Interpreting angular momentum transfer between electromagnetic multipoles using vector spherical harmonics.

PubMed

Grinter, Roger; Jones, Garth A

2018-02-01

The transfer of angular momentum between a quadrupole emitter and a dipole acceptor is investigated theoretically. Vector spherical harmonics are used to describe the angular part of the field of the mediating photon. Analytical results are presented for predicting angular momentum transfer between the emitter and absorber within a quantum electrodynamical framework. We interpret the allowability of such a process, which appears to violate conservation of angular momentum, in terms of the breakdown of the isotropy of space at the point of photon absorption (detection). That is, collapse of the wavefunction results in loss of all angular momentum information. This is consistent with Noether's Theorem and demystifies some common misconceptions about the nature of the photon. The results have implications for interpreting the detection of photons from multipole sources and offers insight into limits on information that can be extracted from quantum measurements in photonic systems.
Resilience of hybrid optical angular momentum qubits to turbulence

PubMed Central

Farías, Osvaldo Jiménez; D'Ambrosio, Vincenzo; Taballione, Caterina; Bisesto, Fabrizio; Slussarenko, Sergei; Aolita, Leandro; Marrucci, Lorenzo; Walborn, Stephen P.; Sciarrino, Fabio

2015-01-01

Recent schemes to encode quantum information into the total angular momentum of light, defining rotation-invariant hybrid qubits composed of the polarization and orbital angular momentum degrees of freedom, present interesting applications for quantum information technology. However, there remains the question as to how detrimental effects such as random spatial perturbations affect these encodings. Here, we demonstrate that alignment-free quantum communication through a turbulent channel based on hybrid qubits can be achieved with unit transmission fidelity. In our experiment, alignment-free qubits are produced with q-plates and sent through a homemade turbulence chamber. The decoding procedure, also realized with q-plates, relies on both degrees of freedom and renders an intrinsic error-filtering mechanism that maps errors into losses. PMID:25672667
Quantum entanglement and quantum information in biological systems (DNA)

NASA Astrophysics Data System (ADS)

Hubač, Ivan; Švec, Miloslav; Wilson, Stephen

2017-12-01

Recent studies of DNA show that the hydrogen bonds between given base pairs can be treated as diabatic systems with spin-orbit coupling. For solid state systems strong diabaticity and spin-orbit coupling the possibility of forming Majorana fermions has been discussed. We analyze the hydrogen bonds in the base pairs in DNA from this perspective. Our analysis is based on a quasiparticle supersymmetric transformation which couples electronic and vibrational motion and includes normal coordinates and the corresponding momenta. We define qubits formed by Majorana fermions in the hydrogen bonds and also discuss the entangled states in base pairs. Quantum information and quantum entropy are introduced. In addition to the well-known classical information connected with the DNA base pairs, we also consider quantum information and show that the classical and quantum information are closely connected.
Instanton dominance over αs at low momenta from lattice QCD simulations at Nf = 0, Nf = 2 + 1 and Nf = 2 + 1 + 1

NASA Astrophysics Data System (ADS)

Athenodorou, Andreas; Boucaud, Philippe; de Soto, Feliciano; Rodríguez-Quintero, José; Zafeiropoulos, Savvas

2018-03-01

We report on an instanton-based analysis of the gluon Green functions in the Landau gauge for low momenta; in particular we use lattice results for αs in the symmetric momentum subtraction scheme (MOM) for large-volume lattice simulations. We have exploited quenched gauge field configurations, Nf = 0, with both Wilson and tree-level Symanzik improved actions, and unquenched ones with Nf = 2 + 1 and Nf = 2 + 1 + 1 dynamical flavors (domain wall and twisted-mass fermions, respectively). We show that the dominance of instanton correlations on the low-momenta gluon Green functions can be applied to the determination of phenomenological parameters of the instanton liquid and, eventually, to a determination of the lattice spacing. We furthermore apply the Gradient Flow to remove short-distance fluctuations. The Gradient Flow gets rid of the QCD scale, ΛQCD, and reveals that the instanton prediction extents to large momenta. For those gauge field configurations free of quantum fluctuations, the direct study of topological charge density shows the appearance of large-scale lumps that can be identified as instantons, giving access to a direct study of the instanton density and size distribution that is compatible with those extracted from the analysis of the Green functions.
Dependencies of lepton angular distribution coefficients on the transverse momentum and rapidity of Z bosons produced in p p collisions at the LHC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chang, Wen -Chen; McClellan, Randall Evan; Peng, Jen -Chieh

Here, high precision data of lepton angular distributions formore » $$\\gamma^*/Z$$ production in $pp$ collisions at the LHC, covering broad ranges of dilepton transverse momenta ($$q_T$$) and rapidity ($y$), were recently reported. Strong $$q_T$$ dependencies were observed for several angular distribution coefficients, $$A_i$$, including $$A_0 - A_4$$. Significant $y$ dependencies were also found for the coefficients $$A_1$$, $$A_3$$ and $$A_4$$, while $$A_0$$ and $$A_2$$ exhibit very weak rapidity dependence. Using an intuitive geometric picture we show that the $$q_T$$ and $y$ dependencies of the angular distributions coefficients can be well described.« less
Dependencies of lepton angular distribution coefficients on the transverse momentum and rapidity of Z bosons produced in p p collisions at the LHC

DOE PAGES

Chang, Wen -Chen; McClellan, Randall Evan; Peng, Jen -Chieh; ...

2017-09-21

Here, high precision data of lepton angular distributions formore » $$\\gamma^*/Z$$ production in $pp$ collisions at the LHC, covering broad ranges of dilepton transverse momenta ($$q_T$$) and rapidity ($y$), were recently reported. Strong $$q_T$$ dependencies were observed for several angular distribution coefficients, $$A_i$$, including $$A_0 - A_4$$. Significant $y$ dependencies were also found for the coefficients $$A_1$$, $$A_3$$ and $$A_4$$, while $$A_0$$ and $$A_2$$ exhibit very weak rapidity dependence. Using an intuitive geometric picture we show that the $$q_T$$ and $y$ dependencies of the angular distributions coefficients can be well described.« less
Random wandering of laser beams with orbital angular momentum during propagation through atmospheric turbulence.

PubMed

Aksenov, Valerii P; Kolosov, Valeriy V; Pogutsa, Cheslav E

2014-06-10

The propagation of laser beams having orbital angular momenta (OAM) in the turbulent atmosphere is studied numerically. The variance of random wandering of these beams is investigated with the use of the Monte Carlo technique. It is found that, among various types of vortex laser beams, such as the Laguerre-Gaussian (LG) beam, modified Bessel-Gaussian beam, and hypergeometric Gaussian beam, having identical initial effective radii and OAM, the LG beam occupying the largest effective volume in space is the most stable one.
Amplification of Angular Rotations Using Weak Measurements

NASA Astrophysics Data System (ADS)

Magaña-Loaiza, Omar S.; Mirhosseini, Mohammad; Rodenburg, Brandon; Boyd, Robert W.

2014-05-01

We present a weak measurement protocol that permits a sensitive estimation of angular rotations based on the concept of weak-value amplification. The shift in the state of a pointer, in both angular position and the conjugate orbital angular momentum bases, is used to estimate angular rotations. This is done by an amplification of both the real and imaginary parts of the weak-value of a polarization operator that has been coupled to the pointer, which is a spatial mode, via a spin-orbit coupling. Our experiment demonstrates the first realization of weak-value amplification in the azimuthal degree of freedom. We have achieved effective amplification factors as large as 100, providing a sensitivity that is on par with more complicated methods that employ quantum states of light or extremely large values of orbital angular momentum.
Novel Detection of Optical Orbital Angular Momentum

DTIC Science & Technology

2014-11-16

spin-orbit coupling at single- photon entanglement and quantum transfer as well as their combinations. Some studies exist on hybrid entanglement . 3.1... Entanglement of the orbital angular momentum states of photons ,” Nature, 412, 313-316 (2001). [9]. D. J. Sanchez and D. W. Oesch, “Orbital angular... photon with no change in its OAM states among traveling inside the atmosphere. Both studies assume only a phase distortion causes by the atmospheric
Orbital Angular Momentum-Entanglement Frequency Transducer.

PubMed

Zhou, Zhi-Yuan; Liu, Shi-Long; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Dong, Ming-Xin; Shi, Bao-Sen; Guo, Guang-Can

2016-09-02

Entanglement is a vital resource for realizing many tasks such as teleportation, secure key distribution, metrology, and quantum computations. To effectively build entanglement between different quantum systems and share information between them, a frequency transducer to convert between quantum states of different wavelengths while retaining its quantum features is indispensable. Information encoded in the photon's orbital angular momentum (OAM) degrees of freedom is preferred in harnessing the information-carrying capacity of a single photon because of its unlimited dimensions. A quantum transducer, which operates at wavelengths from 1558.3 to 525 nm for OAM qubits, OAM-polarization hybrid-entangled states, and OAM-entangled states, is reported for the first time. Nonclassical properties and entanglements are demonstrated following the conversion process by performing quantum tomography, interference, and Bell inequality measurements. Our results demonstrate the capability to create an entanglement link between different quantum systems operating in a photon's OAM degrees of freedom, which will be of great importance in building a high-capacity OAM quantum network.
Entropy for quantum pure states and quantum H theorem

NASA Astrophysics Data System (ADS)

Han, Xizhi; Wu, Biao

2015-06-01

We construct a complete set of Wannier functions that are localized at both given positions and momenta. This allows us to introduce the quantum phase space, onto which a quantum pure state can be mapped unitarily. Using its probability distribution in quantum phase space, we define an entropy for a quantum pure state. We prove an inequality regarding the long-time behavior of our entropy's fluctuation. For a typical initial state, this inequality indicates that our entropy can relax dynamically to a maximized value and stay there most of time with small fluctuations. This result echoes the quantum H theorem proved by von Neumann [Zeitschrift für Physik 57, 30 (1929), 10.1007/BF01339852]. Our entropy is different from the standard von Neumann entropy, which is always zero for quantum pure states. According to our definition, a system always has bigger entropy than its subsystem even when the system is described by a pure state. As the construction of the Wannier basis can be implemented numerically, the dynamical evolution of our entropy is illustrated with an example.
Quantum motion on a torus as a submanifold problem in a generalized Dirac's theory of second-class constraints

NASA Astrophysics Data System (ADS)

Xun, D. M.; Liu, Q. H.; Zhu, X. M.

2013-11-01

A generalization of Dirac's canonical quantization scheme for a system with second-class constraints is proposed, in which the fundamental commutation relations are constituted by all commutators between positions, momenta and Hamiltonian, so they are simultaneously quantized in a self-consistent manner, rather than by those between merely positions and momenta which leads to ambiguous forms of the Hamiltonian and the momenta. The application of the generalized scheme to the quantum motion on a torus leads to a remarkable result: the quantum theory is inconsistent if built up in an intrinsic geometric manner, whereas it becomes consistent within an extrinsic examination of the torus as a submanifold in three dimensional flat space with the use of the Cartesian coordinate system. The geometric momentum and potential are then reasonably reproduced.
Ligand-surface interactions and surface oxidation of colloidal PbSe quantum dots revealed by thin-film positron annihilation methods

NASA Astrophysics Data System (ADS)

Shi, Wenqin; Eijt, Stephan W. H.; Suchand Sandeep, C. S.; Siebbeles, Laurens D. A.; Houtepen, Arjan J.; Kinge, Sachin; Brück, Ekkes; Barbiellini, Bernardo; Bansil, Arun

2016-02-01

Positron Two Dimensional Angular Correlation of Annihilation Radiation (2D-ACAR) measurements reveal modifications of the electronic structure and composition at the surfaces of PbSe quantum dots (QDs), deposited as thin films, produced by various ligands containing either oxygen or nitrogen atoms. In particular, the 2D-ACAR measurements on thin films of colloidal PbSe QDs capped with oleic acid ligands yield an increased intensity in the electron momentum density (EMD) at high momenta compared to PbSe quantum dots capped with oleylamine. Moreover, the EMD of PbSe QDs is strongly affected by the small ethylenediamine ligands, since these molecules lead to small distances between QDs and favor neck formation between near neighbor QDs, inducing electronic coupling between neighboring QDs. The high sensitivity to the presence of oxygen atoms at the surface can be also exploited to monitor the surface oxidation of PbSe QDs upon exposure to air. Our study clearly demonstrates that positron annihilation spectroscopy applied to thin films can probe surface transformations of colloidal semiconductor QDs embedded in functional layers.
Optical spin-to-orbital angular momentum conversion in ultra-thin metasurfaces with arbitrary topological charges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bouchard, Frédéric; De Leon, Israel; Schulz, Sebastian A.

Orbital angular momentum associated with the helical phase-front of optical beams provides an unbounded “space” for both classical and quantum communications. Among the different approaches to generate and manipulate orbital angular momentum states of light, coupling between spin and orbital angular momentum allows a faster manipulation of orbital angular momentum states because it depends on manipulating the polarisation state of light, which is simpler and generally faster than manipulating conventional orbital angular momentum generators. In this work, we design and fabricate an ultra-thin spin-to-orbital angular momentum converter, based on plasmonic nano-antennas and operating in the visible wavelength range that ismore » capable of converting spin to an arbitrary value of orbital angular momentum ℓ. The nano-antennas are arranged in an array with a well-defined geometry in the transverse plane of the beam, possessing a specific integer or half-integer topological charge q. When a circularly polarised light beam traverses this metasurface, the output beam polarisation switches handedness and the orbital angular momentum changes in value by ℓ=±2qℏ per photon. We experimentally demonstrate ℓ values ranging from ±1 to ±25 with conversion efficiencies of 8.6% ± 0.4%. Our ultra-thin devices are integratable and thus suitable for applications in quantum communications, quantum computations, and nano-scale sensing.« less
There are many ways to spin a photon: Half-quantization of a total optical angular momentum

PubMed Central

Ballantine, Kyle E.; Donegan, John F.; Eastham, Paul R.

2016-01-01

The angular momentum of light plays an important role in many areas, from optical trapping to quantum information. In the usual three-dimensional setting, the angular momentum quantum numbers of the photon are integers, in units of the Planck constant ħ. We show that, in reduced dimensions, photons can have a half-integer total angular momentum. We identify a new form of total angular momentum, carried by beams of light, comprising an unequal mixture of spin and orbital contributions. We demonstrate the half-integer quantization of this total angular momentum using noise measurements. We conclude that for light, as is known for electrons, reduced dimensionality allows new forms of quantization. PMID:28861467
Smooth Horizonless Geometries Deep Inside the Black-Hole Regime.

PubMed

Bena, Iosif; Giusto, Stefano; Martinec, Emil J; Russo, Rodolfo; Shigemori, Masaki; Turton, David; Warner, Nicholas P

2016-11-11

We construct the first family of horizonless supergravity solutions that have the same mass, charges, and angular momenta as general supersymmetric rotating D1-D5-P black holes in five dimensions. This family includes solutions with arbitrarily small angular momenta, deep within the regime of quantum numbers and couplings for which a large classical black hole exists. These geometries are well approximated by the black-hole solution, and in particular exhibit the same near-horizon throat. Deep in this throat, the black-hole singularity is resolved into a smooth cap. We also identify the holographically dual states in the N=(4,4) D1-D5 orbifold conformal field theory (CFT). Our solutions are among the states counted by the CFT elliptic genus, and provide examples of smooth microstate geometries within the ensemble of supersymmetric black-hole microstates.
Quantum and classical ripples in graphene

NASA Astrophysics Data System (ADS)

Hašík, Juraj; Tosatti, Erio; MartoÅák, Roman

2018-04-01

Thermal ripples of graphene are well understood at room temperature, but their quantum counterparts at low temperatures are in need of a realistic quantitative description. Here we present atomistic path-integral Monte Carlo simulations of freestanding graphene, which show upon cooling a striking classical-quantum evolution of height and angular fluctuations. The crossover takes place at ever-decreasing temperatures for ever-increasing wavelengths so that a completely quantum regime is never attained. Zero-temperature quantum graphene is flatter and smoother than classical graphene at large scales yet rougher at short scales. The angular fluctuation distribution of the normals can be quantitatively described by coexistence of two Gaussians, one classical strongly T -dependent and one quantum about 2° wide, of zero-point character. The quantum evolution of ripple-induced height and angular spread should be observable in electron diffraction in graphene and other two-dimensional materials, such as MoS2, bilayer graphene, boron nitride, etc.
Origins and demonstrations of electrons with orbital angular momentum

PubMed Central

Agrawal, Amit; Ercius, Peter A.; Grillo, Vincenzo; Herzing, Andrew A.; Harvey, Tyler R.; Linck, Martin; Pierce, Jordan S.

2017-01-01

The surprising message of Allen et al. (Allen et al. 1992 Phys. Rev. A 45, 8185 (doi:10.1103/PhysRevA.45.8185)) was that photons could possess orbital angular momentum in free space, which subsequently launched advancements in optical manipulation, microscopy, quantum optics, communications, many more fields. It has recently been shown that this result also applies to quantum mechanical wave functions describing massive particles (matter waves). This article discusses how electron wave functions can be imprinted with quantized phase vortices in analogous ways to twisted light, demonstrating that charged particles with non-zero rest mass can possess orbital angular momentum in free space. With Allen et al. as a bridge, connections are made between this recent work in electron vortex wave functions and much earlier works, extending a 175 year old tradition in matter wave vortices. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069765
Quark orbital dynamics in the proton from lattice QCD: From Ji to Jaffe-Manohar orbital angular momentum

NASA Astrophysics Data System (ADS)

Engelhardt, M.

2017-05-01

Given a Wigner distribution simultaneously characterizing quark transverse positions and momenta in a proton, one can directly evaluate their cross product, i.e., quark orbital angular momentum. The aforementioned distribution can be obtained by generalizing the proton matrix elements of quark bilocal operators which define transverse momentum-dependent parton distributions (TMDs); the transverse momentum information is supplemented with transverse position information by introducing an additional nonzero momentum transfer. A gauge connection between the quarks must be specified in the quark bilocal operators; the staple-shaped gauge link path used in TMD calculations yields the Jaffe-Manohar definition of orbital angular momentum, whereas a straight path yields the Ji definition. An exploratory lattice calculation, performed at the pion mass mπ=518 MeV , is presented which quasicontinuously interpolates between the two definitions and demonstrates that their difference can be clearly resolved. The resulting Ji orbital angular momentum is confronted with traditional evaluations based on Ji's sum rule. Jaffe-Manohar orbital angular momentum is enhanced in magnitude compared to its Ji counterpart.

On the study of angular velocity in mass asymmetry nuclei

NASA Astrophysics Data System (ADS)

Kaur, Kamaldeep; Kumar, Suneel

2018-05-01

Using isospin-dependent quantum molecular dynamics (IQMD) model, the role of angular velocity (Wy) has been explored by changing the mass asymmetric content of the colliding nuclei at the incident energy of 50 MeV/nucleon for centrality 0.25angular velocity is greatly influenced by the mass-asymmetry as well as by the different rapidity regions. In addition to this, transverse component of angular velocity behaves differently for participant and spectators too.

Instanton dominance over $$a_s$$ at low momenta from lattice QCD simulations at $$N_f=0$$, $$N_f=2+1$$ and $$N_f=2+1+1$$

DOE Office of Scientific and Technical Information (OSTI.GOV)

Athenodorou, Andreas; Boucaud, Philippe; de Soto, Feliciano

We report on an instanton-based analysis of the gluon Green functions in the Landau gauge for low momenta; in particular we use lattice results for αs in the symmetric momentum subtraction scheme (MOM) for large-volume lattice simulations. We have exploited quenched gauge field configurations, Nf = 0, with both Wilson and tree-level Symanzik improved actions, and unquenched ones with Nf = 2 + 1 and Nf = 2 + 1 + 1 dynamical flavors (domain wall and twisted-mass fermions, respectively).We show that the dominance of instanton correlations on the low-momenta gluon Green functions can be applied to the determination ofmore » phenomenological parameters of the instanton liquid and, eventually, to a determination of the lattice spacing.We furthermore apply the Gradient Flow to remove short-distance fluctuations. The Gradient Flow gets rid of the QCD scale, ΛQCD, and reveals that the instanton prediction extents to large momenta. For those gauge field configurations free of quantum fluctuations, the direct study of topological charge density shows the appearance of large-scale lumps that can be identified as instantons, giving access to a direct study of the instanton density and size distribution that is compatible with those extracted from the analysis of the Green functions.« less

Simplified Generation of High-Angular-Momentum Light Beams

NASA Technical Reports Server (NTRS)

Savchenkov, Anatoliy; Maleki, Lute; Matsko, Andrey; Strekalov, Dmitry; Grudinin, Ivan

2007-01-01

polished flat output end. By adjusting the geometry of this apparatus, it is possible to generate a variety of optical beams characterized by a wide range of parameters. These beams generally have high angular momenta and can be of either Bessel or Bessel-related types.

Plasmon excitations with a semi-integer angular momentum.

PubMed

Mendonça, J T; Serbeto, A; Vieira, J

2018-05-18

We provide an explicit model for a spin-1/2 quasi-particle, based on the superposition of plasmon excitations in a quantum plasmas with intrinsic orbital angular momentum. Such quasi-particle solutions can show remarkable similarities with single electrons moving in vacuum: they have spin-1/2, a finite rest mass, and a quantum dispersion. We also show that these quasi-particle solutions satisfy a criterium of energy minimum.

Identification of trunk and pelvis movement compensations in patients with transtibial amputation using angular momentum separation.

PubMed

Gaffney, Brecca M; Murray, Amanda M; Christiansen, Cory L; Davidson, Bradley S

2016-03-01

Patients with unilateral dysvascular transtibial amputation (TTA) have a higher risk of developing low back pain than their healthy counterparts, which may be related to movement compensations used in the absence of ankle function. Assessing components of segmental angular momentum provides a unique framework to identify and interpret these movement compensations alongside traditional observational analyses. Angular momentum separation indicates two components of total angular momentum: (1) transfer momentum and (2) rotational momentum. The objective of this investigation was to assess movement compensations in patients with dysvascular TTA, patients with diabetes mellitus (DM), and healthy controls (HC) by examining patterns of generating and arresting trunk and pelvis segmental angular momenta during gait. We hypothesized that all groups would demonstrate similar patterns of generating/arresting total momentum and transfer momentum in the trunk and pelvis in reference to the groups (patients with DM and HC). We also hypothesized that patients with amputation would demonstrate different (larger) patterns of generating/arresting rotational angular momentum in the trunk. Patients with amputation demonstrated differences in trunk and pelvis transfer angular momentum in the sagittal and transverse planes in comparison to the reference groups, which indicates postural compensations adopted during walking. However, patients with amputation demonstrated larger patterns of generating and arresting of trunk and pelvis rotational angular momentum in comparison to the reference groups. These segmental rotational angular momentum patterns correspond with high eccentric muscle demands needed to arrest the angular momentum, and may lead to consequential long-term effects such as low back pain. Copyright © 2016 Elsevier B.V. All rights reserved.

Elementary Quantum Mechanics in a High-Energy Process

ERIC Educational Resources Information Center

Denville, A.; And Others

1978-01-01

Compares two approaches to strong absorption in elementary quantum mechanics; the black sphere and a model based on the continuum theory of nuclear reactions. Examines the application to proton-antiproton interactions at low momenta and concludes that the second model is the appropriate and simplest to use. (Author/GA)

NLO Higgs+jet at Large Transverse Momenta Including Top Quark Mass Effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neumann, Tobias

We present a next-to-leading order calculation of H+jet in gluon fusion including the effect of a finite top quark massmore » $$m_t$$ at large transverse momenta. Using the recently published two-loop amplitudes in the high energy expansion and our previous setup that includes finite $$m_t$$ effects in a low energy expansion, we are able to obtain $$m_t$$-finite results for transverse momenta below 225 GeV and above 500 GeV with negligible remaining top quark mass uncertainty. The only remaining region that has to rely on the common leading order rescaling approach is the threshold region $$\\sqrt{\\hat s}\\simeq 2m_t$$. We demonstrate that this rescaling provides an excellent approximation in the high $$p_T$$ region. Our calculation settles the issue of top quark mass effects at large transverse momenta. It is implemented in the parton level Monte Carlo code MCFM and is publicly available immediately in version 8.2.« less

Quantum coherent control of the photoelectron angular distribution in bichromatic-field ionization of atomic neon

NASA Astrophysics Data System (ADS)

Gryzlova, E. V.; Grum-Grzhimailo, A. N.; Staroselskaya, E. I.; Douguet, N.; Bartschat, K.

2018-01-01

We investigate the coherent control of the photoelectron angular distribution in bichromatic atomic ionization. Neon is selected as target since it is one of the most popular systems in current gas-phase experiments with free-electron lasers (FELSs). In particular, we tackle practical questions, such as the role of the fine-structure splitting, the pulse length, and the intensity. Time-dependent and stationary perturbation theory are employed, and we also solve the time-dependent Schrödinger equation in a single-active electron model. We consider neon ionized by a FEL pulse whose fundamental frequency is in resonance with either 2 p -3 s or 2 p -4 s excitation. The contribution of the nonresonant two-photon process and its potential constructive or destructive role for quantum coherent control is investigated.

Helicon modes in uniform plasmas. III. Angular momentum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stenzel, R. L.; Urrutia, J. M.

Helicons are electromagnetic waves with helical phase fronts propagating in the whistler mode in magnetized plasmas and solids. They have similar properties to electromagnetic waves with angular momentum in free space. Helicons are circularly polarized waves carrying spin angular momentum and orbital angular momentum due to their propagation around the ambient magnetic field B{sub 0}. These properties have not been considered in the community of researchers working on helicon plasma sources, but are the topic of the present work. The present work focuses on the field topology of helicons in unbounded plasmas, not on helicon source physics. Helicons are excitedmore » in a large uniform laboratory plasma with a magnetic loop antenna whose dipole axis is aligned along or across B{sub 0}. The wave fields are measured in orthogonal planes and extended to three dimensions (3D) by interpolation. Since density and B{sub 0} are uniform, small amplitude waves from loops at different locations can be superimposed to generate complex antenna patterns. With a circular array of phase shifted loops, whistler modes with angular and axial wave propagation, i.e., helicons, are generated. Without boundaries radial propagation also arises. The azimuthal mode number m can be positive or negative while the field polarization remains right-hand circular. The conservation of energy and momentum implies that these field quantities are transferred to matter which causes damping or reflection. Wave-particle interactions with fast electrons are possible by Doppler shifted resonances. The transverse Doppler shift is demonstrated. Wave-wave interactions are also shown by showing collisions between different helicons. Whistler turbulence does not always have to be created by nonlinear wave-interactions but can also be a linear superposition of waves from random sources. In helicon collisions, the linear and/or orbital angular momenta can be canceled, which results in a great variety of field

Large-amplitude nuclear motion formulated in terms of dissipation of quantum fluctuations

NASA Astrophysics Data System (ADS)

Kuzyakin, R. A.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.

2017-01-01

The potential-barrier penetrability and quasi-stationary thermal-decay rate of a metastable state are formulated in terms of microscopic quantum diffusion. Apart from linear coupling in momentum between the collective and internal subsystems, the formalism embraces the more general case of linear couplings in both the momentum and the coordinates. The developed formalism is then used for describing the process of projectile-nucleus capture by a target nucleus at incident energies near and below the Coulomb barrier. The capture partial probability, which determines the cross section for formation of a dinuclear system, is derived in analytical form. The total and partial capture cross sections, mean and root-mean-square angular momenta of the formed dinuclear system, astrophysical -factors, logarithmic derivatives, and barrier distributions are derived for various reactions. Also investigated are the effects of nuclear static deformation and neutron transfer between the interacting nuclei on the capture cross section and its isotopic dependence, and the entrance-channel effects on the capture process. The results of calculations for reactions involving both spherical and deformed nuclei are in good agreement with available experimental data.

Orbital angular momentum of photons and the entanglement of Laguerre-Gaussian modes.

PubMed

Krenn, Mario; Malik, Mehul; Erhard, Manuel; Zeilinger, Anton

2017-02-28

The identification of orbital angular momentum (OAM) as a fundamental property of a beam of light nearly 25 years ago has led to an extensive body of research around this topic. The possibility that single photons can carry OAM has made this degree of freedom an ideal candidate for the investigation of complex quantum phenomena and their applications. Research in this direction has ranged from experiments on complex forms of quantum entanglement to the interaction between light and quantum states of matter. Furthermore, the use of OAM in quantum information has generated a lot of excitement, as it allows for encoding large amounts of information on a single photon. Here, we explain the intuition that led to the first quantum experiment with OAM 15 years ago. We continue by reviewing some key experiments investigating fundamental questions on photonic OAM and the first steps to applying these properties in novel quantum protocols. At the end, we identify several interesting open questions that could form the subject of future investigations with OAM.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Author(s).

Orbital angular momentum of photons and the entanglement of Laguerre–Gaussian modes

PubMed Central

Malik, Mehul; Erhard, Manuel; Zeilinger, Anton

2017-01-01

The identification of orbital angular momentum (OAM) as a fundamental property of a beam of light nearly 25 years ago has led to an extensive body of research around this topic. The possibility that single photons can carry OAM has made this degree of freedom an ideal candidate for the investigation of complex quantum phenomena and their applications. Research in this direction has ranged from experiments on complex forms of quantum entanglement to the interaction between light and quantum states of matter. Furthermore, the use of OAM in quantum information has generated a lot of excitement, as it allows for encoding large amounts of information on a single photon. Here, we explain the intuition that led to the first quantum experiment with OAM 15 years ago. We continue by reviewing some key experiments investigating fundamental questions on photonic OAM and the first steps to applying these properties in novel quantum protocols. At the end, we identify several interesting open questions that could form the subject of future investigations with OAM. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069773

Relativistic properties of a molecule: energy, linear momentum, angular momentum and boost momentum to order 1/c 2

NASA Astrophysics Data System (ADS)

Cameron, Robert P.; Cotter, J. P.

2018-05-01

We give an explicit and general description of the energy, linear momentum, angular momentum and boost momentum of a molecule to order 1/c 2, where it necessary to take account of kinetic contributions made by the electrons and nuclei as well as electromagnetic contributions made by the intramolecular field. A wealth of interesting subtleties are encountered that are not seen at order 1/c 0, including relativistic Hall shifts, anomalous velocities and hidden momenta. Some of these have well known analogues in solid state physics.

Experimental quantum cryptography with qutrits

NASA Astrophysics Data System (ADS)

Gröblacher, Simon; Jennewein, Thomas; Vaziri, Alipasha; Weihs, Gregor; Zeilinger, Anton

2006-05-01

We produce two identical keys using, for the first time, entangled trinary quantum systems (qutrits) for quantum key distribution. The advantage of qutrits over the normally used binary quantum systems is an increased coding density and a higher security margin. The qutrits are encoded into the orbital angular momentum of photons, namely Laguerre Gaussian modes with azimuthal index l + 1, 0 and -1, respectively. The orbital angular momentum is controlled with phase holograms. In an Ekert-type protocol the violation of a three-dimensional Bell inequality verifies the security of the generated keys. A key is obtained with a qutrit error rate of approximately 10%.

Electronic transitions in quantum dots and rings induced by inhomogeneous off-centered light beams.

PubMed

Quinteiro, G F; Lucero, A O; Tamborenea, P I

2010-12-22

We theoretically investigate the effect of inhomogeneous light beams with (twisted light) and without (plane-wave light) orbital angular momentum on semiconductor-based nanostructures, when the symmetry axes of the beam and the nanostructure are displaced parallel to each other. Exact analytical results are obtained by expanding the off-centered light field in terms of the appropriate light modes centered around the nanostructure. We demonstrate how electronic transitions involving the transfer of different amounts of orbital angular momentum are switched on and off as a function of the separation between the axes of the beam and the system. In particular, we show that even off-centered plane-wave beams induce transitions such that the angular momenta of the initial and final states are different.

Optimality of Gaussian attacks in continuous-variable quantum cryptography.

PubMed

Navascués, Miguel; Grosshans, Frédéric; Acín, Antonio

2006-11-10

We analyze the asymptotic security of the family of Gaussian modulated quantum key distribution protocols for continuous-variables systems. We prove that the Gaussian unitary attack is optimal for all the considered bounds on the key rate when the first and second momenta of the canonical variables involved are known by the honest parties.

Quantum angular momentum diffusion of rigid bodies

NASA Astrophysics Data System (ADS)

Papendell, Birthe; Stickler, Benjamin A.; Hornberger, Klaus

2017-12-01

We show how to describe the diffusion of the quantized angular momentum vector of an arbitrarily shaped rigid rotor as induced by its collisional interaction with an environment. We present the general form of the Lindblad-type master equation and relate it to the orientational decoherence of an asymmetric nanoparticle in the limit of small anisotropies. The corresponding diffusion coefficients are derived for gas particles scattering off large molecules and for ambient photons scattering off dielectric particles, using the elastic scattering amplitudes.

Rotating full- and reduced-dimensional quantum chemical models of molecules

NASA Astrophysics Data System (ADS)

Fábri, Csaba; Mátyus, Edit; Császár, Attila G.

2011-02-01

A flexible protocol, applicable to semirigid as well as floppy polyatomic systems, is developed for the variational solution of the rotational-vibrational Schrödinger equation. The kinetic energy operator is expressed in terms of curvilinear coordinates, describing the internal motion, and rotational coordinates, characterizing the orientation of the frame fixed to the nonrigid body. Although the analytic form of the kinetic energy operator might be very complex, it does not need to be known a priori within this scheme as it is constructed automatically and numerically whenever needed. The internal coordinates can be chosen to best represent the system of interest and the body-fixed frame is not restricted to an embedding defined with respect to a single reference geometry. The features of the technique mentioned make it especially well suited to treat large-amplitude nuclear motions. Reduced-dimensional rovibrational models can be defined straightforwardly by introducing constraints on the generalized coordinates. In order to demonstrate the flexibility of the protocol and the associated computer code, the inversion-tunneling of the ammonia (14NH3) molecule is studied using one, two, three, four, and six active vibrational degrees of freedom, within both vibrational and rovibrational variational computations. For example, the one-dimensional inversion-tunneling model of ammonia is considered also for nonzero rotational angular momenta. It turns out to be difficult to significantly improve upon this simple model. Rotational-vibrational energy levels are presented for rotational angular momentum quantum numbers J = 0, 1, 2, 3, and 4.

Quantum Walk Schemes for Universal Quantum Computation

NASA Astrophysics Data System (ADS)

Underwood, Michael S.

Random walks are a powerful tool for the efficient implementation of algorithms in classical computation. Their quantum-mechanical analogues, called quantum walks, hold similar promise. Quantum walks provide a model of quantum computation that has recently been shown to be equivalent in power to the standard circuit model. As in the classical case, quantum walks take place on graphs and can undergo discrete or continuous evolution, though quantum evolution is unitary and therefore deterministic until a measurement is made. This thesis considers the usefulness of continuous-time quantum walks to quantum computation from the perspectives of both their fundamental power under various formulations, and their applicability in practical experiments. In one extant scheme, logical gates are effected by scattering processes. The results of an exhaustive search for single-qubit operations in this model are presented. It is shown that the number of distinct operations increases exponentially with the number of vertices in the scattering graph. A catalogue of all graphs on up to nine vertices that implement single-qubit unitaries at a specific set of momenta is included in an appendix. I develop a novel scheme for universal quantum computation called the discontinuous quantum walk, in which a continuous-time quantum walker takes discrete steps of evolution via perfect quantum state transfer through small 'widget' graphs. The discontinuous quantum-walk scheme requires an exponentially sized graph, as do prior discrete and continuous schemes. To eliminate the inefficient vertex resource requirement, a computation scheme based on multiple discontinuous walkers is presented. In this model, n interacting walkers inhabiting a graph with 2n vertices can implement an arbitrary quantum computation on an input of length n, an exponential savings over previous universal quantum walk schemes. This is the first quantum walk scheme that allows for the application of quantum error correction

Arbitrary spin-to-orbital angular momentum conversion of light

NASA Astrophysics Data System (ADS)

Devlin, Robert C.; Ambrosio, Antonio; Rubin, Noah A.; Mueller, J. P. Balthasar; Capasso, Federico

2017-11-01

Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements—SAM-to-orbital angular momentum (OAM) converters—are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superposition of independent OAM. We designed a metasurface that converts left- and right-circular polarizations into states with independent values of OAM and designed another device that performs this operation for elliptically polarized states. These results illustrate a general material-mediated connection between SAM and OAM of light and may find applications in producing complex structured light and in optical communication.

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Angular dependence of novel magnetic quantum oscillations in a quasi-two-dimensional multiband Fermi liquid with impurities

NASA Astrophysics Data System (ADS)

Bratkovsky, A. M.; Alexandrov, A. S.

2002-03-01

The semiclassical Lifshitz-Kosevich-type description is given for the angular dependence of quantum oscillations with combination frequencies in a multiband quasi-two-dimensional Fermi liquid with a constant number of electrons. The analytical expressions are found for the Dingle, thermal, spin, and amplitude (Yamaji) reduction factors of the novel combination harmonics, where the latter two strongly oscillate with the direction of the field [1]. At the magic angles those factors reduce to the purely two-dimensional expressions given earlier. The combination harmonics are suppressed in the presence of the nonquantized background states, and they decay exponentially faster with temperature and/or disorder compared to the standard harmonics, providing an additional tool for electronic structure determination. The theory is applied to Sr2RuO4. [1] A.M. Bratkovsky and A.S. Alexandrov, Phys. Rev. B 65, xxxx (2002); cond-mat/0104520.

Spin zero Hawking radiation for non-zero-angular momentum mode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ngampitipan, Tritos; Bonserm, Petarpa; Visser, Matt

2015-05-15

Black hole greybody factors carry some quantum black hole information. Studying greybody factors may lead to understanding the quantum nature of black holes. However, solving for exact greybody factors in many black hole systems is impossible. One way to deal with this problem is to place some rigorous analytic bounds on the greybody factors. In this paper, we calculate rigorous bounds on the greybody factors for spin zero hawking radiation for non-zero-angular momentum mode from the Kerr-Newman black holes.

Brillouin Light Scattering by Magnetic Quasivortices in Cavity Optomagnonics

NASA Astrophysics Data System (ADS)

Osada, A.; Gloppe, A.; Hisatomi, R.; Noguchi, A.; Yamazaki, R.; Nomura, M.; Nakamura, Y.; Usami, K.

2018-03-01

A ferromagnetic sphere can support optical vortices in the form of whispering gallery modes and magnetic quasivortices in the form of magnetostatic modes with nontrivial spin textures. These vortices can be characterized by their orbital angular momenta. We experimentally investigate Brillouin scattering of photons in the whispering gallery modes by magnons in the magnetostatic modes, zeroing in on the exchange of the orbital angular momenta between the optical vortices and magnetic quasivortices. We find that the conservation of the orbital angular momentum results in different nonreciprocal behavior in the Brillouin light scattering. New avenues for chiral optics and optospintronics can be opened up by taking the orbital angular momenta as a new degree of freedom for cavity optomagnonics.

Arbitrary spin-to-orbital angular momentum conversion of light.

PubMed

Devlin, Robert C; Ambrosio, Antonio; Rubin, Noah A; Mueller, J P Balthasar; Capasso, Federico

2017-11-17

Optical elements that convert the spin angular momentum (SAM) of light into vortex beams have found applications in classical and quantum optics. These elements-SAM-to-orbital angular momentum (OAM) converters-are based on the geometric phase and only permit the conversion of left- and right-circular polarizations (spin states) into states with opposite OAM. We present a method for converting arbitrary SAM states into total angular momentum states characterized by a superposition of independent OAM. We designed a metasurface that converts left- and right-circular polarizations into states with independent values of OAM and designed another device that performs this operation for elliptically polarized states. These results illustrate a general material-mediated connection between SAM and OAM of light and may find applications in producing complex structured light and in optical communication. Copyright © 2017, American Association for the Advancement of Science.

Galactic Angular Momentum in Cosmological Zoom-in Simulations. I. Disk and Bulge Components and the Galaxy-Halo Connection

NASA Astrophysics Data System (ADS)

Sokołowska, Aleksandra; Capelo, Pedro R.; Fall, S. Michael; Mayer, Lucio; Shen, Sijing; Bonoli, Silvia

2017-02-01

We investigate the angular momentum evolution of four disk galaxies residing in Milky-Way-sized halos formed in cosmological zoom-in simulations with various sub-grid physics and merging histories. We decompose these galaxies, kinematically and photometrically, into their disk and bulge components. The simulated galaxies and their components lie on the observed sequences in the j *-M * diagram, relating the specific angular momentum and mass of the stellar component. We find that galaxies in low-density environments follow the relation {j}* \\propto {M}* α past major mergers, with α ˜ 0.6 in the case of strong feedback, when bulge-to-disk ratios are relatively constant, and α ˜ 1.4 in the other cases, when secular processes operate on shorter timescales. We compute the retention factors (I.e., the ratio of the specific angular momenta of stars and dark matter) for both disks and bulges and show that they vary relatively slowly after averaging over numerous but brief fluctuations. For disks, the retention factors are usually close to unity, while for bulges, they are a few times smaller. Our simulations therefore indicate that galaxies and their halos grow in a quasi-homologous way.

Instability of quantum equilibrium in Bohm's dynamics

PubMed Central

Colin, Samuel; Valentini, Antony

2014-01-01

We consider Bohm's second-order dynamics for arbitrary initial conditions in phase space. In principle, Bohm's dynamics allows for ‘extended’ non-equilibrium, with initial momenta not equal to the gradient of phase of the wave function (as well as initial positions whose distribution departs from the Born rule). We show that extended non-equilibrium does not relax in general and is in fact unstable. This is in sharp contrast with de Broglie's first-order dynamics, for which non-standard momenta are not allowed and which shows an efficient relaxation to the Born rule for positions. On this basis, we argue that, while de Broglie's dynamics is a tenable physical theory, Bohm's dynamics is not. In a world governed by Bohm's dynamics, there would be no reason to expect to see an effective quantum theory today (even approximately), in contradiction with observation. PMID:25383020

High-Dimensional Single-Photon Quantum Gates: Concepts and Experiments.

PubMed

Babazadeh, Amin; Erhard, Manuel; Wang, Feiran; Malik, Mehul; Nouroozi, Rahman; Krenn, Mario; Zeilinger, Anton

2017-11-03

Transformations on quantum states form a basic building block of every quantum information system. From photonic polarization to two-level atoms, complete sets of quantum gates for a variety of qubit systems are well known. For multilevel quantum systems beyond qubits, the situation is more challenging. The orbital angular momentum modes of photons comprise one such high-dimensional system for which generation and measurement techniques are well studied. However, arbitrary transformations for such quantum states are not known. Here we experimentally demonstrate a four-dimensional generalization of the Pauli X gate and all of its integer powers on single photons carrying orbital angular momentum. Together with the well-known Z gate, this forms the first complete set of high-dimensional quantum gates implemented experimentally. The concept of the X gate is based on independent access to quantum states with different parities and can thus be generalized to other photonic degrees of freedom and potentially also to other quantum systems.

Quantum Sets and Clifford Algebras

NASA Astrophysics Data System (ADS)

Finkelstein, David

1982-06-01

The mathematical language presently used for quantum physics is a high-level language. As a lowest-level or basic language I construct a quantum set theory in three stages: (1) Classical set theory, formulated as a Clifford algebra of “ S numbers” generated by a single monadic operation, “bracing,” Br = {…}. (2) Indefinite set theory, a modification of set theory dealing with the modal logical concept of possibility. (3) Quantum set theory. The quantum set is constructed from the null set by the familiar quantum techniques of tensor product and antisymmetrization. There are both a Clifford and a Grassmann algebra with sets as basis elements. Rank and cardinality operators are analogous to Schroedinger coordinates of the theory, in that they are multiplication or “ Q-type” operators. “ P-type” operators analogous to Schroedinger momenta, in that they transform the Q-type quantities, are bracing (Br), Clifford multiplication by a set X, and the creator of X, represented by Grassmann multiplication c( X) by the set X. Br and its adjoint Br* form a Bose-Einstein canonical pair, and c( X) and its adjoint c( X)* form a Fermi-Dirac or anticanonical pair. Many coefficient number systems can be employed in this quantization. I use the integers for a discrete quantum theory, with the usual complex quantum theory as limit. Quantum set theory may be applied to a quantum time space and a quantum automaton.

Spin-Orbit Coupling and the Conservation of Angular Momentum

ERIC Educational Resources Information Center

Hnizdo, V.

2012-01-01

In nonrelativistic quantum mechanics, the total (i.e. orbital plus spin) angular momentum of a charged particle with spin that moves in a Coulomb plus spin-orbit-coupling potential is conserved. In a classical nonrelativistic treatment of this problem, in which the Lagrange equations determine the orbital motion and the Thomas equation yields the…

Application of the top-on-top model to 135Pr

NASA Astrophysics Data System (ADS)

Sugawara-Tanabe, Kazuko; Tanabe, Kosai

2017-09-01

It is proved that the Holstein-Primakoff (HP) boson expansion method is very effective for a case where both total and single-particle angular momenta have the diagonal representation along the same direction. The algebraic solution is described by two kinds of quantum numbers classifying the rotational band’s characteristic of the particle-rotor model. One is related with the wobbling motion of the rotor, and the other to the precession of the single-particle angular momentum. Employing angular-momentum dependent rigid (rig) moments of inertia (MoI), which simulate Coriolis anti-pairing effect based on the constrained self-consistent Hartree-Fock-Bogoliubov (HFB) equation, we obtain good fitting not only to the energy-level scheme, but also to the electromagnetic transition rates and the mixing ratio for 135Pr.

Quantum localisation on the circle

NASA Astrophysics Data System (ADS)

Fresneda, Rodrigo; Gazeau, Jean Pierre; Noguera, Diego

2018-05-01

Covariant integral quantisation using coherent states for semi-direct product groups is implemented for the motion of a particle on the circle. In this case, the phase space is the cylinder, which is viewed as a left coset of the Euclidean group E(2). Coherent states issued from fiducial vectors are labeled by points in the cylinder and depend also on extra parameters. We carry out the corresponding quantisations of the basic classical observables, particularly the angular momentum and the 2π-periodic discontinuous angle function. We compute their corresponding lower symbols. The quantum localisation on the circle is examined through the properties of the angle operator yielded by our procedure, its spectrum and lower symbol, its commutator with the quantum angular momentum, and the resulting Heisenberg inequality. Comparison with other approaches to the long-standing question of the quantum angle is discussed.

On the origin of the angular momentum of galaxies: cosmological tidal torques supplemented by the Coriolis force

NASA Astrophysics Data System (ADS)

Casuso, E.; Beckman, J. E.

2015-05-01

We present here a theoretical model which can at least contribute to the observed relation between the specific angular momenta of galaxies and their masses. This study offers prima facie evidence that the origin of an angular momentum of galaxies could be somewhat more complex than previously proposed. The most recent observations point to a scenario in which, after recombination, matter was organized around bubbles (commonly termed voids), which acquired rotation by tidal torque interaction. Subsequently, a combination of the effects of the gravitational collapse of gas in protogalaxies and the Coriolis force due to the rotation of the voids could produce the rotation of spiral galaxies. Thereafter, the tidal interaction between the objects populating the quasi-spherical voids, in which the galaxies far away from the rotation axes (populating the sheet forming the surface of a void) interact with higher probability with others similarly situated in a neighbouring void, offers a mechanism for transforming some of the galaxies into ellipticals, breaking their spin and yielding galaxies with low net angular momentum, as observed. This model gives an explanation for those observations which suggest a tendency of galactic spins to align along the radius vectors pointing towards the centres of the voids for ellipticals/SO and parallel to filaments and sheets for the spirals. Furthermore, while in simple tidal torque theory the angular momentum supplied to galaxies diminishes drastically with the cosmic expansion, in our approximation for which the Coriolis force acts in addition to tidal torques, the Coriolis force due to void rotation ensures almost continuous angular momentum supply.

Encoding photonic angular momentum information onto surface plasmon polaritons with plasmonic lens.

PubMed

Liu, Aiping; Rui, Guanghao; Ren, Xifeng; Zhan, Qiwen; Guo, Guangcan; Guo, Guoping

2012-10-22

Both spin angular momentum (SAM) and orbital angular momentum (OAM) can be used to carry information in classical optics and quantum optics. In this paper, the encoding of angular momentum (AM) information of photons onto surface plasmon polaritons (SPPs) is demonstrated using a nano-ring plasmonic lens. Near-field energy distribution on the metal surface is measured using a near-field scanning optical microscope (NSOM) when the plasmonic lens is excited by photons with different combinations of SAM and OAM. It is found that both the SAM and OAM can influence the near field energy distribution of SPPs. More interestingly, numerical and experimental studies reveal that the energy distribution on the plasmonic lens surface is determined by the absolute value of the total AM. This gives direct evidences that SPPs can be encoded with the photonic SAM and OAM information simultaneously and the spin degeneracy of the photons can be removed using the interactions between photonic OAM and plasmonic lens. The findings are useful not only for the fundamental understanding of the photonic AM but also for the future design of plasmonic quantum optics devices and systems.

A Multi-instrument and Multi-wavelength High Angular Resolution Study of MWC 614: Quantum Heated Particles Inside the Disk Cavity

NASA Astrophysics Data System (ADS)

Kluska, Jacques; Kraus, Stefan; Davies, Claire L.; Harries, Tim; Willson, Matthew; Monnier, John D.; Aarnio, Alicia; Baron, Fabien; Millan-Gabet, Rafael; Ten Brummelaar, Theo; Che, Xiao; Hinkley, Sasha; Preibisch, Thomas; Sturmann, Judit; Sturmann, Laszlo; Touhami, Yamina

2018-03-01

High angular resolution observations of young stellar objects are required to study the inner astronomical units of protoplanetary disks in which the majority of planets form. As they evolve, gaps open up in the inner disk regions and the disks are fully dispersed within ∼10 Myr. MWC 614 is a pretransitional object with a ∼10 au radius gap. We present a set of high angular resolution observations of this object including SPHERE/ZIMPOL polarimetric and coronagraphic images in the visible, Keck/NIRC2 near-infrared (NIR) aperture masking observations, and Very Large Telescope Interferometer (AMBER, MIDI, and PIONIER) and Center for High Angular Resolution Astronomy (CLASSIC and CLIMB) long-baseline interferometry at infrared wavelengths. We find that all the observations are compatible with an inclined disk (i ∼ 55° at a position angle of ∼20°–30°). The mid-infrared data set confirms that the disk inner rim is at 12.3 ± 0.4 au from the central star. We determined an upper mass limit of 0.34 M ⊙ for a companion inside the cavity. Within the cavity, the NIR emission, usually associated with the dust sublimation region, is unusually extended (∼10 au, 30 times larger than the theoretical sublimation radius) and indicates a high dust temperature (T ∼ 1800 K). As a possible result of companion-induced dust segregation, quantum heated dust grains could explain the extended NIR emission with this high temperature. Our observations confirm the peculiar state of this object where the inner disk has already been accreted onto the star, exposing small particles inside the cavity to direct stellar radiation. Based on observations made with the Keck observatory (NASA program ID N104N2) and with ESO telescopes at the Paranal Observatory (ESO program IDs 073.C-0720, 077.C-0226, 077.C-0521, 083.C-0984, 087.C-0498(A), 190.C-0963, 095.C-0883) and with the Center for High Angular Resolution Astronomy observatory.

Twisting Neutron Waves

NASA Astrophysics Data System (ADS)

Pushin, Dmitry

Most waves encountered in nature can be given a ``twist'', so that their phase winds around an axis parallel to the direction of wave propagation. Such waves are said to possess orbital angular momentum (OAM). For quantum particles such as photons, atoms, and electrons, this corresponds to the particle wavefunction having angular momentum of Lℏ along its propagation axis. Controlled generation and detection of OAM states of photons began in the 1990s, sparking considerable interest in applications of OAM in light and matter waves. OAM states of photons have found diverse applications such as broadband data multiplexing, massive quantum entanglement, optical trapping, microscopy, quantum state determination and teleportation, and interferometry. OAM states of electron beams have been used to rotate nanoparticles, determine the chirality of crystals and for magnetic microscopy. Here I discuss the first demonstration of OAM control of neutrons. Using neutron interferometry with a spatially incoherent input beam, we show the addition and conservation of quantum angular momenta, entanglement between quantum path and OAM degrees of freedom. Neutron-based quantum information science heretofore limited to spin, path, and energy degrees of freedom, now has access to another quantized variable, and OAM modalities of light, x-ray, and electron beams are extended to a massive, penetrating neutral particle. The methods of neutron phase imprinting demonstrated here expand the toolbox available for development of phase-sensitive techniques of neutron imaging. Financial support provided by the NSERC Create and Discovery programs, CERC and the NIST Quantum Information Program is acknowledged.

Quantum state engineering using one-dimensional discrete-time quantum walks

NASA Astrophysics Data System (ADS)

Innocenti, Luca; Majury, Helena; Giordani, Taira; Spagnolo, Nicolò; Sciarrino, Fabio; Paternostro, Mauro; Ferraro, Alessandro

2017-12-01

Quantum state preparation in high-dimensional systems is an essential requirement for many quantum-technology applications. The engineering of an arbitrary quantum state is, however, typically strongly dependent on the experimental platform chosen for implementation, and a general framework is still missing. Here we show that coined quantum walks on a line, which represent a framework general enough to encompass a variety of different platforms, can be used for quantum state engineering of arbitrary superpositions of the walker's sites. We achieve this goal by identifying a set of conditions that fully characterize the reachable states in the space comprising walker and coin and providing a method to efficiently compute the corresponding set of coin parameters. We assess the feasibility of our proposal by identifying a linear optics experiment based on photonic orbital angular momentum technology.

Quantum Theory of Wormholes

NASA Astrophysics Data System (ADS)

González-Díaz, Pedro F.

We re-explore the effects of multiply-connected wormholes on ordinary matter at low energies. It is obtained that the path integral that describes these effects is given in terms of a Planckian probability distribution for the Coleman α-parameters, rather than a classical Gaussian distribution law. This implies that the path integral over all low-energy fields with the wormhole effective interactions can no longer vary continuously, and that the quantities α2 are interpretable as the momenta of a quantum field. Using the new result that, rather than being given in terms of the Coleman-Hawking probability, the Euclidean action must equal negative entropy, the model predicts a very small but still nonzero cosmological constant and quite reasonable values for the pion and neutrino masses. The divergence problems of Euclidean quantum gravity are also discussed in the light of the above results.

Helical quantum states in HgTe quantum dots with inverted band structures.

PubMed

Chang, Kai; Lou, Wen-Kai

2011-05-20

We investigate theoretically the electron states in HgTe quantum dots (QDs) with inverted band structures. In sharp contrast to conventional semiconductor quantum dots, the quantum states in the gap of the HgTe QD are fully spin-polarized and show ringlike density distributions near the boundary of the QD and spin-angular momentum locking. The persistent charge currents and magnetic moments, i.e., the Aharonov-Bohm effect, can be observed in such a QD structure. This feature offers us a practical way to detect these exotic ringlike edge states by using the SQUID technique.

Generating millimeter-wave Bessel beam with orbital angular momentum using reflective-type metasurface inherently integrated with source

NASA Astrophysics Data System (ADS)

Shen, Yizhu; Yang, Jiawei; Meng, Hongfu; Dou, Wenbin; Hu, Sanming

2018-04-01

Metasurfaces, orbital angular momenta (OAM), and non-diffractive Bessel beams have been attracting worldwide research. Combining the benefits of these three promising techniques, this paper proposes a metasurface-based reflective-type approach to generate a first-order Bessel beam carrying OAM. To validate this approach, a millimeter-wave metasurface is analyzed, designed, fabricated, and measured. Experimental results agree well with simulation. Moreover, this reflective-type metasurface, generating a Bessel beam with OAM, is inherently integrated with a planar feeding source in the same single-layer printed circuit board. Therefore, the proposed design features low profile, low cost, easy integration with front-end active circuits, and no alignment error between the feeding source and the metasurface.

Projection of angular momentum via linear algebra

NASA Astrophysics Data System (ADS)

Johnson, Calvin W.; O'Mara, Kevin D.

2017-12-01

Projection of many-body states with good angular momentum from an initial state is usually accomplished by a three-dimensional integral. We show how projection can instead be done by solving a straightforward system of linear equations. We demonstrate the method and give sample applications to 48Cr and 60Fe in the p f shell. This new projection scheme, which is competitive against the standard numerical quadrature, should also be applicable to other quantum numbers such as isospin and particle number.

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Creating high-purity angular-momentum-state Rydberg atoms by a pair of unipolar laser pulses

NASA Astrophysics Data System (ADS)

Xin, PeiPei; Cheng, Hong; Zhang, ShanShan; Wang, HanMu; Xu, ZiShan; Liu, HongPing

2018-04-01

We propose a method of producing high-purity angular-momentum-state Rydberg atoms by a pair of unipolar laser pulses. The first positive-polarity optical half-cycle pulse is used to prepare an excited-state wave packet while the second one is less intense, but with opposite polarity and time delayed, and is employed to drag back the escaping free electron and clip the shape of the bound Rydberg wave packet, selectively increasing or decreasing a fraction of the angular-momentum components. An intelligent choice of laser parameters such as phase and amplitude helps us to control the orbital-angular-momentum composition of an electron wave packet with more facility; thus, a specified angular-momentum state with high purity can be achieved. This scheme of producing high-purity angular-momentum-state Rydberg atoms has significant application in quantum-information processing.

Quantum Chemistry on Quantum Computers: A Polynomial-Time Quantum Algorithm for Constructing the Wave Functions of Open-Shell Molecules.

PubMed

Sugisaki, Kenji; Yamamoto, Satoru; Nakazawa, Shigeaki; Toyota, Kazuo; Sato, Kazunobu; Shiomi, Daisuke; Takui, Takeji

2016-08-18

Quantum computers are capable to efficiently perform full configuration interaction (FCI) calculations of atoms and molecules by using the quantum phase estimation (QPE) algorithm. Because the success probability of the QPE depends on the overlap between approximate and exact wave functions, efficient methods to prepare accurate initial guess wave functions enough to have sufficiently large overlap with the exact ones are highly desired. Here, we propose a quantum algorithm to construct the wave function consisting of one configuration state function, which is suitable for the initial guess wave function in QPE-based FCI calculations of open-shell molecules, based on the addition theorem of angular momentum. The proposed quantum algorithm enables us to prepare the wave function consisting of an exponential number of Slater determinants only by a polynomial number of quantum operations.

Real-time imaging of spin-to-orbital angular momentum hybrid remote state preparation

NASA Astrophysics Data System (ADS)

Erhard, Manuel; Qassim, Hammam; Mand, Harjaspreet; Karimi, Ebrahim; Boyd, Robert W.

2015-08-01

There exists two prominent methods to transfer information between two spatially separated parties, namely Alice (A) and Bob (B): quantum teleportation and remote state preparation. However, the difference between these methods is, in the teleportation scheme, the state to be transferred is completely unknown, whereas in state preparation it should be known to the sender. In addition, photonic state teleportation is probabilistic due to the impossibility of performing a two-particle complete Bell-state analysis with linear optics, while remote state preparation can be performed deterministically. Here we report the first realization of photonic hybrid remote state preparation from spin to orbital angular momentum degrees of freedom. In our scheme, the polarization state of photon A is transferred to orbital angular momentum of photon B. The prepared states are visualized in real time by means of an intensified CCD camera. The quality of the prepared states is verified by performing quantum state tomography, which confirms an average fidelity higher than 99.4%. We believe that this experiment paves the way towards a novel means of quantum communication in which encryption and decryption are carried out in naturally different Hilbert spaces, and therefore may provide a means for enhancing security.

Density matrix reconstruction of a large angular momentum

NASA Astrophysics Data System (ADS)

Klose, Gerd

2001-10-01

A complete description of the quantum state of a physical system is the fundamental knowledge necessary to statistically predict the outcome of measurements. In turning this statement around, Wolfgang Pauli raised already in 1933 the question, whether an unknown quantum state could be uniquely determined by appropriate measurements-a problem that has gained new relevance in recent years. In order to harness the prospects of quantum computing, secure communication, teleportation, and the like, the development of techniques to accurately control and measure quantum states has now become a matter of practical as well as fundamental interest. However, there is no general answer to Pauli's very basic question, and quantum state reconstruction algorithms have been developed and experimentally demonstrated only for a few systems so far. This thesis presents a novel experimental method to measure the unknown and generally mixed quantum state for an angular momentum of arbitrary magnitude. The (2F + 1) x (2F + 1) density matrix describing the quantum state is hereby completely determined from a set of Stern-Gerlach measurements with (4F + 1) different orientations of the quantization axis. This protocol is implemented for laser cooled Cesium atoms in the 6S1/2(F = 4) hyperfine ground state manifold, and is applied to a number of test states prepared by optical pumping and Larmor precession. A comparison of the input and the measured states shows successful reconstructions with fidelities of about 0.95.

Projection of angular momentum via linear algebra

DOE PAGES

Johnson, Calvin W.; O'Mara, Kevin D.

2017-12-01

Projection of many-body states with good angular momentum from an initial state is usually accomplished by a three-dimensional integral. Here, we show how projection can instead be done by solving a straightforward system of linear equations. We demonstrate the method and give sample applications tomore » $$^{48}$$Cr and $$^{60}$$Fe in the $pf$ shell. This new projection scheme, which is competitive against the standard numerical quadrature, should also be applicable to other quantum numbers such as isospin and particle number.« less

Projection of angular momentum via linear algebra

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Calvin W.; O'Mara, Kevin D.

Projection of many-body states with good angular momentum from an initial state is usually accomplished by a three-dimensional integral. Here, we show how projection can instead be done by solving a straightforward system of linear equations. We demonstrate the method and give sample applications tomore » $$^{48}$$Cr and $$^{60}$$Fe in the $pf$ shell. This new projection scheme, which is competitive against the standard numerical quadrature, should also be applicable to other quantum numbers such as isospin and particle number.« less

Revolution evolution: tracing angular momentum during star and planetary system formation

NASA Astrophysics Data System (ADS)

Davies, Claire Louise

2015-04-01

disc to expand. I used spatially resolved submillimetre detections of the dust and gas components of protoplanetary discs, gathered from the literature, to measure the radial extent of discs around low-mass pre-main sequence stars of ∼ 1-10 Myr and probe their viscous evolution. I find no clear observational evidence for the radial expansion of the dust component. However, I find tentative evidence for the expansion ofthe gas component. This suggests that the evolution of the gas and dust components of protoplanetary discs are likely governed by different astrophysical processes. Observations of jets and outflows emanating from protostars and pre-main sequence stars highlight that it may also be possible to remove angular momentum from the circumstellar material. Using the sample of spatially resolved protoplanetary discs, I find no evidence for angular momentum removal during disc evolution. I also use the spatially resolved debris discs from the Submillimetre Common-User Bolometer Array-2 Observations of Nearby Stars survey to constrain the amount of angular momentum retained within planetary systems. This sample is compared to the protoplanetary disc angular momenta and to the angular momentum contained within pre-stellar cores. I find that significant quantities of angular momentum must be removed during disc formation and disc dispersal. This likely occurs via magnetic braking during the formation of the disc, via the launching of a disc or photo-evaporative wind, and/or via ejection of planetary material following dynamical interactions.

Light-front holography and superconformal quantum mechanics: A new approach to hadron structure and color confinement

NASA Astrophysics Data System (ADS)

Brodsky, Stanley J.; Deur, Alexandre; de Téramond, Guy F.; Dosch, Hans Günter

2015-11-01

A primary question in hadron physics is how the mass scale for hadrons consisting of light quarks, such as the proton, emerges from the QCD Lagrangian even in the limit of zero quark mass. If one requires the effective action which underlies the QCD Lagrangian to remain conformally invariant and extends the formalism of de Alfaro, Fubini and Furlan to light-front Hamiltonian theory, then a unique, color-confining potential with a mass parameter κ emerges. The actual value of the parameter κ is not set by the model - only ratios of hadron masses and other hadronic mass scales are predicted. The result is a nonperturbative, relativistic light-front quantum mechanical wave equation, the Light-Front Schrödinger Equation which incorporates color confinement and other essential spectroscopic and dynamical features of hadron physics, including a massless pion for zero quark mass and linear Regge trajectories with the identical slope in the radial quantum number n and orbital angular momentum L. The same light-front equations for mesons with spin J also can be derived from the holographic mapping to QCD (3+1) at fixed light-front time from the soft-wall model modification of AdS5 space with a specific dilaton profile. Light-front holography thus provides a precise relation between the bound-state amplitudes in the fifth dimension of AdS space and the boost-invariant light-front wavefunctions describing the internal structure of hadrons in physical space-time. One can also extend the analysis to baryons using superconformal algebra - 2 × 2 supersymmetric representations of the conformal group. The resulting fermionic LF bound-state equations predict striking similarities between the meson and baryon spectra. In fact, the holographic QCD light-front Hamiltonians for the states on the meson and baryon trajectories are identical if one shifts the internal angular momenta of the meson (LM) and baryon (LB) by one unit: LM = LB + 1. We also show how the mass scale κ

Engineering quantum hyperentangled states in atomic systems

NASA Astrophysics Data System (ADS)

Nawaz, Mehwish; -Islam, Rameez-ul; Abbas, Tasawar; Ikram, Manzoor

2017-11-01

Hyperentangled states have boosted many quantum informatics tasks tremendously due to their high information content per quantum entity. Until now, however, the engineering and manipulation of such states were limited to photonic systems only. In present article, we propose generating atomic hyperentanglement involving atomic internal states as well as atomic external momenta states. Hypersuperposition, hyperentangled cluster, Bell and Greenberger-Horne-Zeilinger states are engineered deterministically through resonant and off-resonant Bragg diffraction of neutral two-level atoms. Based on the characteristic parameters of the atomic Bragg diffraction, such as comparatively large interaction times and spatially well-separated outputs, such decoherence resistant states are expected to exhibit good overall fidelities and offer the evident benefits of full controllability, along with extremely high detection efficiency, over the counterpart photonic states comprised entirely of flying qubits.

Hyperfine-Structure-Induced Depolarization of Impulsively Aligned I2 Molecules

NASA Astrophysics Data System (ADS)

Thomas, Esben F.; Søndergaard, Anders A.; Shepperson, Benjamin; Henriksen, Niels E.; Stapelfeldt, Henrik

2018-04-01

A moderately intense 450 fs laser pulse is used to create rotational wave packets in gas phase I2 molecules. The ensuing time-dependent alignment, measured by Coulomb explosion imaging with a delayed probe pulse, exhibits the characteristic revival structures expected for rotational wave packets but also a complex nonperiodic substructure and decreasing mean alignment not observed before. A quantum mechanical model attributes the phenomena to coupling between the rotational angular momenta and the nuclear spins through the electric quadrupole interaction. The calculated alignment trace agrees very well with the experimental results.

Simultaneous entanglement swapping of multiple orbital angular momentum states of light.

PubMed

Zhang, Yingwen; Agnew, Megan; Roger, Thomas; Roux, Filippus S; Konrad, Thomas; Faccio, Daniele; Leach, Jonathan; Forbes, Andrew

2017-09-21

High-bit-rate long-distance quantum communication is a proposed technology for future communication networks and relies on high-dimensional quantum entanglement as a core resource. While it is known that spatial modes of light provide an avenue for high-dimensional entanglement, the ability to transport such quantum states robustly over long distances remains challenging. To overcome this, entanglement swapping may be used to generate remote quantum correlations between particles that have not interacted; this is the core ingredient of a quantum repeater, akin to repeaters in optical fibre networks. Here we demonstrate entanglement swapping of multiple orbital angular momentum states of light. Our approach does not distinguish between different anti-symmetric states, and thus entanglement swapping occurs for several thousand pairs of spatial light modes simultaneously. This work represents the first step towards a quantum network for high-dimensional entangled states and provides a test bed for fundamental tests of quantum science.Entanglement swapping in high dimensions requires large numbers of entangled photons and consequently suffers from low photon flux. Here the authors demonstrate entanglement swapping of multiple spatial modes of light simultaneously, without the need for increasing the photon numbers with dimension.

Mode-sum regularization of ⟨ϕ2⟩ in the angular-splitting method

NASA Astrophysics Data System (ADS)

Levi, Adam; Ori, Amos

2016-08-01

The computation of the renormalized stress-energy tensor or ⟨ϕ2⟩ren in curved spacetime is a challenging task, at both the conceptual and technical levels. Recently we developed a new approach to compute such renormalized quantities in asymptotically flat curved spacetimes, based on the point-splitting procedure. Our approach requires the spacetime to admit some symmetry. We already implemented this approach to compute ⟨ϕ2⟩ren in a stationary spacetime using t splitting, namely splitting in the time-translation direction. Here we present the angular-splitting version of this approach, aimed for computing renormalized quantities in a general (possibly dynamical) spherically symmetric spacetime. To illustrate how the angular-splitting method works, we use it here to compute ⟨ϕ2⟩ren for a quantum massless scalar field in Schwarzschild background, in various quantum states (Boulware, Unruh, and Hartle-Hawking states). We find excellent agreement with the results obtained from the t -splitting variant and also with other methods. Our main goal in pursuing this new mode-sum approach was to enable the computation of the renormalized stress-energy tensor in a dynamical spherically symmetric background, e.g. an evaporating black hole. The angular-splitting variant presented here is most suitable to this purpose.

On-chip spin-controlled orbital angular momentum directional coupling

NASA Astrophysics Data System (ADS)

Xie, Zhenwei; Lei, Ting; Si, Guangyuan; Du, Luping; Lin, Jiao; Min, Changjun; Yuan, Xiaocong

2018-01-01

Optical vortex beams have many potential applications in the particle trapping, quantum encoding, optical orbital angular momentum (OAM) communications and interconnects. However, the on-chip compact OAM detection is still a big challenge. Based on a holographic configuration and a spin-dependent structure design, we propose and demonstrate an on-chip spin-controlled OAM-mode directional coupler, which can couple the OAM signal to different directions due to its topological charge. While the directional coupling function can be switched on/off by altering the spin of incident beam. Both simulation and experimental measurements verify the validity of the proposed approach. This work would benefit the on-chip OAM devices for optical communications and high dimensional quantum coding/decoding in the future.

Effect of a magnetic field on molecule-solvent angular momentum transfer

NASA Astrophysics Data System (ADS)

Rzadkowski, Wojciech; Lemeshko, Mikhail

2018-03-01

Recently it was shown that a molecule rotating in a quantum solvent can be described in terms of the "angulon" quasiparticle [M. Lemeshko, Phys. Rev. Lett. 118, 095301 (2017)]. Here we extend the angulon theory to the case of molecules possessing an additional spin-1/2 degree of freedom and study the behavior of the system in the presence of a static magnetic field. We show that exchange of angular momentum between the molecule and the solvent can be altered by the field, even though the solvent itself is non-magnetic. In particular, we demonstrate a possibility to control resonant emission of phonons with a given angular momentum using a magnetic field.

Quantum entanglement: facts and fiction - how wrong was Einstein after all?

PubMed

Nordén, Bengt

2016-01-01

Einstein was wrong with his 1927 Solvay Conference claim that quantum mechanics is incomplete and incapable of describing diffraction of single particles. However, the Einstein-Podolsky-Rosen paradox of entangled pairs of particles remains lurking with its 'spooky action at a distance'. In molecules quantum entanglement can be viewed as basis of both chemical bonding and excitonic states. The latter are important in many biophysical contexts and involve coupling between subsystems in which virtual excitations lead to eigenstates of the total Hamiltonian, but not for the separate subsystems. The author questions whether atomic or photonic systems may be probed to prove that particles or photons may stay entangled over large distances and display the immediate communication with each other that so concerned Einstein. A dissociating hydrogen molecule is taken as a model of a zero-spin entangled system whose angular momenta are in principle possible to probe for this purpose. In practice, however, spins randomize as a result of interactions with surrounding fields and matter. Similarly, no experiment seems yet to provide unambiguous evidence of remaining entanglement between single photons at large separations in absence of mutual interaction, or about immediate (superluminal) communication. This forces us to reflect again on what Einstein really had in mind with the paradox, viz. a probabilistic interpretation of a wave function for an ensemble of identically prepared states, rather than as a statement about single particles. Such a prepared state of many particles would lack properties of quantum entanglement that make it so special, including the uncertainty upon which safe quantum communication is assumed to rest. An example is Zewail's experiment showing visible resonance in the dissociation of a coherently vibrating ensemble of NaI molecules apparently violating the uncertainty principle. Einstein was wrong about diffracting single photons where space-like anti

Universality and Quantum Criticality of the One-Dimensional Spinor Bose Gas

NASA Astrophysics Data System (ADS)

PâÅ£u, Ovidiu I.; Klümper, Andreas; Foerster, Angela

2018-06-01

We investigate the universal thermodynamics of the two-component one-dimensional Bose gas with contact interactions in the vicinity of the quantum critical point separating the vacuum and the ferromagnetic liquid regime. We find that the quantum critical region belongs to the universality class of the spin-degenerate impenetrable particle gas which, surprisingly, is very different from the single-component case and identify its boundaries with the peaks of the specific heat. In addition, we show that the compressibility Wilson ratio, which quantifies the relative strength of thermal and quantum fluctuations, serves as a good discriminator of the quantum regimes near the quantum critical point. Remarkably, in the Tonks-Girardeau regime, the universal contact develops a pronounced minimum, reflected in a counterintuitive narrowing of the momentum distribution as we increase the temperature. This momentum reconstruction, also present at low and intermediate momenta, signals the transition from the ferromagnetic to the spin-incoherent Luttinger liquid phase and can be detected in current experiments with ultracold atomic gases in optical lattices.

VizieR Online Data Catalog: ExoMol line lists. XXIV. SiH (Yurchenko+, 2018)

NASA Astrophysics Data System (ADS)

Yurchenko, S. N.; Sinden, F.; Lodi, L.; Hill, C.; Gorman, M. N.; Tennyson, J.

2017-11-01

The data for each isotopologue are in two parts. The first, s_*.dat contain lists of rovibronic states. Each state is labelled with the total angular momentum, state degeneracy, life time, Zeeman Lande-g factor, total (+/-) and e/f parities, vibrational quantum number, projection of the electronic, spin and total angular momenta. Each state has a unique number, which is the number of the row in which it appears in the file. This number is the means by which the state is related to the second part of the data system, the transitions files. The transition files t_*.dat contain four columns: the reference number in the energy file of the upper state; that of the lower state; the Einstein A coefficient of the transition; the transition wavenumber. (8 data files).

Generalized quantum Fokker-Planck, diffusion, and Smoluchowski equations with true probability distribution functions.

PubMed

Banik, Suman Kumar; Bag, Bidhan Chandra; Ray, Deb Shankar

2002-05-01

Traditionally, quantum Brownian motion is described by Fokker-Planck or diffusion equations in terms of quasiprobability distribution functions, e.g., Wigner functions. These often become singular or negative in the full quantum regime. In this paper a simple approach to non-Markovian theory of quantum Brownian motion using true probability distribution functions is presented. Based on an initial coherent state representation of the bath oscillators and an equilibrium canonical distribution of the quantum mechanical mean values of their coordinates and momenta, we derive a generalized quantum Langevin equation in c numbers and show that the latter is amenable to a theoretical analysis in terms of the classical theory of non-Markovian dynamics. The corresponding Fokker-Planck, diffusion, and Smoluchowski equations are the exact quantum analogs of their classical counterparts. The present work is independent of path integral techniques. The theory as developed here is a natural extension of its classical version and is valid for arbitrary temperature and friction (the Smoluchowski equation being considered in the overdamped limit).

Optical Radiation from Integer Quantum Hall States in Dirac Materials

NASA Astrophysics Data System (ADS)

Gullans, Michael; Taylor, Jacob; Ghaemi, Pouyan; Hafezi, Mohammad

Quantum Hall systems exhibit topologically protected edge states, which can have a macroscopic spatial extent. Such edge states provide a unique opportunity to study a quantum emitter whose size far exceeds the wavelength of emitted light. To better understand this limit, we theoretically characterize the optical radiation from integer quantum Hall states in two-dimensional Dirac materials. We show that the scattered light from the bulk reflects the spatial profile of the wavefunctions, enabling spatial imaging of the disorder landscape. We find that the radiation from the edge states are characterized by the presence of large multipole moments in the far-field. This multipole radiation arises from the transfer of angular momentum from the electrons into the scattered light, enabling the generation of coherent light with high orbital angular momentum.

A reductionist perspective on quantum statistical mechanics: Coarse-graining of path integrals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinitskiy, Anton V.; Voth, Gregory A., E-mail: gavoth@uchicago.edu

2015-09-07

Computational modeling of the condensed phase based on classical statistical mechanics has been rapidly developing over the last few decades and has yielded important information on various systems containing up to millions of atoms. However, if a system of interest contains important quantum effects, well-developed classical techniques cannot be used. One way of treating finite temperature quantum systems at equilibrium has been based on Feynman’s imaginary time path integral approach and the ensuing quantum-classical isomorphism. This isomorphism is exact only in the limit of infinitely many classical quasiparticles representing each physical quantum particle. In this work, we present a reductionistmore » perspective on this problem based on the emerging methodology of coarse-graining. This perspective allows for the representations of one quantum particle with only two classical-like quasiparticles and their conjugate momenta. One of these coupled quasiparticles is the centroid particle of the quantum path integral quasiparticle distribution. Only this quasiparticle feels the potential energy function. The other quasiparticle directly provides the observable averages of quantum mechanical operators. The theory offers a simplified perspective on quantum statistical mechanics, revealing its most reductionist connection to classical statistical physics. By doing so, it can facilitate a simpler representation of certain quantum effects in complex molecular environments.« less

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A reductionist perspective on quantum statistical mechanics: Coarse-graining of path integrals.

PubMed

Sinitskiy, Anton V; Voth, Gregory A

2015-09-07

Computational modeling of the condensed phase based on classical statistical mechanics has been rapidly developing over the last few decades and has yielded important information on various systems containing up to millions of atoms. However, if a system of interest contains important quantum effects, well-developed classical techniques cannot be used. One way of treating finite temperature quantum systems at equilibrium has been based on Feynman's imaginary time path integral approach and the ensuing quantum-classical isomorphism. This isomorphism is exact only in the limit of infinitely many classical quasiparticles representing each physical quantum particle. In this work, we present a reductionist perspective on this problem based on the emerging methodology of coarse-graining. This perspective allows for the representations of one quantum particle with only two classical-like quasiparticles and their conjugate momenta. One of these coupled quasiparticles is the centroid particle of the quantum path integral quasiparticle distribution. Only this quasiparticle feels the potential energy function. The other quasiparticle directly provides the observable averages of quantum mechanical operators. The theory offers a simplified perspective on quantum statistical mechanics, revealing its most reductionist connection to classical statistical physics. By doing so, it can facilitate a simpler representation of certain quantum effects in complex molecular environments.

The scalable implementation of quantum walks using classical light

NASA Astrophysics Data System (ADS)

Goyal, Sandeep K.; Roux, F. S.; Forbes, Andrew; Konrad, Thomas

2014-02-01

A quantum walk is the quantum analog of the classical random walks. Despite their simple structure they form a universal platform to implement any algorithm of quantum computation. However, it is very hard to realize quantum walks with a sufficient number of iterations in quantum systems due to their sensitivity to environmental influences and subsequent loss of coherence. Here we present a scalable implementation scheme for one-dimensional quantum walks for arbitrary number of steps using the orbital angular momentum modes of classical light beams. Furthermore, we show that using the same setup with a minor adjustment we can also realize electric quantum walks.

Matrix elements of explicitly correlated Gaussian basis functions with arbitrary angular momentum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joyce, Tennesse; Varga, Kálmán

2016-05-14

A new algorithm for calculating the Hamiltonian matrix elements with all-electron explicitly correlated Gaussian functions for quantum-mechanical calculations of atoms with arbitrary angular momentum is presented. The calculations are checked on several excited states of three and four electron systems. The presented formalism can be used as unified framework for high accuracy calculations of properties of small atoms and molecules.

Experimental Quantum Coin Tossing

NASA Astrophysics Data System (ADS)

Molina-Terriza, G.; Vaziri, A.; Ursin, R.; Zeilinger, A.

2005-01-01

In this Letter we present the first implementation of a quantum coin-tossing protocol. This protocol belongs to a class of “two-party” cryptographic problems, where the communication partners distrust each other. As with a number of such two-party protocols, the best implementation of the quantum coin tossing requires qutrits, resulting in a higher security than using qubits. In this way, we have also performed the first complete quantum communication protocol with qutrits. In our experiment the two partners succeeded to remotely toss a row of coins using photons entangled in the orbital angular momentum. We also show the experimental bounds of a possible cheater and the ways of detecting him.

Measurement of the polarization of W bosons with large transverse momenta in W + jets events at the LHC.

PubMed

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Wu, W; Yang, F; Yumiceva, F; Yun, J C; Acosta, D; Avery, P; Bourilkov, D; Chen, M; De Gruttola, M; Di Giovanni, G P; Dobur, D; Drozdetskiy, A; Field, R D; Fisher, M; Fu, Y; Furic, I K; Gartner, J; Kim, B; Konigsberg, J; Korytov, A; Kropivnitskaya, A; Kypreos, T; Matchev, K; Mitselmakher, G; Muniz, L; Prescott, C; Remington, R; Schmitt, M; Scurlock, B; Sellers, P; Skhirtladze, N; Snowball, M; Wang, D; Yelton, J; Zakaria, M; Ceron, C; Gaultney, V; Kramer, L; Lebolo, L M; Linn, S; Markowitz, P; Martinez, G; Mesa, D; Rodriguez, J L; Adams, T; Askew, A; Bochenek, J; Chen, J; Diamond, B; Gleyzer, S V; Haas, J; Hagopian, S; Hagopian, V; Jenkins, M; Johnson, K F; Prosper, H; Quertenmont, L; Sekmen, S; Veeraraghavan, V; Baarmand, M M; Dorney, B; Guragain, S; Hohlmann, M; Kalakhety, H; Ralich, R; Vodopiyanov, I; Adams, M R; Anghel, I M; Apanasevich, L; Bai, Y; Bazterra, V E; Betts, R R; Callner, J; Cavanaugh, R; Dragoiu, C; Gauthier, L; Gerber, C E; Hamdan, S; Hofman, D J; Khalatyan, S; Kunde, G J; Lacroix, F; Malek, M; O'Brien, C; Silvestre, C; Smoron, A; Strom, D; Varelas, N; Akgun, U; Albayrak, E A; Bilki, B; Clarida, W; Duru, F; Lae, C K; McCliment, E; Merlo, J-P; Mermerkaya, H; Mestvirishvili, A; Moeller, A; Nachtman, J; Newsom, C R; Norbeck, E; Olson, J; Onel, Y; Ozok, F; Sen, S; Wetzel, J; Yetkin, T; Yi, K; Barnett, B A; Blumenfeld, B; Bonato, A; Eskew, C; Fehling, D; Giurgiu, G; Gritsan, A V; Guo, Z J; Hu, G; Maksimovic, P; Rappoccio, S; Swartz, M; Tran, N V; Whitbeck, A; Baringer, P; Bean, A; Benelli, G; Grachov, O; Kenny Iii, R P; Murray, M; Noonan, D; Sanders, S; Wood, J S; Zhukova, V; Barfuss, A f; Bolton, T; Chakaberia, I; Ivanov, A; Khalil, S; Makouski, M; Maravin, Y; Shrestha, S; Svintradze, I; Wan, Z; Gronberg, J; Lange, D; Wright, D; Baden, A; Boutemeur, M; Eno, S C; Ferencek, D; Gomez, J A; Hadley, N J; Kellogg, R G; Kirn, M; Lu, Y; Mignerey, A C; Rossato, K; Rumerio, P; Santanastasio, F; Skuja, A; Temple, J; Tonjes, M B; Tonwar, S C; Twedt, E; Alver, B; Bauer, G; Bendavid, J; Busza, W; Butz, E; Cali, I A; Chan, M; Dutta, V; Everaerts, P; Gomez Ceballos, G; Goncharov, M; Hahn, K A; Harris, P; Kim, Y; Klute, M; Lee, Y-J; Li, W; Loizides, C; Luckey, P D; Ma, T; Nahn, S; Paus, C; Ralph, D; Roland, C; Roland, G; Rudolph, M; Stephans, G S F; Stöckli, F; Sumorok, K; Sung, K; Wenger, E A; Xie, S; Yang, M; Yilmaz, Y; Yoon, A S; Zanetti, M; Cooper, S I; Cushman, P; Dahmes, B; De Benedetti, A; Dudero, P R; Franzoni, G; Haupt, J; Klapoetke, K; Kubota, Y; Mans, J; Rekovic, V; Rusack, R; Sasseville, M; Singovsky, A; Cremaldi, L M; Godang, R; Kroeger, R; Perera, L; Rahmat, R; Sanders, D A; Summers, D; Bloom, K; Bose, S; Butt, J; Claes, D R; Dominguez, A; Eads, M; Keller, J; Kelly, T; Kravchenko, I; Lazo-Flores, J; Malbouisson, H; Malik, S; Snow, G R; Baur, U; Godshalk, A; Iashvili, I; Jain, S; Kharchilava, A; Kumar, A; Shipkowski, S P; Smith, K; Alverson, G; Barberis, E; Baumgartel, D; Boeriu, O; Chasco, M; Reucroft, S; Swain, J; Trocino, D; Wood, D; Zhang, J; 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Lee, S W; Mane, P; Roh, Y; Sill, A; Volobouev, I; Wigmans, R; Yazgan, E; Appelt, E; Brownson, E; Engh, D; Florez, C; Gabella, W; Issah, M; Johns, W; Kurt, P; Maguire, C; Melo, A; Sheldon, P; Snook, B; Tuo, S; Velkovska, J; Arenton, M W; Balazs, M; Boutle, S; Cox, B; Francis, B; Hirosky, R; Ledovskoy, A; Lin, C; Neu, C; Yohay, R; Gollapinni, S; Harr, R; Karchin, P E; Lamichhane, P; Mattson, M; Milstène, C; Sakharov, A; Anderson, M; Bachtis, M; Bellinger, J N; Carlsmith, D; Dasu, S; Efron, J; Flood, K; Gray, L; Grogg, K S; Grothe, M; Hall-Wilton, R; Herndon, M; Klabbers, P; Klukas, J; Lanaro, A; Lazaridis, C; Leonard, J; Loveless, R; Mohapatra, A; Palmonari, F; Reeder, D; Ross, I; Savin, A; Smith, W H; Swanson, J; Weinberg, M

2011-07-08

A first measurement of the polarization of W bosons with large transverse momenta in pp collisions is presented. The measurement is based on 36 pb⁻¹ of data recorded at √s = 7 TeV by the CMS detector at the LHC. The left-handed, right-handed, and longitudinal polarization fractions (f(L), f(R), and f₀, respectively) of W bosons with transverse momenta larger than 50 GeV are determined by using decays to both electrons and muons. The muon final state yields the most precise measurement: (f(L) - f(R))⁻ = 0.240 ± 0.036(stat) ± 0.031(syst) and f₀⁻ = 0.183 ± 0.087(stat) ± 0.123(syst) for negatively charged W bosons and (f(L) - f(R))⁺ = 0.310 ± 0.036(stat) ± 0.017(syst) and f₀⁺ = 0.171 ± 0.085(stat) ± 0.099(syst) for positively charged W bosons. This establishes, for the first time, that W bosons produced in pp collisions with large transverse momenta are predominantly left-handed, as expected in the standard model.

Pion production via proton synchrotron radiation in strong magnetic fields in relativistic field theory: Scaling relations and angular distributions

DOE PAGES

Maruyama, Tomoyuki; Cheoun, Myung-Ki; Kajino, Toshitaka; ...

2016-03-26

We study pion production by proton synchrotron radiation in the presence of a strong magnetic field when the Landau numbers of the initial and final protons are n(i, f) similar to 10(4)-10(5). We find in our relativistic field theory calculations that the pion decay width depends only on the field strength parameter which previously was only conjectured based upon semi-classical arguments. Moreover, we also find new results that the decay width satisfies a robust scaling relation, and that the polar angular distribution of emitted pion momenta is very narrow and can be easily obtained. This scaling implies that one canmore » infer the decay width in more realistic magnetic fields of 10(15) G, where n(i, f) similar to 10(12)-10(13), from the results for n(i, f) similar to 10(4)-10(5). The resultant pion intensity and angular distributions for realistic magnetic field strengths are presented and their physical implications discussed. (C) 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP(3).« less

Quantum Physics

NASA Astrophysics Data System (ADS)

Le Bellac, Michel

2006-03-01

Quantum physics allows us to understand the nature of the physical phenomena which govern the behavior of solids, semi-conductors, lasers, atoms, nuclei, subnuclear particles and light. In Quantum Physics, Le Bellac provides a thoroughly modern approach to this fundamental theory. Throughout the book, Le Bellac teaches the fundamentals of quantum physics using an original approach which relies primarily on an algebraic treatment and on the systematic use of symmetry principles. In addition to the standard topics such as one-dimensional potentials, angular momentum and scattering theory, the reader is introduced to more recent developments at an early stage. These include a detailed account of entangled states and their applications, the optical Bloch equations, the theory of laser cooling and of magneto-optical traps, vacuum Rabi oscillations, and an introduction to open quantum systems. This is a textbook for a modern course on quantum physics, written for advanced undergraduate and graduate students. Completely original and contemporary approach, using algebra and symmetry principles Introduces recent developments at an early stage, including many topics that cannot be found in standard textbooks. Contains 130 physically relevant exercises

Dynamical Causal Modeling from a Quantum Dynamical Perspective

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demiralp, Emre; Demiralp, Metin

Recent research suggests that any set of first order linear vector ODEs can be converted to a set of specific vector ODEs adhering to what we have called ''Quantum Harmonical Form (QHF)''. QHF has been developed using a virtual quantum multi harmonic oscillator system where mass and force constants are considered to be time variant and the Hamiltonian is defined as a conic structure over positions and momenta to conserve the Hermiticity. As described in previous works, the conversion to QHF requires the matrix coefficient of the first set of ODEs to be a normal matrix. In this paper, thismore » limitation is circumvented using a space extension approach expanding the potential applicability of this method. Overall, conversion to QHF allows the investigation of a set of ODEs using mathematical tools available to the investigation of the physical concepts underlying quantum harmonic oscillators. The utility of QHF in the context of dynamical systems and dynamical causal modeling in behavioral and cognitive neuroscience is briefly discussed.« less

Representing and selecting vibrational angular momentum states for quasiclassical trajectory chemical dynamics simulations.

PubMed

Lourderaj, Upakarasamy; Martínez-Núñez, Emilio; Hase, William L

2007-10-18

Linear molecules with degenerate bending modes have states, which may be represented by the quantum numbers N and L. The former gives the total energy for these modes and the latter identifies their vibrational angular momentum jz. In this work, the classical mechanical analog of the N,L-quantum states is reviewed, and an algorithm is presented for selecting initial conditions for these states in quasiclassical trajectory chemical dynamics simulations. The algorithm is illustrated by choosing initial conditions for the N = 3 and L = 3 and 1 states of CO2. Applications of this algorithm are considered for initial conditions without and with zero-point energy (zpe) included in the vibrational angular momentum states and the C-O stretching modes. The O-atom motions in the x,y-plane are determined for these states from classical trajectories in Cartesian coordinates and are compared with the motion predicted by the normal-mode model. They are only in agreement for the N = L = 3 state without vibrational angular momentum zpe. For the remaining states, the Cartesian O-atom motions are considerably different from the elliptical motion predicted by the normal-mode model. This arises from bend-stretch coupling, including centrifugal distortion, in the Cartesian trajectories, which results in tubular instead of elliptical motion. Including zpe in the C-O stretch modes introduces considerable complexity into the O-atom motions for the vibrational angular momentum states. The short-time O-atom motions for these trajectories are highly irregular and do not appear to have any identifiable characteristics. However, the O-atom motions for trajectories integrated for substantially longer period of times acquire unique properties. With C-O stretch zpe included, the long-time O-atom motion becomes tubular for trajectories integrated to approximately 14 ps for the L = 3 states and to approximately 44 ps for the L = 1 states.

Noncommutative quantum mechanics

NASA Astrophysics Data System (ADS)

Gamboa, J.; Loewe, M.; Rojas, J. C.

2001-09-01

A general noncommutative quantum mechanical system in a central potential V=V(r) in two dimensions is considered. The spectrum is bounded from below and, for large values of the anticommutative parameter θ, we find an explicit expression for the eigenvalues. In fact, any quantum mechanical system with these characteristics is equivalent to a commutative one in such a way that the interaction V(r) is replaced by V=V(HHO,Lz), where HHO is the Hamiltonian of the two-dimensional harmonic oscillator and Lz is the z component of the angular momentum. For other finite values of θ the model can be solved by using perturbation theory.

Strange hadron production at low transverse momenta

NASA Astrophysics Data System (ADS)

Veres, Gábor I.; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Noell, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Teng, R.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wyslouch, B.; Zhang, J.

2004-01-01

Some of the latest results of the PHOBOS experiment from the \\sqrt{s_{NN}}= 200\\ GeV Au+Au data are discussed. Those relevant to strangeness production are emphasized. These observations relate to the nature of the matter created when heavy ions collide at the highest achieved energy. The invariant yields of strange and non-strange charged hadrons at very low transverse momentum have been measured, and used to differentiate between different dynamical scenarios. In the intermediate transverse momentum range, the measured ratios of strange and anti-strange kaons approach one, while the antibaryon to baryon ratio is still significantly less, independent of collision centrality and transverse momentum. At high transverse momenta, we find that central and peripheral Au+Au collisions produce similar numbers of charged hadrons per participant nucleon pair, rather than per binary nucleon-nucleon collision. Finally, we describe the upgrades of PHOBOS completed for the 2003 d+Au and p+p run, which extend the transverse momentum range over which particle identification is possible and, at the same time, implement a trigger system selective for high-pT particles.

The transactional interpretation of quantum mechanics

NASA Astrophysics Data System (ADS)

Cramer, John G.

2001-06-01

The transactional interpretation of quantum mechanics [1] was originally published in 1986 and is now about 14 years old. It is an explicitly nonlocal and Lorentz invariant alternative to the Copenhagen interpretation. It interprets the formalism for a quantum interaction as describing a "handshake" between retarded waves (ψ) and advanced waves (ψ*) for each quantum event or "transaction" in which energy, momentum, angular momentum, and other conserved quantities are transferred. The transactional interpretation offers the advantages that (1) it is actually "visible" in the formalism of quantum mechanics, (2) it is economical, involving fewer independent assumptions than its rivals, (3) it is paradox-free, resolving all of the paradoxes of standard quantum theory including nonlocality and wave function collapse, (4) it does not give a privileged role to observers or measurements, and (5) it permits the visualization of quantum events. We will review the transactional interpretation and some of its applications to "quantum paradoxes."

Orbital angular momentum light frequency conversion and interference with quasi-phase matching crystals.

PubMed

Zhou, Zhi-Yuan; Ding, Dong-Sheng; Jiang, Yun-Kun; Li, Yan; Shi, Shuai; Wang, Xi-Shi; Shi, Bao-Sen

2014-08-25

Light with helical phase structures, carrying quantized orbital angular momentum (OAM), has many applications in both classical and quantum optics, such as high-capacity optical communications and quantum information processing. Frequency conversion is a basic technique to expand the frequency range of the fundamental light. The frequency conversion of OAM-carrying light gives rise to new physics and applications such as up-conversion detection of images and generation of high dimensional OAM entanglements. Quasi-phase matching (QPM) nonlinear crystals are good candidates for frequency conversion, particularly due to their high-valued effective nonlinear coefficients and no walk-off effect. Here we report the first experimental second-harmonic generation (SHG) of an OAM-carried light with a QPM crystal, where a UV light with OAM of 100 ℏ is generated. OAM conservation is verified using a specially designed interferometer. With a pump beam carrying an OAM superposition of opposite sign, we observe interesting interference phenomena in the SHG light; specifically, a photonics gear-like structure is obtained that gives direct evidence of OAM conservation, which will be very useful for ultra-sensitive angular measurements. Besides, we also develop a theory to reveal the underlying physics of the phenomena. The methods and theoretical analysis shown here are also applicable to other frequency conversion processes, such as sum frequency generation and difference-frequency generation, and may also be generalized to the quantum regime for single photons.

Experimental test of single-system steering and application to quantum communication

NASA Astrophysics Data System (ADS)

Liu, Zhao-Di; Sun, Yong-Nan; Cheng, Ze-Di; Xu, Xiao-Ye; Zhou, Zong-Quan; Chen, Geng; Li, Chuan-Feng; Guo, Guang-Can

2017-02-01

Einstein-Podolsky-Rosen (EPR) steering describes the ability to steer remotely quantum states of an entangled pair by measuring locally one of its particles. Here we report on an experimental demonstration of single-system steering. The application to quantum communication is also investigated. Single-system steering refers to steering of a single d -dimensional quantum system that can be used in a unifying picture to certify the reliability of tasks employed in both quantum communication and quantum computation. In our experiment, high-dimensional quantum states are implemented by encoding polarization and orbital angular momentum of photons with dimensionality of up to 12.

Optomechanical measurement of photon spin angular momentum and optical torque in integrated photonic devices.

PubMed

He, Li; Li, Huan; Li, Mo

2016-09-01

Photons carry linear momentum and spin angular momentum when circularly or elliptically polarized. During light-matter interaction, transfer of linear momentum leads to optical forces, whereas transfer of angular momentum induces optical torque. Optical forces including radiation pressure and gradient forces have long been used in optical tweezers and laser cooling. In nanophotonic devices, optical forces can be significantly enhanced, leading to unprecedented optomechanical effects in both classical and quantum regimes. In contrast, to date, the angular momentum of light and the optical torque effect have only been used in optical tweezers but remain unexplored in integrated photonics. We demonstrate the measurement of the spin angular momentum of photons propagating in a birefringent waveguide and the use of optical torque to actuate rotational motion of an optomechanical device. We show that the sign and magnitude of the optical torque are determined by the photon polarization states that are synthesized on the chip. Our study reveals the mechanical effect of photon's polarization degree of freedom and demonstrates its control in integrated photonic devices. Exploiting optical torque and optomechanical interaction with photon angular momentum can lead to torsional cavity optomechanics and optomechanical photon spin-orbit coupling, as well as applications such as optomechanical gyroscopes and torsional magnetometry.

Optomechanical measurement of photon spin angular momentum and optical torque in integrated photonic devices

PubMed Central

He, Li; Li, Huan; Li, Mo

2016-01-01

Photons carry linear momentum and spin angular momentum when circularly or elliptically polarized. During light-matter interaction, transfer of linear momentum leads to optical forces, whereas transfer of angular momentum induces optical torque. Optical forces including radiation pressure and gradient forces have long been used in optical tweezers and laser cooling. In nanophotonic devices, optical forces can be significantly enhanced, leading to unprecedented optomechanical effects in both classical and quantum regimes. In contrast, to date, the angular momentum of light and the optical torque effect have only been used in optical tweezers but remain unexplored in integrated photonics. We demonstrate the measurement of the spin angular momentum of photons propagating in a birefringent waveguide and the use of optical torque to actuate rotational motion of an optomechanical device. We show that the sign and magnitude of the optical torque are determined by the photon polarization states that are synthesized on the chip. Our study reveals the mechanical effect of photon’s polarization degree of freedom and demonstrates its control in integrated photonic devices. Exploiting optical torque and optomechanical interaction with photon angular momentum can lead to torsional cavity optomechanics and optomechanical photon spin-orbit coupling, as well as applications such as optomechanical gyroscopes and torsional magnetometry. PMID:27626072

Integral momenta of vortex Bessel-Gaussian beams in turbulent atmosphere.

PubMed

Lukin, Igor P

2016-04-20

The orbital angular momentum of vortex Bessel-Gaussian beams propagating in turbulent atmosphere is studied theoretically. The field of an optical beam is determined through the solution of the paraxial wave equation for a randomly inhomogeneous medium with fluctuations of the refraction index of the turbulent atmosphere. Peculiarities in the behavior of the total power of the vortex Bessel-Gaussian beam at the receiver (or transmitter) are examined. The dependence of the total power of the vortex Bessel-Gaussian beam on optical beam parameters, namely, the transverse wave number of optical radiation, amplitude factor radius, and, especially, topological charge of the optical beam, is analyzed in detail. It turns out that the mean value of the orbital angular momentum of the vortex Bessel-Gaussian beam remains constant during propagation in the turbulent atmosphere. It is shown that the variance of fluctuations of the orbital angular momentum of the vortex Bessel-Gaussian beam propagating in turbulent atmosphere calculated with the "mean-intensity" approximation is equal to zero identically. Thus, it is possible to declare confidently that the variance of fluctuations of the orbital angular momentum of the vortex Bessel-Gaussian beam in turbulent atmosphere is not very large.

Quantum tomography for collider physics: illustrations with lepton-pair production

NASA Astrophysics Data System (ADS)

Martens, John C.; Ralston, John P.; Takaki, J. D. Tapia

2018-01-01

Quantum tomography is a method to experimentally extract all that is observable about a quantum mechanical system. We introduce quantum tomography to collider physics with the illustration of the angular distribution of lepton pairs. The tomographic method bypasses much of the field-theoretic formalism to concentrate on what can be observed with experimental data. We provide a practical, experimentally driven guide to model-independent analysis using density matrices at every step. Comparison with traditional methods of analyzing angular correlations of inclusive reactions finds many advantages in the tomographic method, which include manifest Lorentz covariance, direct incorporation of positivity constraints, exhaustively complete polarization information, and new invariants free from frame conventions. For example, experimental data can determine the entanglement entropy of the production process. We give reproducible numerical examples and provide a supplemental standalone computer code that implements the procedure. We also highlight a property of complex positivity that guarantees in a least-squares type fit that a local minimum of a χ 2 statistic will be a global minimum: There are no isolated local minima. This property with an automated implementation of positivity promises to mitigate issues relating to multiple minima and convention dependence that have been problematic in previous work on angular distributions.

Photonic topological boundary pumping as a probe of 4D quantum Hall physics

NASA Astrophysics Data System (ADS)

Zilberberg, Oded; Huang, Sheng; Guglielmon, Jonathan; Wang, Mohan; Chen, Kevin P.; Kraus, Yaacov E.; Rechtsman, Mikael C.

2018-01-01

When a two-dimensional (2D) electron gas is placed in a perpendicular magnetic field, its in-plane transverse conductance becomes quantized; this is known as the quantum Hall effect. It arises from the non-trivial topology of the electronic band structure of the system, where an integer topological invariant (the first Chern number) leads to quantized Hall conductance. It has been shown theoretically that the quantum Hall effect can be generalized to four spatial dimensions, but so far this has not been realized experimentally because experimental systems are limited to three spatial dimensions. Here we use tunable 2D arrays of photonic waveguides to realize a dynamically generated four-dimensional (4D) quantum Hall system experimentally. The inter-waveguide separation in the array is constructed in such a way that the propagation of light through the device samples over momenta in two additional synthetic dimensions, thus realizing a 2D topological pump. As a result, the band structure has 4D topological invariants (known as second Chern numbers) that support a quantized bulk Hall response with 4D symmetry. In a finite-sized system, the 4D topological bulk response is carried by localized edge modes that cross the sample when the synthetic momenta are modulated. We observe this crossing directly through photon pumping of our system from edge to edge and corner to corner. These crossings are equivalent to charge pumping across a 4D system from one three-dimensional hypersurface to the spatially opposite one and from one 2D hyperedge to another. Our results provide a platform for the study of higher-dimensional topological physics.

Photonic topological boundary pumping as a probe of 4D quantum Hall physics.

PubMed

Zilberberg, Oded; Huang, Sheng; Guglielmon, Jonathan; Wang, Mohan; Chen, Kevin P; Kraus, Yaacov E; Rechtsman, Mikael C

2018-01-03

When a two-dimensional (2D) electron gas is placed in a perpendicular magnetic field, its in-plane transverse conductance becomes quantized; this is known as the quantum Hall effect. It arises from the non-trivial topology of the electronic band structure of the system, where an integer topological invariant (the first Chern number) leads to quantized Hall conductance. It has been shown theoretically that the quantum Hall effect can be generalized to four spatial dimensions, but so far this has not been realized experimentally because experimental systems are limited to three spatial dimensions. Here we use tunable 2D arrays of photonic waveguides to realize a dynamically generated four-dimensional (4D) quantum Hall system experimentally. The inter-waveguide separation in the array is constructed in such a way that the propagation of light through the device samples over momenta in two additional synthetic dimensions, thus realizing a 2D topological pump. As a result, the band structure has 4D topological invariants (known as second Chern numbers) that support a quantized bulk Hall response with 4D symmetry. In a finite-sized system, the 4D topological bulk response is carried by localized edge modes that cross the sample when the synthetic momenta are modulated. We observe this crossing directly through photon pumping of our system from edge to edge and corner to corner. These crossings are equivalent to charge pumping across a 4D system from one three-dimensional hypersurface to the spatially opposite one and from one 2D hyperedge to another. Our results provide a platform for the study of higher-dimensional topological physics.

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Angular Momentum of a Bose-Einstein Condensate in a Synthetic Rotational Field

NASA Astrophysics Data System (ADS)

Qu, Chunlei; Stringari, Sandro

2018-05-01

By applying a position-dependent detuning to a spin-orbit-coupled Hamiltonian with equal Rashba and Dresselhaus coupling, we exploit the behavior of the angular momentum of a harmonically trapped Bose-Einstein condensed atomic gas and discuss the distinctive role of its canonical and spin components. By developing the formalism of spinor hydrodynamics, we predict the precession of the dipole oscillation caused by the synthetic rotational field, in analogy with the precession of the Foucault pendulum, the excitation of the scissors mode, following the sudden switching off of the detuning, and the occurrence of Hall-like effects. When the detuning exceeds a critical value, we observe a transition from a vortex free, rigidly rotating quantum gas to a gas containing vortices with negative circulation which results in a significant reduction of the total angular momentum.

Quantum simulation of 2D topological physics in a 1D array of optical cavities

PubMed Central

Luo, Xi-Wang; Zhou, Xingxiang; Li, Chuan-Feng; Xu, Jin-Shi; Guo, Guang-Can; Zhou, Zheng-Wei

2015-01-01

Orbital angular momentum of light is a fundamental optical degree of freedom characterized by unlimited number of available angular momentum states. Although this unique property has proved invaluable in diverse recent studies ranging from optical communication to quantum information, it has not been considered useful or even relevant for simulating nontrivial physics problems such as topological phenomena. Contrary to this misconception, we demonstrate the incredible value of orbital angular momentum of light for quantum simulation by showing theoretically how it allows to study a variety of important 2D topological physics in a 1D array of optical cavities. This application for orbital angular momentum of light not only reduces required physical resources but also increases feasible scale of simulation, and thus makes it possible to investigate important topics such as edge-state transport and topological phase transition in a small simulator ready for immediate experimental exploration. PMID:26145177

Quantum simulation of 2D topological physics in a 1D array of optical cavities.

PubMed

Luo, Xi-Wang; Zhou, Xingxiang; Li, Chuan-Feng; Xu, Jin-Shi; Guo, Guang-Can; Zhou, Zheng-Wei

2015-07-06

Orbital angular momentum of light is a fundamental optical degree of freedom characterized by unlimited number of available angular momentum states. Although this unique property has proved invaluable in diverse recent studies ranging from optical communication to quantum information, it has not been considered useful or even relevant for simulating nontrivial physics problems such as topological phenomena. Contrary to this misconception, we demonstrate the incredible value of orbital angular momentum of light for quantum simulation by showing theoretically how it allows to study a variety of important 2D topological physics in a 1D array of optical cavities. This application for orbital angular momentum of light not only reduces required physical resources but also increases feasible scale of simulation, and thus makes it possible to investigate important topics such as edge-state transport and topological phase transition in a small simulator ready for immediate experimental exploration.

Manipulating and probing angular momentum and quantized circulation in optical fields and matter waves

NASA Astrophysics Data System (ADS)

Lowney, Joseph Daniel

Methods to generate, manipulate, and measure optical and atomic fields with global or local angular momentum have a wide range of applications in both fundamental physics research and technology development. In optics, the engineering of angular momentum states of light can aid studies of orbital angular momentum (OAM) exchange between light and matter. The engineering of optical angular momentum states can also be used to increase the bandwidth of optical communications or serve as a means to distribute quantum keys, for example. Similar capabilities in Bose-Einstein condensates are being investigated to improve our understanding of superfluid dynamics, superconductivity, and turbulence, the last of which is widely considered to be one of most ubiquitous yet poorly understood subjects in physics. The first part of this two-part dissertation presents an analysis of techniques for measuring and manipulating quantized vortices in BECs. The second part of this dissertation presents theoretical and numerical analyses of new methods to engineer the OAM spectra of optical beams. The superfluid dynamics of a BEC are often well described by a nonlinear Schrodinger equation. The nonlinearity arises from interatomic scattering and enables BECs to support quantized vortices, which have quantized circulation and are fundamental structural elements of quantum turbulence. With the experimental tools to dynamically manipulate and measure quantized vortices, BECs are proving to be a useful medium for testing the theoretical predictions of quantum turbulence. In this dissertation we analyze a method for making minimally destructive in situ observations of quantized vortices in a BEC. Secondly, we numerically study a mechanism to imprint vortex dipoles in a BEC. With these advancements, more robust experiments of vortex dynamics and quantum turbulence will be within reach. A more complete understanding of quantum turbulence will enable principles of microscopic fluid flow to be

Tetraquark resonances computed with static lattice QCD potentials and scattering theory

NASA Astrophysics Data System (ADS)

Bicudo, Pedro; Cardoso, Marco; Peters, Antje; Pflaumer, Martin; Wagner, Marc

2018-03-01

We study tetraquark resonances with lattice QCD potentials computed for two static quarks and two dynamical quarks, the Born-Oppenheimer approximation and the emergent wave method of scattering theory. As a proof of concept we focus on systems with isospin I = 0, but consider different relative angular momenta l of the heavy b quarks. We compute the phase shifts and search for S and T matrix poles in the second Riemann sheet. We predict a new tetraquark resonance for l = 1, decaying into two B mesons, with quantum numbers I(JP) = 0(1-), mass m = 10576-4+4 MeV and decay width Γ = 112-103+90 MeV.

Teleportation of a controllable orbital angular momentum generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen Lixiang; She Weilong

2009-12-15

We report on a teleportation scheme, in which a controllable orbital angular momentum (OAM) generator is teleported. Via our scheme, Alice is able to--according to another independent photon's spin state (polarization) sent by Carol--electrically control the remote OAM generation on Bob's photon. To this end, we introduce a local electrically tunable and spin-dependent OAM generator to transfer a preliminary OAM-OAM entanglement to a spin-OAM hybrid entanglement, which then makes a joint Bell-state measurement on Alice and Carol's photons play its role. We show that the quantum state tomography can be introduced to evaluate the performance of the teleportation.

The Angular Momentum Distribution and Baryon Content of Star-forming Galaxies at z ˜ 1-3

NASA Astrophysics Data System (ADS)

Burkert, A.; Förster Schreiber, N. M.; Genzel, R.; Lang, P.; Tacconi, L. J.; Wisnioski, E.; Wuyts, S.; Bandara, K.; Beifiori, A.; Bender, R.; Brammer, G.; Chan, J.; Davies, R.; Dekel, A.; Fabricius, M.; Fossati, M.; Kulkarni, S.; Lutz, D.; Mendel, J. T.; Momcheva, I.; Nelson, E. J.; Naab, T.; Renzini, A.; Saglia, R.; Sharples, R. M.; Sternberg, A.; Wilman, D.; Wuyts, E.

2016-08-01

We analyze the angular momenta of massive star-forming galaxies (SFGs) at the peak of the cosmic star formation epoch (z ˜ 0.8-2.6). Our sample of ˜360 log(M */M ⊙) ˜ 9.3-11.8 SFGs is mainly based on the KMOS3D and SINS/zC-SINF surveys of Hα kinematics, and collectively provides a representative subset of the massive star-forming population. The inferred halo scale angular momentum distribution is broadly consistent with that theoretically predicted for their dark matter halos, in terms of mean spin parameter < λ > ˜ 0.037 and its dispersion (σ logλ ˜ 0.2). Spin parameters correlate with the disk radial scale and with their stellar surface density, but do not depend significantly on halo mass, stellar mass, or redshift. Our data thus support the long-standing assumption that on average, even at high redshifts, the specific angular momentum of disk galaxies reflects that of their dark matter halos (j d = j DM). The lack of correlation between λ × (j d /j DM) and the nuclear stellar density Σ*(1 kpc) favors a scenario where disk-internal angular momentum redistribution leads to “compaction” inside massive high-redshift disks. For our sample, the inferred average stellar to dark matter mass ratio is ˜2%, consistent with abundance matching results. Including the molecular gas, the total baryonic disk to dark matter mass ratio is ˜5% for halos near 1012 M ⊙, which corresponds to 31% of the cosmologically available baryons, implying that high-redshift disks are strongly baryon dominated. Based on observations obtained at the Very Large Telescope of the European Southern Observatory, Paranal, Chile (ESO Programme IDs 075.A-0466, 076.A-0527, 079.A-0341, 080.A-0330, 080.A-0339, 080.A-0635, 081.B-0568, 081.A-0672, 082.A-0396, 183.A-0781, 087.A-0081, 088.A-0202, 088.A-0209, 091.A-0126, 092.A-0091, 093.A-0079, 094.A-0217, 095.A-0047, 096.A-0025).

Principles of Quantum Mechanics

NASA Astrophysics Data System (ADS)

Landé, Alfred

2013-10-01

Preface; Introduction: 1. Observation and interpretation; 2. Difficulties of the classical theories; 3. The purpose of quantum theory; Part I. Elementary Theory of Observation (Principle of Complementarity): 4. Refraction in inhomogeneous media (force fields); 5. Scattering of charged rays; 6. Refraction and reflection at a plane; 7. Absolute values of momentum and wave length; 8. Double ray of matter diffracting light waves; 9. Double ray of matter diffracting photons; 10. Microscopic observation of ρ (x) and σ (p); 11. Complementarity; 12. Mathematical relation between ρ (x) and σ (p) for free particles; 13. General relation between ρ (q) and σ (p); 14. Crystals; 15. Transition density and transition probability; 16. Resultant values of physical functions; matrix elements; 17. Pulsating density; 18. General relation between ρ (t) and σ (є); 19. Transition density; matrix elements; Part II. The Principle of Uncertainty: 20. Optical observation of density in matter packets; 21. Distribution of momenta in matter packets; 22. Mathematical relation between ρ and σ; 23. Causality; 24. Uncertainty; 25. Uncertainty due to optical observation; 26. Dissipation of matter packets; rays in Wilson Chamber; 27. Density maximum in time; 28. Uncertainty of energy and time; 29. Compton effect; 30. Bothe-Geiger and Compton-Simon experiments; 31. Doppler effect; Raman effect; 32. Elementary bundles of rays; 33. Jeans' number of degrees of freedom; 34. Uncertainty of electromagnetic field components; Part III. The Principle of Interference and Schrödinger's equation: 35. Physical functions; 36. Interference of probabilities for p and q; 37. General interference of probabilities; 38. Differential equations for Ψp (q) and Xq (p); 39. Differential equation for фβ (q); 40. The general probability amplitude Φβ' (Q); 41. Point transformations; 42. General theorem of interference; 43. Conjugate variables; 44. Schrödinger's equation for conservative systems; 45. Schr

The angular electronic band structure and free particle model of aromatic molecules: High-frequency photon-induced ring current

NASA Astrophysics Data System (ADS)

Öncan, Mehmet; Koç, Fatih; Şahin, Mehmet; Köksal, Koray

2017-05-01

This work introduces an analysis of the relationship of first-principles calculations based on DFT method with the results of free particle model for ring-shaped aromatic molecules. However, the main aim of the study is to reveal the angular electronic band structure of the ring-shaped molecules. As in the case of spherical molecules such as fullerene, it is possible to observe a parabolic dispersion of electronic states with the variation of angular quantum number in the planar ring-shaped molecules. This work also discusses the transition probabilities between the occupied and virtual states by analyzing the angular electronic band structure and the possibility of ring currents in the case of spin angular momentum (SAM) or orbital angular momentum (OAM) carrying light. Current study focuses on the benzene molecule to obtain its angular electronic band structure. The obtained electronic band structure can be considered as a useful tool to see the transition probabilities between the electronic states and possible contribution of the states to the ring currents. The photoinduced current due to the transfer of SAM into the benzene molecule has been investigated by using analytical calculations within the frame of time-dependent perturbation theory.

Towards conformal loop quantum gravity

NASA Astrophysics Data System (ADS)

H-T Wang, Charles

2006-03-01

A discussion is given of recent developments in canonical gravity that assimilates the conformal analysis of gravitational degrees of freedom. The work is motivated by the problem of time in quantum gravity and is carried out at the metric and the triad levels. At the metric level, it is shown that by extending the Arnowitt-Deser-Misner (ADM) phase space of general relativity (GR), a conformal form of geometrodynamics can be constructed. In addition to the Hamiltonian and Diffeomorphism constraints, an extra first class constraint is introduced to generate conformal transformations. This phase space consists of York's mean extrinsic curvature time, conformal three-metric and their momenta. At the triad level, the phase space of GR is further enlarged by incorporating spin-gauge as well as conformal symmetries. This leads to a canonical formulation of GR using a new set of real spin connection variables. The resulting gravitational constraints are first class, consisting of the Hamiltonian constraint and the canonical generators for spin-gauge and conformorphism transformations. The formulation has a remarkable feature of being parameter-free. Indeed, it is shown that a conformal parameter of the Barbero-Immirzi type can be absorbed by the conformal symmetry of the extended phase space. This gives rise to an alternative approach to loop quantum gravity that addresses both the conceptual problem of time and the technical problem of functional calculus in quantum gravity.

Triple coupling and parameter resonance in quantum optomechanics with a single atom

NASA Astrophysics Data System (ADS)

Chang, Yue; Ian, H.; Sun, C. P.

2009-11-01

We study the energy level structure and quantum dynamics for a cavity optomechanical system assisted by a single atom. It is found that a triple coupling involving a photon, a phonon and an atom cannot be described only by the quasi-orbital angular momentum at frequency resonance, there also exists the phenomenon of parameter resonance, namely, when the system parameters are matched in some way, the evolution of the end mirror of the cavity is conditioned by the dressed states of the photon-atom subsystem. The quantum decoherence due to this conditional dynamics is studied in detail. In the quasi-classical limit of very large angular momentum, this system will behave like a standard cavity-QED system described by the Jaynes-Cummings (J-C) model when the angular momentum operators are transformed to bosonic operators of a single mode. We test this observation with an experimentally accessible parameter.

Wigner Distribution for Angle Coordinates in Quantum Mechanics.

ERIC Educational Resources Information Center

Mukunda, N.

1979-01-01

Shows how to extend Wigner distribution functions, and Weyl correspondence between quantum and classical variables, from the usual kind of canonically conjugate position and momentum operators to the case of an angle and angular momentum operator pair. (Author/GA)

Relocking of intrinsic angular momenta in collisions of diatoms with ions: Capture of H2(j = 0,1) by H2+

NASA Astrophysics Data System (ADS)

Dashevskaya, E. I.; Litvin, I.; Nikitin, E. E.; Troe, J.

2016-12-01

Rate coefficients for capture of H2(j = 0,1) by H2+ are calculated in perturbed rotor approximation, i.e., at collision energies considerably lower than Bhc (where B denotes the rotational constant of H2). The results are compared with the results from an axially nonadiabatic channel (ANC) approach, the latter providing a very good approximation from the low-temperature Bethe-Wigner to the high temperature Langevin limit. The classical ANC approximation performs satisfactorily at temperatures above 0.1 K. At 0.1 K, the rate coefficient for j =1 is about 25% higher than that for j = 0 while the latter is close to the Langevin rate coefficient. The Bethe-Wigner limit of the rate coefficient for j = 1 is about twice that for j = 0. The analysis of the relocking of the intrinsic angular momentum of H2 during the course of the collision illustrates the significance of relocking in capture dynamics in general.

Realizing Rec. 2020 color gamut with quantum dot displays.

PubMed

Zhu, Ruidong; Luo, Zhenyue; Chen, Haiwei; Dong, Yajie; Wu, Shin-Tson

2015-09-07

We analyze how to realize Rec. 2020 wide color gamut with quantum dots. For photoluminescence, our simulation indicates that we are able to achieve over 97% of the Rec. 2020 standard with quantum dots by optimizing the emission spectra and redesigning the color filters. For electroluminescence, by optimizing the emission spectra of quantum dots is adequate to render over 97% of the Rec. 2020 standard. We also analyze the efficiency and angular performance of these devices, and then compare results with LCDs using green and red phosphors-based LED backlight. Our results indicate that quantum dot display is an outstanding candidate for achieving wide color gamut and high optical efficiency.

Uncertainty relations for angular momentum eigenstates in two and three spatial dimensions

NASA Astrophysics Data System (ADS)

Bracher, Christian

2011-03-01

I reexamine Heisenberg's uncertainty relation for two- and three-dimensional wave packets with fixed angular momentum quantum numbers m or ℓ. A simple proof shows that the product of the average extent Δr and Δp of a two-dimensional wave packet in position and momentum space is bounded from below by ΔrΔp ≥ℏ(|m|+1). The minimum uncertainty is attained by modified Gaussian wave packets that are special eigenstates of the two-dimensional isotropic harmonic oscillator, which include the ground states of electrons in a uniform magnetic field. Similarly, the inequality ΔrΔp ≥ℏ(ℓ +3/2) holds for three-dimensional wave packets with fixed total angular momentum ℓ and the equality holds for a Gaussian radial profile. I also discuss some applications of these uncertainty relations.

Mean transverse momenta correlations in hadron-hadron collisions in MC toy model with repulsing strings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Altsybeev, Igor

2016-01-22

In the present work, Monte-Carlo toy model with repulsing quark-gluon strings in hadron-hadron collisions is described. String repulsion creates transverse boosts for the string decay products, giving modifications of observables. As an example, long-range correlations between mean transverse momenta of particles in two observation windows are studied in MC toy simulation of the heavy-ion collisions.

Higher order explicit symmetric integrators for inseparable forms of coordinates and momenta

NASA Astrophysics Data System (ADS)

Liu, Lei; Wu, Xin; Huang, Guoqing; Liu, Fuyao

2016-06-01

Pihajoki proposed the extended phase-space second-order explicit symmetric leapfrog methods for inseparable Hamiltonian systems. On the basis of this work, we survey a critical problem on how to mix the variables in the extended phase space. Numerical tests show that sequent permutations of coordinates and momenta can make the leapfrog-like methods yield the most accurate results and the optimal long-term stabilized error behaviour. We also present a novel method to construct many fourth-order extended phase-space explicit symmetric integration schemes. Each scheme represents the symmetric production of six usual second-order leapfrogs without any permutations. This construction consists of four segments: the permuted coordinates, triple product of the usual second-order leapfrog without permutations, the permuted momenta and the triple product of the usual second-order leapfrog without permutations. Similarly, extended phase-space sixth, eighth and other higher order explicit symmetric algorithms are available. We used several inseparable Hamiltonian examples, such as the post-Newtonian approach of non-spinning compact binaries, to show that one of the proposed fourth-order methods is more efficient than the existing methods; examples include the fourth-order explicit symplectic integrators of Chin and the fourth-order explicit and implicit mixed symplectic integrators of Zhong et al. Given a moderate choice for the related mixing and projection maps, the extended phase-space explicit symplectic-like methods are well suited for various inseparable Hamiltonian problems. Samples of these problems involve the algorithmic regularization of gravitational systems with velocity-dependent perturbations in the Solar system and post-Newtonian Hamiltonian formulations of spinning compact objects.

Electroweak corrections to hadronic production of W bosons at large transverse momenta

NASA Astrophysics Data System (ADS)

Kühn, Johann H.; Kulesza, A.; Pozzorini, S.; Schulze, M.

2008-07-01

To match the precision of present and future measurements of W-boson production at hadron colliders electroweak radiative corrections must be included in the theory predictions. In this paper we consider their effect on the transverse momentum ( p) distribution of W bosons, with emphasis on large p. We evaluate the full electroweak O(α) corrections to the processes pp→W+jet and pp¯→W+jet including virtual and real photonic contributions. We present the explicit expressions in analytical form for the virtual corrections and provide results for the real corrections, discussing in detail the treatment of soft and collinear singularities. We also provide compact approximate expressions which are valid in the high-energy region, where the electroweak corrections are strongly enhanced by logarithms of sˆ/MW2. These expressions describe the complete asymptotic behaviour at one loop as well as the leading and next-to-leading logarithms at two loops. Numerical results are presented for proton-proton collisions at 14 TeV and proton-antiproton collisions at 2 TeV. The corrections are negative and their size increases with p. At the LHC, where transverse momenta of 2 TeV or more can be reached, the one- and two-loop corrections amount up to -40% and +10%, respectively, and will be important for a precise analysis of W production. At the Tevatron, transverse momenta up to 300 GeV are within reach. In this case the electroweak corrections amount up to -10% and are thus larger than the expected statistical error.

Thermal stability of charged rotating quantum black holes

NASA Astrophysics Data System (ADS)

Sinha, Aloke Kumar; Majumdar, Parthasarathi

2017-12-01

Criteria for thermal stability of charged rotating black holes of any dimension are derived for horizon areas that are large relative to the Planck area (in these dimensions). The derivation is based on generic assumptions of quantum geometry, supported by some results of loop quantum gravity, and equilibrium statistical mechanics of the Grand Canonical ensemble. There is no explicit use of classical spacetime geometry in this analysis. The only assumption is that the mass of the black hole is a function of its horizon area, charge and angular momentum. Our stability criteria are then tested in detail against specific classical black holes in spacetime dimensions 4 and 5, whose metrics provide us with explicit relations for the dependence of the mass on the charge and angular momentum of the black holes. This enables us to predict which of these black holes are expected to be thermally unstable under Hawking radiation.

Quantum Monte Carlo methods for nuclear physics

DOE PAGES

Carlson, Joseph A.; Gandolfi, Stefano; Pederiva, Francesco; ...

2014-10-19

Quantum Monte Carlo methods have proved very valuable to study the structure and reactions of light nuclei and nucleonic matter starting from realistic nuclear interactions and currents. These ab-initio calculations reproduce many low-lying states, moments and transitions in light nuclei, and simultaneously predict many properties of light nuclei and neutron matter over a rather wide range of energy and momenta. We review the nuclear interactions and currents, and describe the continuum Quantum Monte Carlo methods used in nuclear physics. These methods are similar to those used in condensed matter and electronic structure but naturally include spin-isospin, tensor, spin-orbit, and three-bodymore » interactions. We present a variety of results including the low-lying spectra of light nuclei, nuclear form factors, and transition matrix elements. We also describe low-energy scattering techniques, studies of the electroweak response of nuclei relevant in electron and neutrino scattering, and the properties of dense nucleonic matter as found in neutron stars. A coherent picture of nuclear structure and dynamics emerges based upon rather simple but realistic interactions and currents.« less

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Three-particle hyper-entanglement: teleportation and quantum key distribution

NASA Astrophysics Data System (ADS)

Perumangatt, Chithrabhanu; Abdul Rahim, Aadhi; Salla, Gangi Reddy; Prabhakar, Shashi; Samanta, Goutam Kumar; Paul, Goutam; Singh, Ravindra Pratap

2015-10-01

We present a scheme to generate three-particle hyper-entanglement utilizing polarization and orbital angular momentum (OAM) of photons. We show that the generated state can be used to teleport a two-qubit state described by the polarization and the OAM. The proposed quantum system has also been used to describe a new efficient quantum key distribution (QKD) protocol. We give a sketch of the experimental arrangement to realize the proposed teleportation and the QKD.

Non-adiabatic molecular dynamics with complex quantum trajectories. I. The diabatic representation.

PubMed

Zamstein, Noa; Tannor, David J

2012-12-14

We extend a recently developed quantum trajectory method [Y. Goldfarb, I. Degani, and D. J. Tannor, J. Chem. Phys. 125, 231103 (2006)] to treat non-adiabatic transitions. Each trajectory evolves on a single surface according to Newton's laws with complex positions and momenta. The transfer of amplitude between surfaces stems naturally from the equations of motion, without the need for surface hopping. In this paper we derive the equations of motion and show results in the diabatic representation, which is rarely used in trajectory methods for calculating non-adiabatic dynamics. We apply our method to the first two benchmark models introduced by Tully [J. Chem. Phys. 93, 1061 (1990)]. Besides giving the probability branching ratios between the surfaces, the method also allows the reconstruction of the time-dependent wavepacket. Our results are in quantitative agreement with converged quantum mechanical calculations.

Single-atom edgelike states via quantum interference

NASA Astrophysics Data System (ADS)

Pelegrí, G.; Polo, J.; Turpin, A.; Lewenstein, M.; Mompart, J.; Ahufinger, V.

2017-01-01

We demonstrate how quantum interference may lead to the appearance of robust edgelike states of a single ultracold atom in a two-dimensional optical ribbon. We show that these states can be engineered within the manifold of either local ground states of the sites forming the ribbon or states carrying one unit of angular momentum. In the former case, we show that the implementation of edgelike states can be extended to other geometries, such as tilted square lattices. In the latter case, we suggest using the winding number associated to the angular momentum as a synthetic dimension.

Quantum teleportation in the spin-orbit variables of photon pairs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khoury, A. Z.; Milman, P.; Laboratoire Materiaux et Phenomenes Quantiques, CNRS UMR 7162, Universite Paris Diderot, F-75013, Paris

2011-06-15

We propose a polarization to orbital angular momentum teleportation scheme using entangled photon pairs generated by spontaneous parametric down-conversion. By making a joint detection of the polarization and angular momentum parity of a single photon, we are able to detect all the Bell states and perform, in principle, perfect teleportation from a discrete to a continuous system using minimal resources. The proposed protocol implementation demands experimental resources that are currently available in quantum optics laboratories.

Trajectories of electrons with large longitudinal momenta in the phase plane during surfatron acceleration by an electromagnetic wave

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mkrtichyan, G. S., E-mail: hay-13@mail.ru

2015-07-15

The trajectories of electrons with large longitudinal momenta in the phase plane in the course of their surfatron acceleration by an electromagnetic wave propagating in space plasma across the external magnetic field are analyzed. Electrons with large longitudinal momenta are trapped immediately if the initial wave phase Ψ(0) on the particle trajectory is positive. For negative values of Ψ(0), no electrons trapping by the wave is observed over the available computational times. According to numerical calculations, the trajectories of trapped particles in the phase plane have a singular point of the stable focus type and the behavior of the trajectorymore » corresponds to the motion in a complex nonstationary effective potential well. For some initial phases, electrons are confined in the region of the accelerating electric field for relatively short time, the energy gain being about 50–130% and more.« less

Quantum Dynamics of Multi Harmonic Oscillators Described by Time Variant Conic Hamiltonian and their Use in Contemporary Sciences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demiralp, Metin

This work focuses on the dynamics of a system of quantum multi harmonic oscillators whose Hamiltonian is conic in positions and momenta with time variant coefficients. While it is simple, this system is useful for modeling the dynamics of a number of systems in contemporary sciences where the equations governing spatial or temporal changes are described by sets of ODEs. The dynamical causal models used readily in neuroscience can be indirectly described by these systems. In this work, we want to show that it is possible to describe these systems using quantum wave function type entities and expectations if themore » dynamic of the system is related to a set of ODEs.« less

Large angular scale CMB anisotropy from an excited initial mode

NASA Astrophysics Data System (ADS)

Sojasi, A.; Mohsenzadeh, M.; Yusofi, E.

2016-07-01

According to inflationary cosmology, the CMB anisotropy gives an opportunity to test predictions of new physics hypotheses. The initial state of quantum fluctuations is one of the important options at high energy scale, as it can affect observables such as the CMB power spectrum. In this study a quasi-de Sitter inflationary background with approximate de Sitter mode function built over the Bunch-Davies mode is applied to investigate the scale-dependency of the CMB anisotropy. The recent Planck constraint on spectral index motivated us to examine the effect of a new excited mode function (instead of pure de Sitter mode) on the CMB anisotropy at large angular scales. In so doing, it is found that the angular scale-invariance in the CMB temperature fluctuations is broken and in the limit ℓ < 200 a tiny deviation appears. Also, it is shown that the power spectrum of CMB anisotropy is dependent on a free parameter with mass dimension H << M * < M p and on the slow-roll parameter ɛ. Supported by the Islamic Azad University, Rasht Branch, Rasht, Iran

Coherent control of photoelectron wavepacket angular interferograms

NASA Astrophysics Data System (ADS)

Hockett, P.; Wollenhaupt, M.; Baumert, T.

2015-11-01

Coherent control over photoelectron wavepackets, via the use of polarization-shaped laser pulses, can be understood as a time and polarization-multiplexed process, where the final (time-integrated) observable coherently samples all instantaneous states of the light-matter interaction. In this work, we investigate this multiplexing via computation of the observable photoelectron angular interferograms resulting from multi-photon atomic ionization with polarization-shaped laser pulses. We consider the polarization sensitivity of both the instantaneous and cumulative continuum wavefunction; the nature of the coherent control over the resultant photoelectron interferogram is thus explored in detail. Based on this understanding, the use of coherent control with polarization-shaped pulses as a methodology for a highly multiplexed coherent quantum metrology is also investigated, and defined in terms of the information content of the observable.

Semiclassical analysis of angular differential cross sections for single-electron capture in 250-eV H++H collisions

NASA Astrophysics Data System (ADS)

Frémont, F.

2015-05-01

A classical model based on the resolution of Hamilton equations of motion is used to determine the angular distribution of H projectiles following single-electron capture in H++H collisions at an incident projectile energy of 250 eV. At such low energies, the experimental charge-exchange probability and angular differential cross sections exhibit oscillatory structures that are classically related to the number of swaps the electron experiences between the target and the projectile during the collision. These oscillations are well reproduced by models based on quantum mechanics. In the present paper, the angular distribution of H projectiles is determined classically, at angles varying from 0.1° up to 7°. The variation in intensity due to interferences caused by the indiscernibility between different trajectories is calculated, and the role of these interferences is discussed.

Teleporting photonic qudits using multimode quantum scissors.

PubMed

Goyal, Sandeep K; Konrad, Thomas

2013-12-19

Teleportation plays an important role in the communication of quantum information between the nodes of a quantum network and is viewed as an essential ingredient for long-distance Quantum Cryptography. We describe a method to teleport the quantum information carried by a photon in a superposition of a number d of light modes (a "qudit") by the help of d additional photons based on transcription. A qudit encoded into a single excitation of d light modes (in our case Laguerre-Gauss modes which carry orbital angular momentum) is transcribed to d single-rail photonic qubits, which are spatially separated. Each single-rail qubit consists of a superposition of vacuum and a single photon in each one of the modes. After successful teleportation of each of the d single-rail qubits by means of "quantum scissors" they are converted back into a qudit carried by a single photon which completes the teleportation scheme.

Teleporting photonic qudits using multimode quantum scissors

NASA Astrophysics Data System (ADS)

Goyal, Sandeep K.; Konrad, Thomas

2013-12-01

Teleportation plays an important role in the communication of quantum information between the nodes of a quantum network and is viewed as an essential ingredient for long-distance Quantum Cryptography. We describe a method to teleport the quantum information carried by a photon in a superposition of a number d of light modes (a ``qudit'') by the help of d additional photons based on transcription. A qudit encoded into a single excitation of d light modes (in our case Laguerre-Gauss modes which carry orbital angular momentum) is transcribed to d single-rail photonic qubits, which are spatially separated. Each single-rail qubit consists of a superposition of vacuum and a single photon in each one of the modes. After successful teleportation of each of the d single-rail qubits by means of ``quantum scissors'' they are converted back into a qudit carried by a single photon which completes the teleportation scheme.

Angular-domain scattering interferometry.

PubMed

Shipp, Dustin W; Qian, Ruobing; Berger, Andrew J

2013-11-15

We present an angular-scattering optical method that is capable of measuring the mean size of scatterers in static ensembles within a field of view less than 20 μm in diameter. Using interferometry, the method overcomes the inability of intensity-based models to tolerate the large speckle grains associated with such small illumination areas. By first estimating each scatterer's location, the method can model between-scatterer interference as well as traditional single-particle Mie scattering. Direct angular-domain measurements provide finer angular resolution than digitally transformed image-plane recordings. This increases sensitivity to size-dependent scattering features, enabling more robust size estimates. The sensitivity of these angular-scattering measurements to various sizes of polystyrene beads is demonstrated. Interferometry also allows recovery of the full complex scattered field, including a size-dependent phase profile in the angular-scattering pattern.

Investigating and Improving Student Understanding of Key Ideas in Quantum Mechanics throughout Instruction

NASA Astrophysics Data System (ADS)

Emigh, Paul Jeffrey

This dissertation describes research on student understanding of quantum mechanics across multiple levels of instruction. The primary focus has been to identify patterns in student reasoning related to key concepts in quantum mechanics. The specific topics include quantum measurements, time dependence, vector spaces, and angular momentum. The research has spanned a variety of different quantum courses intended for introductory physics students, upper-division physics majors, and graduate students in physics. The results of this research have been used to develop a set of curriculum, Tutorials in Physics: Quantum Mechanics, for addressing the most persistent student difficulties. We document both the development of this curriculum and how it has impacted and improved student understanding of quantum mechanics.

Quantum entropy and uncertainty for two-mode squeezed, coherent and intelligent spin states

NASA Technical Reports Server (NTRS)

Aragone, C.; Mundarain, D.

1993-01-01

We compute the quantum entropy for monomode and two-mode systems set in squeezed states. Thereafter, the quantum entropy is also calculated for angular momentum algebra when the system is either in a coherent or in an intelligent spin state. These values are compared with the corresponding values of the respective uncertainties. In general, quantum entropies and uncertainties have the same minimum and maximum points. However, for coherent and intelligent spin states, it is found that some minima for the quantum entropy turn out to be uncertainty maxima. We feel that the quantum entropy we use provides the right answer, since it is given in an essentially unique way.

Dynamic approach to description of entrance channel effects in angular distributions of fission fragments

NASA Astrophysics Data System (ADS)

Eremenko, D. O.; Drozdov, V. A.; Fotina, O. V.; Platonov, S. Yu.; Yuminov, O. A.

2016-07-01

Background: It is well known that the anomalous behavior of angular anisotropies of fission fragments at sub- and near-barrier energies is associated with a memory of conditions in the entrance channel of the heavy-ion reactions, particularly, deformations and spins of colliding nuclei that determine the initial distributions for the components of the total angular momentum over the symmetry axis of the fissioning system and the beam axis. Purpose: We develop a new dynamic approach, which allows the description of the memory effects in the fission fragment angular distributions and provides new information on fusion and fission dynamics. Methods: The approach is based on the dynamic model of the fission fragment angular distributions which takes into account stochastic aspects of nuclear fission and thermal fluctuations for the tilting mode that is characterized by the projection of the total angular momentum onto the symmetry axis of the fissioning system. Another base of our approach is the quantum mechanical method to calculate the initial distributions over the components of the total angular momentum of the nuclear system immediately following complete fusion. Results: A method is suggested for calculating the initial distributions of the total angular momentum projection onto the symmetry axis for the nuclear systems formed in the reactions of complete fusion of deformed nuclei with spins. The angular distributions of fission fragments for the 16O+232Th,12C+235,236,238, and 13C+235U reactions have been analyzed within the dynamic approach over a range of sub- and above-barrier energies. The analysis allowed us to determine the relaxation time for the tilting mode and the fraction of fission events occurring in times not larger than the relaxation time for the tilting mode. Conclusions: It is shown that the memory effects play an important role in the formation of the angular distributions of fission fragments for the reactions induced by heavy ions. The

Studies of quantum dots in the quantum Hall regime

NASA Astrophysics Data System (ADS)

Goldmann, Eyal

We present two studies of quantum dots in the quantum Hall regime. In the first study, presented in Chapter 3, we investigate the edge reconstruction phenomenon believed to occur when the quantum dot filling fraction is n≲1 . Our approach involves the examination of large dots (≤40 electrons) using a partial diagonalization technique in which the occupancies of the deep interior orbitals are frozen. To interpret the results of this calculation, we evaluate the overlap between the diagonalized ground state and a set of trial wavefunctions which we call projected necklace (PN) states. A PN state is simply the angular momentum projection of a maximum density droplet surrounded by a ring of localized electrons. Our calculations reveal that PN states have up to 99% overlap with the diagonalized ground states, and are lower in energy than the states identified in Chamon and Wen's study of the edge reconstruction. In the second study, presented in Chapter 4, we investigate quantum dots in the fractional quantum Hall regime using a Hartree formulation of composite fermion theory. We find that under appropriate conditions, the chemical potential of the dots oscillates periodically with B due to the transfer of composite fermions between quasi-Landau bands. This effect is analogous the addition spectrum oscillations which occur in quantum dots in the integer quantum Hall regime. Period f0 oscillations are found in sharply confined dots with filling factors nu = 2/5 and nu = 2/3. Period 3 f0 oscillations are found in a parabolically confined nu = 2/5 dot. More generally, we argue that the oscillation period of dots with band pinning should vary continuously with B, whereas the period of dots without band pinning is f0 .

Quantum scattering beyond the plane-wave approximation

NASA Astrophysics Data System (ADS)

Karlovets, Dmitry

2017-12-01

While a plane-wave approximation in high-energy physics works well in a majority of practical cases, it becomes inapplicable for scattering of the vortex particles carrying orbital angular momentum, of Airy beams, of the so-called Schrödinger cat states, and their generalizations. Such quantum states of photons, electrons and neutrons have been generated experimentally in recent years, opening up new perspectives in quantum optics, electron microscopy, particle physics, and so forth. Here we discuss the non-plane-wave effects in scattering brought about by the novel quantum numbers of these wave packets. For the well-focused electrons of intermediate energies, already available at electron microscopes, the corresponding contribution can surpass that of the radiative corrections. Moreover, collisions of the cat-like superpositions of such focused beams with atoms allow one to probe effects of the quantum interference, which have never played any role in particle scattering.

Factors influencing perceived angular velocity.

PubMed

Kaiser, M K; Calderone, J B

1991-11-01

The assumption that humans are able to perceive and process angular kinematics is critical to many structure-from-motion and optical flow models. The current studies investigate this sensitivity, and examine several factors likely to influence angular velocity perception. In particular, three factors are considered: (1) the extent to which perceived angular velocity is determined by edge transitions of surface elements, (2) the extent to which angular velocity estimates are influenced by instantaneous linear velocities of surface elements, and (3) whether element-velocity effects are related to three-dimensional (3-D) tangential velocities or to two-dimensional (2-D) image velocities. Edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities influenced perceived angular velocity; this bias was related to 2-D image velocity rather than 3-D tangential velocity. Despite these biases, however, judgments were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter was surprisingly good, for rotations both in depth (y-axis) and parallel to the line of sight (z-axis).

Engineering two-photon high-dimensional states through quantum interference

PubMed Central

Zhang, Yingwen; Roux, Filippus S.; Konrad, Thomas; Agnew, Megan; Leach, Jonathan; Forbes, Andrew

2016-01-01

Many protocols in quantum science, for example, linear optical quantum computing, require access to large-scale entangled quantum states. Such systems can be realized through many-particle qubits, but this approach often suffers from scalability problems. An alternative strategy is to consider a lesser number of particles that exist in high-dimensional states. The spatial modes of light are one such candidate that provides access to high-dimensional quantum states, and thus they increase the storage and processing potential of quantum information systems. We demonstrate the controlled engineering of two-photon high-dimensional states entangled in their orbital angular momentum through Hong-Ou-Mandel interference. We prepare a large range of high-dimensional entangled states and implement precise quantum state filtering. We characterize the full quantum state before and after the filter, and are thus able to determine that only the antisymmetric component of the initial state remains. This work paves the way for high-dimensional processing and communication of multiphoton quantum states, for example, in teleportation beyond qubits. PMID:26933685

Energy Weighted Angular Correlations Between Hadrons Produced in Electron-Positron Annihilation.

NASA Astrophysics Data System (ADS)

Strharsky, Roger Joseph

Electron-positron annihilation at large center of mass energy produces many hadronic particles. Experimentalists then measure the energies of these particles in calorimeters. This study investigated correlations between the angular locations of one or two such calorimeters and the angular orientation of the electron beam in the laboratory frame of reference. The calculation of these correlations includes weighting by the fraction of the total center of mass energy which the calorimeter measures. Starting with the assumption that the reaction proceeeds through the intermediate production of a single quark/anti-quark pair, a simple statistical model was developed to provide a phenomenological description of the distribution of final state hadrons. The model distributions were then used to calculate the one- and two-calorimeter correlation functions. Results of these calculations were compared with available data and several predictions were made for those quantities which had not yet been measured. Failure of the model to reproduce all of the data was discussed in terms of quantum chromodynamics, a fundamental theory which includes quark interactions.

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Quantum Monte Carlo methods for nuclear physics

DOE PAGES

Carlson, J.; Gandolfi, S.; Pederiva, F.; ...

2015-09-09

Quantum Monte Carlo methods have proved valuable to study the structure and reactions of light nuclei and nucleonic matter starting from realistic nuclear interactions and currents. These ab-initio calculations reproduce many low-lying states, moments, and transitions in light nuclei, and simultaneously predict many properties of light nuclei and neutron matter over a rather wide range of energy and momenta. The nuclear interactions and currents are reviewed along with a description of the continuum quantum Monte Carlo methods used in nuclear physics. These methods are similar to those used in condensed matter and electronic structure but naturally include spin-isospin, tensor, spin-orbit,more » and three-body interactions. A variety of results are presented, including the low-lying spectra of light nuclei, nuclear form factors, and transition matrix elements. Low-energy scattering techniques, studies of the electroweak response of nuclei relevant in electron and neutrino scattering, and the properties of dense nucleonic matter as found in neutron stars are also described. Furthermore, a coherent picture of nuclear structure and dynamics emerges based upon rather simple but realistic interactions and currents.« less

Study of jet transverse momentum and jet rapidity dependence of dijet azimuthal decorrelations with the DO detector

NASA Astrophysics Data System (ADS)

Chakravarthula, Kiran

In a collision experiment involving highly energetic particles such as hadrons, processes at high momentum transfers can provide information useful for many studies involving Quantum Chromodynamics (QCD). One way of analyzing these interactions is through angular distributions. In hadron-hadron collisions, the angular distribution between the two leading jets with the largest transverse momentum (pT) is affected by the production of additional jets. While soft radiation causes small differences in the azimuthal angular distribution of the two leading jets produced in a collision event, additional hard jets produced in the event have more pronounced influence on the distribution of the two leading jets produced in the collision. Thus, the dijet azimuthal angular distribution can serve as a variable that can be used to study the transition from soft to hard QCD processes in a collision event. This dissertation presents a triple-differential study involving the azimuthal angular distribution and the jet transverse momenta, and jet rapidities of the first two leading jets. The data used for this research are obtained from proton-antiproton (pp¯) collisions occurring at a center of mass energy of 1.96 TeV, using the DØ detector in Run II of the Tevatron Collider at the Fermi National Accelerator Laboratory (FNAL) in Illinois, USA. Comparisons are made to perturbative QCD (pQCD) predictions at next-to-leading order (NLO).

Self-healing of quantum entanglement after an obstruction.

PubMed

McLaren, Melanie; Mhlanga, Thandeka; Padgett, Miles J; Roux, Filippus S; Forbes, Andrew

2014-01-01

Quantum entanglement between photon pairs is fragile and can easily be masked by losses in transmission path and noise in the detection system. When observing the quantum entanglement between the spatial states of photon pairs produced by parametric down-conversion, the presence of an obstruction introduces losses that can mask the correlations associated with the entanglement. Here we show that we can overcome these losses by measuring in the Bessel basis, thus once again revealing the entanglement after propagation beyond the obstruction. We confirm that, for the entanglement of orbital angular momentum, measurement in the Bessel basis is more robust to these losses than measuring in the usually employed Laguerre-Gaussian basis. Our results show that appropriate choice of measurement basis can overcome some limitations of the transmission path, perhaps offering advantages in free-space quantum communication or quantum processing systems.

Topological photonic orbital-angular-momentum switch

NASA Astrophysics Data System (ADS)

Luo, Xi-Wang; Zhang, Chuanwei; Guo, Guang-Can; Zhou, Zheng-Wei

2018-04-01

The large number of available orbital-angular-momentum (OAM) states of photons provides a unique resource for many important applications in quantum information and optical communications. However, conventional OAM switching devices usually rely on precise parameter control and are limited by slow switching rate and low efficiency. Here we propose a robust, fast, and efficient photonic OAM switch device based on a topological process, where photons are adiabatically pumped to a target OAM state on demand. Such topological OAM pumping can be realized through manipulating photons in a few degenerate main cavities and involves only a limited number of optical elements. A large change of OAM at ˜10q can be realized with only q degenerate main cavities and at most 5 q pumping cycles. The topological photonic OAM switch may become a powerful device for broad applications in many different fields and motivate a topological design of conventional optical devices.

Spatial Quantum Beats in Vibrational Resonant Inelastic Soft X-Ray Scattering at Dissociating States in Oxygen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pietzsch, A.; Kennedy, B.; Sun, Y.-P.

2011-04-15

Resonant inelastic soft x-ray scattering (RIXS) spectra excited at the 1{sigma}{sub g}{yields}3{sigma}{sub u} resonance in gas-phase O{sub 2} show excitations due to the nuclear degrees of freedom with up to 35 well-resolved discrete vibronic states and a continuum due to the kinetic energy distribution of the separated atoms. The RIXS profile demonstrates spatial quantum beats caused by two interfering wave packets with different momenta as the atoms separate. Thomson scattering strongly affects both the spectral profile and the scattering anisotropy.

Quantum walks and wavepacket dynamics on a lattice with twisted photons.

PubMed

Cardano, Filippo; Massa, Francesco; Qassim, Hammam; Karimi, Ebrahim; Slussarenko, Sergei; Paparo, Domenico; de Lisio, Corrado; Sciarrino, Fabio; Santamato, Enrico; Boyd, Robert W; Marrucci, Lorenzo

2015-03-01

The "quantum walk" has emerged recently as a paradigmatic process for the dynamic simulation of complex quantum systems, entanglement production and quantum computation. Hitherto, photonic implementations of quantum walks have mainly been based on multipath interferometric schemes in real space. We report the experimental realization of a discrete quantum walk taking place in the orbital angular momentum space of light, both for a single photon and for two simultaneous photons. In contrast to previous implementations, the whole process develops in a single light beam, with no need of interferometers; it requires optical resources scaling linearly with the number of steps; and it allows flexible control of input and output superposition states. Exploiting the latter property, we explored the system band structure in momentum space and the associated spin-orbit topological features by simulating the quantum dynamics of Gaussian wavepackets. Our demonstration introduces a novel versatile photonic platform for quantum simulations.

The NINJA-2 project: detecting and characterizing gravitational waveforms modelled using numerical binary black hole simulations

NASA Astrophysics Data System (ADS)

Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Accadia, T.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Agathos, M.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Andersen, M.; Anderson, R.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Austin, L.; Aylott, B. E.; Babak, S.; Baker, P. T.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauchrowitz, J.; Bauer, Th S.; Behnke, B.; Bejger, M.; Beker, M. G.; Belczynski, C.; Bell, A. S.; Bell, C.; Bergmann, G.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bloemen, S.; Blom, M.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; Bosi, L.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brückner, F.; Buchman, S.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burman, R.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Calderón Bustillo, J.; Calloni, E.; Camp, J. B.; Campsie, P.; Cannon, K. C.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Carbone, L.; Caride, S.; Castiglia, A.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Celerier, C.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, X.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Chow, J.; Christensen, N.; Chu, Q.; Chua, S. S. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C.; Colombini, M.; Cominsky, L.; Constancio, M., Jr.; Conte, A.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corpuz, A.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coughlin, S.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Dal Canton, T.; Damjanic, M.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; Dayanga, T.; Debreczeni, G.; Degallaix, J.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Donath, A.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dossa, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Effler, A.; Eggenstein, H.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Endrőczi, G.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Feroz, F.; Ferrante, I.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gair, J.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, C.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grover, K.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Hammer, D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Hooper, S.; Hopkins, P.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hu, Y.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Iyer, B. R.; Izumi, K.; Jacobson, M.; James, E.; Jang, H.; Jaranowski, P.; Ji, Y.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karlen, J.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Keiser, G. M.; Keitel, D.; Kelley, D. B.; Kells, W.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, C.; Kim, K.; Kim, N.; Kim, N. G.; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kline, J.; Koehlenbeck, S.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kremin, A.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, A.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Kwee, P.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J.; Leonardi, M.; Leong, J. R.; Le Roux, A.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B.; Lewis, J.; Li, T. G. F.; Libbrecht, K.; Libson, A.; Lin, A. C.; Littenberg, T. B.; Litvine, V.; Lockerbie, N. A.; Lockett, V.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Lubinski, M. J.; Lück, H.; Luijten, E.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macarthur, J.; Macdonald, E. P.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-Sandoval, F.; Mageswaran, M.; Maglione, C.; Mailand, K.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Manca, G. M.; Mandel, I.; Mandic, V.; Mangano, V.; Mangini, N.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Martinelli, L.; Martynov, D.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McLin, K.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Meinders, M.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyers, P.; Miao, H.; Michel, C.; Mikhailov, E. E.; Milano, L.; Milde, S.; Miller, J.; Minenkov, Y.; Mingarelli, C. M. F.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Moesta, P.; Mohan, M.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nagy, M. F.; Nanda Kumar, D.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nelemans, G.; Neri, I.; Neri, M.; Newton, G.; Nguyen, T.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Ochsner, E.; O'Dell, J.; Oelker, E.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oppermann, P.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Palashov, O.; Palomba, C.; Pan, H.; Pan, Y.; Pankow, C.; Paoletti, F.; Paoletti, R.; Papa, M. A.; Paris, H.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Pedraza, M.; Penn, S.; Perreca, A.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J.; Poggiani, R.; Poteomkin, A.; Powell, J.; Prasad, J.; Premachandra, S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Qin, J.; Quetschke, V.; Quintero, E.; Quiroga, G.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Raja, S.; Rajalakshmi, G.; Rakhmanov, M.; Ramet, C.; Ramirez, K.; Rapagnani, P.; Raymond, V.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Reid, S.; Reitze, D. H.; Rhoades, E.; Ricci, F.; Riles, K.; Robertson, N. A.; Robinet, F.; Rocchi, A.; Rodruck, M.; Rolland, L.; Rollins, J. G.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J. R.; Sannibale, V.; Santiago-Prieto, I.; Saracco, E.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R.; Scheuer, J.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siellez, K.; Siemens, X.; Sigg, D.; Simakov, D.; Singer, A.; Singer, L.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Son, E. J.; Sorazu, B.; Souradeep, T.; Sperandio, L.; Staley, A.; Stebbins, J.; Steinlechner, J.; Steinlechner, S.; Stephens, B. C.; Steplewski, S.; Stevenson, S.; Stone, R.; Stops, D.; Strain, K. A.; Straniero, N.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, R.; ter Braack, A. P. M.; Thirugnanasambandam, M. P.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C. V.; Torrie, C. I.; Travasso, F.; Traylor, G.; Tse, M.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Urbanek, K.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van der Sluys, M. V.; van Heijningen, J.; van Veggel, A. A.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Verma, S. S.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vousden, W. D.; Vyachanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Walker, M.; Wallace, L.; Wang, M.; Wang, X.; Ward, R. L.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Williams, K.; Williams, L.; Williams, R.; Williams, T.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yang, Z.; Yoshida, S.; Yvert, M.; Zadrożny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, Fan; Zhang, L.; Zhao, C.; Zhu, X. J.; Zucker, M. E.; Zuraw, S.; Zweizig, J.; Boyle, M.; Brügmann, B.; Buchman, L. T.; Campanelli, M.; Chu, T.; Etienne, Z. B.; Hannam, M.; Healy, J.; Hinder, I.; Kidder, L. E.; Laguna, P.; Liu, Y. T.; London, L.; Lousto, C. O.; Lovelace, G.; MacDonald, I.; Marronetti, P.; Mösta, P.; Müller, D.; Mundim, B. C.; Nakano, H.; Paschalidis, V.; Pekowsky, L.; Pollney, D.; Pfeiffer, H. P.; Ponce, M.; Pürrer, M.; Reifenberger, G.; Reisswig, C.; Santamaría, L.; Scheel, M. A.; Shapiro, S. L.; Shoemaker, D.; Sopuerta, C. F.; Sperhake, U.; Szilágyi, B.; Taylor, N. W.; Tichy, W.; Tsatsin, P.; Zlochower, Y.

2014-06-01

The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave (GW) astrophysics communities. The purpose of NINJA is to study the ability to detect GWs emitted from merging binary black holes (BBH) and recover their parameters with next-generation GW observatories. We report here on the results of the second NINJA project, NINJA-2, which employs 60 complete BBH hybrid waveforms consisting of a numerical portion modelling the late inspiral, merger, and ringdown stitched to a post-Newtonian portion modelling the early inspiral. In a ‘blind injection challenge’ similar to that conducted in recent Laser Interferometer Gravitational Wave Observatory (LIGO) and Virgo science runs, we added seven hybrid waveforms to two months of data recoloured to predictions of Advanced LIGO (aLIGO) and Advanced Virgo (AdV) sensitivity curves during their first observing runs. The resulting data was analysed by GW detection algorithms and 6 of the waveforms were recovered with false alarm rates smaller than 1 in a thousand years. Parameter-estimation algorithms were run on each of these waveforms to explore the ability to constrain the masses, component angular momenta and sky position of these waveforms. We find that the strong degeneracy between the mass ratio and the BHs’ angular momenta will make it difficult to precisely estimate these parameters with aLIGO and AdV. We also perform a large-scale Monte Carlo study to assess the ability to recover each of the 60 hybrid waveforms with early aLIGO and AdV sensitivity curves. Our results predict that early aLIGO and AdV will have a volume-weighted average sensitive distance of 300 Mpc (1 Gpc) for 10M⊙ + 10M⊙ (50M⊙ + 50M⊙) BBH coalescences. We demonstrate that neglecting the component angular momenta in the waveform models used in matched-filtering will result in a reduction in sensitivity for systems with large component angular momenta. This

Momentum-Resolved Observation of Thermal and Quantum Depletion in a Bose Gas

NASA Astrophysics Data System (ADS)

Chang, R.; Bouton, Q.; Cayla, H.; Qu, C.; Aspect, A.; Westbrook, C. I.; Clément, D.

2016-12-01

We report on the single-atom-resolved measurement of the distribution of momenta ℏk in a weakly interacting Bose gas after a 330 ms time of flight. We investigate it for various temperatures and clearly separate two contributions to the depletion of the condensate by their k dependence. The first one is the thermal depletion. The second contribution falls off as k-4, and its magnitude increases with the in-trap condensate density as predicted by the Bogoliubov theory at zero temperature. These observations suggest associating it with the quantum depletion. How this contribution can survive the expansion of the released interacting condensate is an intriguing open question.

Secure Quantum Technologies

NASA Astrophysics Data System (ADS)

Malik, Mehul

Over the past three decades, quantum mechanics has allowed the development of technologies that provide unconditionally secure communication. In parallel, the quantum nature of the transverse electromagnetic field has spawned the field of quantum imaging that encompasses technologies such as quantum lithography, quantum ghost imaging, and high-dimensional quantum key distribution (QKD). The emergence of such quantum technologies also highlights the need for the development of accurate and efficient methods of measuring and characterizing the elusive quantum state itself. In this thesis, I present new technologies that use the quantum properties of light for security. The first of these is a technique that extends the principles behind QKD to the field of imaging and optical ranging. By applying the polarization-based BB84 protocol to individual photons in an active imaging system, we obtained images that were secure against any intercept-resend jamming attacks. The second technology presented in this thesis is based on an extension of quantum ghost imaging, a technique that uses position-momentum entangled photons to create an image of an object without directly gaining any spatial information from it. We used a holographic filtering technique to build a quantum ghost image identification system that uses a few pairs of photons to identify an object from a set of known objects. The third technology addressed in this thesis is a high-dimensional QKD system that uses orbital-angular-momentum (OAM) modes of light for encoding. Moving to a high-dimensional state space in QKD allows one to impress more information on each photon, as well as introduce higher levels of security. I discuss the development of two OAM-QKD protocols based on the BB84 and Ekert protocols of QKD. In addition, I present a study characterizing the effects of turbulence on a communication system using OAM modes for encoding. The fourth and final technology presented in this thesis is a relatively

Quantum gravity in the sky: interplay between fundamental theory and observations

NASA Astrophysics Data System (ADS)

Ashtekar, Abhay; Gupt, Brajesh

2017-01-01

Observational missions have provided us with a reliable model of the evolution of the universe starting from the last scattering surface all the way to future infinity. Furthermore given a specific model of inflation, using quantum field theory on curved space-times this history can be pushed back in time to the epoch when space-time curvature was some 1062 times that at the horizon of a solar mass black hole! However, to extend the history further back to the Planck regime requires input from quantum gravity. An important aspect of this input is the choice of the background quantum geometry and of the Heisenberg state of cosmological perturbations thereon, motivated by Planck scale physics. This paper introduces first steps in that direction. Specifically we propose two principles that link quantum geometry and Heisenberg uncertainties in the Planck epoch with late time physics and explore in detail the observational consequences of the initial conditions they select. We find that the predicted temperature-temperature (T-T) correlations for scalar modes are indistinguishable from standard inflation at small angular scales even though the initial conditions are now set in the deep Planck regime. However, there is a specific power suppression at large angular scales. As a result, the predicted spectrum provides a better fit to the PLANCK mission data than standard inflation, where the initial conditions are set in the general relativity regime. Thus, our proposal brings out a deep interplay between the ultraviolet and the infrared. Finally, the proposal also leads to specific predictions for power suppression at large angular scales also for the (T-E and E-E) correlations involving electric polarization3. The PLANCK team is expected to release this data in the coming year.

Experimental realization of entanglement in multiple degrees of freedom between two quantum memories.

PubMed

Zhang, Wei; Ding, Dong-Sheng; Dong, Ming-Xin; Shi, Shuai; Wang, Kai; Liu, Shi-Long; Li, Yan; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

2016-11-14

Entanglement in multiple degrees of freedom has many benefits over entanglement in a single one. The former enables quantum communication with higher channel capacity and more efficient quantum information processing and is compatible with diverse quantum networks. Establishing multi-degree-of-freedom entangled memories is not only vital for high-capacity quantum communication and computing, but also promising for enhanced violations of nonlocality in quantum systems. However, there have been yet no reports of the experimental realization of multi-degree-of-freedom entangled memories. Here we experimentally established hyper- and hybrid entanglement in multiple degrees of freedom, including path (K-vector) and orbital angular momentum, between two separated atomic ensembles by using quantum storage. The results are promising for achieving quantum communication and computing with many degrees of freedom.

Experimental realization of entanglement in multiple degrees of freedom between two quantum memories

PubMed Central

Zhang, Wei; Ding, Dong-Sheng; Dong, Ming-Xin; Shi, Shuai; Wang, Kai; Liu, Shi-Long; Li, Yan; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

2016-01-01

Entanglement in multiple degrees of freedom has many benefits over entanglement in a single one. The former enables quantum communication with higher channel capacity and more efficient quantum information processing and is compatible with diverse quantum networks. Establishing multi-degree-of-freedom entangled memories is not only vital for high-capacity quantum communication and computing, but also promising for enhanced violations of nonlocality in quantum systems. However, there have been yet no reports of the experimental realization of multi-degree-of-freedom entangled memories. Here we experimentally established hyper- and hybrid entanglement in multiple degrees of freedom, including path (K-vector) and orbital angular momentum, between two separated atomic ensembles by using quantum storage. The results are promising for achieving quantum communication and computing with many degrees of freedom. PMID:27841274

Photoexcitation cascade and quantum-relativistic jet formation in graphene

NASA Astrophysics Data System (ADS)

Lewandowski, Cyprian; Levitov, Leonid

Interactions between ultra-relativistic particles can lead to striking behavior in which a high-energy particle creates showers of softer particles characterized by a collimated angular distribution aligned with the particle velocity. These showers, known as jets, are a generic phenomenon relevant for all quantum cascades of linearly dispersing particles. This talk will discuss jets formed upon photoexcitation in graphene, which due to its linear dispersion provides an appealing medium for exploring quantum-relativistic phenomena. We will study the cascade generated by carrier-carrier collisions in photon absorption, wherein a single photon creates an electron-hole (e-h) excitation that decays producing multiple near-collinear secondary e-h excitations. We will argue that the cascade can occur through an off-shell mechanism such that all the particles and holes involved reside outside the energy-momentum dispersion manifold, relieving the bottleneck arising in the on-shell process due to energy and momentum conservation. The characteristics of the jets such as the angular and energy distribution of the particles will be discussed. Photogenerated jets provide an interesting setting to investigate the carrier-carrier collision processes in graphene and other Dirac materials. We acknowledge support of the Center for Integrated Quantum Materials (CIQM) under NSF award DMR-1231319.

The Misapplication of Probability Theory in Quantum Mechanics

NASA Astrophysics Data System (ADS)

Racicot, Ronald

2014-03-01

This article is a revision of two papers submitted to the APS in the past two and a half years. In these papers, arguments and proofs are summarized for the following: (1) The wrong conclusion by EPR that Quantum Mechanics is incomplete, perhaps requiring the addition of ``hidden variables'' for completion. Theorems that assume such ``hidden variables,'' such as Bell's theorem, are also wrong. (2) Quantum entanglement is not a realizable physical phenomenon and is based entirely on assuming a probability superposition model for quantum spin. Such a model directly violates conservation of angular momentum. (3) Simultaneous multiple-paths followed by a quantum particle traveling through space also cannot possibly exist. Besides violating Noether's theorem, the multiple-paths theory is based solely on probability calculations. Probability calculations by themselves cannot possibly represent simultaneous physically real events. None of the reviews of the submitted papers actually refuted the arguments and evidence that was presented. These analyses should therefore be carefully evaluated since the conclusions reached have such important impact in quantum mechanics and quantum information theory.

Angular momentum of dwarf galaxies

NASA Astrophysics Data System (ADS)

Kurapati, Sushma; Chengalur, Jayaram N.; Pustilnik, Simon; Kamphuis, Peter

2018-05-01

Mass and specific angular momentum are two fundamental physical parameters of galaxies. We present measurements of the baryonic mass and specific angular momentum of 11 void dwarf galaxies derived from neutral hydrogen (HI) synthesis data. Rotation curves were measured using 3D and 2D tilted ring fitting routines, and the derived curves generally overlap within the error bars, except in the central regions where, as expected, the 3D routines give steeper curves. The specific angular momentum of void dwarfs is found to be high compared to an extrapolation of the trends seen for higher mass bulge-less spirals, but comparable to that of other dwarf irregular galaxies that lie outside of voids. As such, our data show no evidence for a dependence of the specific angular momentum on the large scale environment. Combining our data with the data from the literature, we find a baryonic threshold of ˜109.1 M⊙ for this increase in specific angular momentum. Interestingly, this threshold is very similar to the mass threshold below which the galaxy discs start to become systematically thicker. This provides qualitative support to the suggestion that the thickening of the discs, as well as the increase in specific angular momentum, are both results of a common physical mechanism, such as feedback from star formation. Quantitatively, however, the amount of star formation observed in our dwarfs appears insufficient to produce the observed increase in specific angular momentum. It is hence likely that other processes, such as cold accretion of high angular momentum gas, also play a role in increasing the specific angular momentum.

Phase space theory of evaporation in neon clusters: the role of quantum effects.

PubMed

Calvo, F; Parneix, P

2009-12-31

Unimolecular evaporation of neon clusters containing between 14 and 148 atoms is theoretically investigated in the framework of phase space theory. Quantum effects are incorporated in the vibrational densities of states, which include both zero-point and anharmonic contributions, and in the possible tunneling through the centrifugal barrier. The evaporation rates, kinetic energy released, and product angular momentum are calculated as a function of excess energy or temperature in the parent cluster and compared to the classical results. Quantum fluctuations are found to generally increase both the kinetic energy released and the angular momentum of the product, but the effects on the rate constants depend nontrivially on the excess energy. These results are interpreted as due to the very few vibrational states available in the product cluster when described quantum mechanically. Because delocalization also leads to much narrower thermal energy distributions, the variations of evaporation observables as a function of canonical temperature appear much less marked than in the microcanonical ensemble. While quantum effects tend to smooth the caloric curve in the product cluster, the melting phase change clearly keeps a signature on these observables. The microcanonical temperature extracted from fitting the kinetic energy released distribution using an improved Arrhenius form further suggests a backbending in the quantum Ne(13) cluster that is absent in the classical system. Finally, in contrast to delocalization effects, quantum tunneling through the centrifugal barrier does not play any appreciable role on the evaporation kinetics of these rather heavy clusters.

Light-sheet generation in inhomogeneous media using self-reconstructing beams and the STED-principle.

PubMed

Gohn-Kreuz, Cristian; Rohrbach, Alexander

2016-03-21

Self-reconstruction of Bessel beams in inhomogeneous media is beneficial in light-sheet based microscopy. Although the beam's ring system enables propagation stability, the resulting image contrast is reduced. Here, we show that by a combination of two self-reconstructing beams with different orbital angular momenta it is possible to inhibit fluorescence from the ring system by using stimulated emission depletion (STED) even in strongly scattering media. Our theoretical study shows that the remaining fluorescence γ depends non-linearly on the beams' relative radial and orbital angular momenta. For various scattering media we demonstrate that γ remains remarkably stable over long beam propagation distances.

Study of collective flows of protons and π^{{-}}_{} -mesons in p+C, Ta and He+Li, C collisions at momenta of 4.2, 4.5 and 10 AGeV/c

NASA Astrophysics Data System (ADS)

Chkhaidze, L.; Chlachidze, G.; Djobava, T.; Galoyan, A.; Kharkhelauri, L.; Togoo, R.; Uzhinsky, V.

2016-11-01

Collective flows of protons and π- -mesons are studied at the momenta of 4.2, 4.5 and 10AGeV/ c for p+C, Ta and He+Li, C interactions. The data were obtained from the streamer chamber (SKM-200-GIBS) and from the Propane Bubble Chamber (PBC-500) systems utilized at JINR. A method of Danielewicz and Odyniec has been employed in determining a directed transverse flow of particles. The values of the transverse flow parameter and the strength of the anisotropic emission were defined for each interacting nuclear pair. It is found that the directed flows of protons and pions decrease with increasing the energy and the mass numbers of colliding nucleus pairs. The π^{{-}}_{} -meson and proton flows exhibit opposite directions in all studied interactions, and the flows of protons are directed in the reaction plane. The Ultra-relativistic Quantum Molecular Dynamical Model (UrQMD) coupled with the Statistical Multi-fragmentation Model (SMM), satisfactorily describes the obtained experimental results.

Quantum Hilbert Hotel.

PubMed

Potoček, Václav; Miatto, Filippo M; Mirhosseini, Mohammad; Magaña-Loaiza, Omar S; Liapis, Andreas C; Oi, Daniel K L; Boyd, Robert W; Jeffers, John

2015-10-16

In 1924 David Hilbert conceived a paradoxical tale involving a hotel with an infinite number of rooms to illustrate some aspects of the mathematical notion of "infinity." In continuous-variable quantum mechanics we routinely make use of infinite state spaces: here we show that such a theoretical apparatus can accommodate an analog of Hilbert's hotel paradox. We devise a protocol that, mimicking what happens to the guests of the hotel, maps the amplitudes of an infinite eigenbasis to twice their original quantum number in a coherent and deterministic manner, producing infinitely many unoccupied levels in the process. We demonstrate the feasibility of the protocol by experimentally realizing it on the orbital angular momentum of a paraxial field. This new non-Gaussian operation may be exploited, for example, for enhancing the sensitivity of NOON states, for increasing the capacity of a channel, or for multiplexing multiple channels into a single one.

Angular distributions for the inelastic scattering of NO(X2Π ) with O2(X3Σg-)

NASA Astrophysics Data System (ADS)

Brouard, M.; Gordon, S. D. S.; Nichols, B.; Squires, E.; Walpole, V.; Aoiz, F. J.; Stolte, S.

2017-05-01

The inelastic scattering of NO(X2Π ) by O2(X3Σg-) was studied at a mean collision energy of 550 cm-1 using velocity-map ion imaging. The initial quantum state of the NO(X2Π , v = 0, j = 0.5, Ω =0.5 , 𝜖 = -1 , f) molecule was selected using a hexapole electric field, and specific Λ-doublet levels of scattered NO were probed using (1 +1' ) resonantly enhanced multiphoton ionization. A modified "onion-peeling" algorithm was employed to extract angular scattering information from the series of "pancaked," nested Newton spheres arising as a consequence of the rotational excitation of the molecular oxygen collision partner. The extracted differential cross sections for NO(X) f →f and f →e Λ-doublet resolved, spin-orbit conserving transitions, partially resolved in the oxygen co-product rotational quantum state, are reported, along with O2 fragment pair-correlated rotational state population. The inelastic scattering of NO with O2 is shown to share many similarities with the scattering of NO(X) with the rare gases. However, subtle differences in the angular distributions between the two collision partners are observed.

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Chiral Modes at Exceptional Points in Exciton-Polariton Quantum Fluids

NASA Astrophysics Data System (ADS)

Gao, T.; Li, G.; Estrecho, E.; Liew, T. C. H.; Comber-Todd, D.; Nalitov, A.; Steger, M.; West, K.; Pfeiffer, L.; Snoke, D. W.; Kavokin, A. V.; Truscott, A. G.; Ostrovskaya, E. A.

2018-02-01

We demonstrate the generation of chiral modes-vortex flows with fixed handedness in exciton-polariton quantum fluids. The chiral modes arise in the vicinity of exceptional points (non-Hermitian spectral degeneracies) in an optically induced resonator for exciton polaritons. In particular, a vortex is generated by driving two dipole modes of the non-Hermitian ring resonator into degeneracy. Transition through the exceptional point in the space of the system's parameters is enabled by precise manipulation of real and imaginary parts of the closed-wall potential forming the resonator. As the system is driven to the vicinity of the exceptional point, we observe the formation of a vortex state with a fixed orbital angular momentum (topological charge). This method can be extended to generate higher-order orbital angular momentum states through coalescence of multiple non-Hermitian spectral degeneracies. Our Letter demonstrates the possibility of exploiting nontrivial and counterintuitive properties of waves near exceptional points in macroscopic quantum systems.

Quantum Evaporation from Liquid 4He by Rotons

NASA Astrophysics Data System (ADS)

Hope, F. R.; Baird, M. J.; Wyatt, A. F. G.

1984-04-01

We have shown that rotons as well as phonons can evaporate 4He atoms in a single-quantum process. Measurements of the time of flight and the angular distribution of the evaporated atoms clearly distinguish between evaporation by phonons and rotons. The results indicate that energy and the parallel component of momentum are conserved at the free liquid surface.

Quantum walks and wavepacket dynamics on a lattice with twisted photons

PubMed Central

Cardano, Filippo; Massa, Francesco; Qassim, Hammam; Karimi, Ebrahim; Slussarenko, Sergei; Paparo, Domenico; de Lisio, Corrado; Sciarrino, Fabio; Santamato, Enrico; Boyd, Robert W.; Marrucci, Lorenzo

2015-01-01

The “quantum walk” has emerged recently as a paradigmatic process for the dynamic simulation of complex quantum systems, entanglement production and quantum computation. Hitherto, photonic implementations of quantum walks have mainly been based on multipath interferometric schemes in real space. We report the experimental realization of a discrete quantum walk taking place in the orbital angular momentum space of light, both for a single photon and for two simultaneous photons. In contrast to previous implementations, the whole process develops in a single light beam, with no need of interferometers; it requires optical resources scaling linearly with the number of steps; and it allows flexible control of input and output superposition states. Exploiting the latter property, we explored the system band structure in momentum space and the associated spin-orbit topological features by simulating the quantum dynamics of Gaussian wavepackets. Our demonstration introduces a novel versatile photonic platform for quantum simulations. PMID:26601157

Angular-Rate Estimation Using Quaternion Measurements

NASA Technical Reports Server (NTRS)

Azor, Ruth; Bar-Itzhack, Y.; Deutschmann, Julie K.; Harman, Richard R.

1998-01-01

In most spacecraft (SC) there is a need to know the SC angular rate. Precise angular rate is required for attitude determination, and a coarse rate is needed for attitude control damping. Classically, angular rate information is obtained from gyro measurements. These days, there is a tendency to build smaller, lighter and cheaper SC, therefore the inclination now is to do away with gyros and use other means and methods to determine the angular rate. The latter is also needed even in gyro equipped satellites when performing high rate maneuvers whose angular-rate is out of range of the on board gyros or in case of gyro failure. There are several ways to obtain the angular rate in a gyro-less SC. When the attitude is known, one can differentiate the attitude in whatever parameters it is given and use the kinematics equation that connects the derivative of the attitude with the satellite angular-rate and compute the latter. Since SC usually utilize vector measurements for attitude determination, the differentiation of the attitude introduces a considerable noise component in the computed angular-rate vector.

Quantum Backreaction on Three-Dimensional Black Holes and Naked Singularities.

PubMed

Casals, Marc; Fabbri, Alessandro; Martínez, Cristián; Zanelli, Jorge

2017-03-31

We analytically investigate backreaction by a quantum scalar field on two rotating Bañados-Teitelboim-Zanelli (BTZ) geometries: that of a black hole and that of a naked singularity. In the former case, we explore the quantum effects on various regions of relevance for a rotating black hole space-time. We find that the quantum effects lead to a growth of both the event horizon and the radius of the ergosphere, and to a reduction of the angular velocity, compared to the unperturbed values. Furthermore, they give rise to the formation of a curvature singularity at the Cauchy horizon and show no evidence of the appearance of a superradiant instability. In the case of a naked singularity, we find that quantum effects lead to the formation of a horizon that shields it, thus supporting evidence for the rôle of quantum mechanics as a cosmic censor in nature.

Optical beams with embedded vortices: building blocks for atom optics and quantum information

NASA Astrophysics Data System (ADS)

Chattrapiban, N.; Arakelyan, I.; Mitra, S.; Hill, W. T., III

2006-05-01

Laser beams with embedded vortices, Bessel or Laguerre-Gaussian modes, provide a unique opportunity for creating elements for atom optics, entangling photons and, potentially, mediating novel quantum interconnects between photons and matter. High-order Bessel modes, for example, contain intensity voids and propagate nearly diffraction-free for tens of meters. These vortices can be exploited to produce dark channels oriented longitudinally (hollow beams) or transversely to the laser propagation direction. Such channels are ideal for generating networks or circuits to guide and manipulate cold neutral atoms, an essential requirement for realizing future applications associated with atom interferometry, atom lithography and even some neutral atom-based quantum computing architectures. Recently, we divided a thermal cloud of neutral atoms moving within a blue-detuned beam into two clouds with two different momenta by crossing two hollow beams. In this presentation, we will describe these results and discuss the prospects for extending the process to coherent ensembles of matter.

High-capacity quantum key distribution via hyperentangled degrees of freedom

NASA Astrophysics Data System (ADS)

Simon, David S.; Sergienko, Alexander V.

2014-06-01

Quantum key distribution (QKD) has long been a promising area for the application of quantum effects in solving real-world problems. However, two major obstacles have stood in the way of its widespread application: low secure key generation rates and short achievable operating distances. In this paper, a new physical mechanism for dealing with the first of these problems is proposed: the interplay between different degrees of freedom in a hyperentangled system (parametric down-conversion) is used to increase the Hilbert space dimension available for key generation while maintaining security. Polarization-based Bell tests provide security checking, while orbital angular momentum (OAM) and total angular momentum (TAM) provide a higher key generation rate. Whether to measure TAM or OAM is decided randomly in each trial. The concurrent noncommutativity of TAM with OAM and polarization provides the physical basis for quantum security. TAM measurements link polarization to OAM, so that if the legitimate participants measure OAM while the eavesdropper measures TAM (or vice-versa), then polarization entanglement is lost, revealing the eavesdropper. In contrast to other OAM-based QKD methods, complex active switching between OAM bases is not required; instead, passive switching by beam splitters combined with much simpler active switching between polarization bases makes implementation at high OAM more practical.

Angular velocity discrimination

NASA Technical Reports Server (NTRS)

Kaiser, Mary K.

1990-01-01

Three experiments designed to investigate the ability of naive observers to discriminate rotational velocities of two simultaneously viewed objects are described. Rotations are constrained to occur about the x and y axes, resulting in linear two-dimensional image trajectories. The results indicate that observers can discriminate angular velocities with a competence near that for linear velocities. However, perceived angular rate is influenced by structural aspects of the stimuli.

Single-photon-level quantum image memory based on cold atomic ensembles

PubMed Central

Ding, Dong-Sheng; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

2013-01-01

A quantum memory is a key component for quantum networks, which will enable the distribution of quantum information. Its successful development requires storage of single-photon light. Encoding photons with spatial shape through higher-dimensional states significantly increases their information-carrying capability and network capacity. However, constructing such quantum memories is challenging. Here we report the first experimental realization of a true single-photon-carrying orbital angular momentum stored via electromagnetically induced transparency in a cold atomic ensemble. Our experiments show that the non-classical pair correlation between trigger photon and retrieved photon is retained, and the spatial structure of input and retrieved photons exhibits strong similarity. More importantly, we demonstrate that single-photon coherence is preserved during storage. The ability to store spatial structure at the single-photon level opens the possibility for high-dimensional quantum memories. PMID:24084711

Quantum Anomalous Hall Effect in Low-buckled Honeycomb Lattice with In-plane Magnetization

NASA Astrophysics Data System (ADS)

Ren, Yafei; Pan, Hui; Yang, Fei; Li, Xin; Qiao, Zhenhua; Zhenhua Qiao's Group Team; Hui Pan's Group Team

With out-of-plane magnetization, the quantum anomalous Hall effect has been extensively studied in quantum wells and two-dimensional atomic crystal layers. Here, we investigate the possibility of realizing quantum anomalous Hall effect (QAHE) in honeycomb lattices with in-plane magnetization. We show that the QAHE can only occur in low-buckled honeycomb lattice where both intrinsic and intrinsic Rashba spin-orbit coupling appear spontaneously. The extrinsic Rashba spin-orbit coupling is detrimental to this phase. In contrast to the out-of-plane magnetization induced QAHE, the QAHE from in-plane magnetization is achieved in the vicinity of the time reversal symmetric momenta at M points rather than Dirac points. In monolayer case, the QAHE can be characterized by Chern number  = +/- 1 whereas additional phases with Chern number  = +/- 2 appear in chiral stacked bilayer system. The Chern number strongly depends on the orientation of the magnetization. The bilayer system also provides additional tunability via out-of-plane electric field, which can reduce the critical magnetization strength required to induce QAHE. It can also lead to topological phase transitions from  = +/- 2 to +/- 1 and finally to 0 Equal contribution from Yafei Ren and Hui Pan.

Electric dipole moment of magnetoexciton in concentric quantum rings

NASA Astrophysics Data System (ADS)

García, L. F.; Mikhailov, I. D.; Revinova, S. Yu

2017-12-01

We study properties of exciton in a weakly coupled concentric quantum rings, penetrated by an axially directed magnetic flux and subjected to an electric field in the ring’s plane. To this end, we adopt a simple model of quasi-one-dimensional rotator, for which the wave functions and the corresponding energies we found by using the double Fourier series expansion method. Revealed multiple intersections of the energy levels provide conditions for abrupt changes of the radial and the angular quantum numbers, making possible the tunnelling of carriers between rings and allowing the formation of a permanent large dipole moment. We show that the electric and magnetic polarizability of concentric quantum rings with a trapped exciton are very sensible to external electric and magnetic fields.

Photoelectron angular distributions from rotationally resolved autoionizing states of N 2

DOE PAGES

Chartrand, A. M.; McCormack, E. F.; Jacovella, U.; ...

2017-12-08

The single-photon, photoelectron-photoion coincidence spectrum of N 2 has been recorded at high (~1.5 cm -1) resolution in the region between the N 2 + X 2Σ g +, v + = 0 and 1 ionization thresholds by using a double imaging spectrometer and intense vacuum-ultraviolet light from the Synchrotron SOLEIL. This approach provides the relative photoionization cross section, the photoelectron energy distribution, and the photoelectron angular distribution as a function of photon energy. The region of interest contains autoionizing valence states, vibrationally autoionizing Rydberg states converging to vibrationally excited levels of the N 2 + X 2Σ g +more » ground state, and electronically autoionizing states converging to the N 2 + A 2Π and B 2Σ u + states. The wavelength resolution is sufficient to resolve rotational structure in the autoionizing states, but the electron energy resolution is insufficient to resolve rotational structure in the photoion spectrum. Here, a simplified approach based on multichannel quantum defect theory is used to predict the photoelectron angular distribution parameters, β, and the results are in reasonably good agreement with experiment.« less

DVL Angular Velocity Recorder

NASA Technical Reports Server (NTRS)

Liebe, Wolfgang

1944-01-01

In many studies, especially of nonstationary flight motion, it is necessary to determine the angular velocities at which the airplane rotates about its various axes. The three-component recorder is designed to serve this purpose. If the angular velocity for one flight attitude is known, other important quantities can be derived from its time rate of change, such as the angular acceleration by differentiations, or - by integration - the angles of position of the airplane - that is, the angles formed by the airplane axes with the axis direction presented at the instant of the beginning of the motion that is to be investigated.

Measures and models for angular correlation and angular-linear correlation. [correlation of random variables

NASA Technical Reports Server (NTRS)

Johnson, R. A.; Wehrly, T.

1976-01-01

Population models for dependence between two angular measurements and for dependence between an angular and a linear observation are proposed. The method of canonical correlations first leads to new population and sample measures of dependence in this latter situation. An example relating wind direction to the level of a pollutant is given. Next, applied to pairs of angular measurements, the method yields previously proposed sample measures in some special cases and a new sample measure in general.

Quantum mechanical treatment of the F+H2 --> HF+H reaction

NASA Astrophysics Data System (ADS)

Baer, Michael; Jellinek, Julius; Kouri, D. J.

1983-03-01

In this paper is presented a quantum dynamical study of the F+H2 reaction within the infinite order sudden approximation for the energy range Etot=0.28-0.50 eV. Results at various stages of the calculation are given ranging from the most detailed phases and S matrices to the total integral cross sections. The accuracy of the IOS is assessed by comparisons of the average l-labeled quantal IOS results with exact classical, initial-l labeled classical IOS, and l-initial labeled quantum IOS results. Comparison with experiment indicates that the qualitative state-to-state angular distributions are reproduced within this method. On the other hand, vibrational branching ratios for the product HF molecule are only partially reproduced. The main part of the discussion in the paper is devoted to the recent hypothesis concerning the existence of a superposition of resonances which strongly influence the angular distributions as a function of final vibrational state of the HF product.

Observation of entanglement witnesses for orbital angular momentum states

NASA Astrophysics Data System (ADS)

Agnew, M.; Leach, J.; Boyd, R. W.

2012-06-01

Entanglement witnesses provide an efficient means of determining the level of entanglement of a system using the minimum number of measurements. Here we demonstrate the observation of two-dimensional entanglement witnesses in the high-dimensional basis of orbital angular momentum (OAM). In this case, the number of potentially entangled subspaces scales as d(d - 1)/2, where d is the dimension of the space. The choice of OAM as a basis is relevant as each subspace is not necessarily maximally entangled, thus providing the necessary state for certain tests of nonlocality. The expectation value of the witness gives an estimate of the state of each two-dimensional subspace belonging to the d-dimensional Hilbert space. These measurements demonstrate the degree of entanglement and therefore the suitability of the resulting subspaces for quantum information applications.

Experimental Demonstration of Coherent Control in Quantum Chaotic Systems

NASA Astrophysics Data System (ADS)

Bitter, M.; Milner, V.

2017-01-01

We experimentally demonstrate coherent control of a quantum system, whose dynamics is chaotic in the classical limit. Interaction of diatomic molecules with a periodic sequence of ultrashort laser pulses leads to the dynamical localization of the molecular angular momentum, a characteristic feature of the chaotic quantum kicked rotor. By changing the phases of the rotational states in the initially prepared coherent wave packet, we control the rotational distribution of the final localized state and its total energy. We demonstrate the anticipated sensitivity of control to the exact parameters of the kicking field, as well as its disappearance in the classical regime of excitation.

A quantum analogy to the classical gravitomagnetic clock effect

NASA Astrophysics Data System (ADS)

Faruque, S. B.

2018-06-01

We present an approximation to the solution of Dirac equation in Schwarzschild field found through the use of Foldy-Wouthuysen Hamiltonian. We solve the equation for the positive energy states and found the frequencies by which the states oscillate. Difference of the periods of oscillation of the two states with two different total angular momentum quantum number j has an analogical form of the classical clock effect found in general relativity. But unlike the term that appears as clock effect in classical physics, here the term is quantized. Thus, we find a quantum analogue of the classical gravitomagnetic clock effect.

Angular Positioning Sensor for Space Mechanisms

NASA Astrophysics Data System (ADS)

Steiner, Nicolas; Chapuis, Dominique

2013-09-01

Angular position sensors are used on various rotating mechanisms such as solar array drive mechanisms, antenna pointing mechanisms, scientific instruments, motors or actuators.Now a days, potentiometers and encoders are mainly used for angular measurement purposes. Both of them have their own pros and cons.As alternative, Ruag Space Switzerland Nyon (RSSN) is developing and qualifying two innovative technologies of angular position sensors which offer easy implementation, medium to very high lifetime and high flexibility with regards to the output signal shape/type.The Brushed angular position sensor uses space qualified processes which are already flying on RSSN's sliprings for many years. A large variety of output signal shape can be implemented to fulfill customer requirements (digital, analog, customized, etc.).The contactless angular position sensor consists in a new radiation hard Application Specific Integrated Circuit (ASIC) based on the Hall effect and providing the angular position without complex processing algorithm.

Synthetic-lattice enabled all-optical devices based on orbital angular momentum of light.

PubMed

Luo, Xi-Wang; Zhou, Xingxiang; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can; Zhang, Chuanwei; Zhou, Zheng-Wei

2017-07-14

All-optical photonic devices are crucial for many important photonic technologies and applications, ranging from optical communication to quantum information processing. Conventional design of all-optical devices is based on photon propagation and interference in real space, which may rely on large numbers of optical elements, and the requirement of precise control makes this approach challenging. Here we propose an unconventional route for engineering all-optical devices using the photon's internal degrees of freedom, which form photonic crystals in such synthetic dimensions for photon propagation and interference. We demonstrate this design concept by showing how important optical devices such as quantum memory and optical filters can be realized using synthetic orbital angular momentum (OAM) lattices in degenerate cavities. The design route utilizing synthetic photonic lattices may significantly reduce the requirement for numerous optical elements and their fine tuning in conventional design, paving the way for realistic all-optical photonic devices with novel functionalities.

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Synthetic-lattice enabled all-optical devices based on orbital angular momentum of light

PubMed Central

Luo, Xi-Wang; Zhou, Xingxiang; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can; Zhang, Chuanwei; Zhou, Zheng-Wei

2017-01-01

All-optical photonic devices are crucial for many important photonic technologies and applications, ranging from optical communication to quantum information processing. Conventional design of all-optical devices is based on photon propagation and interference in real space, which may rely on large numbers of optical elements, and the requirement of precise control makes this approach challenging. Here we propose an unconventional route for engineering all-optical devices using the photon’s internal degrees of freedom, which form photonic crystals in such synthetic dimensions for photon propagation and interference. We demonstrate this design concept by showing how important optical devices such as quantum memory and optical filters can be realized using synthetic orbital angular momentum (OAM) lattices in degenerate cavities. The design route utilizing synthetic photonic lattices may significantly reduce the requirement for numerous optical elements and their fine tuning in conventional design, paving the way for realistic all-optical photonic devices with novel functionalities. PMID:28706215

Electrostatically confined quantum rings in bilayer graphene.

PubMed

Zarenia, M; Pereira, J M; Peeters, F M; Farias, G A

2009-12-01

We propose a new system where electron and hole states are electrostatically confined into a quantum ring in bilayer graphene. These structures can be created by tuning the gap of the graphene bilayer using nanostructured gates or by position-dependent doping. The energy levels have a magnetic field (B(0)) dependence that is strikingly distinct from that of usual semiconductor quantum rings. In particular, the eigenvalues are not invariant under a B(0) --> -B(0) transformation and, for a fixed total angular momentum index m, their field dependence is not parabolic, but displays two minima separated by a saddle point. The spectra also display several anticrossings, which arise due to the overlap of gate-confined and magnetically confined states.

Photodissociation of ultracold diatomic strontium molecules with quantum state control.

PubMed

McDonald, M; McGuyer, B H; Apfelbeck, F; Lee, C-H; Majewska, I; Moszynski, R; Zelevinsky, T

2016-07-07

Chemical reactions at ultracold temperatures are expected to be dominated by quantum mechanical effects. Although progress towards ultracold chemistry has been made through atomic photoassociation, Feshbach resonances and bimolecular collisions, these approaches have been limited by imperfect quantum state selectivity. In particular, attaining complete control of the ground or excited continuum quantum states has remained a challenge. Here we achieve this control using photodissociation, an approach that encodes a wealth of information in the angular distribution of outgoing fragments. By photodissociating ultracold (88)Sr2 molecules with full control of the low-energy continuum, we access the quantum regime of ultracold chemistry, observing resonant and nonresonant barrier tunnelling, matter-wave interference of reaction products and forbidden reaction pathways. Our results illustrate the failure of the traditional quasiclassical model of photodissociation and instead are accurately described by a quantum mechanical model. The experimental ability to produce well-defined quantum continuum states at low energies will enable high-precision studies of long-range molecular potentials for which accurate quantum chemistry models are unavailable, and may serve as a source of entangled states and coherent matter waves for a wide range of experiments in quantum optics.

Variation in Angular Velocity and Angular Acceleration of a Particle in Rectilinear Motion

ERIC Educational Resources Information Center

Mashood, K. K.; Singh, V. A.

2012-01-01

We discuss the angular velocity ([image omitted]) and angular acceleration ([image omitted]) associated with a particle in rectilinear motion with constant acceleration. The discussion was motivated by an observation that students and even teachers have difficulty in ascribing rotational motion concepts to a particle when the trajectory is a…

Generalized uncertainty principle and quantum gravity phenomenology

NASA Astrophysics Data System (ADS)

Bosso, Pasquale

The fundamental physical description of Nature is based on two mutually incompatible theories: Quantum Mechanics and General Relativity. Their unification in a theory of Quantum Gravity (QG) remains one of the main challenges of theoretical physics. Quantum Gravity Phenomenology (QGP) studies QG effects in low-energy systems. The basis of one such phenomenological model is the Generalized Uncertainty Principle (GUP), which is a modified Heisenberg uncertainty relation and predicts a deformed canonical commutator. In this thesis, we compute Planck-scale corrections to angular momentum eigenvalues, the hydrogen atom spectrum, the Stern-Gerlach experiment, and the Clebsch-Gordan coefficients. We then rigorously analyze the GUP-perturbed harmonic oscillator and study new coherent and squeezed states. Furthermore, we introduce a scheme for increasing the sensitivity of optomechanical experiments for testing QG effects. Finally, we suggest future projects that may potentially test QG effects in the laboratory.

Extraction of conformal data in critical quantum spin chains using the Koo-Saleur formula

NASA Astrophysics Data System (ADS)

Milsted, Ashley; Vidal, Guifre

2017-12-01

We study the emergence of two-dimensional conformal symmetry in critical quantum spin chains on the finite circle. Our goal is to characterize the conformal field theory (CFT) describing the universality class of the corresponding quantum phase transition. As a means to this end, we propose and demonstrate automated procedures which, using only the lattice Hamiltonian H =∑jhj as an input, systematically identify the low-energy eigenstates corresponding to Virasoro primary and quasiprimary operators, and assign the remaining low-energy eigenstates to conformal towers. The energies and momenta of the primary operator states are needed to determine the primary operator scaling dimensions and conformal spins, an essential part of the conformal data that specifies the CFT. Our techniques use the action, on the low-energy eigenstates of H , of the Fourier modes Hn of the Hamiltonian density hj. The Hn were introduced as lattice representations of the Virasoro generators by Koo and Saleur [Nucl. Phys. B 426, 459 (1994), 10.1016/0550-3213(94)90018-3]. In this paper, we demonstrate that these operators can be used to extract conformal data in a nonintegrable quantum spin chain.

High proton momenta and nucleon-nucleon correlations in the reaction /sup 3/He(e,e'p)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marchand, C.; Bernheim, M.; Dunn, P.C.

1988-04-25

Electron-scattering cross sections for the reaction /sup 3/He(e,e'p) have been measured for recoil momenta between 300 and 600 MeV/c and for missing energies up to 90 MeV. Proton momentum distributions in /sup 3/He, corrected for final-state--interaction and meson-exchange effects, have been obtained from 318 to 600 MeV/c for the pd channel and from 290 to 515 MeV/c for the ppn channel. Explicit evidence for nucleon-nucleon correlations is presented.

Shapes of rotating superfluid helium nanodroplets

DOE PAGES

Bernando, Charles; Tanyag, Rico Mayro P.; Jones, Curtis; ...

2017-02-16

Rotating superfluid He droplets of approximately 1 μm in diameter were obtained in a free nozzle beam expansion of liquid He in vacuum and were studied by single-shot coherent diffractive imaging using an x-ray free electron laser. The formation of strongly deformed droplets is evidenced by large anisotropies and intensity anomalies (streaks) in the obtained diffraction images. The analysis of the images shows that in addition to previously described axially symmetric oblate shapes, some droplets exhibit prolate shapes. Forward modeling of the diffraction images indicates that the shapes of rotating superfluid droplets are very similar to their classical counterparts, givingmore » direct access to the droplet angular momenta and angular velocities. Here, the analyses of the radial intensity distribution and appearance statistics of the anisotropic images confirm the existence of oblate metastable superfluid droplets with large angular momenta beyond the classical bifurcation threshold.« less

Shapes of rotating superfluid helium nanodroplets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernando, Charles; Tanyag, Rico Mayro P.; Jones, Curtis

Rotating superfluid He droplets of approximately 1 μm in diameter were obtained in a free nozzle beam expansion of liquid He in vacuum and were studied by single-shot coherent diffractive imaging using an x-ray free electron laser. The formation of strongly deformed droplets is evidenced by large anisotropies and intensity anomalies (streaks) in the obtained diffraction images. The analysis of the images shows that in addition to previously described axially symmetric oblate shapes, some droplets exhibit prolate shapes. Forward modeling of the diffraction images indicates that the shapes of rotating superfluid droplets are very similar to their classical counterparts, givingmore » direct access to the droplet angular momenta and angular velocities. Here, the analyses of the radial intensity distribution and appearance statistics of the anisotropic images confirm the existence of oblate metastable superfluid droplets with large angular momenta beyond the classical bifurcation threshold.« less

Angular behavior of synchrotron radiation harmonics.

PubMed

Bagrov, V G; Bulenok, V G; Gitman, D M; Jara, Jose Acosta; Tlyachev, V B; Jarovoi, A T

2004-04-01

The detailed analysis of angular dependence of the synchrotron radiation (SR) is presented. Angular distributions of linear and circular polarization integrated over all harmonics, well known for relativistic electron energies, are extended to include radiation from electrons that are not fully relativistic. In particular, we analyze the angular dependence of the integral SR intensity and peculiarities of the angular dependence of the first harmonics SR. Studying spectral SR intensities, we have discovered their unexpected angular behavior, completely different from that of the integral SR intensity; namely, for any given synchrotron frequency, maxima of the spectral SR intensities recede from the orbit plane with increasing particle energy. Thus, in contrast with the integral SR intensity, the spectral ones have the tendency to deconcentrate themselves on the orbit plane.

Unveiling Angular Momentum

NASA Astrophysics Data System (ADS)

Robinson, Stephen

2015-03-01

Angular momentum is a notoriously difficult concept to grasp. Visualization often requires three-dimensional pictures of vectors pointing in seemingly arbitrary directions. A simple student-run laboratory experiment coupled with intuitive explanations by an instructor can clear up some of the inherent ambiguity of rotational motion. Specifically, the precessional period of a suspended spinning bicycle wheel can be related to the spinning frequency through a simple algebraic expression. An explanation of this precession apart from the concept of angular momentum will be given.

Horizon Quantum Mechanics: Spherically Symmetric and Rotating Sources

NASA Astrophysics Data System (ADS)

Casadio, Roberto; Giugno, Andrea; Giusti, Andrea; Micu, Octavian

2018-04-01

The Horizon Quantum Mechanics is an approach that allows one to analyse the gravitational radius of spherically symmetric systems and compute the probability that a given quantum state is a black hole. We first review the (global) formalism and show how it reproduces a gravitationally inspired GUP relation. This results leads to unacceptably large fluctuations in the horizon size of astrophysical black holes if one insists in describing them as (smeared) central singularities. On the other hand, if they are extended systems, like in the corpuscular models, no such issue arises and one can in fact extend the formalism to include asymptotic mass and angular momentum with the harmonic model of rotating corpuscular black holes. The Horizon Quantum Mechanics then shows that, in simple configurations, the appearance of the inner horizon is suppressed and extremal (macroscopic) geometries seem disfavoured.

Factors influencing perceived angular velocity

NASA Technical Reports Server (NTRS)

Kaiser, Mary K.; Calderone, Jack B.

1991-01-01

Angular velocity perception is examined for rotations both in depth and in the image plane and the influence of several object properties on this motion parameter is explored. Two major object properties are considered, namely, texture density which determines the rate of edge transitions for rotations in depth, i.e., the number of texture elements that pass an object's boundary per unit of time, and object size which determines the tangential linear velocities and 2D image velocities of texture elements for a given angular velocity. Results of experiments show that edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities had an impact on perceived angular velocity; this bias was associated with 2D image velocity rather than 3D tangential velocity. Despite these biases judgements were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter appeared to be good for rotations both in depth (y-axis) and parallel to the line of sight (z-axis).

Angular Acceleration without Torque?

ERIC Educational Resources Information Center

Kaufman, Richard D.

2012-01-01

Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

Excess of J/ψ yield at very low transverse momenta in A+A collisions measured by the STAR experiment

NASA Astrophysics Data System (ADS)

Zha, Wangmei; STAR Collaboration

2017-08-01

In this article, we report the STAR measurements of J / ψ production at very low transverse momenta (pT) in hadronic Au+Au collisions at √{sNN } = 200 GeV and U+U collisions at √{sNN } = 193 GeV at mid-rapidity. Centrality dependence of J / ψ yields and nuclear modification factors at very low pT are presented.

Quantum Rotational Effects in Nanomagnetic Systems

NASA Astrophysics Data System (ADS)

O'Keeffe, Michael F.

Quantum tunneling of the magnetic moment in a nanomagnet must conserve the total angular momentum. For a nanomagnet embedded in a rigid body, reversal of the magnetic moment will cause the body to rotate as a whole. When embedded in an elastic environment, tunneling of the magnetic moment will cause local elastic twists of the crystal structure. In this thesis, I will present a theoretical study of the interplay between magnetization and rotations in a variety of nanomagnetic systems which have some degree of rotational freedom. We investigate the effect of rotational freedom on the tunnel splitting of a nanomagnet which is free to rotate about its easy axis. Calculating the exact instanton of the coupled equations of motion shows that mechanical freedom of the particle renormalizes the easy axis anisotropy, increasing the tunnel splitting. To understand magnetization dynamics in free particles, we study a quantum mechanical model of a tunneling spin embedded in a rigid rotor. The exact energy levels for a symmetric rotor exhibit first and second order quantum phase transitions between states with different values the magnetic moment. A quantum phase diagram is obtained in which the magnetic moment depends strongly on the moments of inertia. An intrinsic contribution to decoherence of current oscillations of a flux qubit must come from the angular momentum it transfers to the surrounding body. Within exactly solvable models of a qubit embedded in a rigid body and an elastic medium, we show that slow decoherence is permitted if the solid is macroscopically large. The spin-boson model is one of the simplest representations of a two-level system interacting with a quantum harmonic oscillator, yet has eluded a closed-form solution. I investigate some possible approaches to understanding its spectrum. The Landau-Zener dynamics of a tunneling spin coupled to a torsional resonator show that for certain parameter ranges the system exhibits multiple Landau-Zener transitions

Generalized centripetal force law and quantization of motion constrained on 2D surfaces

NASA Astrophysics Data System (ADS)

Liu, Q. H.; Zhang, J.; Lian, D. K.; Hu, L. D.; Li, Z.

2017-03-01

For a particle of mass μ moves on a 2D surface f(x) = 0 embedded in 3D Euclidean space of coordinates x, there is an open and controversial problem whether the Dirac's canonical quantization scheme for the constrained motion allows for the geometric potential that has been experimentally confirmed. We note that the Dirac's scheme hypothesizes that the symmetries indicated by classical brackets among positions x and momenta p and Hamiltonian Hc remain in quantum mechanics, i.e., the following Dirac brackets [ x ,Hc ] D and [ p ,Hc ] D holds true after quantization, in addition to the fundamental ones [ x , x ] D, [ x , p ] D and [ p , p ] D. This set of hypotheses implies that the Hamiltonian operator is simultaneously determined during the quantization. The quantum mechanical relations corresponding to the classical mechanical ones p / μ =[ x ,Hc ] D directly give the geometric momenta. The time t derivative of the momenta p ˙ =[ p ,Hc ] D in classical mechanics is in fact the generalized centripetal force law for particle on the 2D surface, which in quantum mechanics permits both the geometric momenta and the geometric potential.

Einstein-Podolsky-Rosen Entanglement of Narrow-Band Photons from Cold Atoms.

PubMed

Lee, Jong-Chan; Park, Kwang-Kyoon; Zhao, Tian-Ming; Kim, Yoon-Ho

2016-12-16

Einstein-Podolsky-Rosen (EPR) entanglement introduced in 1935 deals with two particles that are entangled in their positions and momenta. Here we report the first experimental demonstration of EPR position-momentum entanglement of narrow-band photon pairs generated from cold atoms. By using two-photon quantum ghost imaging and ghost interference, we demonstrate explicitly that the narrow-band photon pairs violate the separability criterion, confirming EPR entanglement. We further demonstrate continuous variable EPR steering for positions and momenta of the two photons. Our new source of EPR-entangled narrow-band photons is expected to play an essential role in spatially multiplexed quantum information processing, such as, storage of quantum correlated images, quantum interface involving hyperentangled photons, etc.

Einstein-Podolsky-Rosen Entanglement of Narrow-Band Photons from Cold Atoms

NASA Astrophysics Data System (ADS)

Lee, Jong-Chan; Park, Kwang-Kyoon; Zhao, Tian-Ming; Kim, Yoon-Ho

2016-12-01

Einstein-Podolsky-Rosen (EPR) entanglement introduced in 1935 deals with two particles that are entangled in their positions and momenta. Here we report the first experimental demonstration of EPR position-momentum entanglement of narrow-band photon pairs generated from cold atoms. By using two-photon quantum ghost imaging and ghost interference, we demonstrate explicitly that the narrow-band photon pairs violate the separability criterion, confirming EPR entanglement. We further demonstrate continuous variable EPR steering for positions and momenta of the two photons. Our new source of EPR-entangled narrow-band photons is expected to play an essential role in spatially multiplexed quantum information processing, such as, storage of quantum correlated images, quantum interface involving hyperentangled photons, etc.

Microscopic analysis of homogeneous electron gas by considering dipole-dipole interaction

NASA Astrophysics Data System (ADS)

Bordbar, G. H.; Pouresmaeeli, F.

2017-12-01

Implying perturbation theory, the impact of the dipole-dipole interaction (DDI) on the thermodynamic properties of a homogeneous electron gas at zero temperature is investigated. Through the second quantization formalism, the analytic expressions for the ground state energy and the DDI energy are obtained. In this paper, the DDI energy has similarities with the previous works done by others. We show that its general behavior depends on density and the total angular momentum. Especially, it is found that the DDI energy has a highly state-dependent behavior. With the growth of density, the magnitude of DDI energy, which is found to be the summation of all energy contributions of the states with even and odd total angular momenta, grows linearly. It is also found that for the states with even and odd total angular momenta, the DDI energy contributions are corresponding to the positive and negative values, respectively. In particular, an increase of total angular momentum leads to decline in the magnitude of energy contribution. Therefore, the dipole-dipole interaction reveals distinct characteristics in comparison with central-like interactions.

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The Saga of Light-Matter Interaction and Magneto-optical Effects Applications to Atomic Magnetometry, Laser-cooled Atoms, Atomic Clocks, Geomagnetism, and Plant Bio-magnetism

NASA Astrophysics Data System (ADS)

Corsini, Eric P.

The quest to expand the limited sensorial domain, in particular to bridge the inability to gauge magnetic fields near and far, has driven the fabrication of remedial tools. The interaction of ferromagnetic material with a magnetic field had been the only available technique to gauge that field for several millennium. The advent of electricity and associated classical phenomena captured in the four Maxwell equations, were a step forward. In the early 1900s, the model of quantum mechanics provided a two-way leap forward. One came from the newly understood interaction of light and matter, and more specifically the three-way coupling of photons, atoms' angular momenta, and magnetic field, which are the foundations of atomic magnetometry. The other came from magnetically sensitive quantum effects in a fabricated energy-ladder form of matter cooled to a temperature below that of the energy steps; these quantum effects gave rise to the superconducting quantum interference device (SQUID). Research using atomic magnetometers and SQUIDs has resulted in thousands of publications, text books, and conferences. The current status in each field is well described in Refs. [48,49,38,42] and all references therein. In this work we develop and investigate techniques and applications pertaining to atomic magnetometry. [Full text: eric.corsini gmail.com].

Free-space measurement-device-independent quantum-key-distribution protocol using decoy states with orbital angular momentum

NASA Astrophysics Data System (ADS)

Wang, Le; Zhao, Sheng-Mei; Gong, Long-Yan; Cheng, Wei-Wen

2015-12-01

In this paper, we propose a measurement-device-independent quantum-key-distribution (MDI-QKD) protocol using orbital angular momentum (OAM) in free space links, named the OAM-MDI-QKD protocol. In the proposed protocol, the OAM states of photons, instead of polarization states, are used as the information carriers to avoid the reference frame alignment, the decoy-state is adopted to overcome the security loophole caused by the weak coherent pulse source, and the high efficient OAM-sorter is adopted as the measurement tool for Charlie to obtain the output OAM state. Here, Charlie may be an untrusted third party. The results show that the authorized users, Alice and Bob, could distill a secret key with Charlie’s successful measurements, and the key generation performance is slightly better than that of the polarization-based MDI-QKD protocol in the two-dimensional OAM cases. Simultaneously, Alice and Bob can reduce the number of flipping the bits in the secure key distillation. It is indicated that a higher key generation rate performance could be obtained by a high dimensional OAM-MDI-QKD protocol because of the unlimited degree of freedom on OAM states. Moreover, the results show that the key generation rate and the transmission distance will decrease as the growth of the strength of atmospheric turbulence (AT) and the link attenuation. In addition, the decoy states used in the proposed protocol can get a considerable good performance without the need for an ideal source. Project supported by the National Natural Science Foundation of China (Grant Nos. 61271238 and 61475075), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20123223110003), the Natural Science Research Foundation for Universities of Jiangsu Province of China (Grant No. 11KJA510002), the Open Research Fund of Key Laboratory of Broadband Wireless Communication and Sensor Network Technology, Ministry of Education, China (Grant No. NYKL2015011), and the

Vector-mean-field theory of the fractional quantum Hall effect

NASA Astrophysics Data System (ADS)

Rejaei, B.; Beenakker, C. W. J.

1992-12-01

A mean-field theory of the fractional quantum Hall effect is formulated based on the adiabatic principle of Greiter and Wilczek. The theory is tested on known bulk properties (excitation gap, fractional charge, and statistics), and then applied to a confined region in a two-dimensional electron gas (quantum dot). For a small number N of electrons in the dot, the exact ground-state energy has cusps at the same angular momentum values as the mean-field theory. For large N, Wen's algebraic decay of the probability for resonant tunneling through the dot is reproduced, albeit with a different exponent.

Mars: destruction of the tropical belt and building up extra tropics is a physical requirement of angular momentum equilibration between zones with different distances to the rotation axis

NASA Astrophysics Data System (ADS)

Kochemasov, G. G.

2012-09-01

Often observed a sensible difference in appearance and structure between tropical and extra-t ropical zones of various heavenly bodies including rocky and gas planets, satellites and Sun (Fig. 6) compels to look for a common reason of such phenomenon [1-3]. All bodies rotate and their spherical shape makes zones at different lat itudes to have differing angular momenta as a distance to the rotation axis diminishes gradually from the equator to the poles (Fig. 1) (this is felt particularly when one launches rockets into space -preferable cheaper launches are from the equatorial regions - Kourou in the French Guyana is better than Baikonur in Kazakhstan). One of remarkable changes occurs at tropics. As a total rotating planetary body tends to have angular momenta of its tectonic blocks equilibrated it starts mechanisms leveling this basic physical property. At tropical zones (bulged also due to the rotation ellipsoid) the outer shell - crust as a consequence tends to be destroyed, sunk, subsided and shrunk; a density of crust material changes; the atmosphere reacts changing chemistry and structure; in terrestrial anthroposphere man looses its mass and stature (well known pygmioidness process). Ext ratropical belts, on the contrary, tend to add material and increase radius. Thus, a body tends to be like a cucumber but mighty gravity always makes it globular. According to the Le Chatelier rule mechanisms with opposing tendencies also begin to act. However, traces of this cosmic "struggle" very often are seen on surfaces of heavenly bodies as structurally distinguished tropical and extra-t ropical zones (Fig. 1, 6) [1-3]. At Mars the widespread "enigmatic" chaotic and fretted terrains at the highland-lowland boundary could be considered as traces of the crust destruction along the wide tropical belt (Fig. 2-4). A system of hillocks and their relics, mesas, ridges, cliffs and separating them depressions or plains (deep up to 1-2 km) is controlled by a crosscutting

Natural roller bearing fault detection by angular measurement of true instantaneous angular speed

NASA Astrophysics Data System (ADS)

Renaudin, L.; Bonnardot, F.; Musy, O.; Doray, J. B.; Rémond, D.

2010-10-01

The challenge in many production activities involving large mechanical devices like power transmissions consists in reducing the machine downtime, in managing repairs and in improving operating time. Most online monitoring systems are based on conventional vibration measurement devices for gear transmissions or bearings in mechanical components. In this paper, we propose an alternative way of bearing condition monitoring based on the instantaneous angular speed measurement. By the help of a large experimental investigation on two different applications, we prove that localized faults like pitting in bearing generate small angular speed fluctuations which are measurable with optical or magnetic encoders. We also emphasize the benefits of measuring instantaneous angular speed with the pulse timing method through an implicit angular sampling which ensures insensitivity to speed fluctuation. A wide range of operating conditions have been tested for the two applications with varying speed, load, external excitations, gear ratio, etc. The tests performed on an automotive gearbox or on actual operating vehicle wheels also establish the robustness of the proposed methodology. By the means of a conventional Fourier transform, angular frequency channels kinematically related to the fault periodicity show significant magnitude differences related to the damage severity. Sideband effects are evidently seen when the fault is located on rotating parts of the bearing due to load modulation. Additionally, slip effects are also suspected to be at the origin of enlargement of spectrum peaks in the case of double row bearings loaded in a pure radial direction.

Density effects on the electronic contribution to hydrogen Lyman alpha Stark profiles

NASA Astrophysics Data System (ADS)

Motapon, O.

1998-01-01

The quantum unified theory of Stark broadening (Tran Minh et al. 1975, Feautrier et al. 1976) is used to study the density effects on the electronic contribution to the hydrogen Lyman alpha lineshape. The contribution of the first angular momenta to the total profile is obtained by an extrapolation method, and the results agree with other approaches. The comparison made with Vidal et al. (1973) shows a good agreement; and the electronic profile is found to be linear in density for | Delta lambda right | greater than 8 Angstroms for densities below 10(17) cm(-3) , while the density dependence becomes more complex for | Delta lambda right | less than 8 Angstroms. The wing profiles are calculated at various temperatures scaling from 2500 to 40000K and a polynomial fit of these profiles is given.

Measuring qutrit-qutrit entanglement of orbital angular momentum states of an atomic ensemble and a photon.

PubMed

Inoue, R; Yonehara, T; Miyamoto, Y; Koashi, M; Kozuma, M

2009-09-11

Three-dimensional entanglement of orbital angular momentum states of an atomic qutrit and a single photon qutrit has been observed. Their full state was reconstructed using quantum state tomography. The fidelity to the maximally entangled state of Schmidt rank 3 exceeds the threshold 2/3. This result confirms that the density matrix cannot be decomposed into an ensemble of pure states of Schmidt rank 1 or 2. That is, the Schmidt number of the density matrix must be equal to or greater than 3.

Angular shear plate

DOEpatents

Ruda, Mitchell C [Tucson, AZ; Greynolds, Alan W [Tucson, AZ; Stuhlinger, Tilman W [Tucson, AZ

2009-07-14

One or more disc-shaped angular shear plates each include a region thereon having a thickness that varies with a nonlinear function. For the case of two such shear plates, they are positioned in a facing relationship and rotated relative to each other. Light passing through the variable thickness regions in the angular plates is refracted. By properly timing the relative rotation of the plates and by the use of an appropriate polynomial function for the thickness of the shear plate, light passing therethrough can be focused at variable positions.

Multiple orbital angular momentum generated by dielectric hybrid phase element

NASA Astrophysics Data System (ADS)

Wang, Xuewen; Kuchmizhak, Aleksandr; Hu, Dejiao; Li, Xiangping

2017-09-01

Vortex beam carrying multiple orbital angular momentum provides a new degree of freedom to manipulate light leading to the various exciting applications as trapping, quantum optics, information multiplexing, etc. Helical wavefront can be generated either via the geometric or the dynamic phase arising from a space-variant birefringence (q-plate) or from phase accumulation through propagation (spiral-phase-plate), respectively. Using fast direct laser writing technique we fabricate and characterize novel hybrid q-plate generating vortex beam simultaneously carrying two different high-order topological charges, which arise from the spin-orbital conversion and the azimuthal height variation of the recorded structures. We approve the versatile concept to generate multiple-OAM vortex beams combining the spin-orbital interaction and the phase accumulation in a single micro-scale device, a hybrid dielectric phase plate.

Inelastic electron tunneling mediated by a molecular quantum rotator

NASA Astrophysics Data System (ADS)

Sugimoto, Toshiki; Kunisada, Yuji; Fukutani, Katsuyuki

2017-12-01

Inelastic electron tunneling (IET) accompanying nuclear motion is not only of fundamental physical interest but also has strong impacts on chemical and biological processes in nature. Although excitation of rotational motion plays an important role in enhancing electric conductance at a low bias, the mechanism of rotational excitation remains veiled. Here, we present a basic theoretical framework of IET that explicitly takes into consideration quantum angular momentum, focusing on a molecular H2 rotator trapped in a nanocavity between two metallic electrodes as a model system. It is shown that orientationally anisotropic electrode-rotator coupling is the origin of angular-momentum exchange between the electron and molecule; we found that the anisotropic coupling imposes rigorous selection rules in rotational excitation. In addition, rotational symmetry breaking induced by the anisotropic potential lifts the degeneracy of the energy level of the degenerated rotational state of the quantum rotator and tunes the threshold bias voltage that triggers rotational IET. Our theoretical results provide a paradigm for physical understanding of the rotational IET process and spectroscopy, as well as molecular-level design of electron-rotation coupling in nanoelectronics.

Influence of atmospheric turbulence on optical communications using orbital angular momentum for encoding.

PubMed

Malik, Mehul; O'Sullivan, Malcolm; Rodenburg, Brandon; Mirhosseini, Mohammad; Leach, Jonathan; Lavery, Martin P J; Padgett, Miles J; Boyd, Robert W

2012-06-04

We describe an experimental implementation of a free-space 11-dimensional communication system using orbital angular momentum (OAM) modes. This system has a maximum measured OAM channel capacity of 2.12 bits/photon. The effects of Kolmogorov thin-phase turbulence on the OAM channel capacity are quantified. We find that increasing the turbulence leads to a degradation of the channel capacity. We are able to mitigate the effects of turbulence by increasing the spacing between detected OAM modes. This study has implications for high-dimensional quantum key distribution (QKD) systems. We describe the sort of QKD system that could be built using our current technology.

Nonlinear optical memory for manipulation of orbital angular momentum of light.

PubMed

de Oliveira, R A; Borba, G C; Martins, W S; Barreiro, S; Felinto, D; Tabosa, J W R

2015-11-01

We report on the demonstration of a nonlinear optical memory (NOM) for storage and on-demand manipulation of orbital angular momentum (OAM) of light via higher-order nonlinear processes in cold cesium atoms. A spatially resolved phase-matching technique is used to select each order of the nonlinear susceptibility associated, respectively, with time-delayed four-, six-, and eight-wave mixing processes. For a specific configuration of the stored OAM of the incident beams, we demonstrated that the OAM of the retrieved beam can be manipulated according to the order of the nonlinear process chosen by the operator for reading out the NOM. This demonstration indicates new pathways for applications in classical and quantum information processing where OAM of light is used to encode optical information.

Non-Colinearity of Angular Velocity and Angular Momentum

ERIC Educational Resources Information Center

Burr, A. F.

1974-01-01

Discusses the principles, construction, and operation of an apparatus which serves to demonstrate the non-colinearity of the angular velocity and momentum vectors as well as the inertial tensors. Applications of the apparatus to teaching of advanced undergraduate mechanics courses are recommended. (CC)

A Concise Introduction to Quantum Mechanics

NASA Astrophysics Data System (ADS)

Swanson, Mark S.

2018-02-01

Assuming a background in basic classical physics, multivariable calculus, and differential equations, A Concise Introduction to Quantum Mechanics provides a self-contained presentation of the mathematics and physics of quantum mechanics. The relevant aspects of classical mechanics and electrodynamics are reviewed, and the basic concepts of wave-particle duality are developed as a logical outgrowth of experiments involving blackbody radiation, the photoelectric effect, and electron diffraction. The Copenhagen interpretation of the wave function and its relation to the particle probability density is presented in conjunction with Fourier analysis and its generalization to function spaces. These concepts are combined to analyze the system consisting of a particle confined to a box, developing the probabilistic interpretation of observations and their associated expectation values. The Schrödinger equation is then derived by using these results and demanding both Galilean invariance of the probability density and Newtonian energy-momentum relations. The general properties of the Schrödinger equation and its solutions are analyzed, and the theory of observables is developed along with the associated Heisenberg uncertainty principle. Basic applications of wave mechanics are made to free wave packet spreading, barrier penetration, the simple harmonic oscillator, the Hydrogen atom, and an electric charge in a uniform magnetic field. In addition, Dirac notation, elements of Hilbert space theory, operator techniques, and matrix algebra are presented and used to analyze coherent states, the linear potential, two state oscillations, and electron diffraction. Applications are made to photon and electron spin and the addition of angular momentum, and direct product multiparticle states are used to formulate both the Pauli exclusion principle and quantum decoherence. The book concludes with an introduction to the rotation group and the general properties of angular momentum.

Study of collective flows of protons and $$ \\pi^{{-}}_{}$$ π - -mesons in p+C, Ta and He+Li, C collisions at momenta of 4.2, 4.5 and 10 AGeV/c

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chkhaidze, L.; Chlachidze, G.; Djobava, T.

Collective flows of protons andmore » $$\\pi^{-}$$ -mesons are studied at the momenta of 4.2, 4.5 and 10AGeV/c for p+C, Ta and He+Li, C interactions. The data were obtained from the streamer chamber (SKM-200-GIBS) and from the Propane Bubble Chamber (PBC-500) systems utilized at JINR. A method of Danielewicz and Odyniec has been employed in determining a directed transverse flow of particles. The values of the transverse flow parameter and the strength of the anisotropic emission were defined for each interacting nuclear pair. It is found that the directed flows of protons and pions decrease with increasing the energy and the mass numbers of colliding nucleus pairs. The $$ \\pi^{{-}}_{}$$ -meson and proton flows exhibit opposite directions in all studied interactions, and the flows of protons are directed in the reaction plane. Lastly, the Ultra-relativistic Quantum Molecular Dynamical Model (UrQMD) coupled with the Statistical Multi-fragmentation Model (SMM), satisfactorily describes the obtained experimental results.« less

Study of collective flows of protons and $$ \\pi^{{-}}_{}$$ π - -mesons in p+C, Ta and He+Li, C collisions at momenta of 4.2, 4.5 and 10 AGeV/c

DOE PAGES

Chkhaidze, L.; Chlachidze, G.; Djobava, T.; ...

2016-11-01

Collective flows of protons andmore » $$\\pi^{-}$$ -mesons are studied at the momenta of 4.2, 4.5 and 10AGeV/c for p+C, Ta and He+Li, C interactions. The data were obtained from the streamer chamber (SKM-200-GIBS) and from the Propane Bubble Chamber (PBC-500) systems utilized at JINR. A method of Danielewicz and Odyniec has been employed in determining a directed transverse flow of particles. The values of the transverse flow parameter and the strength of the anisotropic emission were defined for each interacting nuclear pair. It is found that the directed flows of protons and pions decrease with increasing the energy and the mass numbers of colliding nucleus pairs. The $$ \\pi^{{-}}_{}$$ -meson and proton flows exhibit opposite directions in all studied interactions, and the flows of protons are directed in the reaction plane. Lastly, the Ultra-relativistic Quantum Molecular Dynamical Model (UrQMD) coupled with the Statistical Multi-fragmentation Model (SMM), satisfactorily describes the obtained experimental results.« less

Intrinsic Angular Momentum of Light.

ERIC Educational Resources Information Center

Santarelli, Vincent

1979-01-01

Derives a familiar torque-angular momentum theorem for the electromagnetic field, and includes the intrinsic torques exerted by the fields on the polarized medium. This inclusion leads to the expressions for the intrinsic angular momentum carried by the radiation traveling through a charge-free medium. (Author/MA)

Quantum oscillations and coherent interlayer transport in a new topological Dirac semimetal candidate YbMnSb2

NASA Astrophysics Data System (ADS)

Wang, Yi-Yan; Xu, Sheng; Sun, Lin-Lin; Xia, Tian-Long

2018-02-01

Dirac semimetals, which host Dirac fermions and represent a new state of quantum matter, have been studied intensively in condensed-matter physics. The exploration of new materials with topological states is important in both physics and materials science. We report the synthesis and the transport properties of high-quality single crystals of YbMnSb2. YbMnSb2 is a new compound with metallic behavior. Quantum oscillations, including Shubnikov-de Haas (SdH) oscillation and de Haas-van Alphen-type oscillation, have been observed at low temperature and high magnetic field. Small effective masses and nontrivial Berry phase are extracted from the analyses of quantum oscillations, which provide the transport evidence for the possible existence of Dirac fermions in YbMnSb2. The measurements of angular-dependent interlayer magnetoresistance indicate that the interlayer transport is coherent. The Fermi surface of YbMnSb2 possesses a quasi-two-dimensional characteristic as determined by the angular dependence of SdH oscillation frequency. These findings suggest that YbMnSb2 is a new candidate of topological Dirac semimetals.

Observation of correlated excitations in bimolecular collisions

NASA Astrophysics Data System (ADS)

Gao, Zhi; Karman, Tijs; Vogels, Sjoerd N.; Besemer, Matthieu; van der Avoird, Ad; Groenenboom, Gerrit C.; van de Meerakker, Sebastiaan Y. T.

2018-02-01

Although collisions between atoms and molecules are largely understood, collisions between two molecules have proven much harder to study. In both experiment and theory, our ability to determine quantum-state-resolved bimolecular cross-sections lags behind their atom-molecule counterparts by decades. For many bimolecular systems, even rules of thumb—much less intuitive understanding—of scattering cross sections are lacking. Here, we report the measurement of state-to-state differential cross sections on the collision of state-selected and velocity-controlled nitric oxide (NO) radicals and oxygen (O2) molecules. Using velocity map imaging of the scattered NO radicals, the full product-pair correlations of rotational excitation that occurs in both collision partners from individual encounters are revealed. The correlated cross sections show surprisingly good agreement with quantum scattering calculations using ab initio NO-O2 potential energy surfaces. The observations show that the well-known energy-gap law that governs atom-molecule collisions does not generally apply to bimolecular excitation processes, and reveal a propensity rule for the vector correlation of product angular momenta.

Holographic stress-energy tensor near the Cauchy horizon inside a rotating black hole

NASA Astrophysics Data System (ADS)

Ishibashi, Akihiro; Maeda, Kengo; Mefford, Eric

2017-07-01

We investigate a stress-energy tensor for a conformal field theory (CFT) at strong coupling inside a small five-dimensional rotating Myers-Perry black hole with equal angular momenta by using the holographic method. As a gravitational dual, we perturbatively construct a black droplet solution by applying the "derivative expansion" method, generalizing the work of Haddad [Classical Quantum Gravity 29, 245001 (2012), 10.1088/0264-9381/29/24/245001] and analytically compute the holographic stress-energy tensor for our solution. We find that the stress-energy tensor is finite at both the future and past outer (event) horizons and that the energy density is negative just outside the event horizons due to the Hawking effect. Furthermore, we apply the holographic method to the question of quantum instability of the Cauchy horizon since, by construction, our black droplet solution also admits a Cauchy horizon inside. We analytically show that the null-null component of the holographic stress-energy tensor negatively diverges at the Cauchy horizon, suggesting that a singularity appears there, in favor of strong cosmic censorship.

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Quantum primary rainbows in transmission of positrons through very short carbon nanotubes

NASA Astrophysics Data System (ADS)

Ćosić, M.; Petrović, S.; Nešković, N.

2016-04-01

This paper is devoted to a quantum mechanical consideration of the transmission of positrons of a kinetic energy of 1 MeV through very short (11, 9) single-wall chiral carbon nanotubes. The nanotube lengths are between 50 and 320 nm. The transmission process is determined by the rainbow effects. The interaction potential of a positron and the nanotube is deduced from the Molire's interaction potential of the positron and a nanotube atom using the continuum approximation. We solve numerically the time-dependent Schrödinger equation, and calculate the spatial and angular distributions of transmitted positrons. The initial positron beam is assumed to be an ensemble of non-interacting Gaussian wave packets. We generate the spatial and angular distributions using the computer simulation method. The examination is focused on the spatial and angular primary rainbows. It begins with an analysis of the corresponding classical rainbows, and continues with a detailed investigation of the amplitudes and phases of the wave functions of transmitted positrons. These analyses enable one to identify the principal and supernumerary primary rainbows appearing in the spatial and angular distributions. They also result in a detailed explanation of the way of their generation, which includes the effects of wrinkling of each wave packet during its deflection from the nanotube wall, and of its concentration just before a virtual barrier lying close to the corresponding classical rainbow. The wrinkling of the wave packets occurs due to their internal focusing. In addition, the wave packets wrinkle in a mutually coordinated way. This explanation may induce new theoretical and experimental investigations of quantum rainbows occurring in various atomic collision processes.

Fractional quantum Hall systems near nematicity: Bimetric theory, composite fermions, and Dirac brackets

NASA Astrophysics Data System (ADS)

Nguyen, Dung Xuan; Gromov, Andrey; Son, Dam Thanh

2018-05-01

We perform a detailed comparison of the Dirac composite fermion and the recently proposed bimetric theory for a quantum Hall Jain states near half filling. By tuning the composite Fermi liquid to the vicinity of a nematic phase transition, we find that the two theories are equivalent to each other. We verify that the single mode approximation for the response functions and the static structure factor becomes reliable near the phase transition. We show that the dispersion relation of the nematic mode near the phase transition can be obtained from the Dirac brackets between the components of the nematic order parameter. The dispersion is quadratic at low momenta and has a magnetoroton minimum at a finite momentum, which is not related to any nearby inhomogeneous phase.

Quantum mechanical reality according to Copenhagen 2.0

NASA Astrophysics Data System (ADS)

Din, Allan M.

2016-05-01

The long-standing conceptual controversies concerning the interpretation of nonrelativistic quantum mechanics are argued, on one hand, to be due to its incompleteness, as affirmed by Einstein. But on the other hand, it appears to be possible to complete it at least partially, as Bohr might have appreciated it, in the framework of its standard mathematical formalism with observables as appropriately defined self-adjoint operators. This completion of quantum mechanics is based on the requirement on laboratory physics to be effectively confined to a bounded space region and on the application of the von Neumann deficiency theorem to properly define a set of self-adjoint extensions of standard observables, e.g. the momenta and the Hamiltonian, in terms of certain isometries on the region boundary. This is formalized mathematically in the setting of a boundary ontology for the so-called Qbox in which the wave function acquires a supplementary dependence on a set of Additional Boundary Variables (ABV). It is argued that a certain geometric subset of the ABV parametrizing Quasi-Periodic Translational Isometries (QPTI) has a particular physical importance by allowing for the definition of an ontic wave function, which has the property of epitomizing the spatial wave function “collapse.” Concomitantly the standard wave function in an unbounded geometry is interpreted as an epistemic wave function, which together with the ontic QPTI wave function gives rise to the notion of two-wave duality, replacing the standard concept of wave-particle duality. More generally, this approach to quantum physics in a bounded geometry provides a novel analytical basis for a better understanding of several conceptual notions of quantum mechanics, including reality, nonlocality, entanglement and Heisenberg’s uncertainty relation. The scope of this analysis may be seen as a foundational update of the multiple versions 1.x of the Copenhagen interpretation of quantum mechanics, which is

Evidence of quantum phase transition in real-space vacuum entanglement of higher derivative scalar quantum field theories.

PubMed

Kumar, S Santhosh; Shankaranarayanan, S

2017-11-17

In a bipartite set-up, the vacuum state of a free Bosonic scalar field is entangled in real space and satisfies the area-law- entanglement entropy scales linearly with area of the boundary between the two partitions. In this work, we show that the area law is violated in two spatial dimensional model Hamiltonian having dynamical critical exponent z = 3. The model physically corresponds to next-to-next-to-next nearest neighbour coupling terms on a lattice. The result reported here is the first of its kind of violation of area law in Bosonic systems in higher dimensions and signals the evidence of a quantum phase transition. We provide evidence for quantum phase transition both numerically and analytically using quantum Information tools like entanglement spectra, quantum fidelity, and gap in the energy spectra. We identify the cause for this transition due to the accumulation of large number of angular zero modes around the critical point which catalyses the change in the ground state wave function due to the next-to-next-to-next nearest neighbor coupling. Lastly, using Hubbard-Stratanovich transformation, we show that the effective Bosonic Hamiltonian can be obtained from an interacting fermionic theory and provide possible implications for condensed matter systems.

Free-space quantum key distribution by rotation-invariant twisted photons.

PubMed

Vallone, Giuseppe; D'Ambrosio, Vincenzo; Sponselli, Anna; Slussarenko, Sergei; Marrucci, Lorenzo; Sciarrino, Fabio; Villoresi, Paolo

2014-08-08

"Twisted photons" are photons carrying a well-defined nonzero value of orbital angular momentum (OAM). The associated optical wave exhibits a helical shape of the wavefront (hence the name) and an optical vortex at the beam axis. The OAM of light is attracting a growing interest for its potential in photonic applications ranging from particle manipulation, microscopy, and nanotechnologies to fundamental tests of quantum mechanics, classical data multiplexing, and quantum communication. Hitherto, however, all results obtained with optical OAM were limited to laboratory scale. Here, we report the experimental demonstration of a link for free-space quantum communication with OAM operating over a distance of 210 m. Our method exploits OAM in combination with optical polarization to encode the information in rotation-invariant photonic states, so as to guarantee full independence of the communication from the local reference frames of the transmitting and receiving units. In particular, we implement quantum key distribution, a protocol exploiting the features of quantum mechanics to guarantee unconditional security in cryptographic communication, demonstrating error-rate performances that are fully compatible with real-world application requirements. Our results extend previous achievements of OAM-based quantum communication by over 2 orders of magnitude in the link scale, providing an important step forward in achieving the vision of a worldwide quantum network.

Free-Space Quantum Key Distribution by Rotation-Invariant Twisted Photons

NASA Astrophysics Data System (ADS)

Vallone, Giuseppe; D'Ambrosio, Vincenzo; Sponselli, Anna; Slussarenko, Sergei; Marrucci, Lorenzo; Sciarrino, Fabio; Villoresi, Paolo

2014-08-01

"Twisted photons" are photons carrying a well-defined nonzero value of orbital angular momentum (OAM). The associated optical wave exhibits a helical shape of the wavefront (hence the name) and an optical vortex at the beam axis. The OAM of light is attracting a growing interest for its potential in photonic applications ranging from particle manipulation, microscopy, and nanotechnologies to fundamental tests of quantum mechanics, classical data multiplexing, and quantum communication. Hitherto, however, all results obtained with optical OAM were limited to laboratory scale. Here, we report the experimental demonstration of a link for free-space quantum communication with OAM operating over a distance of 210 m. Our method exploits OAM in combination with optical polarization to encode the information in rotation-invariant photonic states, so as to guarantee full independence of the communication from the local reference frames of the transmitting and receiving units. In particular, we implement quantum key distribution, a protocol exploiting the features of quantum mechanics to guarantee unconditional security in cryptographic communication, demonstrating error-rate performances that are fully compatible with real-world application requirements. Our results extend previous achievements of OAM-based quantum communication by over 2 orders of magnitude in the link scale, providing an important step forward in achieving the vision of a worldwide quantum network.

Electric currents induced by twisted light in Quantum Rings.

PubMed

Quinteiro, G F; Berakdar, J

2009-10-26

We theoretically investigate the generation of electric currents in quantum rings resulting from the optical excitation with twisted light. Our model describes the kinetics of electrons in a two-band model of a semiconductor-based mesoscopic quantum ring coupled to light having orbital angular momentum (twisted light). We find the analytical solution, which exhibits a "circular" photon-drag effect and an induced magnetization, suggesting that this system is the circular analog of that of a bulk semiconductor excited by plane waves. For realistic values of the electric field and material parameters, the computed electric current can be as large as microA; from an applied perspective, this opens new possibilities to the optical control of the magnetization in semiconductors.

High angular resolution at LBT

NASA Astrophysics Data System (ADS)

Conrad, A.; Arcidiacono, C.; Bertero, M.; Boccacci, P.; Davies, A. G.; Defrere, D.; de Kleer, K.; De Pater, I.; Hinz, P.; Hofmann, K. H.; La Camera, A.; Leisenring, J.; Kürster, M.; Rathbun, J. A.; Schertl, D.; Skemer, A.; Skrutskie, M.; Spencer, J. R.; Veillet, C.; Weigelt, G.; Woodward, C. E.

2015-12-01

High angular resolution from ground-based observatories stands as a key technology for advancing planetary science. In the window between the angular resolution achievable with 8-10 meter class telescopes, and the 23-to-40 meter giants of the future, LBT provides a glimpse of what the next generation of instruments providing higher angular resolution will provide. We present first ever resolved images of an Io eruption site taken from the ground, images of Io's Loki Patera taken with Fizeau imaging at the 22.8 meter LBT [Conrad, et al., AJ, 2015]. We will also present preliminary analysis of two data sets acquired during the 2015 opposition: L-band fringes at Kurdalagon and an occultation of Loki and Pele by Europa (see figure). The light curves from this occultation will yield an order of magnitude improvement in spatial resolution along the path of ingress and egress. We will conclude by providing an overview of the overall benefit of recent and future advances in angular resolution for planetary science.

Superposition and detection of two helical beams for optical orbital angular momentum communication

NASA Astrophysics Data System (ADS)

Liu, Yi-Dong; Gao, Chunqing; Gao, Mingwei; Qi, Xiaoqing; Weber, Horst

2008-07-01

A loop-like system with a Dove prism is used to generate a collinear superposition of two helical beams with different azimuthal quantum numbers in this manuscript. After the generation of the helical beams distributed on the circle centered at the optical axis by using a binary amplitude grating, the diffractive field is separated into two polarized ones with the same distribution. Rotated by the Dove prism in the loop-like system in counter directions and combined together, the two fields will generate the collinear superposition of two helical beams in certain direction. The experiment shows consistency with the theoretical analysis. This method has potential applications in optical communication by using orbital angular momentum of laser beams (optical vortices).

Variations in atmospheric angular momentum

NASA Technical Reports Server (NTRS)

Rosen, R. D.; Salstein, D. A.

1981-01-01

Twice-daily values of the atmosphere's angular momentum about the polar axis during the five years from 1976 through 1980 are presented in graphs and a table. The compilation is based on a global data set, incorporating 90 percent of the mass of the atmosphere. The relationship between changes in the angular momentum of the atmosphere and changes in the length of day is described, as are the main sources of error in the data. The variability in angular momentum is revealed in a preliminary fashion by means of a spectral decomposition. The data presented should stimulate comparisons with other measures of the length of day and so provide a basis for greater understanding of Earth-atmosphere interactions.

Angular integrals in d dimensions

NASA Astrophysics Data System (ADS)

Somogyi, Gábor

2011-08-01

We discuss the evaluation of certain d-dimensional angular integrals which arise in perturbative field theory calculations. We find that the angular integral with n denominators can be computed in terms of a certain special function, the so-called H-function of several variables. We also present several illustrative examples of the general result and briefly consider some applications.

Fluidic angular velocity sensor

NASA Technical Reports Server (NTRS)

Berdahl, C. M. (Inventor)

1986-01-01

A fluidic sensor providing a differential pressure signal proportional to the angular velocity of a rotary input is described. In one embodiment the sensor includes a fluid pump having an impeller coupled to a rotary input. A housing forming a constricting fluid flow chamber is connected to the fluid input of the pump. The housing is provided with a fluid flow restrictive input to the flow chamber and a port communicating with the interior of the flow chamber. The differential pressure signal measured across the flow restrictive input is relatively noise free and proportional to the square of the angular velocity of the impeller. In an alternative embodiment, the flow chamber has a generally cylindrical configuration and plates having flow restrictive apertures are disposed within the chamber downstream from the housing port. In this embodiment, the differential pressure signal is found to be approximately linear with the angular velocity of the impeller.

Test of mutually unbiased bases for six-dimensional photonic quantum systems

PubMed Central

D'Ambrosio, Vincenzo; Cardano, Filippo; Karimi, Ebrahim; Nagali, Eleonora; Santamato, Enrico; Marrucci, Lorenzo; Sciarrino, Fabio

2013-01-01

In quantum information, complementarity of quantum mechanical observables plays a key role. The eigenstates of two complementary observables form a pair of mutually unbiased bases (MUBs). More generally, a set of MUBs consists of bases that are all pairwise unbiased. Except for specific dimensions of the Hilbert space, the maximal sets of MUBs are unknown in general. Even for a dimension as low as six, the identification of a maximal set of MUBs remains an open problem, although there is strong numerical evidence that no more than three simultaneous MUBs do exist. Here, by exploiting a newly developed holographic technique, we implement and test different sets of three MUBs for a single photon six-dimensional quantum state (a “qusix”), encoded exploiting polarization and orbital angular momentum of photons. A close agreement is observed between theory and experiments. Our results can find applications in state tomography, quantitative wave-particle duality, quantum key distribution. PMID:24067548

Test of mutually unbiased bases for six-dimensional photonic quantum systems.

PubMed

D'Ambrosio, Vincenzo; Cardano, Filippo; Karimi, Ebrahim; Nagali, Eleonora; Santamato, Enrico; Marrucci, Lorenzo; Sciarrino, Fabio

2013-09-25

In quantum information, complementarity of quantum mechanical observables plays a key role. The eigenstates of two complementary observables form a pair of mutually unbiased bases (MUBs). More generally, a set of MUBs consists of bases that are all pairwise unbiased. Except for specific dimensions of the Hilbert space, the maximal sets of MUBs are unknown in general. Even for a dimension as low as six, the identification of a maximal set of MUBs remains an open problem, although there is strong numerical evidence that no more than three simultaneous MUBs do exist. Here, by exploiting a newly developed holographic technique, we implement and test different sets of three MUBs for a single photon six-dimensional quantum state (a "qusix"), encoded exploiting polarization and orbital angular momentum of photons. A close agreement is observed between theory and experiments. Our results can find applications in state tomography, quantitative wave-particle duality, quantum key distribution.

Experimental ladder proof of Hardy's nonlocality for high-dimensional quantum systems

NASA Astrophysics Data System (ADS)

Chen, Lixiang; Zhang, Wuhong; Wu, Ziwen; Wang, Jikang; Fickler, Robert; Karimi, Ebrahim

2017-08-01

Recent years have witnessed a rapidly growing interest in high-dimensional quantum entanglement for fundamental studies as well as towards novel applications. Therefore, the ability to verify entanglement between physical qudits, d -dimensional quantum systems, is of crucial importance. To show nonclassicality, Hardy's paradox represents "the best version of Bell's theorem" without using inequalities. However, so far it has only been tested experimentally for bidimensional vector spaces. Here, we formulate a theoretical framework to demonstrate the ladder proof of Hardy's paradox for arbitrary high-dimensional systems. Furthermore, we experimentally demonstrate the ladder proof by taking advantage of the orbital angular momentum of high-dimensionally entangled photon pairs. We perform the ladder proof of Hardy's paradox for dimensions 3 and 4, both with the ladder up to the third step. Our paper paves the way towards a deeper understanding of the nature of high-dimensionally entangled quantum states and may find applications in quantum information science.

Photodissociation of HBr/LiF(001): A quantum mechanical model

NASA Technical Reports Server (NTRS)

Seideman, Tamar

1993-01-01

The photodissociation dynamics of HBr adsorbed on a LiF(001) surface is studied using time-independent quantum mechanics. The photodissociation lineshape and the Br(P(sub 1/2)-2)/Br(P(sub 3/2)-2) yield ratio are computed and compared with the corresponding quantities for gas phase photodissociation. The angular distribution of the hydrogen photofragments following excitation of adsorbed HBr is computed and found to agree qualitatively with experimental data. The effect of polarization of the photon is illustrated and discussed. The field polarization is found to affect significantly the magnitude of the photodissociation signal but not the angular dependence of the photofragment distribution, in agreement with experiment and in accord with expectations for a strongly aligned adsorbed phase.

Photodissociation of HBr/LiF(001) - A quantum mechanical model

NASA Technical Reports Server (NTRS)

Seideman, Tamar

1993-01-01

The photodissociation dynamics of HBr adsorbed on an LiF(001) surface is studied using time-independent quantum mechanics. The photodissociation line shape and the Br(2P(1/2))/Br(2P(3/2)) yield ratio are computed and compared with the corresponding quantities for gas phase photodissociation. The angular distribution of the hydrogen photofragments following excitation of adsorbed HBr is computed and found to agree qualitatively with experimental data. The effect of polarization of the photon is illustrated and discussed. We find the field polarization to affect significantly the magnitude of the photodissociation signal but not the angular dependence of the photofragment distribution, in agreement with experiment and in accord with expectations for a strongly aligned adsorbed phase.

Exact wave functions of two-electron quantum rings.

PubMed

Loos, Pierre-François; Gill, Peter M W

2012-02-24

We demonstrate that the Schrödinger equation for two electrons on a ring, which is the usual paradigm to model quantum rings, is solvable in closed form for particular values of the radius. We show that both polynomial and irrational solutions can be found for any value of the angular momentum and that the singlet and triplet manifolds, which are degenerate, have distinct geometric phases. We also study the nodal structure associated with these two-electron states.

Knockout of deuterons and tritons with large transverse momenta in pA collisions involving 50-GeV protons

NASA Astrophysics Data System (ADS)

Antonov, N. N.; Baldin, A. A.; Viktorov, V. A.; Gapienko, V. A.; Gapienko, G. S.; Gres', V. N.; Ilyushin, M. A.; Korotkov, V. A.; Mysnik, A. I.; Prudkoglyad, A. F.; Semak, A. A.; Terekhov, V. I.; Uglekov, V. Ya.; Ukhanov, M. N.; Chuiko, B. V.; Shimanskii, S. S.

2016-11-01

Formation of the d and t cumulative light nuclear fragments emitted from the nucleus with large transverse momenta at an angle of 35° in the laboratory frame is investigated. The data on collisions of 50-GeV protons with the C, Al, Cu, and W nuclei are collected using the extracted proton beam of the IHEP accelerator and the SPIN detector. The results indicate that the dominant contribution to formation of nuclear fragments comes from the local process of direct knockout from the nucleus.

Controlled finite momentum pairing and spatially varying order parameter in proximitized HgTe quantum wells

NASA Astrophysics Data System (ADS)

Hart, Sean; Ren, Hechen; Kosowsky, Michael; Ben-Shach, Gilad; Leubner, Philipp; Bruene, Christoph; Buhmann, Hartmut; Molenkamp, Laurens; Halperin, Bertrand; Yacoby, Amir

Conventional s-wave superconductivity arises from singlet pairing of electrons with opposite Fermi momenta, forming Cooper pairs with zero net momentum. Recent studies have focused on coupling s-wave superconductors to systems with an unusual configuration of electronic spin and momentum at the Fermi surface, where the nature of the paired state can be modified and the system may even undergo a topological phase transition. Here we present measurements on Josephson junctions based on HgTe quantum wells coupled to aluminum or niobium superconductors, and subject to a magnetic field in the plane of the quantum well. We observe that the in-plane magnetic field modulates the Fraunhofer interference pattern, and that this modulation depends both on electron density and on the direction of the in-plane field with respect to the junction. However, the orientation of the junction with respect to the underlying crystal lattice does not impact the measurements. These findings suggest that spin-orbit coupling plays a role in the observed behavior, and that measurements of Josephson junctions in the presence of an in-plane field can elucidate the Fermi surface properties of the weak link material. NSF DMR-1206016; STC Center for Integrated Quantum Materials under NSF Grant No. DMR-1231319; NSF GRFP under Grant DGE1144152, Microsoft Corporation Project Q.

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Study of transverse momenta of charged hadrons produced in ν p andbar vp charged current interactions

NASA Astrophysics Data System (ADS)

Jones, G. T.; Kennedy, B. W.; Middleton, R. P.; O'Neale, S. W.; Cooper, A. M.; Grant, A.; Klein, H.; Mittendorfer, J.; Morrison, D. R. O.; Parker, A.; Schmid, P.; Wachsmuth, H.; Hamisi, F.; Mobayyen, M. M.; Villalobos-Baillie, O.; Aderholz, M.; Deck, L.; Schmitz, N.; Wittek, W.; Corrigan, G.; Myatt, G.; Radojicic, D.; Retter, M.

1984-06-01

Data from a neutrino and antineutrino hydrogen experiment with BEBC are used to investigate transverse properties of the produced charged hadrons. Measurements are presented on average transverse momenta of charged pions as functions of Feynman- x and the hadronic mass, on the transverse momentum flow within an event and on jet-related quantities. The main features of the data are well described by the LUND model. The data favour a version of the model in which soft gluon effects are included and the primordial transverse momentum of the quarks in the proton is small. Effects from 1st order QCD (hard gluon emission) are negligible.

Polarization properties of long-lived stimulated photon echo

NASA Astrophysics Data System (ADS)

Reshetov, V. A.; Popov, E. N.

2015-01-01

The polarization properties of the long-lived stimulated photon echo formed on the transition ja → jb with the atomic levels degenerate in the projections of the angular momenta are studied theoretically. The two particular transitions ja = 1 → jb = 0 and ja = 1 → jb = 1 with degenerate ground state ja = 1 are discussed. For the transitions ja = 1 → jb = 1 the polarizations and areas of the first (‘write’) and the third (‘read’) excitation pulses are found when the echo polarization faithfully reproduces the arbitrary polarization of the weak (single-photon) second (‘information’) pulse, so that this echo scheme may implement the quantum memory for a single-photon polarization qubit, while for the transitions ja = 1 → jb = 0 it is shown, that the echo polarization differs from that of the second pulse at any conditions.

Fluctuation analysis of relativistic nucleus-nucleus collisions in emulsion chambers

NASA Technical Reports Server (NTRS)

Mcguire, Stephen C.

1988-01-01

An analytical technique was developed for identifying enhanced fluctuations in the angular distributions of secondary particles produced from relativistic nucleus-nucleus collisions. The method is applied under the assumption that the masses of the produced particles are small compared to their linear momenta. The importance of particles rests in the fact that enhanced fluctuations in the rapidity distributions is considered to be an experimental signal for the creation of the quark-gluon-plasma (QGP), a state of nuclear matter predicted from the quantum chromodynamics theory (QCD). In the approach, Monte Carlo simulations are employed that make use of a portable random member generator that allow the calculations to be performed on a desk-top computer. The method is illustrated with data taken from high altitude emulsion exposures and is immediately applicable to similar data from accelerator-based emulsion exposures.

Thermodynamics and Hawking radiation of five-dimensional rotating charged Goedel black holes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu Shuangqing; Peng Junjin; College of Science, Wuhan Textile University, Wuhan, Hubei 430074

2011-02-15

We study the thermodynamics of Goedel-type rotating charged black holes in five-dimensional minimal supergravity. These black holes exhibit some peculiar features such as the presence of closed timelike curves and the absence of a globally spatial-like Cauchy surface. We explicitly compute their energies, angular momenta, and electric charges that are consistent with the first law of thermodynamics. Besides, we extend the covariant anomaly cancellation method, as well as the approach of the effective action, to derive their Hawking fluxes. Both the methods of the anomaly cancellation and the effective action give the same Hawking fluxes as those from the Planckmore » distribution for blackbody radiation in the background of the charged rotating Goedel black holes. Our results further support that Hawking radiation is a quantum phenomenon arising at the event horizon.« less

ZFIRE: 3D Modeling of Rotation, Dispersion, and Angular Momentum of Star-forming Galaxies at z ∼ 2

NASA Astrophysics Data System (ADS)

Alcorn, Leo Y.; Tran, Kim-Vy; Glazebrook, Karl; Straatman, Caroline M.; Cowley, Michael; Forrest, Ben; Kacprzak, Glenn G.; Kewley, Lisa J.; Labbé, Ivo; Nanayakkara, Themiya; Spitler, Lee R.; Tomczak, Adam; Yuan, Tiantian

2018-05-01

We perform a kinematic and morphological analysis of 44 star-forming galaxies at z ∼ 2 in the COSMOS legacy field using near-infrared spectroscopy from Keck/MOSFIRE and F160W imaging from CANDELS/3D-HST as part of the ZFIRE survey. Our sample consists of cluster and field galaxies from 2.0 < z < 2.5 with K-band multi-object slit spectroscopic measurements of their Hα emission lines. Hα rotational velocities and gas velocity dispersions are measured using the Heidelberg Emission Line Algorithm (HELA), which compares directly to simulated 3D data cubes. Using a suite of simulated emission lines, we determine that HELA reliably recovers input S 0.5 and angular momentum at small offsets, but V 2.2/σ g values are offset and highly scattered. We examine the role of regular and irregular morphology in the stellar mass kinematic scaling relations, deriving the kinematic measurement S 0.5, and finding {log}({S}0.5)=(0.38+/- 0.07){log}(M/{M}ȯ -10)+(2.04+/- 0.03) with no significant offset between morphological populations and similar levels of scatter (∼0.16 dex). Additionally, we identify a correlation between M ⋆ and V 2.2/σ g for the total sample, showing an increasing level of rotation dominance with increasing M ⋆, and a high level of scatter for both regular and irregular galaxies. We estimate the specific angular momenta (j disk) of these galaxies and find a slope of 0.36 ± 0.12, shallower than predicted without mass-dependent disk growth, but this result is possibly due to measurement uncertainty at M ⋆ < 9.5 However, through a Kolmogorov–Smirnov test we find irregular galaxies to have marginally higher j disk values than regular galaxies, and high scatter at low masses in both populations.

Spatial intensity distribution of controlled-NOT gate carrying orbital angular momentum via photonic band gap structure

NASA Astrophysics Data System (ADS)

Zhang, Yan; Wang, Xiaorui; Zhe Zhang, Yun

2018-07-01

By employing the different topological charges of a Laguerre–Gaussian beam as a qubit, we experimentally demonstrate a controlled-NOT (CNOT) gate with light beams carrying orbital angular momentum via a photonic band gap structure in a hot atomic ensemble. Through a degenerate four-wave mixing process, the spatial distribution of the CNOT gate including splitting and spatial shift can be affected by the Kerr nonlinear effect in multilevel atomic systems. Moreover, the intensity variations of the CNOT gate can be controlled by the relative phase modulation. This research can be useful for applications in quantum information processing.

Photodissociation of quantum state-selected diatomic molecules yields new insight into ultracold chemistry

NASA Astrophysics Data System (ADS)

McDonald, Mickey; McGuyer, Bart H.; Lee, Chih-Hsi; Apfelbeck, Florian; Zelevinsky, Tanya

2016-05-01

When a molecule is subjected to a sufficiently energetic photon it can break apart into fragments through a process called ``photodissociation''. For over 70 years this simple chemical reaction has served as a vital experimental tool for acquiring information about molecular structure, since the character of the photodissociative transition can be inferred by measuring the 3D photofragment angular distribution (PAD). While theoretical understanding of this process has gradually evolved from classical considerations to a fully quantum approach, experiments to date have not yet revealed the full quantum nature of this process. In my talk I will describe recent experiments involving the photodissociation of ultracold, optical lattice-trapped, and fully quantum state-resolved 88Sr2 molecules. Optical absorption images of the PADs produced in these experiments reveal features which are inherently quantum mechanical in nature, such as matter-wave interference between output channels, and are sensitive to the quantum statistics of the molecular wavefunctions. The results of these experiments cannot be predicted using quasiclassical methods. Instead, we describe our results with a fully quantum mechanical model yielding new intuition about ultracold chemistry.

Effects of electronic interactions near the topological semimetal-insulator quantum phase transition in two dimensions

NASA Astrophysics Data System (ADS)

Roy, Bitan; Foster, Matthew

The quasiparticle dispersion of gapless excitations residing at the quantum critical point (QCP) separating a two dimensional topological Dirac semimetal and a symmetry preserving band insulator, displays distinct power-law dependence with various components of spatial momenta. In this talk first I will review scaling of various thermodynamic and transport quantities at this QCP. Next I will demonstrate that even though such noninteracting QCP is stable against sufficiently weak but generic short-range interaction, the direct transition between the Dirac semimetal and band insulator can either (i) become a fluctuation driven first order transition, or (ii) get eliminated by an intervening broken symmetry phase, with staggered pattern in charge or spin being two prominent candidates, for sufficiently strong interactions. The novel quantum critical phenomena associated with the instability of critical excitations toward the formation of various broken symmetry phases will be discussed. Relevance of our study in strained graphene, black phosphorus, pressured organic compounds and oxide heterostructure will be highlighted. Welch Foundation Grant No. C-1809, NSF CAREER Grant No. DMR-1552327.

Gas Accretion and Angular Momentum

NASA Astrophysics Data System (ADS)

Stewart, Kyle R.

In this chapter, we review the role of gas accretion to the acquisition of angular momentum, both in galaxies and in their gaseous halos. We begin by discussing angular momentum in dark matter halos, with a brief review of tidal torque theory and the importance of mergers, followed by a discussion of the canonical picture of galaxy formation within this framework, where halo gas is presumed to shock-eat to the virial temperature of the halo, following the same spin distribution as the dark matter halo before cooling to the center of the halo to form a galaxy there. In the context of recent observational evidence demonstrating the presence of high angular momentum gas in galaxy halos, we review recent cosmological hydrodynamic simulations that have begun to emphasize the role of "cold flow" accretion—anisotropic gas accretion along cosmic filaments that does not shock-heat before sinking to the central galaxy. We discuss the implications of these simulations, reviewing a number of recent developments in the literature, and suggest a revision to the canonical model as it relates to the expected angular momentum content of gaseous halos around galaxies.

Electrostatically confined trilayer graphene quantum dots

NASA Astrophysics Data System (ADS)

Mirzakhani, M.; Zarenia, M.; Vasilopoulos, P.; Peeters, F. M.

2017-04-01

Electrically gating of trilayer graphene (TLG) opens a band gap offering the possibility to electrically engineer TLG quantum dots. We study the energy levels of such quantum dots and investigate their dependence on a perpendicular magnetic field B and different types of stacking of the graphene layers. The dots are modeled as circular and confined by a truncated parabolic potential which can be realized by nanostructured gates or position-dependent doping. The energy spectra exhibit the intervalley symmetry EKe(m ) =-EK'h(m ) for the electron (e ) and hole (h ) states, where m is the angular momentum quantum number and K and K ' label the two valleys. The electron and hole spectra for B =0 are twofold degenerate due to the intervalley symmetry EK(m ) =EK'[-(m +1 ) ] . For both ABC [α =1.5 (1.2) for large (small) R ] and ABA (α =1 ) stackings, the lowest-energy levels show approximately a R-α dependence on the dot radius R in contrast with the 1 /R3 one for ABC-stacked dots with infinite-mass boundary. As functions of the field B , the oscillator strengths for dipole-allowed transitions differ drastically for the two types of stackings.

Orbital angular momentum modes of high-gain parametric down-conversion

NASA Astrophysics Data System (ADS)

Beltran, Lina; Frascella, Gaetano; Perez, Angela M.; Fickler, Robert; Sharapova, Polina R.; Manceau, Mathieu; Tikhonova, Olga V.; Boyd, Robert W.; Leuchs, Gerd; Chekhova, Maria V.

2017-04-01

Light beams with orbital angular momentum (OAM) are convenient carriers of quantum information. They can also be used for imparting rotational motion to particles and providing high resolution in imaging. Due to the conservation of OAM in parametric down-conversion (PDC), signal and idler photons generated at low gain have perfectly anti-correlated OAM values. It is interesting to study the OAM properties of high-gain PDC, where the same OAM modes can be populated with large, but correlated, numbers of photons. Here we investigate the OAM spectrum of high-gain PDC and show that the OAM mode content can be controlled by varying the pump power and the configuration of the source. In our experiment, we use a source consisting of two nonlinear crystals separated by an air gap. We discuss the OAM properties of PDC radiation emitted by this source and suggest possible modifications.

Wigner crystalline edges in ν<~1 quantum dots

NASA Astrophysics Data System (ADS)

Goldmann, Eyal; Renn, Scot R.

1999-12-01

We investigate the edge reconstruction phenomenon believed to occur in quantum dots in the quantum Hall regime when the filling fraction is ν<~1. Our approach involves the examination of large dots (<= 40 electrons) using a partial diagonalization technique in which the occupancies of the deep interior orbitals are frozen. To interpret the results of this calculation, we evaluate the overlap between the diagonalized ground state and a set of trial wave functions which we call projected necklace (PN) states. A PN state is simply the angular momentum projection of a maximum density droplet surrounded by a ring of localized electrons. Our calculations reveal that PN states have up to 99% overlap with the diagonalized ground states, and are lower in energy than the states identified in Chamon and Wen's study of the edge reconstruction.

Whole-body angular momentum during stair ascent and descent.

PubMed

Silverman, Anne K; Neptune, Richard R; Sinitski, Emily H; Wilken, Jason M

2014-04-01

The generation of whole-body angular momentum is essential in many locomotor tasks and must be regulated in order to maintain dynamic balance. However, angular momentum has not been investigated during stair walking, which is an activity that presents a biomechanical challenge for balance-impaired populations. We investigated three-dimensional whole-body angular momentum during stair ascent and descent and compared it to level walking. Three-dimensional body-segment kinematic and ground reaction force (GRF) data were collected from 30 healthy subjects. Angular momentum was calculated using a 13-segment whole-body model. GRFs, external moment arms and net joint moments were used to interpret the angular momentum results. The range of frontal plane angular momentum was greater for stair ascent relative to level walking. In the transverse and sagittal planes, the range of angular momentum was smaller in stair ascent and descent relative to level walking. Significant differences were also found in the ground reaction forces, external moment arms and net joint moments. The sagittal plane angular momentum results suggest that individuals alter angular momentum to effectively counteract potential trips during stair ascent, and reduce the range of angular momentum to avoid falling forward during stair descent. Further, significant differences in joint moments suggest potential neuromuscular mechanisms that account for the differences in angular momentum between walking conditions. These results provide a baseline for comparison to impaired populations that have difficulty maintaining dynamic balance, particularly during stair ascent and descent. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantum theory of the generalised uncertainty principle

NASA Astrophysics Data System (ADS)

Bruneton, Jean-Philippe; Larena, Julien

2017-04-01

We extend significantly previous works on the Hilbert space representations of the generalized uncertainty principle (GUP) in 3 + 1 dimensions of the form [X_i,P_j] = i F_{ij} where F_{ij} = f({{P}}^2) δ _{ij} + g({{P}}^2) P_i P_j for any functions f. However, we restrict our study to the case of commuting X's. We focus in particular on the symmetries of the theory, and the minimal length that emerge in some cases. We first show that, at the algebraic level, there exists an unambiguous mapping between the GUP with a deformed quantum algebra and a quadratic Hamiltonian into a standard, Heisenberg algebra of operators and an aquadratic Hamiltonian, provided the boost sector of the symmetries is modified accordingly. The theory can also be mapped to a completely standard Quantum Mechanics with standard symmetries, but with momentum dependent position operators. Next, we investigate the Hilbert space representations of these algebraically equivalent models, and focus specifically on whether they exhibit a minimal length. We carry the functional analysis of the various operators involved, and show that the appearance of a minimal length critically depends on the relationship between the generators of translations and the physical momenta. In particular, because this relationship is preserved by the algebraic mapping presented in this paper, when a minimal length is present in the standard GUP, it is also present in the corresponding Aquadratic Hamiltonian formulation, despite the perfectly standard algebra of this model. In general, a minimal length requires bounded generators of translations, i.e. a specific kind of quantization of space, and this depends on the precise shape of the function f defined previously. This result provides an elegant and unambiguous classification of which universal quantum gravity corrections lead to the emergence of a minimal length.

Excess of J/ψ Production at Very Low Transverse Momenta in A+A Collisions from STAR

NASA Astrophysics Data System (ADS)

Zha, Wangmei

A significant excess of J/ψ yield at very low transverse momentum (pT < 0.3 GeV/c) has been observed by the ALICE Collaboration in peripheral Pb+Pb collisions, which points to evidence of coherent photoproduction of J/ψ in violent hadronic interactions. The survival of photoproduced J/ψ merits more experimental investigations. In this article, we report on the STAR measurements of J/ψ production at very low transverse momenta (pT) in hadronic Au+Au collisions at sNN = 200 GeV and U+U collisions at sNN = 193 GeV at mid-rapidity. Centrality dependence of J/ψ yields and nuclear modification factors at very low pT are presented.

THE IMPACT OF STELLAR FEEDBACK ON THE STRUCTURE, SIZE, AND MORPHOLOGY OF GALAXIES IN MILKY-WAY-SIZED DARK MATTER HALOS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Agertz, Oscar; Kravtsov, Andrey V., E-mail: o.agertz@surrey.ac.uk

We use cosmological zoom-in simulations of galaxy formation in a Milky-Way-sized halo started from identical initial conditions to investigate the evolution of galaxy sizes, baryon fractions, morphologies, and angular momenta in runs with different parameters of the star formation–feedback cycle. Our fiducial model with a high local star formation efficiency, which results in efficient feedback, produces a realistic late-type galaxy that matches the evolution of basic properties of late-type galaxies: stellar mass, disk size, morphology dominated by a kinematically cold disk, stellar and gas surface density profiles, and specific angular momentum. We argue that feedback’s role in this success ismore » twofold: (1) removal of low angular momentum gas, and (2) maintaining a low disk-to-halo mass fraction, which suppresses disk instabilities that lead to angular momentum redistribution and a central concentration of baryons. However, our model with a low local star formation efficiency, but large energy input per supernova, chosen to produce a galaxy with a similar star formation history as our fiducial model, leads to a highly irregular galaxy with no kinematically cold component, overly extended stellar distribution, and low angular momentum. This indicates that only when feedback is allowed to become vigorous via locally efficient star formation in dense cold gas do resulting galaxy sizes, gas/stellar surface density profiles, and stellar disk angular momenta agree with observed z = 0 galaxies.« less

Quantum entanglement and spin control in silicon nanocrystal.

PubMed

Berec, Vesna

2012-01-01

Selective coherence control and electrically mediated exchange coupling of single electron spin between triplet and singlet states using numerically derived optimal control of proton pulses is demonstrated. We obtained spatial confinement below size of the Bohr radius for proton spin chain FWHM. Precise manipulation of individual spins and polarization of electron spin states are analyzed via proton induced emission and controlled population of energy shells in pure (29)Si nanocrystal. Entangled quantum states of channeled proton trajectories are mapped in transverse and angular phase space of (29)Si <100> axial channel alignment in order to avoid transversal excitations. Proton density and proton energy as impact parameter functions are characterized in single particle density matrix via discretization of diagonal and nearest off-diagonal elements. We combined high field and low densities (1 MeV/92 nm) to create inseparable quantum state by superimposing the hyperpolarizationed proton spin chain with electron spin of (29)Si. Quantum discretization of density of states (DOS) was performed by the Monte Carlo simulation method using numerical solutions of proton equations of motion. Distribution of gaussian coherent states is obtained by continuous modulation of individual spin phase and amplitude. Obtained results allow precise engineering and faithful mapping of spin states. This would provide the effective quantum key distribution (QKD) and transmission of quantum information over remote distances between quantum memory centers for scalable quantum communication network. Furthermore, obtained results give insights in application of channeled protons subatomic microscopy as a complete versatile scanning-probe system capable of both quantum engineering of charged particle states and characterization of quantum states below diffraction limit linear and in-depth resolution.PACS NUMBERS: 03.65.Ud, 03.67.Bg, 61.85.+p, 67.30.hj.

Angular Momentum

ERIC Educational Resources Information Center

Shakur, Asif; Sinatra, Taylor

2013-01-01

The gyroscope in a smartphone was employed in a physics laboratory setting to verify the conservation of angular momentum and the nonconservation of rotational kinetic energy. As is well-known, smartphones are ubiquitous on college campuses. These devices have a panoply of built-in sensors. This creates a unique opportunity for a new paradigm in…

Squashed, magnetized black holes in D = 5 minimal gauged supergravity

NASA Astrophysics Data System (ADS)

Blázquez-Salcedo, Jose Luis; Kunz, Jutta; Navarro-Lérida, Francisco; Radu, Eugen

2018-02-01

We construct a new class of black hole solutions in five-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant. These configurations are cohomogeneity-1, with two equal-magnitude angular momenta. In the generic case, they possess a non-vanishing magnetic potential at infinity with a boundary metric which is the product of time and a squashed three-dimensional sphere. Both extremal and non-extremal black holes are studied. The non-extremal black holes satisfying a certain relation between electric charge, angular momenta and magnitude of the magnetic potential at infinity do not trivialize in the limit of vanishing event horizon size, becoming particle-like (non-topological) solitonic configurations. Among the extremal black holes, we show the existence of a new one-parameter family of supersymmetric solutions, which bifurcate from a critical Gutowski-Reall configuration.

Quantum teleportation of multiple degrees of freedom of a single photon

NASA Astrophysics Data System (ADS)

Wang, Xi-Lin; Cai, Xin-Dong; Su, Zu-En; Chen, Ming-Cheng; Wu, Dian; Li, Li; Liu, Nai-Le; Lu, Chao-Yang; Pan, Jian-Wei

2015-02-01

Quantum teleportation provides a `disembodied' way to transfer quantum states from one object to another at a distant location, assisted by previously shared entangled states and a classical communication channel. As well as being of fundamental interest, teleportation has been recognized as an important element in long-distance quantum communication, distributed quantum networks and measurement-based quantum computation. There have been numerous demonstrations of teleportation in different physical systems such as photons, atoms, ions, electrons and superconducting circuits. All the previous experiments were limited to the teleportation of one degree of freedom only. However, a single quantum particle can naturally possess various degrees of freedom--internal and external--and with coherent coupling among them. A fundamental open challenge is to teleport multiple degrees of freedom simultaneously, which is necessary to describe a quantum particle fully and, therefore, to teleport it intact. Here we demonstrate quantum teleportation of the composite quantum states of a single photon encoded in both spin and orbital angular momentum. We use photon pairs entangled in both degrees of freedom (that is, hyper-entangled) as the quantum channel for teleportation, and develop a method to project and discriminate hyper-entangled Bell states by exploiting probabilistic quantum non-demolition measurement, which can be extended to more degrees of freedom. We verify the teleportation for both spin-orbit product states and hybrid entangled states, and achieve a teleportation fidelity ranging from 0.57 to 0.68, above the classical limit. Our work is a step towards the teleportation of more complex quantum systems, and demonstrates an increase in our technical control of scalable quantum technologies.

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Quantum teleportation of multiple degrees of freedom of a single photon.

PubMed

Wang, Xi-Lin; Cai, Xin-Dong; Su, Zu-En; Chen, Ming-Cheng; Wu, Dian; Li, Li; Liu, Nai-Le; Lu, Chao-Yang; Pan, Jian-Wei

2015-02-26

Quantum teleportation provides a 'disembodied' way to transfer quantum states from one object to another at a distant location, assisted by previously shared entangled states and a classical communication channel. As well as being of fundamental interest, teleportation has been recognized as an important element in long-distance quantum communication, distributed quantum networks and measurement-based quantum computation. There have been numerous demonstrations of teleportation in different physical systems such as photons, atoms, ions, electrons and superconducting circuits. All the previous experiments were limited to the teleportation of one degree of freedom only. However, a single quantum particle can naturally possess various degrees of freedom--internal and external--and with coherent coupling among them. A fundamental open challenge is to teleport multiple degrees of freedom simultaneously, which is necessary to describe a quantum particle fully and, therefore, to teleport it intact. Here we demonstrate quantum teleportation of the composite quantum states of a single photon encoded in both spin and orbital angular momentum. We use photon pairs entangled in both degrees of freedom (that is, hyper-entangled) as the quantum channel for teleportation, and develop a method to project and discriminate hyper-entangled Bell states by exploiting probabilistic quantum non-demolition measurement, which can be extended to more degrees of freedom. We verify the teleportation for both spin-orbit product states and hybrid entangled states, and achieve a teleportation fidelity ranging from 0.57 to 0.68, above the classical limit. Our work is a step towards the teleportation of more complex quantum systems, and demonstrates an increase in our technical control of scalable quantum technologies.

Search for new physics with dijet angular distributions in proton-proton collisions at √{s}=13 TeV

NASA Astrophysics Data System (ADS)

Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; König, A.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rad, N.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Strauss, J.; Waltenberger, W.; Wulz, C.-E.; Dvornikov, O.; Makarenko, V.; Mossolov, V.; Suarez Gonzalez, J.; Zykunov, V.; Shumeiko, N.; Alderweireldt, S.; De Wolf, E. A.; Janssen, X.; Lauwers, J.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; De Bruyn, I.; Deroover, K.; Lowette, S.; Moortgat, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Skovpen, K.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Parijs, I.; Brun, H.; Clerbaux, B.; De Lentdecker, G.; Delannoy, H.; Fasanella, G.; Favart, L.; Goldouzian, R.; Grebenyuk, A.; Karapostoli, G.; Lenzi, T.; Léonard, A.; Luetic, J.; Maerschalk, T.; Marinov, A.; Randle-conde, A.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Vannerom, D.; Yonamine, R.; Zenoni, F.; Zhang, F.; Cimmino, A.; Cornelis, T.; Dobur, D.; Fagot, A.; Gul, M.; Khvastunov, I.; Poyraz, D.; Salva, S.; Schöfbeck, R.; Tytgat, M.; Van Driessche, W.; Yazgan, E.; Zaganidis, N.; Bakhshiansohi, H.; Beluffi, C.; Bondu, O.; Brochet, S.; Bruno, G.; Caudron, A.; De Visscher, S.; Delaere, C.; Delcourt, M.; Francois, B.; Giammanco, A.; Jafari, A.; Komm, M.; Krintiras, G.; Lemaitre, V.; Magitteri, A.; Mertens, A.; Musich, M.; Piotrzkowski, K.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Wertz, S.; Beliy, N.; Aldá Júnior, W. L.; Alves, F. L.; Alves, G. A.; Brito, L.; Hensel, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; Da Silveira, G. G.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Torres Da Silva De Araujo, F.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Hadjiiska, R.; Iaydjiev, P.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Fang, W.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Chen, Y.; Cheng, T.; Jiang, C. H.; Leggat, D.; Liu, Z.; Romeo, F.; Ruan, M.; Shaheen, S. M.; Spiezia, A.; Tao, J.; Wang, C.; Wang, Z.; Zhang, H.; Zhao, J.; Ban, Y.; Chen, G.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; González Hernández, C. F.; Ruiz Alvarez, J. D.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Puljak, I.; Ribeiro Cipriano, P. M.; Sculac, T.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Ferencek, D.; Kadija, K.; Mesic, B.; Susa, T.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Tsiakkouri, D.; Finger, M.; Finger, M.; Carrera Jarrin, E.; Abdelalim, A. A.; Mohammed, Y.; Salama, E.; Kadastik, M.; Perrini, L.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Järvinen, T.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Ghosh, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Kucher, I.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Abdulsalam, A.; Antropov, I.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Davignon, O.; Granier de Cassagnac, R.; Jo, M.; Lisniak, S.; Miné, P.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Pigard, P.; Regnard, S.; Salerno, R.; Sirois, Y.; Strebler, T.; Yilmaz, Y.; Zabi, A.; Zghiche, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Buttignol, M.; Chabert, E. C.; Chanon, N.; Collard, C.; Conte, E.; Coubez, X.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Le Bihan, A.-C.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Bernet, C.; Boudoul, G.; Carrillo Montoya, C. A.; Chierici, R.; Contardo, D.; Courbon, B.; Depasse, P.; El Mamouni, H.; Fay, J.; Gascon, S.; Gouzevitch, M.; Grenier, G.; Ille, B.; Lagarde, F.; Laktineh, I. B.; Lethuillier, M.; Mirabito, L.; Pequegnot, A. L.; Perries, S.; Popov, A.; Sabes, D.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Toriashvili, T.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Feld, L.; Kiesel, M. K.; Klein, K.; Lipinski, M.; Preuten, M.; Schomakers, C.; Schulz, J.; Verlage, T.; Albert, A.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Endres, M.; Erdmann, M.; Erdweg, S.; Esch, T.; Fischer, R.; Güth, A.; Hamer, M.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Knutzen, S.; Merschmeyer, M.; Meyer, A.; Millet, P.; Mukherjee, S.; Olschewski, M.; Padeken, K.; Pook, T.; Radziej, M.; Reithler, H.; Rieger, M.; Scheuch, F.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Cherepanov, V.; Flügge, G.; Kargoll, B.; Kress, T.; Künsken, A.; Lingemann, J.; Müller, T.; Nehrkorn, A.; Nowack, A.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Arndt, T.; Asawatangtrakuldee, C.; Beernaert, K.; Behnke, O.; Behrens, U.; Bin Anuar, A. A.; Borras, K.; Campbell, A.; Connor, P.; Contreras-Campana, C.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Eren, E.; Gallo, E.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Grados Luyando, J. M.; Grohsjean, A.; Gunnellini, P.; Harb, A.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Karacheban, O.; Kasemann, M.; Keaveney, J.; Kleinwort, C.; Korol, I.; Krücker, D.; Lange, W.; Lelek, A.; Lenz, T.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Mankel, R.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Roland, B.; Sahin, M. Ö.; Saxena, P.; SchoernerSadenius, T.; Spannagel, S.; Stefaniuk, N.; Van Onsem, G. P.; Walsh, R.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Dreyer, T.; Garutti, E.; Gonzalez, D.; Haller, J.; Hoffmann, M.; Junkes, A.; Klanner, R.; Kogler, R.; Kovalchuk, N.; Lapsien, T.; Marchesini, I.; Marconi, D.; Meyer, M.; Niedziela, M.; Nowatschin, D.; Pantaleo, F.; Peiffer, T.; Perieanu, A.; Poehlsen, J.; Scharf, C.; Schleper, P.; Schmidt, A.; Schumann, S.; Schwandt, J.; Stadie, H.; Steinbrück, G.; Stober, F. M.; Stöver, M.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Vormwald, B.; Akbiyik, M.; Barth, C.; Baur, S.; Baus, C.; Berger, J.; Butz, E.; Caspart, R.; Chwalek, T.; Colombo, F.; De Boer, W.; Dierlamm, A.; Fink, S.; Freund, B.; Friese, R.; Giffels, M.; Gilbert, A.; Goldenzweig, P.; Haitz, D.; Hartmann, F.; Heindl, S. M.; Husemann, U.; Katkov, I.; Kudella, S.; Mildner, H.; Mozer, M. U.; Müller, Th.; Plagge, M.; Quast, G.; Rabbertz, K.; Röcker, S.; Roscher, F.; Schröder, M.; Shvetsov, I.; Sieber, G.; Simonis, H. J.; Ulrich, R.; Wayand, S.; Weber, M.; Weiler, T.; Williamson, S.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Topsis-Giotis, I.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Tziaferi, E.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Filipovic, N.; Pasztor, G.; Bencze, G.; Hajdu, C.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Makovec, A.; Molnar, J.; Szillasi, Z.; Bartók, M.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Komaragiri, J. R.; Bahinipati, S.; Bhowmik, S.; Choudhury, S.; Mal, P.; Mandal, K.; Nayak, A.; Sahoo, D. K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Kumari, P.; Mehta, A.; Mittal, M.; Singh, J. B.; Walia, G.; Kumar, Ashok; Bhardwaj, A.; Choudhary, B. C.; Garg, R. B.; Keshri, S.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, R.; Sharma, V.; Bhattacharya, R.; Bhattacharya, S.; Chatterjee, K.; Dey, S.; Dutt, S.; Dutta, S.; Ghosh, S.; Majumdar, N.; Modak, A.; Mondal, K.; Mukhopadhyay, S.; Nandan, S.; Purohit, A.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Thakur, S.; Behera, P. K.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Netrakanti, P. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Dugad, S.; Kole, G.; Mahakud, B.; Mitra, S.; Mohanty, G. B.; Parida, B.; Sur, N.; Sutar, B.; Banerjee, S.; Dewanjee, R. K.; Ganguly, S.; Guchait, M.; Jain, Sa.; Kumar, S.; Maity, M.; Majumder, G.; Mazumdar, K.; Sarkar, T.; Wickramage, N.; Chauhan, S.; Dube, S.; Hegde, V.; Kapoor, A.; Kothekar, K.; Pandey, S.; Rane, A.; Sharma, S.; Chenarani, S.; Eskandari Tadavani, E.; Etesami, S. M.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Colaleo, A.; Creanza, D.; Cristella, L.; De Filippis, N.; De Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Sharma, A.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Battilana, C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Chhibra, S. S.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. 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T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Spagnolo, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Barone, L.; Cavallari, F.; Cipriani, M.; Del Re, D.; Diemoz, M.; Gelli, S.; Longo, E.; Margaroli, F.; Marzocchi, B.; Meridiani, P.; Organtini, G.; Paramatti, R.; Preiato, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bartosik, N.; Bellan, R.; Biino, C.; Cartiglia, N.; Cenna, F.; Costa, M.; Covarelli, R.; Degano, A.; Demaria, N.; Finco, L.; Kiani, B.; Mariotti, C.; Maselli, S.; Migliore, E.; Monaco, V.; Monteil, E.; Monteno, M.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Ravera, F.; Romero, A.; Ruspa, M.; Sacchi, R.; Shchelina, K.; Sola, V.; Solano, A.; Staiano, A.; Traczyk, P.; Belforte, S.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Zanetti, A.; Kim, D. H.; Kim, G. N.; Kim, M. S.; Lee, S.; Lee, S. W.; Oh, Y. 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R.; Apanasevich, L.; Berry, D.; Betts, R. R.; Bucinskaite, I.; Cavanaugh, R.; Evdokimov, O.; Gauthier, L.; Gerber, C. E.; Hofman, D. J.; Jung, K.; Sandoval Gonzalez, I. D.; Varelas, N.; Wang, H.; Wu, Z.; Zakaria, M.; Zhang, J.; Bilki, B.; Clarida, W.; Dilsiz, K.; Durgut, S.; Gandrajula, R. P.; Haytmyradov, M.; Khristenko, V.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Snyder, C.; Tiras, E.; Wetzel, J.; Yi, K.; Anderson, I.; Blumenfeld, B.; Cocoros, A.; Eminizer, N.; Fehling, D.; Feng, L.; Gritsan, A. V.; Maksimovic, P.; Roskes, J.; Sarica, U.; Swartz, M.; Xiao, M.; Xin, Y.; You, C.; Al-bataineh, A.; Baringer, P.; Bean, A.; Boren, S.; Bowen, J.; Castle, J.; Forthomme, L.; Kenny, R. P.; Khalil, S.; Kropivnitskaya, A.; Majumder, D.; Mcbrayer, W.; Murray, M.; Sanders, S.; Stringer, R.; Takaki, J. D. Tapia; Wang, Q.; Ivanov, A.; Kaadze, K.; Maravin, Y.; Mohammadi, A.; Saini, L. K.; Skhirtladze, N.; Toda, S.; Rebassoo, F.; Wright, D.; Anelli, C.; Baden, A.; Baron, O.; Belloni, A.; Calvert, B.; Eno, S. C.; Ferraioli, C.; Gomez, J. A.; Hadley, N. J.; Jabeen, S.; Jeng, G. Y.; Kellogg, R. G.; Kolberg, T.; Kunkle, J.; Mignerey, A. C.; Ricci-Tam, F.; Shin, Y. H.; Skuja, A.; Tonjes, M. B.; Tonwar, S. C.; Abercrombie, D.; Allen, B.; Apyan, A.; Azzolini, V.; Barbieri, R.; Baty, A.; Bi, R.; Bierwagen, K.; Brandt, S.; Busza, W.; Cali, I. A.; D'Alfonso, M.; Demiragli, Z.; Di Matteo, L.; Gomez Ceballos, G.; Goncharov, M.; Hsu, D.; Iiyama, Y.; Innocenti, G. M.; Klute, M.; Kovalskyi, D.; Krajczar, K.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Maier, B.; Marini, A. C.; Mcginn, C.; Mironov, C.; Narayanan, S.; Niu, X.; Paus, C.; Roland, C.; Roland, G.; Salfeld-Nebgen, J.; Stephans, G. S. F.; Tatar, K.; Varma, M.; Velicanu, D.; Veverka, J.; Wang, J.; Wang, T. W.; Wyslouch, B.; Yang, M.; Benvenuti, A. C.; Chatterjee, R. M.; Evans, A.; Hansen, P.; Kalafut, S.; Kao, S. C.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Claes, D. R.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Kravchenko, I.; Malta Rodrigues, A.; Meier, F.; Monroy, J.; Siado, J. E.; Snow, G. R.; Stieger, B.; Alyari, M.; Dolen, J.; Godshalk, A.; Harrington, C.; Iashvili, I.; Kaisen, J.; Nguyen, D.; Parker, A.; Rappoccio, S.; Roozbahani, B.; Alverson, G.; Barberis, E.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira De Lima, R.; Trocino, D.; Wang, R.-J.; Wood, D.; Bhattacharya, S.; Charaf, O.; Hahn, K. A.; Kumar, A.; Mucia, N.; Odell, N.; Pollack, B.; Schmitt, M. H.; Sung, K.; Trovato, M.; Velasco, M.; Dev, N.; Hildreth, M.; Hurtado Anampa, K.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Planer, M.; Reinsvold, A.; Ruchti, R.; Rupprecht, N.; Smith, G.; Taroni, S.; Wayne, M.; Wolf, M.; Woodard, A.; Alimena, J.; Antonelli, L.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Francis, B.; Hart, A.; Hill, C.; Hughes, R.; Ji, W.; Liu, B.; Luo, W.; Puigh, D.; Winer, B. L.; Wulsin, H. W.; Cooperstein, S.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Lange, D.; Luo, J.; Marlow, D.; Medvedeva, T.; Mei, K.; Ojalvo, I.; Olsen, J.; Palmer, C.; Piroué, P.; Stickland, D.; Svyatkovskiy, A.; Tully, C.; Malik, S.; Barker, A.; Barnes, V. E.; Folgueras, S.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, A. W.; Khatiwada, A.; Miller, D. H.; Neumeister, N.; Schulte, J. F.; Shi, X.; Sun, J.; Wang, F.; Xie, W.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Duh, Y. t.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Hindrichs, O.; Khukhunaishvili, A.; Lo, K. H.; Tan, P.; Verzetti, M.; Agapitos, A.; Chou, J. P.; Gershtein, Y.; Gómez Espinosa, T. A.; Halkiadakis, E.; Heindl, M.; Hughes, E.; Kaplan, S.; Elayavalli, R. Kunnawalkam; Kyriacou, S.; Lath, A.; Nash, K.; Osherson, M.; Saka, H.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Delannoy, A. G.; Foerster, M.; Heideman, J.; Riley, G.; Rose, K.; Spanier, S.; Thapa, K.; Bouhali, O.; Celik, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Gilmore, J.; Huang, T.; Juska, E.; Kamon, T.; Mueller, R.; Pakhotin, Y.; Patel, R.; Perloff, A.; Perniè, L.; Rathjens, D.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; De Guio, F.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Gurpinar, E.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Peltola, T.; Undleeb, S.; Volobouev, I.; Wang, Z.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Melo, A.; Ni, H.; Sheldon, P.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Barria, P.; Cox, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Neu, C.; Sinthuprasith, T.; Sun, X.; Wang, Y.; Wolfe, E.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Sturdy, J.; Belknap, D. A.; Buchanan, J.; Caillol, C.; Dasu, S.; Dodd, L.; Duric, S.; Gomber, B.; Grothe, M.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Perry, T.; Pierro, G. A.; Polese, G.; Ruggles, T.; Savin, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.

2017-07-01

A search is presented for extra spatial dimensions, quantum black holes, and quark contact interactions in measurements of dijet angular distributions in proton-proton collisions at √{s}=13 TeV. The data were collected with the CMS detector at the LHC and correspond to an integrated luminosity of 2.6 fb-1. The distributions are found to be in agreement with predictions from perturbative quantum chromodynamics that include electroweak corrections. Limits for different contact interaction models are obtained. In a benchmark model, valid to next-to-leading order in QCD and in which only left-handed quarks participate, quark contact interactions are excluded up to a scale of 11.5 and 14.7 TeV for destructive or constructive interference, respectively. The production of quantum black holes is excluded for masses below 7.8 or 5.3 TeV, depending on the model. The lower limits for the scales of virtual graviton exchange in the Arkani-Hamed-Dimopoulos-Dvali model of extra spatial dimensions are in the range 7.9-11.2 TeV, and are the most stringent set of limits available.

Search for new physics with dijet angular distributions in proton-proton collisions at $$\\sqrt{s}$$ = 13 TeV

DOE PAGES

Sirunyan, Albert M.

2017-07-05

A search is presented for extra spatial dimensions, quantum black holes, and quark contact interactions in measurements of dijet angular distributions in proton-proton collisions at √s = 13 TeV. The data were collected with the CMS detector at the LHC and correspond to an integrated luminosity of 2.6 fb –1. The distributions are found to be in agreement with predictions from perturbative quantum chromodynamics that include electroweak corrections. Limits for different contact interaction models are obtained in a benchmark model, valid to next-to-leading order in QCD, in which only left-handed quarks participate, with quark contact interactions excluded up to amore » scale of 11.5 or 14.7 TeV for destructive or constructive interference, respectively. The production of quantum black holes is excluded for masses below 7.8 or 5.3 TeV, depending on the model. Finally, the lower limits for the scales of virtual graviton exchange in the Arkani-Hamed--Dimopoulos--Dvali model of extra spatial dimensions are in the range 7.9-11.2 TeV, and are the most stringent set of limits available.« less

Chirality and the angular momentum of light

PubMed Central

Götte, Jörg B.; Barnett, Stephen M.; Yao, Alison M.

2017-01-01

Chirality is exhibited by objects that cannot be rotated into their mirror images. It is far from obvious that this has anything to do with the angular momentum of light, which owes its existence to rotational symmetries. There is nevertheless a subtle connection between chirality and the angular momentum of light. We demonstrate this connection and, in particular, its significance in the context of chiral light–matter interactions. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069764

Interferometric measurement of angular motion.

PubMed

Peña Arellano, Fabián Erasmo; Panjwani, Hasnain; Carbone, Ludovico; Speake, Clive C

2013-04-01

This paper describes the design and realization of a homodyne polarization interferometer for measuring angular motion. The optical layout incorporates carefully designed cat's eye retroreflectors that maximize the measurable range of angular motion and facilitate initial alignment. The retroreflectors are optimized and numerically characterized in terms of defocus and spherical aberrations using Zemax software for optical design. The linearity of the measurement is then calculated in terms of the aberrations. The actual physical interferometer is realized as a compact device with optical components from stock and without relying on adjustable holders. Evaluation of its performance using a commercial autocollimator confirmed a reproducibility within 0.1%, a non-linearity of less than 1 ppm with respect to the autocollimator, an upper limit to its sensitivity of about 5 × 10(-11) rad/Hz from audioband down to 100 mHz and an angular measurement range of more than ±1°.

Jet angularity measurements for single inclusive jet production

NASA Astrophysics Data System (ADS)

Kang, Zhong-Bo; Lee, Kyle; Ringer, Felix

2018-04-01

We study jet angularity measurements for single-inclusive jet production at the LHC. Jet angularities depend on a continuous parameter a allowing for a smooth interpolation between different traditional jet shape observables. We establish a factorization theorem within Soft Collinear Effective Theory (SCET) where we consistently take into account in- and out-of-jet radiation by making use of semi-inclusive jet functions. For comparison, we elaborate on the differences to jet angularities measured on an exclusive jet sample. All the necessary ingredients for the resummation at next-to-leading logarithmic (NLL) accuracy are presented within the effective field theory framework. We expect semiinclusive jet angularity measurements to be feasible at the LHC and we present theoretical predictions for the relevant kinematic range. In addition, we investigate the potential impact of jet angularities for quark-gluon discrimination.

Locality for quantum systems on graphs depends on the number field

NASA Astrophysics Data System (ADS)

Hall, H. Tracy; Severini, Simone

2013-07-01

Adapting a definition of Aaronson and Ambainis (2005 Theory Comput. 1 47-79), we call a quantum dynamics on a digraph saturated Z-local if the nonzero transition amplitudes specifying the unitary evolution are in exact correspondence with the directed edges (including loops) of the digraph. This idea appears recurrently in a variety of contexts including angular momentum, quantum chaos, and combinatorial matrix theory. Complete characterization of the digraph properties that allow such a process to exist is a long-standing open question that can also be formulated in terms of minimum rank problems. We prove that saturated Z-local dynamics involving complex amplitudes occur on a proper superset of the digraphs that allow restriction to the real numbers or, even further, the rationals. Consequently, among these fields, complex numbers guarantee the largest possible choice of topologies supporting a discrete quantum evolution. A similar construction separates complex numbers from the skew field of quaternions. The result proposes a concrete ground for distinguishing between complex and quaternionic quantum mechanics.

Quantum measurement and orientation tracking of fluorescent nanodiamonds inside living cells

NASA Astrophysics Data System (ADS)

McGuinness, L. P.; Yan, Y.; Stacey, A.; Simpson, D. A.; Hall, L. T.; MacLaurin, D.; Prawer, S.; Mulvaney, P.; Wrachtrup, J.; Caruso, F.; Scholten, R. E.; Hollenberg, L. C. L.

2011-06-01

Fluorescent particles are routinely used to probe biological processes. The quantum properties of single spins within fluorescent particles have been explored in the field of nanoscale magnetometry, but not yet in biological environments. Here, we demonstrate optically detected magnetic resonance of individual fluorescent nanodiamond nitrogen-vacancy centres inside living human HeLa cells, and measure their location, orientation, spin levels and spin coherence times with nanoscale precision. Quantum coherence was measured through Rabi and spin-echo sequences over long (>10 h) periods, and orientation was tracked with effective 1° angular precision over acquisition times of 89 ms. The quantum spin levels served as fingerprints, allowing individual centres with identical fluorescence to be identified and tracked simultaneously. Furthermore, monitoring decoherence rates in response to changes in the local environment may provide new information about intracellular processes. The experiments reported here demonstrate the viability of controlled single spin probes for nanomagnetometry in biological systems, opening up a host of new possibilities for quantum-based imaging in the life sciences.

Implications of causality for quantum biology - I: topology change

NASA Astrophysics Data System (ADS)

Scofield, D. F.; Collins, T. C.

2018-06-01

A framework for describing the causal, topology changing, evolution of interacting biomolecules is developed. The quantum dynamical manifold equations (QDMEs) derived from this framework can be related to the causality restrictions implied by a finite speed of light and to Planck's constant to set a transition frequency scale. The QDMEs imply conserved stress-energy, angular-momentum and Noether currents. The functional whose extremisation leads to this result provides a causal, time-dependent, non-equilibrium generalisation of the Hohenberg-Kohn theorem. The system of dynamical equations derived from this functional and the currents J derived from the QDMEs are shown to be causal and consistent with the first and second laws of thermodynamics. This has the potential of allowing living systems to be quantum mechanically distinguished from non-living ones.

Stern-Gerlach-like approach to electron orbital angular momentum measurement

DOE PAGES

Harvey, Tyler R.; Grillo, Vincenzo; McMorran, Benjamin J.

2017-02-28

Many methods now exist to prepare free electrons into orbital-angular-momentum states, and the predicted applications of these electron states as probes of materials and scattering processes are numerous. The development of electron orbital-angular-momentum measurement techniques has lagged behind. We show that coupling between electron orbital angular momentum and a spatially varying magnetic field produces an angular-momentum-dependent focusing effect. We propose a design for an orbital-angular-momentum measurement device built on this principle. As the method of measurement is noninterferometric, the device works equally well for mixed, superposed, and pure final orbital-angular-momentum states. The energy and orbital-angular-momentum distributions of inelastically scattered electronsmore » may be simultaneously measurable with this technique.« less

Stern-Gerlach-like approach to electron orbital angular momentum measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harvey, Tyler R.; Grillo, Vincenzo; McMorran, Benjamin J.

Many methods now exist to prepare free electrons into orbital-angular-momentum states, and the predicted applications of these electron states as probes of materials and scattering processes are numerous. The development of electron orbital-angular-momentum measurement techniques has lagged behind. We show that coupling between electron orbital angular momentum and a spatially varying magnetic field produces an angular-momentum-dependent focusing effect. We propose a design for an orbital-angular-momentum measurement device built on this principle. As the method of measurement is noninterferometric, the device works equally well for mixed, superposed, and pure final orbital-angular-momentum states. The energy and orbital-angular-momentum distributions of inelastically scattered electronsmore » may be simultaneously measurable with this technique.« less

Explorations in fuzzy physics and non-commutative geometry

NASA Astrophysics Data System (ADS)

Kurkcuoglu, Seckin

Fuzzy spaces arise as discrete approximations to continuum manifolds. They are usually obtained through quantizing coadjoint orbits of compact Lie groups and they can be described in terms of finite-dimensional matrix algebras, which for large matrix sizes approximate the algebra of functions of the limiting continuum manifold. Their ability to exactly preserve the symmetries of their parent manifolds is especially appealing for physical applications. Quantum Field Theories are built over them as finite-dimensional matrix models preserving almost all the symmetries of their respective continuum models. In this dissertation, we first focus our attention to the study of fuzzy supersymmetric spaces. In this regard, we obtain the fuzzy supersphere S2,2F through quantizing the supersphere, and demonstrate that it has exact supersymmetry. We derive a finite series formula for the *-product of functions over S2,2F and analyze the differential geometric information encoded in this formula. Subsequently, we show that quantum field theories on S2,2F are realized as finite-dimensional supermatrix models, and in particular we obtain the non-linear sigma model over the fuzzy supersphere by constructing the fuzzy supersymmetric extensions of a certain class of projectors. We show that this model too, is realized as a finite-dimensional supermatrix model with exact supersymmetry. Next, we show that fuzzy spaces have a generalized Hopf algebra structure. By focusing on the fuzzy sphere, we establish that there is a *-homomorphism from the group algebra SU(2)* of SU(2) to the fuzzy sphere. Using this and the canonical Hopf algebra structure of SU(2)* we show that both the fuzzy sphere and their direct sum are Hopf algebras. Using these results, we discuss processes in which a fuzzy sphere with angular momenta J splits into fuzzy spheres with angular momenta K and L. Finally, we study the formulation of Chern-Simons (CS) theory on an infinite strip of the non-commutative plane. We

Hybrid threshold adaptable quantum secret sharing scheme with reverse Huffman-Fibonacci-tree coding.

PubMed

Lai, Hong; Zhang, Jun; Luo, Ming-Xing; Pan, Lei; Pieprzyk, Josef; Xiao, Fuyuan; Orgun, Mehmet A

2016-08-12

With prevalent attacks in communication, sharing a secret between communicating parties is an ongoing challenge. Moreover, it is important to integrate quantum solutions with classical secret sharing schemes with low computational cost for the real world use. This paper proposes a novel hybrid threshold adaptable quantum secret sharing scheme, using an m-bonacci orbital angular momentum (OAM) pump, Lagrange interpolation polynomials, and reverse Huffman-Fibonacci-tree coding. To be exact, we employ entangled states prepared by m-bonacci sequences to detect eavesdropping. Meanwhile, we encode m-bonacci sequences in Lagrange interpolation polynomials to generate the shares of a secret with reverse Huffman-Fibonacci-tree coding. The advantages of the proposed scheme is that it can detect eavesdropping without joint quantum operations, and permits secret sharing for an arbitrary but no less than threshold-value number of classical participants with much lower bandwidth. Also, in comparison with existing quantum secret sharing schemes, it still works when there are dynamic changes, such as the unavailability of some quantum channel, the arrival of new participants and the departure of participants. Finally, we provide security analysis of the new hybrid quantum secret sharing scheme and discuss its useful features for modern applications.

Transverse angular momentum in topological photonic crystals

NASA Astrophysics Data System (ADS)

Deng, Wei-Min; Chen, Xiao-Dong; Zhao, Fu-Li; Dong, Jian-Wen

2018-01-01

Engineering local angular momentum of structured light fields in real space enables applications in many fields, in particular, the realization of unidirectional robust transport in topological photonic crystals with a non-trivial Berry vortex in momentum space. Here, we show transverse angular momentum modes in silicon topological photonic crystals when considering transverse electric polarization. Excited by a chiral external source with either transverse spin angular momentum or transverse phase vortex, robust light flow propagating along opposite directions is observed in several kinds of sharp-turn interfaces between two topologically-distinct silicon photonic crystals. A transverse orbital angular momentum mode with alternating phase vortex exists at the boundary of two such photonic crystals. In addition, unidirectional transport is robust to the working frequency even when the ring size or location of the pseudo-spin source varies in a certain range, leading to the superiority of the broadband photonic device. These findings enable one to make use of transverse angular momentum, a kind of degree of freedom, to achieve unidirectional robust transport in the telecom region and other potential applications in integrated photonic circuits, such as on-chip robust delay lines.

Deep learning as a tool to distinguish between high orbital angular momentum optical modes

NASA Astrophysics Data System (ADS)

Knutson, E. M.; Lohani, Sanjaya; Danaci, Onur; Huver, Sean D.; Glasser, Ryan T.

2016-09-01

The generation of light containing large degrees of orbital angular momentum (OAM) has recently been demon- strated in both the classical and quantum regimes. Since there is no fundamental limit to how many quanta of OAM a single photon can carry, optical states with an arbitrarily high difference in this quantum number may, in principle, be entangled. This opens the door to investigations into high-dimensional entanglement shared between states in superpositions of nonzero OAM. Additionally, making use of non-zero OAM states can allow for a dramatic increase in the amount of information carried by a single photon, thus increasing the information capacity of a communication channel. In practice, however, it is difficult to differentiate between states with high OAM numbers with high precision. Here we investigate the ability of deep neural networks to differentiate between states that contain large values of OAM. We show that such networks may be used to differentiate be- tween nearby OAM states that contain realistic amounts of noise, with OAM values of up to 100. Additionally, we examine how the classification accuracy scales with the signal-to-noise ratio of images that are used to train the network, as well as those being tested. Finally, we demonstrate the simultaneous classification of < 100 OAM states with greater than 70 % accuracy. We intend to verify our system with experimentally-produced classi- cal OAM states, as well as investigate possibilities that would allow this technique to work in the few-photon quantum regime.

Interferometric measurement of angular motion

NASA Astrophysics Data System (ADS)

Peña Arellano, Fabián Erasmo; Panjwani, Hasnain; Carbone, Ludovico; Speake, Clive C.

2013-04-01

This paper describes the design and realization of a homodyne polarization interferometer for measuring angular motion. The optical layout incorporates carefully designed cat's eye retroreflectors that maximize the measurable range of angular motion and facilitate initial alignment. The retroreflectors are optimized and numerically characterized in terms of defocus and spherical aberrations using Zemax software for optical design. The linearity of the measurement is then calculated in terms of the aberrations. The actual physical interferometer is realized as a compact device with optical components from stock and without relying on adjustable holders. Evaluation of its performance using a commercial autocollimator confirmed a reproducibility within 0.1%, a non-linearity of less than 1 ppm with respect to the autocollimator, an upper limit to its sensitivity of about 5 × 10-11 rad/sqrt{textrm {Hz}} from audioband down to 100 mHz and an angular measurement range of more than ±1°.

Hybrid ququart-encoded quantum cryptography protected by Kochen-Specker contextuality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabello, Adan; Department of Physics, Stockholm University, S-10691 Stockholm; D'Ambrosio, Vincenzo

2011-09-15

Quantum cryptographic protocols based on complementarity are not secure against attacks in which complementarity is imitated with classical resources. The Kochen-Specker (KS) theorem provides protection against these attacks, without requiring entanglement or spatially separated composite systems. We analyze the maximum tolerated noise to guarantee the security of a KS-protected cryptographic scheme against these attacks and describe a photonic realization of this scheme using hybrid ququarts defined by the polarization and orbital angular momentum of single photons.

Spatially multiplexed orbital-angular-momentum-encoded single photon and classical channels in a free-space optical communication link.

PubMed

Ren, Yongxiong; Liu, Cong; Pang, Kai; Zhao, Jiapeng; Cao, Yinwen; Xie, Guodong; Li, Long; Liao, Peicheng; Zhao, Zhe; Tur, Moshe; Boyd, Robert W; Willner, Alan E

2017-12-01

We experimentally demonstrate spatial multiplexing of an orbital angular momentum (OAM)-encoded quantum channel and a classical Gaussian beam with a different wavelength and orthogonal polarization. Data rates as large as 100 MHz are achieved by encoding on two different OAM states by employing a combination of independently modulated laser diodes and helical phase holograms. The influence of OAM mode spacing, encoding bandwidth, and interference from the co-propagating Gaussian beam on registered photon count rates and quantum bit error rates is investigated. Our results show that the deleterious effects of intermodal crosstalk effects on system performance become less important for OAM mode spacing Δ≥2 (corresponding to a crosstalk value of less than -18.5 dB). The use of OAM domain can additionally offer at least 10.4 dB isolation besides that provided by wavelength and polarization, leading to a further suppression of interference from the classical channel.

Elementary Aharonov-Bohm system in three space dimensions: Quantum attraction with no classical force

NASA Astrophysics Data System (ADS)

Goldhaber, Alfred; Requist, Ryan

2003-07-01

As a consequence of the Aharonov-Bohm effect, there is a quantum-induced attraction between a charged particle and a rigid, impenetrable hoop made from an arbitrarily thin tube containing a superconductor quantum of magnetic flux. This is remarkable because in classical physics there is no force between the two objects, and quantum-mechanical effects (associated with uncertainty-principle energy) generally are repulsive rather than attractive. For an incident spinless charged particle in a P wave (in a configuration with total angular momentum zero) we verify a resonance just above threshold using the Kohn variational principle in its S-matrix form. Even if optimistic choices of parameters describing a model system with these properties were feasible, the temperature required to observe the resonance would be far lower than has yet been attained in the laboratory.

High-Dimensional Quantum Information Processing with Linear Optics

NASA Astrophysics Data System (ADS)

Fitzpatrick, Casey A.

Quantum information processing (QIP) is an interdisciplinary field concerned with the development of computers and information processing systems that utilize quantum mechanical properties of nature to carry out their function. QIP systems have become vastly more practical since the turn of the century. Today, QIP applications span imaging, cryptographic security, computation, and simulation (quantum systems that mimic other quantum systems). Many important strategies improve quantum versions of classical information system hardware, such as single photon detectors and quantum repeaters. Another more abstract strategy engineers high-dimensional quantum state spaces, so that each successful event carries more information than traditional two-level systems allow. Photonic states in particular bring the added advantages of weak environmental coupling and data transmission near the speed of light, allowing for simpler control and lower system design complexity. In this dissertation, numerous novel, scalable designs for practical high-dimensional linear-optical QIP systems are presented. First, a correlated photon imaging scheme using orbital angular momentum (OAM) states to detect rotational symmetries in objects using measurements, as well as building images out of those interactions is reported. Then, a statistical detection method using chains of OAM superpositions distributed according to the Fibonacci sequence is established and expanded upon. It is shown that the approach gives rise to schemes for sorting, detecting, and generating the recursively defined high-dimensional states on which some quantum cryptographic protocols depend. Finally, an ongoing study based on a generalization of the standard optical multiport for applications in quantum computation and simulation is reported upon. The architecture allows photons to reverse momentum inside the device. This in turn enables realistic implementation of controllable linear-optical scattering vertices for

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Electron-acoustic solitary waves in dense quantum electron-ion plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Misra, A. P.; Shukla, P. K.; Bhowmik, C.

2007-08-15

A quantum hydrodynamic (QHD) model is used to investigate the propagation characteristics of nonlinear electron-acoustic solitary waves (EASWs) in a dense quantum plasma whose constituents are two groups of electrons: one inertial cold electrons and other inertialess hot electrons, and the stationary ions which form the neutralizing background. By using the standard reductive perturbation technique, a Kadomtsev-Petviashvili (KP) equation, which governs the dynamics of EASWs, is derived in both spherical and cylindrical geometry. The effects of cold electrons and the density correlations due to quantum fluctuations on the profiles of the amplitudes and widths of the solitary structures are examinedmore » numerically. The nondimensional parameter {delta}=n{sub c0}/n{sub h0}, which is the equilibrium density ratio of the cold to hot electron component, is shown to play a vital role in the formation of both bright and dark solitons. It is also found that the angular dependence of the physical quantities and the presence of cold electrons in a quantum plasma lead to the coexistence of some new interesting novel solitary structures quite distinctive from the classical ones.« less

Fast and simple high-capacity quantum cryptography with error detection

PubMed Central

Lai, Hong; Luo, Ming-Xing; Pieprzyk, Josef; Zhang, Jun; Pan, Lei; Li, Shudong; Orgun, Mehmet A.

2017-01-01

Quantum cryptography is commonly used to generate fresh secure keys with quantum signal transmission for instant use between two parties. However, research shows that the relatively low key generation rate hinders its practical use where a symmetric cryptography component consumes the shared key. That is, the security of the symmetric cryptography demands frequent rate of key updates, which leads to a higher consumption of the internal one-time-pad communication bandwidth, since it requires the length of the key to be as long as that of the secret. In order to alleviate these issues, we develop a matrix algorithm for fast and simple high-capacity quantum cryptography. Our scheme can achieve secure private communication with fresh keys generated from Fibonacci- and Lucas- valued orbital angular momentum (OAM) states for the seed to construct recursive Fibonacci and Lucas matrices. Moreover, the proposed matrix algorithm for quantum cryptography can ultimately be simplified to matrix multiplication, which is implemented and optimized in modern computers. Most importantly, considerably information capacity can be improved effectively and efficiently by the recursive property of Fibonacci and Lucas matrices, thereby avoiding the restriction of physical conditions, such as the communication bandwidth. PMID:28406240

Fast and simple high-capacity quantum cryptography with error detection.

PubMed

Lai, Hong; Luo, Ming-Xing; Pieprzyk, Josef; Zhang, Jun; Pan, Lei; Li, Shudong; Orgun, Mehmet A

2017-04-13

Quantum cryptography is commonly used to generate fresh secure keys with quantum signal transmission for instant use between two parties. However, research shows that the relatively low key generation rate hinders its practical use where a symmetric cryptography component consumes the shared key. That is, the security of the symmetric cryptography demands frequent rate of key updates, which leads to a higher consumption of the internal one-time-pad communication bandwidth, since it requires the length of the key to be as long as that of the secret. In order to alleviate these issues, we develop a matrix algorithm for fast and simple high-capacity quantum cryptography. Our scheme can achieve secure private communication with fresh keys generated from Fibonacci- and Lucas- valued orbital angular momentum (OAM) states for the seed to construct recursive Fibonacci and Lucas matrices. Moreover, the proposed matrix algorithm for quantum cryptography can ultimately be simplified to matrix multiplication, which is implemented and optimized in modern computers. Most importantly, considerably information capacity can be improved effectively and efficiently by the recursive property of Fibonacci and Lucas matrices, thereby avoiding the restriction of physical conditions, such as the communication bandwidth.

Fast and simple high-capacity quantum cryptography with error detection

NASA Astrophysics Data System (ADS)

Lai, Hong; Luo, Ming-Xing; Pieprzyk, Josef; Zhang, Jun; Pan, Lei; Li, Shudong; Orgun, Mehmet A.

2017-04-01

Quantum cryptography is commonly used to generate fresh secure keys with quantum signal transmission for instant use between two parties. However, research shows that the relatively low key generation rate hinders its practical use where a symmetric cryptography component consumes the shared key. That is, the security of the symmetric cryptography demands frequent rate of key updates, which leads to a higher consumption of the internal one-time-pad communication bandwidth, since it requires the length of the key to be as long as that of the secret. In order to alleviate these issues, we develop a matrix algorithm for fast and simple high-capacity quantum cryptography. Our scheme can achieve secure private communication with fresh keys generated from Fibonacci- and Lucas- valued orbital angular momentum (OAM) states for the seed to construct recursive Fibonacci and Lucas matrices. Moreover, the proposed matrix algorithm for quantum cryptography can ultimately be simplified to matrix multiplication, which is implemented and optimized in modern computers. Most importantly, considerably information capacity can be improved effectively and efficiently by the recursive property of Fibonacci and Lucas matrices, thereby avoiding the restriction of physical conditions, such as the communication bandwidth.

Quantum oscillation evidence for a topological semimetal phase in ZrSnTe

NASA Astrophysics Data System (ADS)

Hu, Jin; Zhu, Yanglin; Gui, Xin; Graf, David; Tang, Zhijie; Xie, Weiwei; Mao, Zhiqiang

2018-04-01

The layered WHM-type (W =Zr /Hf /La , H =Si /Ge /Sn /Sb , M =S /Se /Te ) materials represent a large family of topological semimetals, which provides an excellent platform to study the evolution of topological semimetal state with the fine tuning of spin-orbit coupling and structural dimensionality for various combinations of W , H , and M elements. In this work, through high field de Haas-van Alphen (dHvA) quantum oscillation studies, we have found evidence for the predicted topological nontrivial bands in ZrSnTe. Furthermore, from the angular dependence of quantum oscillation frequency, we have revealed the three-dimensional Fermi surface topologies of this layered material owing to strong interlayer coupling.

Modern Spectroscopy

ERIC Educational Resources Information Center

Barrow, Gordon M.

1970-01-01

Presents the basic ideas of modern spectroscopy. Both the angular momenta and wave-nature approaches to the determination of energy level patterns for atomic and molecular systems are discussed. The interpretation of spectra, based on atomic and molecular models, is considered. (LC)

Difference in perception of angular displacement according to applied waveforms.

PubMed

Kushiro, Keisuke; Goto, Fumiyuki

2013-05-01

This study shows that the differences in the waveforms of angular rotation affect the perception and memory of angular displacement. During daily life, when we turn our head during various activities, our brain calculates how much angular displacement our head has undergone. However, how we obtain an accurate estimation of this angular displacement remains unclarified. This study aims to clarify this issue by investigating the perception and memory of passive rotation for three different waveforms of angular velocity rotation (sinusoidal (sine), triangle, and step). Thirteen healthy young subjects sitting on a servo-controlled chair were passively rotated at 60° or 120° about the earth-vertical axis by using one of these three angular velocity waveforms. They then attempted to reproduce the rotation angle by rotating the chair in the same direction in which they had been passively rotated using a handheld controller. The gain (reproduced angle/passively rotated angle) was calculated and used for the evaluation of the perception and memory of angular rotation. The gain for step rotation was larger than that for sine and triangle rotations, with statistical significance. This confirms that the difference in the waveforms of angular rotation affects the perception and memory of angular displacement.

The distribution of rotational velocities for low-mass stars in the Pleiades

NASA Technical Reports Server (NTRS)

Stauffer, John R.; Hartmann, Lee W.

1987-01-01

The available spectral type and color data for late-type Pleiades members have been reanalyzed, and new reddening estimates are obtained. New photometry for a small number of stars and a compilation of H-alpha equivalent widths for Pleiades dwarfs are presented. These data are used to examine the location of the rapid rotators in color-magnitude diagrams and the correlation between chromospheric activity and rotation. It is shown that the wide range of angular momenta exhibited by Pleiades K and M dwarfs is not necessarily produced by a combination of main-sequence spin-downs and a large age spread; it can also result from a plausible spread in initial angular momenta, coupled with initial main-sequence spin-down rates that are only weakly dependent on rotation. The new reddening estimates confirm Breger's (1985) finding of large extinctions confined to a small region in the southern portion of the Merope nebula.

Light scattering by magnons in whispering gallery mode cavities

NASA Astrophysics Data System (ADS)

Sharma, Sanchar; Blanter, Yaroslav M.; Bauer, Gerrit E. W.

2017-09-01

Brillouin light scattering is an established technique to study magnons, the elementary excitations of a magnet. Its efficiency can be enhanced by cavities that concentrate the light intensity. Here, we theoretically study inelastic scattering of photons by a magnetic sphere that supports optical whispering gallery modes in a plane normal to the magnetization. Magnons with low angular momenta scatter the light in the forward direction with a pronounced asymmetry in the Stokes and the anti-Stokes scattering strength, consistent with earlier studies. Magnons with large angular momenta constitute Damon-Eschbach modes which are shown to inelastically reflect light. The reflection spectrum contains either a Stokes or anti-Stokes peak, depending on the direction of the magnetization, a selection rule that can be explained by the chirality of the Damon-Eshbach magnons. The controllable energy transfer can be used to manage the thermodynamics of the magnet by light.

Angular-velocity control approach for stance-control orthoses.

PubMed

Lemaire, Edward D; Goudreau, Louis; Yakimovich, Terris; Kofman, Jonathan

2009-10-01

Currently, stance-control knee orthoses require external control mechanisms to control knee flexion during stance and allow free knee motion during the swing phase of gait. A new angular-velocity control approach that uses a rotary-hydraulic device to resist knee flexion when the knee angular velocity passes a preset threshold is presented. This angular-velocity approach for orthotic stance control is based on the premise that knee-flexion angular velocity during a knee-collapse event, such as a stumble or fall, is greater than that during walking. The new hydraulic knee-flexion control device does not require an external control mechanism to switch from free motion to stance control mode. Functional test results demonstrated that the hydraulic angular-velocity activated knee joint provided free knee motion during walking, engaged upon knee collapse, and supported body weight while the end-user recovered to a safe body position. The joint was tested to 51.6 Nm in single loading tests and passed 200,000 repeated loading cycles with a peak load of 88 Nm per cycle. The hydraulic, angular velocity activation approach has potential to improve safety and security for people with lower extremity weakness or when recovering from joint trauma.

Minimal scales from an extended Hilbert space

NASA Astrophysics Data System (ADS)

Kober, Martin; Nicolini, Piero

2010-12-01

We consider an extension of the conventional quantum Heisenberg algebra, assuming that coordinates as well as momenta fulfil nontrivial commutation relations. As a consequence, a minimal length and a minimal mass scale are implemented. Our commutators do not depend on positions and momenta and we provide an extension of the coordinate coherent state approach to noncommutative geometry. We explore, as a toy model, the corresponding quantum field theory in a (2+1)-dimensional spacetime. Then we investigate the more realistic case of a (3+1)-dimensional spacetime, foliated into noncommutative planes. As a result, we obtain propagators, which are finite in the ultraviolet as well as the infrared regime.

Spectra of double-cumulative photons in the central rapidity region at high transverse momenta

NASA Astrophysics Data System (ADS)

Alekseev, I. G.; Golubev, A. A.; Goryachev, V. S.; Dzubenko, G. B.; Dolgolenko, A. G.; Zhigareva, N. M.; Kiselev, S. M.; Mikhaylov, K. R.; Morozova, E. A.; Polozov, P. A.; Prokudin, M. S.; Romanov, D. V.; Svirida, D. N.; Stavinsky, A. V.; Stolin, V. L.; Sharkov, G. B.

2015-11-01

The spectra of photons produced in the interaction between carbon ions of kinetic energy 2.0 and 3.2 GeV per nucleon and beryllium nuclei were measured at the FLINT facility by means of electromagnetic calorimeters that is deployed at the accelerator of the Institute for Theoretical and Experimental Physics (ITEP, Moscow). The spectra in question were measured in the central rapidity region (at angles between 35° and 73° in the laboratory frame) at photon energies of 1 to 3 GeV by using a cumulative-photon trigger. An analysis of the data obtained in this way reveals that the interaction of multinucleon fluctuation in the projectile nucleus with a multinucleon fluctuation in the target nucleus is a dominant process that leads to photon production in the measured region of angles and momenta. As a development of the generally accepted terminology, an interaction of this type may be called a double cumulative interaction.

Smoothed dissipative particle dynamics with angular momentum conservation

NASA Astrophysics Data System (ADS)

Müller, Kathrin; Fedosov, Dmitry A.; Gompper, Gerhard

2015-01-01

Smoothed dissipative particle dynamics (SDPD) combines two popular mesoscopic techniques, the smoothed particle hydrodynamics and dissipative particle dynamics (DPD) methods, and can be considered as an improved dissipative particle dynamics approach. Despite several advantages of the SDPD method over the conventional DPD model, the original formulation of SDPD by Español and Revenga (2003) [9], lacks angular momentum conservation, leading to unphysical results for problems where the conservation of angular momentum is essential. To overcome this limitation, we extend the SDPD method by introducing a particle spin variable such that local and global angular momentum conservation is restored. The new SDPD formulation (SDPD+a) is directly derived from the Navier-Stokes equation for fluids with spin, while thermal fluctuations are incorporated similarly to the DPD method. We test the new SDPD method and demonstrate that it properly reproduces fluid transport coefficients. Also, SDPD with angular momentum conservation is validated using two problems: (i) the Taylor-Couette flow with two immiscible fluids and (ii) a tank-treading vesicle in shear flow with a viscosity contrast between inner and outer fluids. For both problems, the new SDPD method leads to simulation predictions in agreement with the corresponding analytical theories, while the original SDPD method fails to capture properly physical characteristics of the systems due to violation of angular momentum conservation. In conclusion, the extended SDPD method with angular momentum conservation provides a new approach to tackle fluid problems such as multiphase flows and vesicle/cell suspensions, where the conservation of angular momentum is essential.

Radially dependent angular acceleration of twisted light.

PubMed

Webster, Jason; Rosales-Guzmán, Carmelo; Forbes, Andrew

2017-02-15

While photons travel in a straight line at constant velocity in free space, the intensity profile of structured light may be tailored for acceleration in any degree of freedom. Here we propose a simple approach to control the angular acceleration of light. Using Laguerre-Gaussian modes as our twisted beams carrying orbital angular momentum, we show that superpositions of opposite handedness result in a radially dependent angular acceleration as they pass through a focus (waist plane). Due to conservation of orbital angular momentum, we find that propagation dynamics are complex despite the free-space medium: the outer part of the beam (rings) rotates in an opposite direction to the inner part (petals), and while the outer part accelerates, the inner part decelerates. We outline the concepts theoretically and confirm them experimentally. Such exotic structured light beams are topical due to their many applications, for instance in optical trapping and tweezing, metrology, and fundamental studies in optics.

Nonperturbative-transverse-momentum effects and evolution in dihadron and direct photon-hadron angular correlations in p + p collisions at s = 510 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adare, A.; Aidala, C.; Ajitanand, N. N.

Dihadron and isolated direct photon-hadron angular correlations are measured in p+p collisions at √s=510 GeV. Correlations of charged hadrons of 0.7T<10 GeV/c with π 0 mesons of 4T<15 GeV/c or isolated direct photons of 7T direct photon or π 0. Nonperturbative evolution effects are extracted from Gaussian fits to the away-side inclusive-charged-hadron yields for different trigger-particle transverse momenta (pmore » $$trig\\atop{T}$$). The Gaussian widths and root mean square of p out are reported as a function of the interaction hard scale p$$trig\\atop{T}$$ to investigate possible transverse-momentum-dependent evolution differences between the π 0-h ± and direct photon-h ± correlations and factorization breaking effects. The widths are found to decrease with p$$trig\\atop{T}$$, which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in p+p collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.« less

Nonperturbative-transverse-momentum effects and evolution in dihadron and direct photon-hadron angular correlations in p + p collisions at s = 510 GeV

DOE PAGES

Adare, A.; Aidala, C.; Ajitanand, N. N.; ...

2017-04-04

Dihadron and isolated direct photon-hadron angular correlations are measured in p+p collisions at √s=510 GeV. Correlations of charged hadrons of 0.7T<10 GeV/c with π 0 mesons of 4T<15 GeV/c or isolated direct photons of 7T direct photon or π 0. Nonperturbative evolution effects are extracted from Gaussian fits to the away-side inclusive-charged-hadron yields for different trigger-particle transverse momenta (pmore » $$trig\\atop{T}$$). The Gaussian widths and root mean square of p out are reported as a function of the interaction hard scale p$$trig\\atop{T}$$ to investigate possible transverse-momentum-dependent evolution differences between the π 0-h ± and direct photon-h ± correlations and factorization breaking effects. The widths are found to decrease with p$$trig\\atop{T}$$, which indicates that the Collins-Soper-Sterman soft factor is not driving the evolution with the hard scale in nearly back-to-back dihadron and direct photon-hadron production in p+p collisions. This behavior is in contrast to Drell-Yan and semi-inclusive deep-inelastic scattering measurements.« less

Uniaxial angular accelerometers

NASA Astrophysics Data System (ADS)

Seleznev, A. V.; Shvab, I. A.

1985-05-01

The basic mechanical components of an angular accelerometer are the sensor, the damper, and the transducer. Penumatic dampers are simplest in construction, but the viscosity of air is very low and, therefore, dampers with special purpose oils having a high temperature stability (synthetic silicon or organosilicon oils) are most widely used. The most common types of viscous dampers are lamellar with meshed opposed arrays of fixed and movable vanes in the dashpot, piston dampers regulated by an adjustable-length capillary tube, and dampers with paddle wheel in closed tank. Another type of damper is an impact-inertial one with large masses absorbing the rotational energy upon collision with the sensor. Conventional measuring elements are resistive, capacitive, electromagnetic, photoelectric, and penumatic or hydraulic. Novel types of angular accelerometers are based on inertia of gas jets, electron beams, and ion beams, the piezoelectric effect in p-n junctions of diode and transistors, the electrokinetic effect in fluids, and cryogenic suspension of the sensor.

Demonstrating the conservation of angular momentum using spherical magnets

NASA Astrophysics Data System (ADS)

Lindén, Johan; Slotte, Joakim; Källman, Kjell-Mikael

2018-01-01

An experimental setup for demonstrating the conservation of angular momentum of rotating spherical magnets is described. Two spherical Nd-Fe-B magnets are placed on a double inclined plane and projected towards each other with pre-selected impact parameters ranging from zero to a few tens of millimeters. After impact, the two magnets either revolve vigorously around the common center of mass or stop immediately, depending on the value of the impact parameter. Using a pick-up coil connected to an oscilloscope, the angular frequency for the rotating magnets was measured, and an estimate for the angular momentum was obtained. A high-speed video camera captured the impact and was used for measuring linear and angular velocities of the magnets. A very good agreement between the initial angular momentum before the impact and the final angular momentum of the revolving dumbbell is observed. The two rotating magnets, and the rotating electromagnetic field emanating from them, can also be viewed as a toy model for the newly discovered gravitational waves, where two black holes collide after revolving around each other. (Enhanced online)

Inefficient Angular Momentum Transport in Accretion Disk Boundary Layers: Angular Momentum Belt in the Boundary Layer

NASA Astrophysics Data System (ADS)

Belyaev, Mikhail A.; Quataert, Eliot

2018-04-01

We present unstratified 3D MHD simulations of an accretion disk with a boundary layer (BL) that have a duration ˜1000 orbital periods at the inner radius of the accretion disk. We find the surprising result that angular momentum piles up in the boundary layer, which results in a rapidly rotating belt of accreted material at the surface of the star. The angular momentum stored in this belt increases monotonically in time, which implies that angular momentum transport mechanisms in the BL are inefficient and do not couple the accretion disk to the star. This is in spite of the fact that magnetic fields are advected into the BL from the disk and supersonic shear instabilities in the BL excite acoustic waves. In our simulations, these waves only carry a small fraction (˜10%) of the angular momentum required for steady state accretion. Using analytical theory and 2D viscous simulations in the R - ϕ plane, we derive an analytical criterion for belt formation to occur in the BL in terms of the ratio of the viscosity in the accretion disk to the viscosity in the BL. Our MHD simulations have a dimensionless viscosity (α) in the BL that is at least a factor of ˜100 smaller than that in the disk. We discuss the implications of these results for BL dynamics and emission.

Feeding supermassive black holes by collisional cascades

NASA Astrophysics Data System (ADS)

Faber, Christian; Dehnen, Walter

2018-05-01

The processes driving gas accretion on to supermassive black holes (SMBHs) are still poorly understood. Angular momentum conservation prevents gas within ˜10 pc of the black hole from reaching radii ˜10-3 pc where viscous accretion becomes efficient. Here we present simulations of the collapse of a clumpy shell of swept-up isothermal gas, which is assumed to have formed as a result of feedback from a previous episode of AGN activity. The gas falls towards the SMBH forming clumps and streams, which intersect, collide, and often form a disc. These collisions promote partial cancellations of angular momenta, resulting in further infall and more collisions. This continued collisional cascade generates a tail of gas with sufficiently small angular momenta and provides a viable route for gas inflow to sub-parsec scales. The efficiency of this process hardly depends on details, such as gas temperature, initial virial ratio and power spectrum of the gas distribution, as long as it is not strongly rotating. Adding star formation to this picture might explain the near-simultaneous formation of the S-stars (from tidally disrupted binaries formed in plunging gas streams) and the sub-parsec young stellar disc around Sgr A⋆.

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Feeding supermassive black holes by collisional cascades

NASA Astrophysics Data System (ADS)

Faber, Christian; Dehnen, Walter

2018-07-01

The processes driving gas accretion on to supermassive black holes (SMBHs) are still poorly understood. Angular momentum conservation prevents gas within ˜10 pc of the black hole from reaching radii ˜10-3pc where viscous accretion becomes efficient. Here we present simulations of the collapse of a clumpy shell of swept-up isothermal gas, which is assumed to have formed as a result of feedback from a previous episode of AGN activity. The gas falls towards the SMBH forming clumps and streams, which intersect, collide and often form a disc. These collisions promote partial cancellations of angular momenta, resulting in further infall and more collisions. This continued collisional cascade generates a tail of gas with sufficiently small angular momenta and provides a viable route for gas inflow to sub-parsec scales. The efficiency of this process hardly depends on details, such as gas temperature, initial virial ratio and power spectrum of the gas distribution, as long as it is not strongly rotating. Adding star formation to this picture might explain the near-simultaneous formation of the S-stars (from tidally disrupted binaries formed in plunging gas streams) and the sub-parsec young stellar disc around Sgr A⋆.

Work production of quantum rotor engines

NASA Astrophysics Data System (ADS)

Seah, Stella; Nimmrichter, Stefan; Scarani, Valerio

2018-04-01

We study the mechanical performance of quantum rotor heat engines in terms of common notions of work using two prototypical models: a mill driven by the heat flow from a hot to a cold mode, and a piston driven by the alternate heating and cooling of a single working mode. We evaluate the extractable work in terms of ergotropy, the kinetic energy associated to net directed rotation, as well as the intrinsic work based on the exerted torque under autonomous operation, and we compare them to the energy output for the case of an external dissipative load and for externally driven engine cycles. Our results connect work definitions from both physical and information-theoretical perspectives. In particular, we find that apart from signatures of angular momentum quantization, the ergotropy is consistent with the intuitive notion of work in the form of net directed motion. It also agrees with the energy output to an external load or agent under optimal conditions. This sets forth a consistent thermodynamical description of rotating quantum motors, flywheels, and clocks.

Hybrid threshold adaptable quantum secret sharing scheme with reverse Huffman-Fibonacci-tree coding

PubMed Central

Lai, Hong; Zhang, Jun; Luo, Ming-Xing; Pan, Lei; Pieprzyk, Josef; Xiao, Fuyuan; Orgun, Mehmet A.

2016-01-01

With prevalent attacks in communication, sharing a secret between communicating parties is an ongoing challenge. Moreover, it is important to integrate quantum solutions with classical secret sharing schemes with low computational cost for the real world use. This paper proposes a novel hybrid threshold adaptable quantum secret sharing scheme, using an m-bonacci orbital angular momentum (OAM) pump, Lagrange interpolation polynomials, and reverse Huffman-Fibonacci-tree coding. To be exact, we employ entangled states prepared by m-bonacci sequences to detect eavesdropping. Meanwhile, we encode m-bonacci sequences in Lagrange interpolation polynomials to generate the shares of a secret with reverse Huffman-Fibonacci-tree coding. The advantages of the proposed scheme is that it can detect eavesdropping without joint quantum operations, and permits secret sharing for an arbitrary but no less than threshold-value number of classical participants with much lower bandwidth. Also, in comparison with existing quantum secret sharing schemes, it still works when there are dynamic changes, such as the unavailability of some quantum channel, the arrival of new participants and the departure of participants. Finally, we provide security analysis of the new hybrid quantum secret sharing scheme and discuss its useful features for modern applications. PMID:27515908

Improved grating angular sensor for LISA and MGRS

NASA Astrophysics Data System (ADS)

Sun, Ke-Xun; Lu, Patrick; Byer, Robert L.

2009-03-01

LISA requires high precision angular beam pointing and telescope steering. In this paper, we report recent results for an improved grating angular sensor. We have achieved better than 0.2 nrad/Hz1/2 at 1 kHz with 14 mW of incident power, a factor of 5 improvement over our previously reported results. At 1 Hz we achieved 1-2 nrad/Hz1/2. We realized these improvements by enclosing the grating angular sensor assembly in a vacuum chamber and mounting the optics components on a zerodur glass plate, thereby lowering the noise floor at low frequencies. Furthermore, by upgrading the electronics and thus the detector power handing capability, we also investigated sensitivity scaling versus incident laser power. The results will benefit the design of grating angular sensors.

Peculiarities of the momentum distribution functions of strongly correlated charged fermions

NASA Astrophysics Data System (ADS)

Larkin, A. S.; Filinov, V. S.; Fortov, V. E.

2018-01-01

New numerical version of the Wigner approach to quantum thermodynamics of strongly coupled systems of particles has been developed for extreme conditions, when analytical approximations based on different kinds of perturbation theories cannot be applied. An explicit analytical expression of the Wigner function has been obtained in linear and harmonic approximations. Fermi statistical effects are accounted for by effective pair pseudopotential depending on coordinates, momenta and degeneracy parameter of particles and taking into account Pauli blocking of fermions. A new quantum Monte-Carlo method for calculations of average values of arbitrary quantum operators has been developed. Calculations of the momentum distribution functions and the pair correlation functions of degenerate ideal Fermi gas have been carried out for testing the developed approach. Comparison of the obtained momentum distribution functions of strongly correlated Coulomb systems with the Maxwell-Boltzmann and the Fermi distributions shows the significant influence of interparticle interaction both at small momenta and in high energy quantum ‘tails’.

The usability of the optical parametric amplification of light for high-angular-resolution imaging and fast astrometry

NASA Astrophysics Data System (ADS)

Kurek, A. R.; Stachowski, A.; Banaszek, K.; Pollo, A.

2018-05-01

High-angular-resolution imaging is crucial for many applications in modern astronomy and astrophysics. The fundamental diffraction limit constrains the resolving power of both ground-based and spaceborne telescopes. The recent idea of a quantum telescope based on the optical parametric amplification (OPA) of light aims to bypass this limit for the imaging of extended sources by an order of magnitude or more. We present an updated scheme of an OPA-based device and a more accurate model of the signal amplification by such a device. The semiclassical model that we present predicts that the noise in such a system will form so-called light speckles as a result of light interference in the optical path. Based on this model, we analysed the efficiency of OPA in increasing the angular resolution of the imaging of extended targets and the precise localization of a distant point source. According to our new model, OPA offers a gain in resolved imaging in comparison to classical optics. For a given time-span, we found that OPA can be more efficient in localizing a single distant point source than classical telescopes.

Model of biological quantum logic in DNA.

PubMed

Mihelic, F Matthew

2013-08-02

The DNA molecule has properties that allow it to act as a quantum logic processor. It has been demonstrated that there is coherent conduction of electrons longitudinally along the DNA molecule through pi stacking interactions of the aromatic nucleotide bases, and it has also been demonstrated that electrons moving longitudinally along the DNA molecule are subject to a very efficient electron spin filtering effect as the helicity of the DNA molecule interacts with the spin of the electron. This means that, in DNA, electrons are coherently conducted along a very efficient spin filter. Coherent electron spin is held in a logically and thermodynamically reversible chiral symmetry between the C2-endo and C3-endo enantiomers of the deoxyribose moiety in each nucleotide, which enables each nucleotide to function as a quantum gate. The symmetry break that provides for quantum decision in the system is determined by the spin direction of an electron that has an orbital angular momentum that is sufficient to overcome the energy barrier of the double well potential separating the C2-endo and C3-endo enantiomers, and that enantiomeric energy barrier is appropriate to the Landauer limit of the energy necessary to randomize one bit of information.

The three-body problem with short-range interactions

NASA Astrophysics Data System (ADS)

Nielsen, E.; Fedorov, D. V.; Jensen, A. S.; Garrido, E.

2001-06-01

The quantum mechanical three-body problem is studied for general short-range interactions. We work in coordinate space to facilitate accurate computations of weakly bound and spatially extended systems. Hyperspherical coordinates are used in both the interpretation and as an integral part of the numerical method. Universal properties and model independence are discussed throughout the report. We present an overview of the hyperspherical adiabatic Faddeev equations. The wave function is expanded on hyperspherical angular eigenfunctions which in turn are found numerically using the Faddeev equations. We generalize the formalism to any dimension of space d greater or equal to two. We present two numerical techniques for solving the Faddeev equations on the hypersphere. These techniques are effective for short and intermediate/large distances including use for hard core repulsive potentials. We study the asymptotic limit of large hyperradius and derive the analytic behaviour of the angular eigenvalues and eigenfunctions. We discuss four applications of the general method. We first analyze the Efimov and Thomas effects for arbitrary angular momenta and for arbitrary dimensions d. Second we apply the method to extract the general behaviour of weakly bound three-body systems in two dimensions. Third we illustrate the method in three dimensions by structure computations of Borromean halo nuclei, the hypertriton and helium molecules. Fourth we investigate in three dimensions three-body continuum properties of Borromean halo nuclei and recombination reactions of helium atoms as an example of direct relevance for the stability of Bose-Einstein condensates.

High-capacity quantum secure direct communication using hyper-entanglement of photonic qubits

NASA Astrophysics Data System (ADS)

Cai, Jiarui; Pan, Ziwen; Wang, Tie-Jun; Wang, Sihai; Wang, Chuan

2016-11-01

Hyper-entanglement is a system constituted by photons entangled in multiple degrees of freedom (DOF), being considered as a promising way of increasing channel capacity and guaranteeing powerful eavesdropping safeguard. In this work, we propose a coding scheme based on a 3-particle hyper-entanglement of polarization and orbital angular momentum (OAM) system and its application as a quantum secure direct communication (QSDC) protocol. The OAM values are specially encoded by Fibonacci sequence and the polarization carries information by defined unitary operations. The internal relations of the secret message enhances security due to principle of quantum mechanics and Fibonacci sequence. We also discuss the coding capacity and security property along with some simulation results to show its superiority and extensibility.

Angular Impulse and Balance Regulation During the Golf Swing.

PubMed

Peterson, Travis J; Wilcox, Rand R; McNitt-Gray, Jill L

2016-08-01

Our aim was to determine how skilled players regulate linear and angular impulse while maintaining balance during the golf swing. Eleven highly-skilled golf players performed swings with a 6-iron and driver. Components contributing to linear and angular impulse generated by the rear and target legs (resultant horizontal reaction force [RFh], RFh-angle, and moment arm) were quantified and compared across the group and within a player (α = .05). Net angular impulse generated by both the rear and target legs was greater for the driver than the 6-iron. Mechanisms used to regulate angular impulse generation between clubs varied across players and required coordination between the legs. Increases in net angular impulse with a driver involved increases in target leg RFh. Rear leg RFh-angle was maintained between clubs whereas target leg RFh became more aligned with the target line. Net linear impulse perpendicular to the target line remained near zero, preserving balance, while net linear impulse along the target line decreased in magnitude. These results indicate that the net angular impulse was regulated between clubs by coordinating force generation of the rear and target legs while sustaining balance throughout the task.

Families of vector-like deformations of relativistic quantum phase spaces, twists and symmetries

NASA Astrophysics Data System (ADS)

Meljanac, Daniel; Meljanac, Stjepan; Pikutić, Danijel

2017-12-01

Families of vector-like deformed relativistic quantum phase spaces and corresponding realizations are analyzed. A method for a general construction of the star product is presented. The corresponding twist, expressed in terms of phase space coordinates, in the Hopf algebroid sense is presented. General linear realizations are considered and corresponding twists, in terms of momenta and Poincaré-Weyl generators or gl(n) generators are constructed and R-matrix is discussed. A classification of linear realizations leading to vector-like deformed phase spaces is given. There are three types of spaces: (i) commutative spaces, (ii) κ -Minkowski spaces and (iii) κ -Snyder spaces. The corresponding star products are (i) associative and commutative (but non-local), (ii) associative and non-commutative and (iii) non-associative and non-commutative, respectively. Twisted symmetry algebras are considered. Transposed twists and left-right dual algebras are presented. Finally, some physical applications are discussed.

Asteroid orbit fitting with radar and angular observations

NASA Astrophysics Data System (ADS)

Baturin, A. P.

2013-12-01

The asteroid orbit fitting problem using their radar and angular observations has been considered. The problem was solved in a standanrd way by means of minimization of weighted sum of squares of residuals. In the orbit fitting both kinds of radar observa-tions have been used: the observations of time delays and of Doppler frequency shifts. The weight for angular observations has been set the same for all of them and has been determined as inverse mean-square residual obtained in the orbit fitting using just angular observations. The weights of radar observations have been set as inverse squared errors of these observations published together with them in the Minor Planet Center electronical circulars (MPECs). For the orbit fitting some five asteroids have been taken from these circulars. The asteroids have been chosen fulfilling the requirement of more than six radar observations of them to be available. The asteroids are 1950 DA, 1999 RQ36, 2002 NY40, 2004 DC and 2005 EU2. Several orbit fittings for these aster-oids have been done: with just angular observations; with just radar observations; with both angular and radar observations. The obtained results are quite acceptable because in the last case the mean-square angular residuals are approximately equal to the same ones obtained in the fitting with just angular observations. As to radar observations mean-square residuals, the time delay residuals for three asteroids do not exceed 1 μs, for two others ˜ 10 μs and the Doppler shift residuals for three asteroids do not exceed 1 Hz, for two others ˜ 10 Hz. The motion equations included perturbations from 9 planets and the Moon using their ephemerides DE422. The numerical integration has been performed with Everhart 27-order method with variable step. All calculations have been exe-cuted to a 34-digit decimal precision (i.e. using 128-bit floating-point numbers). Further, the sizes of confidence ellipsoids of im-proved orbit parameters have been compared. It

Motion fading is driven by perceived, not actual angular velocity.

PubMed

Kohler, P J; Caplovitz, G P; Hsieh, P-J; Sun, J; Tse, P U

2010-06-01

After prolonged viewing of a slowly drifting or rotating pattern under strict fixation, the pattern appears to slow down and then momentarily stop. Here we examine the relationship between such 'motion fading' and perceived angular velocity. Using several different dot patterns that generate emergent virtual contours, we demonstrate that whenever there is a difference in the perceived angular velocity of two patterns of dots that are in fact rotating at the same angular velocity, there is also a difference in the time to undergo motion fading for those two patterns. Conversely, whenever two patterns show no difference in perceived angular velocity, even if in fact rotating at different angular velocities, we find no difference in the time to undergo motion fading. Thus, motion fading is driven by the perceived rather than actual angular velocity of a rotating stimulus. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Study on optical 3D angular deformations measurement

NASA Astrophysics Data System (ADS)

Gao, Yang; Wang, Xingshu; Huang, Zongsheng; Yang, Jinliang

2013-12-01

3D angular deformations will be inevitable when ships are sailing, due to the changes of the environmental temperature and external stresses. The measurement of 3D angular deformations is one of the most critical and difficult issues in navy and shipbuilding industry around the world. In this paper, we propose an optical method to measure 3D ship angular deformations and discuss the measurement errors in detail. Theoretical analysis shows that the measured errors of the pitching and yawing deformations are induced by the installation errors of the image aperture, and the measured error of the rolling deformation depends on the subpixel location algorithm in image processing. It indicates that the measured errors of the optical measurement proposed in this paper are at the magnitude of angular seconds, when the elaborated installation and precise image processing technology are both performed.

Observation of circular dichroism in photoelectron angular distributions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Appling, J.R.; White, M.G.; Orlando, T.M.

1986-12-01

The first observations of dichroic effects in photoelectron angular distributions are reported for photoionization of aligned molecular excited states with circularly polarized light. Photoelectron angular distributions resulting from the two-color, (2+1) REMPI of NO via the A /sup 2/summation/sup +/, v = 0, J = 3/2,5/2 excited states exhibit significant left--right asymmetry. The experimental CD angular distributions are found to be well described by the general theoretical framework recently developed by Dubs, Dixit, and McKoy and are in good qualitative agreement with their calculated REMPI--CD distributions.

Observation of circular dichroism in photoelectron angular distributions

NASA Astrophysics Data System (ADS)

Appling, Jeffrey R.; White, Michael G.; Orlando, Thomas M.; Anderson, Scott L.

1986-12-01

The first observations of dichroic effects in photoelectron angular distributions are reported for photoionization of aligned molecular excited states with circularly polarized light. Photoelectron angular distributions resulting from the two-color, (2+1) REMPI of NO via the A 2∑+, v=0, J=3/2,5/2 excited states exhibit significant left-right asymmetry. The experimental CD angular distributions are found to be well described by the general theoretical framework recently developed by Dubs, Dixit, and McKoy and are in good qualitative agreement with their calculated REMPI-CD distributions.

Multimode cavity-assisted quantum storage via continuous phase-matching control

NASA Astrophysics Data System (ADS)

Kalachev, Alexey; Kocharovskaya, Olga

2013-09-01

A scheme for spatial multimode quantum memory is developed such that spatial-temporal structure of a weak signal pulse can be stored and recalled via cavity-assisted off-resonant Raman interaction with a strong angular-modulated control field in an extended Λ-type atomic ensemble. It is shown that effective multimode storage is possible when the Raman coherence spatial grating involves wave vectors with different longitudinal components relative to the paraxial signal field. The possibilities of implementing the scheme in the solid-state materials are discussed.

Dynamic optimization and its relation to classical and quantum constrained systems

NASA Astrophysics Data System (ADS)

Contreras, Mauricio; Pellicer, Rely; Villena, Marcelo

2017-08-01

We study the structure of a simple dynamic optimization problem consisting of one state and one control variable, from a physicist's point of view. By using an analogy to a physical model, we study this system in the classical and quantum frameworks. Classically, the dynamic optimization problem is equivalent to a classical mechanics constrained system, so we must use the Dirac method to analyze it in a correct way. We find that there are two second-class constraints in the model: one fix the momenta associated with the control variables, and the other is a reminder of the optimal control law. The dynamic evolution of this constrained system is given by the Dirac's bracket of the canonical variables with the Hamiltonian. This dynamic results to be identical to the unconstrained one given by the Pontryagin equations, which are the correct classical equations of motion for our physical optimization problem. In the same Pontryagin scheme, by imposing a closed-loop λ-strategy, the optimality condition for the action gives a consistency relation, which is associated to the Hamilton-Jacobi-Bellman equation of the dynamic programming method. A similar result is achieved by quantizing the classical model. By setting the wave function Ψ(x , t) =e iS(x , t) in the quantum Schrödinger equation, a non-linear partial equation is obtained for the S function. For the right-hand side quantization, this is the Hamilton-Jacobi-Bellman equation, when S(x , t) is identified with the optimal value function. Thus, the Hamilton-Jacobi-Bellman equation in Bellman's maximum principle, can be interpreted as the quantum approach of the optimization problem.

Chiral Luttinger liquids and a generalized Luttinger theorem in fractional quantum Hall edges via finite-entanglement scaling

NASA Astrophysics Data System (ADS)

Varjas, Dániel; Zaletel, Michael P.; Moore, Joel E.

2013-10-01

We use bosonic field theories and the infinite system density matrix renormalization group method to study infinite strips of fractional quantum Hall states starting from microscopic Hamiltonians. Finite-entanglement scaling allows us to accurately measure chiral central charge, edge-mode exponents, and momenta without finite-size errors. We analyze states in the first and second levels of the standard hierarchy and compare our results to predictions of the chiral Luttinger liquid theory. The results confirm the universality of scaling exponents in chiral edges and demonstrate that renormalization is subject to universal relations in the nonchiral case. We prove a generalized Luttinger theorem involving all singularities in the momentum-resolved density, which naturally arises when mapping Landau levels on a cylinder to a fermion chain and deepens our understanding of non-Fermi liquids in one dimension.

Recovering information of tunneling spectrum from weakly isolated horizon

NASA Astrophysics Data System (ADS)

Chen, Ge-Rui; Huang, Yong-Chang

2015-02-01

In this paper we investigate the properties of tunneling spectrum from weakly isolated horizon (WIH)—a locally defined black hole. We find that there exist correlations among Hawking radiations from a WIH, information can be carried out by such correlations, and the radiation is an entropy conservation process. Through revisiting the calculation of the tunneling spectrum from a WIH, we find that Zhang et al.'s (Ann Phys 326:350, 2011) requirement that radiated particles have the same angular momenta of a unit mass as that of the black hole is unnecessary, and the energy and angular momenta of the emitted particles are very arbitrary, restricted only by keeping the cosmic censorship hypothesis of black holes. So we resolve the information loss paradox based on the method of Zhang et al. (Phys Lett B 675:98, 2009; Ann Phys 326:350, 2011; Int J Mod Phys D 22:1341014, 2013) in a general case.

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Hydrogenic molecular transitions in double concentric quantum donuts by changing geometrical parameters

NASA Astrophysics Data System (ADS)

Ospina-Londoño, D. A.; Fulla, M. R.; Marín, J. H.

2013-03-01

In this work it is considered a versatile model to study two different ionization processes starting from a D20 homonuclear hydrogenic molecule confined in double concentric quantum donuts. Very narrow quantum donut circular cross sections are considered to separate the radial and angular variables in the D20 Hamiltonian by using the well-known adiabatic approximation D20 total energy as a function of the inter donor spacing and the outer donut center line radius is calculated. The salient features of an artificial D20 hydrogenic molecule such as the dissociation energy and the equilibrium length are strongly dependent on the quantum donut geometrical parameters. By increasing systematically the quantum donut outer center line radius, it is possible to understand a first ionization process: D20→D2++e-. A second ionization process D20→D-+D+ can be carried out by fixing the first donor position and gradually moving away the second one. The results obtained in this study are in good agreement with those previously obtained in the limiting cases of very large inter donor separation. The model proposed here is computationally economical and provides a realistic description of both ionization processes and the few-particle system confined in double concentric quantum donuts.

Maximum angular accuracy of pulsed laser radar in photocounting limit.

PubMed

Elbaum, M; Diament, P; King, M; Edelson, W

1977-07-01

To estimate the angular position of targets with pulsed laser radars, their images may be sensed with a fourquadrant noncoherent detector and the image photocounting distribution processed to obtain the angular estimates. The limits imposed on the accuracy of angular estimation by signal and background radiation shot noise, dark current noise, and target cross-section fluctuations are calculated. Maximum likelihood estimates of angular positions are derived for optically rough and specular targets and their performances compared with theoretical lower bounds.

Quantum Structure of Space and Time

NASA Astrophysics Data System (ADS)

Duff, M. J.; Isham, C. J.

2012-07-01

Foreword Abdus Salam; Preface; List of participants; Part I. Quantum Gravity, Fields and Topology: 1. Some remarks on gravity and quantum mechanics Roger Penrose; 2. An experimental test of quantum gravity Don N. Page and C. D. Geilker; 3. Quantum mechanical origin of the sandwich theorem in classical gravitation theory Claudio Teitelboim; 4. θ-States induced by the diffeomorphism group in canonically quantized gravity C. J. Isham; 5. Strong coupling quantum gravity: an introduction Martin Pilati; 6. Quantizing fourth order gravity theories S. M. Christensen; 7. Green's functions, states and renormalisation M. R. Brown and A. C. Ottewill; 8. Introduction to quantum regge calculus Martin Roček and Ruth Williams; 9. Spontaneous symmetry breaking in curved space-time D. J. Toms; 10. Spontaneous symmetry breaking near a black hole M. S. Fawcett and B. F. Whiting; 11. Yang-Mills vacua in a general three-space G. Kunstatter; 12. Fermion fractionization in physics R. Jackiw; Part II. Supergravity: 13. The new minimal formulation of N=1 supergravity and its tensor calculus M. F. Sohnius and P. C. West; 14. A new deteriorated energy-momentum tensor M. J. Duff and P. K. Townsend; 15. Off-shell N=2 and N=4 supergravity in five dimensions P. Howe; 16. Supergravity in high dimensions P. van Niewenhuizen; 17. Building linearised extended supergravities J. G. Taylor; 18. (Super)gravity in the complex angular momentum plane M. T. Grisaru; 19. The multiplet structure of solitons in the O(2) supergravity theory G. W. Gibbons; 20. Ultra-violet properties of supersymmetric gauge theory S. Ferrara; 21. Extended supercurrents and the ultra-violet finiteness of N=4 supersymmetric Yang-Mills theories K. S. Stelle; 22. Duality rotations B. Zumino; Part III. Cosmology and the Early Universe: 23. Energy, stability and cosmological constant S. Deser; 24. Phase transitions in the early universe T. W. B. Kibble; 25. Complete cosmological theories L. P. Grishchuk and Ya. B. Zeldovich; 26. The

Vibration signal correction of unbalanced rotor due to angular speed fluctuation

NASA Astrophysics Data System (ADS)

Cao, Hongrui; He, Dong; Xi, Songtao; Chen, Xuefeng

2018-07-01

The rotating speed of a rotor is hardly constant in practice due to angular speed fluctuation, which affects the balancing accuracy of the rotor. In this paper, the effect of angular speed fluctuation on vibration responses of the unbalanced rotor is analyzed quantitatively. Then, a vibration signal correction method based on zoom synchrosqueezing transform (ZST) and tacholess order tracking is proposed. The instantaneous angular speed (IAS) of the rotor is extracted by the ZST firstly and then used to calculate the instantaneous phase. The vibration signal is further resampled in angular domain to reduce the effect of angular speed fluctuation. The signal obtained in angular domain is transformed into order domain using discrete Fourier transform (DFT) to estimate the amplitude and phase of the vibration signal. Simulated and experimental results show that the proposed method can successfully correct the amplitude and phase of the vibration signal due to angular speed fluctuation.

Rabi like angular splitting in Surface Plasmon Polariton - Exciton interaction in ATR configuration

NASA Astrophysics Data System (ADS)

Hassan, Heba; Abdallah, T.; Negm, S.; Talaat, H.

2018-05-01

We have studied the coupling of propagating Surface Plasmon Polaritons (SPP) on silver films and excitons in CdS quantum dots (QDs). We employed the Kretschmann-Raether configuration of the attenuated total reflection (ATR) to propagate the SPP on silver film of thickness 47.5 nm at three different wavelengths. The CdS QD have been chemically synthesized with particular size such that its exciton of energy would resonate with SPP. High resolution transmission electron microscopy (HRTEM) and scan tunneling microscopy (STM) were used to measure the corresponding QDs size and confirm its shape. Further confirmation of the size has been performed by the effective mass approximation (EMA) model utilizing the band gap of the prepared QDs. The band gaps have been measured through UV-vis absorption spectra as well as scan tunneling spectroscopy (STS). The coupling has been observed as two branching dips in the ATR spectra indicating Rabi like splitting. To the best of our knowledge, this is the first time that Rabi interaction is directly observed in an ATR angular spectra. This observation is attributed to the use a high resolution angular scan (±0.005°), in addition to the Doppler width of the laser line as well as the energy distribution of the excitons. The effect of three different linker molecules (TOPO, HDA), (Pyridine) and (Tri-butylamine) as surface ligands, on SPP-Exciton interaction has been examined.

Computer network defense through radial wave functions

NASA Astrophysics Data System (ADS)

Malloy, Ian J.

The purpose of this research is to synthesize basic and fundamental findings in quantum computing, as applied to the attack and defense of conventional computer networks. The concept focuses on uses of radio waves as a shield for, and attack against traditional computers. A logic bomb is analogous to a landmine in a computer network, and if one was to implement it as non-trivial mitigation, it will aid computer network defense. As has been seen in kinetic warfare, the use of landmines has been devastating to geopolitical regions in that they are severely difficult for a civilian to avoid triggering given the unknown position of a landmine. Thus, the importance of understanding a logic bomb is relevant and has corollaries to quantum mechanics as well. The research synthesizes quantum logic phase shifts in certain respects using the Dynamic Data Exchange protocol in software written for this work, as well as a C-NOT gate applied to a virtual quantum circuit environment by implementing a Quantum Fourier Transform. The research focus applies the principles of coherence and entanglement from quantum physics, the concept of expert systems in artificial intelligence, principles of prime number based cryptography with trapdoor functions, and modeling radio wave propagation against an event from unknown parameters. This comes as a program relying on the artificial intelligence concept of an expert system in conjunction with trigger events for a trapdoor function relying on infinite recursion, as well as system mechanics for elliptic curve cryptography along orbital angular momenta. Here trapdoor both denotes the form of cipher, as well as the implied relationship to logic bombs.

Angular-spectrum representation of nondiffracting X waves

NASA Astrophysics Data System (ADS)

Fagerholm, Juha; Friberg, Ari T.; Huttunen, Juhani; Morgan, David P.; Salomaa, Martti M.

1996-10-01

We derive the nondiffracting X waves, first discussed within acoustics by Lu and Greenleaf [IEEE Trans. Ultrason. Ferroelec. Freq. Contr. 39, 19 (1992)], using the general mathematical formalism based on an angular spectrum of plane waves. This serves to provide a unified treatment of not only the fundamental zeroth-order X waves of Lu and Greenleaf, but also of the lesser-known higher-order derivative X waves, first discussed here in terms of a single, universal, angular spectrum. The characteristic crossed (letter-X-like) shape and the special properties of the X waves, as well as of their angular-spectrum representation, are discussed and illustrated in detail. Asymptotically, for increasing order, the appearance of the X waves is found to transform into a triangular wedgelike waveform.

Aspects of warped AdS3/CFT2 correspondence

NASA Astrophysics Data System (ADS)

Chen, Bin; Zhang, Jia-Ju; Zhang, Jian-Dong; Zhong, De-Liang

2013-04-01

In this paper we apply the thermodynamics method to investigate the holographic pictures for the BTZ black hole, the spacelike and the null warped black holes in three-dimensional topologically massive gravity (TMG) and new massive gravity (NMG). Even though there are higher derivative terms in these theories, the thermodynamics method is still effective. It gives consistent results with the ones obtained by using asymptotical symmetry group (ASG) analysis. In doing the ASG analysis we develop a brute-force realization of the Barnich-Brandt-Compere formalism with Mathematica code, which also allows us to calculate the masses and the angular momenta of the black holes. In particular, we propose the warped AdS3/CFT2 correspondence in the new massive gravity, which states that quantum gravity in the warped spacetime could holographically dual to a two-dimensional CFT with {c_R}={c_L}=24 /{Gm{β^2√{{2( {21-4{β^2}} )}}}}.

Projective Ponzano-Regge spin networks and their symmetries

NASA Astrophysics Data System (ADS)

Aquilanti, Vincenzo; Marzuoli, Annalisa

2018-02-01

We present a novel hierarchical construction of projective spin networks of the Ponzano-Regge type from an assembling of five quadrangles up to the combinatorial 4-simplex compatible with a geometrical realization in Euclidean 4-space. The key ingredients are the projective Desargues configuration and the incidence structure given by its space-dual, on the one hand, and the Biedenharn-Elliott identity for the 6j symbol of SU(2), on the other. The interplay between projective-combinatorial and algebraic features relies on the recoupling theory of angular momenta, an approach to discrete quantum gravity models carried out successfully over the last few decades. The role of Regge symmetry-an intriguing discrete symmetry of the 6j which goes beyond the standard tetrahedral symmetry of this symbol-will be also discussed in brief to highlight its role in providing a natural regularization of projective spin networks that somehow mimics the standard regularization through a q-deformation of SU(2).

Demonstrating the Direction of Angular Velocity in Circular Motion

NASA Astrophysics Data System (ADS)

Demircioglu, Salih; Yurumezoglu, Kemal; Isik, Hakan

2015-09-01

Rotational motion is ubiquitous in nature, from astronomical systems to household devices in everyday life to elementary models of atoms. Unlike the tangential velocity vector that represents the instantaneous linear velocity (magnitude and direction), an angular velocity vector is conceptually more challenging for students to grasp. In physics classrooms, the direction of an angular velocity vector is taught by the right-hand rule, a mnemonic tool intended to aid memory. A setup constructed for instructional purposes may provide students with a more easily understood and concrete method to observe the direction of the angular velocity. This article attempts to demonstrate the angular velocity vector using the observable motion of a screw mounted to a remotely operated toy car.

VizieR Online Data Catalog: j-M law from dwarf to massive spirals (Posti+, 2018)

NASA Astrophysics Data System (ADS)

Posti, L.; Fraternali, F.; di Teodoro, E. M.; Pezzulli, G.

2018-04-01

The table contains the estimates of the stellar masses and specific angular momenta of 92 spiral galaxies in the SPARC sample (Lelli et al., 2016, Cat. J/AJ/152/157). Estimates are given both for the whole galaxy and only for its disc component, together with standard uncertainties. Two flags on the quality of the measurements, assessing whether the observed specific angular momentum profiles have reached convergence (defined in Eq. 2 in the paper), are also provided. (1 data file).

A Novel Permanent Magnetic Angular Acceleration Sensor

PubMed Central

Zhao, Hao; Feng, Hao

2015-01-01

Angular acceleration is an important parameter for status monitoring and fault diagnosis of rotary machinery. Therefore, we developed a novel permanent magnetic angular acceleration sensor, which is without rotation angle limitations and could directly measure the instantaneous angular acceleration of the rotating system. The sensor rotor only needs to be coaxially connected with the rotating system, which enables convenient sensor installation. For the cup structure of the sensor rotor, it has a relatively small rotational inertia. Due to the unique mechanical structure of the sensor, the output signal of the sensor can be directed without a slip ring, which avoids signal weakening effect. In this paper, the operating principle of the sensor is described, and simulated using finite element method. The sensitivity of the sensor is calibrated by torsional pendulum and angle sensor, yielding an experimental result of about 0.88 mV/(rad·s−2). Finally, the angular acceleration of the actual rotating system has been tested, using both a single-phase asynchronous motor and a step motor. Experimental result confirms the operating principle of the sensor and indicates that the sensor has good practicability. PMID:26151217

Break-technique handheld dynamometry: relation between angular velocity and strength measurements.

PubMed

Burns, Stephen P; Spanier, David E

2005-07-01

To determine whether the muscle strength, as measured with break-technique handheld dynamometry (HHD), is dependent on the angular velocity achieved during testing and to compare reliability at different angular velocities. Repeated-measures study. Participants underwent HHD by using make-technique (isometric) and break-technique (eccentric) dynamometry at 3 prespecified angular velocities. Elbow movement was recorded with an electrogoniometer. Inpatient spinal cord injury unit. Convenience sample of 20 persons with tetraplegia with weakness of elbow flexors or extensors. Not applicable. Elbow angular velocity and muscle strength recorded during HHD. With the break technique, angular velocities averaging 15 degrees , 33 degrees , and 55 degrees /s produced 16%, 30%, and 51% greater strength measurements, respectively, than velocities recorded by using the make technique (all P < .006 for comparisons between successive techniques). The intraclass correlation coefficient for intrarater reliability was .89 or greater for all testing techniques. Greater strength is recorded with faster angular velocities during HHD. Differences in angular velocity may explain the wide range previously reported for break- versus make-technique strength measurements. Variation in angular velocity is a potential source of variability in serial HHD strength measurements, and for this reason the make technique may be preferable.

Coulomb-free and Coulomb-distorted recolliding quantum orbits in photoelectron holography

NASA Astrophysics Data System (ADS)

Maxwell, A. S.; Figueira de Morisson Faria, C.

2018-06-01

We perform a detailed analysis of the different types of orbits in the Coulomb quantum orbit strong-field approximation (CQSFA), ranging from direct to those undergoing hard collisions. We show that some of them exhibit clear counterparts in the standard formulations of the strong-field approximation for direct and rescattered above-threshold ionization, and show that the standard orbit classification commonly used in Coulomb-corrected models is over-simplified. We identify several types of rescattered orbits, such as those responsible for the low-energy structures reported in the literature, and determine the momentum regions in which they occur. We also find formerly overlooked interference patterns caused by backscattered Coulomb-corrected orbits and assess their effect on photoelectron angular distributions. These orbits improve the agreement of photoelectron angular distributions computed with the CQSFA with the outcome of ab initio methods for high energy phtotoelectrons perpendicular to the field polarization axis.

Measurement of angular velocity in the perception of rotation.

PubMed

Barraza, José F; Grzywacz, Norberto M

2002-09-01

Humans are sensitive to the parameters of translational motion, namely, direction and speed. At the same time, people have special mechanisms to deal with more complex motions, such as rotations and expansions. One wonders whether people may also be sensitive to the parameters of these complex motions. Here, we report on a series of experiments that explore whether human subjects can use angular velocity to evaluate how fast a rotational motion is. In four experiments, subjects were required to perform a task of speed-of-rotation discrimination by comparing two annuli of different radii in a temporal 2AFC paradigm. Results showed that humans could rely on a sensitive measurement of angular velocity to perform this discrimination task. This was especially true when the quality of the rotational signal was high (given by the number of dots composing the annulus). When the signal quality decreased, a bias towards linear velocity of 5-80% appeared, suggesting the existence of separate mechanisms for angular and linear velocity. This bias was independent from the reference radius. Finally, we asked whether the measurement of angular velocity required a rigid rotation, that is, whether the visual system makes only one global estimate of angular velocity. For this purpose, a random-dot disk was built such that all the dots were rotating with the same tangential speed, irrespectively of radius. Results showed that subjects do not estimate a unique global angular velocity, but that they perceive a non-rigid disk, with angular velocity falling inversely proportionally with radius.

Grating angle magnification enhanced angular sensor and scanner

NASA Technical Reports Server (NTRS)

Sun, Ke-Xun (Inventor); Byer, Robert L. (Inventor)

2009-01-01

An angular magnification effect of diffraction is exploited to provide improved sensing and scanning. This effect is most pronounced for a normal or near-normal incidence angle in combination with a grazing diffraction angle, so such configurations are preferred. Angular sensitivity can be further enhanced because the width of the diffracted beam can be substantially less than the width of the incident beam. Normal incidence configurations with two symmetric diffracted beams are preferred, since rotation and vertical displacement can be readily distinguished. Increased sensitivity to vertical displacement can be provided by incorporating an interferometer into the measurement system. Quad cell detectors can be employed to provide sensitivity to rotation about the grating surface normal. A 2-D grating can be employed to provide sensitivity to angular displacements in two different planes (e.g., pitch and yaw). Combined systems can provide sensitivity to vertical displacement and to all three angular degrees of freedom.

Differentiability of correlations in realistic quantum mechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabrera, Alejandro; Faria, Edson de; Pujals, Enrique

2015-09-15

We prove a version of Bell’s theorem in which the locality assumption is weakened. We start by assuming theoretical quantum mechanics and weak forms of relativistic causality and of realism (essentially the fact that observable values are well defined independently of whether or not they are measured). Under these hypotheses, we show that only one of the correlation functions that can be formulated in the framework of the usual Bell theorem is unknown. We prove that this unknown function must be differentiable at certain angular configuration points that include the origin. We also prove that, if this correlation is assumedmore » to be twice differentiable at the origin, then we arrive at a version of Bell’s theorem. On the one hand, we are showing that any realistic theory of quantum mechanics which incorporates the kinematic aspects of relativity must lead to this type of rough correlation function that is once but not twice differentiable. On the other hand, this study brings us a single degree of differentiability away from a relativistic von Neumann no hidden variables theorem.« less

Time-resolved orbital angular momentum spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noyan, Mehmet A.; Kikkawa, James M.

We introduce pump-probe magneto-orbital spectroscopy, wherein Laguerre-Gauss optical pump pulses impart orbital angular momentum to the electronic states of a material and subsequent dynamics are studied with 100 fs time resolution. The excitation uses vortex modes that distribute angular momentum over a macroscopic area determined by the spot size, and the optical probe studies the chiral imbalance of vortex modes reflected off the sample. First observations in bulk GaAs yield transients that evolve on time scales distinctly different from population and spin relaxation, as expected, but with surprisingly large lifetimes.

Angular momentum

NASA Astrophysics Data System (ADS)

Shakur, Asif; Sinatra, Taylor

2013-12-01

The gyroscope in a smartphone was employed in a physics laboratory setting to verify the conservation of angular momentum and the nonconservation of rotational kinetic energy. As is well-known, smartphones are ubiquitous on college campuses. These devices have a panoply of built-in sensors. This creates a unique opportunity for a new paradigm in the physics laboratory. Many traditional physics experiments can now be performed very conveniently in a pedagogically enlightening environment while simultaneously reducing the laboratory budget substantially by using student-owned smartphones.

Quantum gravity effects on scalar particle tunneling from rotating BTZ black hole

NASA Astrophysics Data System (ADS)

Meitei, I. Ablu; Singh, T. Ibungochouba; Devi, S. Gayatri; Devi, N. Premeshwari; Singh, K. Yugindro

2018-04-01

Tunneling of scalar particles across the event horizon of rotating BTZ black hole is investigated using the Generalized Uncertainty Principle to study the corrected Hawking temperature and entropy in the presence of quantum gravity effects. We have determined explicitly the various correction terms in the entropy of rotating BTZ black hole including the logarithmic term of the Bekenstein-Hawking entropy (SBH), the inverse term of SBH and terms with inverse powers of SBH, in terms of properties of the black hole and the emitted particles — mass, energy and angular momentum. In the presence of quantum gravity effects, for the emission of scalar particles, the Hawking radiation and thermodynamics of rotating BTZ black hole are observed to be related to the metric element, hence to the curvature of space-time.

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A modified Stern-Gerlach experiment using a quantum two-state magnetic field

NASA Astrophysics Data System (ADS)

Daghigh, Ramin G.; Green, Michael D.; West, Christopher J.

2018-06-01

The Stern-Gerlach experiment has played an important role in our understanding of quantum behavior. We propose and analyze a modified version of this experiment where the magnetic field of the detector is in a quantum superposition, which may be experimentally realized using a superconducting flux qubit. We show that if incident spin-1/2 particles couple with the two-state magnetic field, a discrete target distribution results that resembles the distribution in the classical Stern-Gerlach experiment. As an application of the general result, we compute the distribution for a Gaussian waveform of the incident fermion. This analysis allows us to demonstrate theoretically: (1) the quantization of the intrinsic angular momentum of a spin-1/2 particle, and (2) a correlation between EPR pairs leading to nonlocality, without necessarily collapsing the particle's spin wavefunction.

Baryon spectrum from superconformal quantum mechanics and its light-front holographic embedding

DOE PAGES

de Teramond, Guy F.; Dosch, Hans Gunter; Brodsky, Stanley J.

2015-02-27

We describe the observed light-baryon spectrum by extending superconformal quantum mechanics to the light front and its embedding in AdS space. This procedure uniquely determines the confinement potential for arbitrary half-integer spin. To this end, we show that fermionic wave equations in AdS space are dual to light-front supersymmetric quantum-mechanical bound-state equations in physical space-time. The specific breaking of conformal invariance explains hadronic properties common to light mesons and baryons, such as the observed mass pattern in the radial and orbital excitations, from the spectrum generating algebra. Lastly, the holographic embedding in AdS also explains distinctive and systematic features, suchmore » as the spin-J degeneracy for states with the same orbital angular momentum, observed in the light-baryon spectrum.« less

Properties of strong-coupling magneto-bipolaron qubit in quantum dot under magnetic field

NASA Astrophysics Data System (ADS)

Xu-Fang, Bai; Ying, Zhang; Wuyunqimuge; Eerdunchaolu

2016-07-01

Based on the variational method of Pekar type, we study the energies and the wave-functions of the ground and the first-excited states of magneto-bipolaron, which is strongly coupled to the LO phonon in a parabolic potential quantum dot under an applied magnetic field, thus built up a quantum dot magneto-bipolaron qubit. The results show that the oscillation period of the probability density of the two electrons in the qubit decreases with increasing electron-phonon coupling strength α, resonant frequency of the magnetic field ω c, confinement strength of the quantum dot ω 0, and dielectric constant ratio of the medium η the probability density of the two electrons in the qubit oscillates periodically with increasing time t, angular coordinate φ 2, and dielectric constant ratio of the medium η the probability of electron appearing near the center of the quantum dot is larger, and the probability of electron appearing away from the center of the quantum dot is much smaller. Project supported by the Natural Science Foundation of Hebei Province, China (Grant No. E2013407119) and the Items of Institution of Higher Education Scientific Research of Hebei Province and Inner Mongolia, China (Grant Nos. ZD20131008, Z2015149, Z2015219, and NJZY14189).

Electronic structure and orientation relationship of Li nanoclusters embedded in MgO studied by depth-selective positron annihilation two-dimensional angular correlation

NASA Astrophysics Data System (ADS)

Falub, C. V.; Mijnarends, P. E.; Eijt, S. W.; van Huis, M. A.; van Veen, A.; Schut, H.

2002-08-01

Quantum-confined positrons are sensitive probes for determining the electronic structure of nanoclusters embedded in materials. In this work, a depth-selective positron annihilation 2D-ACAR (two-dimensional angular correlation of annihilation radiation) method is used to determine the electronic structure of Li nanoclusters formed by implantation of 1016-cm-2 30-keV 6Li ions in MgO (100) and (110) crystals and by subsequent annealing at 950 K. Owing to the difference between the positron affinities of lithium and MgO, the Li nanoclusters act as quantum dots for positrons. 2D-ACAR distributions for different projections reveal a semicoherent fitting of the embedded metallic Li nanoclusters to the host MgO lattice. Ab initio Korringa-Kohn-Rostoker calculations of the momentum density show that the anisotropies of the experimental distributions are consistent with an fcc crystal structure of the Li nanoclusters. The observed reduction of the width of the experimental 2D-ACAR distribution is attributed to positron trapping in vacancies associated with Li clusters. This work proposes a method for studying the electronic structure of metallic quantum dots embedded in an insulating material.

Aliasing Detection and Reduction Scheme on Angularly Undersampled Light Fields.

PubMed

Xiao, Zhaolin; Wang, Qing; Zhou, Guoqing; Yu, Jingyi

2017-05-01

When using plenoptic camera for digital refocusing, angular undersampling can cause severe (angular) aliasing artifacts. Previous approaches have focused on avoiding aliasing by pre-processing the acquired light field via prefiltering, demosaicing, reparameterization, and so on. In this paper, we present a different solution that first detects and then removes angular aliasing at the light field refocusing stage. Different from previous frequency domain aliasing analysis, we carry out a spatial domain analysis to reveal whether the angular aliasing would occur and uncover where in the image it would occur. The spatial analysis also facilitates easy separation of the aliasing versus non-aliasing regions and angular aliasing removal. Experiments on both synthetic scene and real light field data sets (camera array and Lytro camera) demonstrate that our approach has a number of advantages over the classical prefiltering and depth-dependent light field rendering techniques.

The 3D Entangled Structure of the Proton: Transverse Degrees of Freedom in QCD, Momenta, Spins and More

NASA Astrophysics Data System (ADS)

Mulders, P. J.

2018-03-01

Light-front quantized quark and gluon states (partons) play a dominant role in high energy scattering processes. Initial state hadrons are mixed ensembles of partons, while produced pure partonic states appear as mixed ensembles of hadrons. The transition from collinear hard physics to the 3D structure including partonic transverse momenta is related to confinement which links color and spatial degrees of freedom. We outline ideas on emergent symmetries in the Standard Model and their connection to the 3D structure of hadrons. Wilson loops, including those with light-like Wilson lines such as used in the studies of transverse momentum dependent distribution functions may play a crucial role here, establishing a direct link between transverse spatial degrees of freedom and gluonic degrees of freedom.

Particle production at very low transverse momenta in Au+Au collisions at √(sNN )=200 GeV

NASA Astrophysics Data System (ADS)

Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S.; Sukhanov, A.; Tang, J.-L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

2004-11-01

We present results on charged particle production at very low transverse momenta in the 15% most central Au+Au collisions at √(sNN )=200 GeV obtained with the PHOBOS detector at the Relativistic Heavy Ion Collider. The invariant yields were measured at midrapidity in the transverse momentum ranges from 30 to 50 MeV/c for charged pions, 90 to 130 MeV/c for charged kaons and 140 to 210 MeV/c for protons and antiprotons. No significant enhancement in low transverse momentum particle production is observed as compared to extrapolations of identified particle spectra measured at an intermediate pT range. The spectra tend to flatten at low pT , consistent with the expectations of transverse expansion of the system.

Phase-Covariant Cloning and EPR Correlations in Entangled Macroscopic Quantum Systems

NASA Astrophysics Data System (ADS)

de Martini, Francesco; Sciarrino, Fabio

2007-03-01

Theoretical and experimental results on the Quantum Injected Optical Parametric Amplification (QI-OPA) of optical qubits in the high gain regime are reported. The large size of the gain parameter in the collinear configuration, g = 4.5, allows the generation of EPR nonlocally correlated bunches containing about 4000 photons. The entanglement of the related Schroedinger Cat-State (SCS) is demonstrated as well as the establishment of Phase-Covariant quantum cloning. The cloning ``fidelity'' has been found to match the theoretical results. According to the original 1935 definition of the SCS, the overall apparatus establishes for the first time the nonlocal correlations between a microcopic spin (qubit) and a high J angular momentum i.e. a mesoscopic multiparticle system close to the classical limit. The results of the first experimental realization of the Herbert proposal for superluminal communication via nonlocality will be presented.

The mass and angular momentum of reconstructed metric perturbations

NASA Astrophysics Data System (ADS)

van de Meent, Maarten

2017-06-01

We prove a key result regarding the mass and angular momentum content of linear vacuum perturbations of the Kerr metric obtained through the formalism developed by Chrzarnowski, Cohen, and Kegeles (CCK). More precisely, we prove that the Abbott-Deser mass and angular momentum integrals of any such perturbation vanish when that perturbation was obtained from a regular Fourier mode of the Hertz potential. As a corollary we obtain a generalization of previous results on the completion of the ‘no string’ radiation gauge metric perturbation generated by a point particle. We find that for any bound orbit around a Kerr black hole, the mass and angular momentum perturbations completing the CCK metric are simply the energy and angular momentum of the particle ‘outside’ the orbit and vanish ‘inside’ the orbit.

Ground state transitions in vertically coupled N-layer single electron quantum dots

NASA Astrophysics Data System (ADS)

Xie, Wenfang; Wang, Anmei

2003-12-01

A method is proposed to exactly diagonalize the Hamiltonian of a N-layer quantum dot containing a single electron in each dot in arbitrary magnetic fields. For N=4, the energy spectra of the dot are calculated as a function of the applied magnetic field. We find discontinuous ground-state energy transitions induced by an external magnetic field in the case of strong coupling. However, in the case of weak coupling, such a transition does not occur and the angular momentum remains zero.

Resonant states for the scattering of slow particles by screened potentials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruk, Yu. M., E-mail: yubruk@gmail.com; Voloshchuk, A. N.

2016-09-15

Partial resonant situations for the scattering of slow particles with nonzero angular momenta by short-range screened Yukawa and Buckingham potentials are considered. The problem of electron scattering by a hydrogen atom placed in a plasma medium is discussed. A general scheme of resonances has been constructed in the Pais approximation.

The Angular Momentum of Baryons and Dark Matter Halos Revisited

NASA Technical Reports Server (NTRS)

Kimm, Taysun; Devriendt, Julien; Slyz, Adrianne; Pichon, Christophe; Kassin, Susan A.; Dubois, Yohan

2011-01-01

Recent theoretical studies have shown that galaxies at high redshift are fed by cold, dense gas filaments, suggesting angular momentum transport by gas differs from that by dark matter. Revisiting this issue using high-resolution cosmological hydrodynamics simulations with adaptive-mesh refinement (AMR), we find that at the time of accretion, gas and dark matter do carry a similar amount of specific angular momentum, but that it is systematically higher than that of the dark matter halo as a whole. At high redshift, freshly accreted gas rapidly streams into the central region of the halo, directly depositing this large amount of angular momentum within a sphere of radius r = 0.1R(sub vir). In contrast, dark matter particles pass through the central region unscathed, and a fraction of them ends up populating the outer regions of the halo (r/R(sub vir) > 0.1), redistributing angular momentum in the process. As a result, large-scale motions of the cosmic web have to be considered as the origin of gas angular momentum rather than its virialised dark matter halo host. This generic result holds for halos of all masses at all redshifts, as radiative cooling ensures that a significant fraction of baryons remain trapped at the centre of the halos. Despite this injection of angular momentum enriched gas, we predict an amount for stellar discs which is in fair agreement with observations at z=0. This arises because the total specific angular momentum of the baryons (gas and stars) remains close to that of dark matter halos. Indeed, our simulations indicate that any differential loss of angular momentum amplitude between the two components is minor even though dark matter halos continuously lose between half and two-thirds of their specific angular momentum modulus as they evolve. In light of our results, a substantial revision of the standard theory of disc formation seems to be required. We propose a new scenario where gas efficiently carries the angular momentum generated

Semiclassical (qft) and Quantum (string) Rotating Black Holes and Their Evaporation:. New Results

NASA Astrophysics Data System (ADS)

Bouchareb, A.; Ramón Medrano, M.; Sánchez, N. G.

Combination of both quantum field theory (QFT) and string theory in curved backgrounds in a consistent framework, the string analogue model, allows us to provide a full picture of the Kerr-Newman black hole and its evaporation going beyond the current picture. We compute the quantum emission cross-section of strings by a Kerr-Newman black hole (KNbh). It shows the black hole emission at the Hawking temperature Tsem in the early stage of evaporation and the new string emission featuring a Hagedorn transition into a string state of temperature Ts at the last stages. New bounds on J and Q emerge in the quantum string regime (besides the known ones of the classical/semiclassical QFT regime). The last state of evaporation of a semiclassical Kerr-Newman black hole with mass M > mPl, angular momentum J and charge Q is a string state of temperature Ts, string mass Ms, J = 0 and Q = 0, decaying as usual quantum strings do into all kinds of particles. (Naturally, in this framework, there is no loss of information, (there is no paradox at all).) We compute the string entropy Ss(m, j) from the microscopic string density of states of mass m and spin mode j, ρ(m, j). (Besides the Hagedorn transition at Ts) we find for high j (extremal string states j → m2α‧c), a new phase transition at a temperature Tsj = √ {j/hbar }Ts, higher than Ts. By precisely identifying the semiclassical and quantum (string) gravity regimes, we find a new formula for the Kerr black hole entropy Ssem(M, J), as a function of the usual Bekenstein-Hawking entropy S sem(0). For M ≫ mPl and J < GM2/c, S sem(0) is the leading term, but for high angular momentum, (nearly extremal case J = GM2/c), a gravitational phase transition operates and the whole entropy Ssem is drastically different from the Bekenstein-Hawking entropy S sem(0). This new extremal black hole transition occurs at a temperature Tsem J = (J/ℏ)Tsem, higher than the Hawking temperature Tsem.

A systematic construction of microstate geometries with low angular momentum

NASA Astrophysics Data System (ADS)

Bena, Iosif; Heidmann, Pierre; Ramírez, Pedro F.

2017-10-01

We outline a systematic procedure to obtain horizonless microstate geometries that have the same charges as three-charge five-dimensional black holes with a macroscopically-large horizon area and an arbitrarily-small angular momentum. There are two routes through which such solutions can be constructed: using multi-center Gibbons-Hawking (GH) spaces or using superstratum technology. So far the only solutions corre-sponding to microstate geometries for black holes with no angular momentum have been obtained via superstrata [1], and multi-center Gibbons-Hawking spaces have been believed to give rise only to microstate geometries of BMPV black holes with a large angular mo-mentum [2]. We perform a thorough search throughout the parameter space of smooth horizonless solutions with four GH centers and find that these have an angular momentum that is generally larger than 80% of the cosmic censorship bound. However, we find that solutions with three GH centers and one supertube (which are smooth in six-dimensional supergravity) can have an arbitrarily-low angular momentum. Our construction thus gives a recipe to build large classes of microstate geometries for zero-angular-momentum black holes without resorting to superstratum technology.

Coherent π-electron dynamics of (P)-2,2'-biphenol induced by ultrashort linearly polarized UV pulses: angular momentum and ring current.

PubMed

Mineo, H; Lin, S H; Fujimura, Y

2013-02-21

The results of a theoretical investigation of coherent π-electron dynamics for nonplanar (P)-2,2'-biphenol induced by ultrashort linearly polarized UV pulses are presented. Expressions for the time-dependent coherent angular momentum and ring current are derived by using the density matrix method. The time dependence of these coherences is determined by the off-diagonal density matrix element, which can be obtained by solving the coupled equations of motion of the electronic-state density matrix. Dephasing effects on coherent angular momentum and ring current are taken into account within the Markov approximation. The magnitudes of the electronic angular momentum and current are expressed as the sum of expectation values of the corresponding operators in the two phenol rings (L and R rings). Here, L (R) denotes the phenol ring in the left (right)-hand side of (P)-2,2'-biphenol. We define the bond current between the nearest neighbor carbon atoms Ci and Cj as an electric current through a half plane perpendicular to the Ci-Cj bond. The bond current can be expressed in terms of the inter-atomic bond current. The inter-atomic bond current (bond current) depends on the position of the half plane on the bond and has the maximum value at the center. The coherent ring current in each ring is defined by averaging over the bond currents. Since (P)-2,2'-biphenol is nonplanar, the resultant angular momentum is not one-dimensional. Simulations of the time-dependent coherent angular momentum and ring current of (P)-2,2'-biphenol excited by ultrashort linearly polarized UV pulses are carried out using the molecular parameters obtained by the time-dependent density functional theory (TD-DFT) method. Oscillatory behaviors in the time-dependent angular momentum (ring current), which can be called angular momentum (ring current) quantum beats, are classified by the symmetry of the coherent state, symmetric or antisymmetric. The bond current of the bridge bond linking the L and R

Computational comparison of quantum-mechanical models for multistep direct reactions

NASA Astrophysics Data System (ADS)

Koning, A. J.; Akkermans, J. M.

1993-02-01

We have carried out a computational comparison of all existing quantum-mechanical models for multistep direct (MSD) reactions. The various MSD models, including the so-called Feshbach-Kerman-Koonin, Tamura-Udagawa-Lenske and Nishioka-Yoshida-Weidenmüller models, have been implemented in a single computer system. All model calculations thus use the same set of parameters and the same numerical techniques; only one adjustable parameter is employed. The computational results have been compared with experimental energy spectra and angular distributions for several nuclear reactions, namely, 90Zr(p,p') at 80 MeV, 209Bi(p,p') at 62 MeV, and 93Nb(n,n') at 25.7 MeV. In addition, the results have been compared with the Kalbach systematics and with semiclassical exciton model calculations. All quantum MSD models provide a good fit to the experimental data. In addition, they reproduce the systematics very well and are clearly better than semiclassical model calculations. We furthermore show that the calculated predictions do not differ very strongly between the various quantum MSD models, leading to the conclusion that the simplest MSD model (the Feshbach-Kerman-Koonin model) is adequate for the analysis of experimental data.

Hole Fermi surface in Bi2Se3 probed by quantum oscillations

NASA Astrophysics Data System (ADS)

Piot, B. A.; Desrat, W.; Maude, D. K.; Orlita, M.; Potemski, M.; Martinez, G.; Hor, Y. S.

2016-04-01

Transport and torque magnetometry measurements are performed at high magnetic fields and low temperatures in a series of p-type (Ca-doped) Bi2Se3 crystals. The angular dependence of the Shubnikov-de Haas and de Haas-van Alphen quantum oscillations enables us to determine the Fermi surface of the bulk valence band states as a function of the carrier density. At low density, the angular dependence exhibits a downturn in the oscillations frequency between 0∘ and 90∘, reflecting a bag-shaped hole Fermi surface. The detection of a single frequency for all tilt angles rules out the existence of a Fermi surface with different extremal cross sections down to 24 meV. There is therefore no signature of a camelback in the valence band of our bulk samples, in accordance with the direct band gap predicted by G W calculations.

Alignment of gold nanorods by angular photothermal depletion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Adam B.; Chow, Timothy T. Y.; Chon, James W. M., E-mail: jchon@swin.edu.au

2014-02-24

In this paper, we demonstrate that a high degree of alignment can be imposed upon randomly oriented gold nanorod films by angular photothermal depletion with linearly polarized laser irradiation. The photothermal reshaping of gold nanorods is observed to follow quadratic melting model rather than the threshold melting model, which distorts the angular and spectral hole created on 2D distribution map of nanorods to be an open crater shape. We have accounted these observations to the alignment procedures and demonstrated good agreement between experiment and simulations. The use of multiple laser depletion wavelengths allowed alignment criteria over a large range ofmore » aspect ratios, achieving 80% of the rods in the target angular range. We extend the technique to demonstrate post-alignment in a multilayer of randomly oriented gold nanorod films, with arbitrary control of alignment shown across the layers. Photothermal angular depletion alignment of gold nanorods is a simple, promising post-alignment method for creating future 3D or multilayer plasmonic nanorod based devices and structures.« less

Quenching of dynamic nuclear polarization by spin-orbit coupling in GaAs quantum dots.

PubMed

Nichol, John M; Harvey, Shannon P; Shulman, Michael D; Pal, Arijeet; Umansky, Vladimir; Rashba, Emmanuel I; Halperin, Bertrand I; Yacoby, Amir

2015-07-17

The central-spin problem is a widely studied model of quantum decoherence. Dynamic nuclear polarization occurs in central-spin systems when electronic angular momentum is transferred to nuclear spins and is exploited in quantum information processing for coherent spin manipulation. However, the mechanisms limiting this process remain only partially understood. Here we show that spin-orbit coupling can quench dynamic nuclear polarization in a GaAs quantum dot, because spin conservation is violated in the electron-nuclear system, despite weak spin-orbit coupling in GaAs. Using Landau-Zener sweeps to measure static and dynamic properties of the electron spin-flip probability, we observe that the size of the spin-orbit and hyperfine interactions depends on the magnitude and direction of applied magnetic field. We find that dynamic nuclear polarization is quenched when the spin-orbit contribution exceeds the hyperfine, in agreement with a theoretical model. Our results shed light on the surprisingly strong effect of spin-orbit coupling in central-spin systems.

A hybrid quantum eraser scheme for characterization of free-space and fiber communication channels

NASA Astrophysics Data System (ADS)

Nape, Isaac; Kyeremah, Charlotte; Vallés, Adam; Rosales-Guzmán, Carmelo; Buah-Bassuah, Paul K.; Forbes, Andrew

2018-02-01

We demonstrate a simple projective measurement based on the quantum eraser concept that can be used to characterize the disturbances of any communication channel. Quantum erasers are commonly implemented as spatially separated path interferometric schemes. Here we exploit the advantages of redefining the which-path information in terms of spatial modes, replacing physical paths with abstract paths of orbital angular momentum (OAM). Remarkably, vector modes (natural modes of free-space and fiber) have a non-separable feature of spin-orbit coupled states, equivalent to the description of two independently marked paths. We explore the effects of fiber perturbations by probing a step-index optical fiber channel with a vector mode, relevant to high-order spatial mode encoding of information for ultra-fast fiber communications.

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Chiral Luttinger liquids and a generalized Luttinger's theorem in fractional quantum Hall edges via finite-entanglement scaling

NASA Astrophysics Data System (ADS)

Varjas, Daniel; Zaletel, Michael; Moore, Joel

2014-03-01

We use bosonic field theories and the infinite system density matrix renormalization group (iDMRG) method to study infinite strips of fractional quantum Hall (FQH) states starting from microscopic Hamiltonians. Finite-entanglement scaling allows us to accurately measure chiral central charge, edge mode exponents and momenta without finite-size errors. We analyze states in the first and second level of the standard hierarchy and compare our results to predictions of the chiral Luttinger liquid (χLL) theory. The results confirm the universality of scaling exponents in chiral edges and demonstrate that renormalization is subject to universal relations in the non-chiral case. We prove a generalized Luttinger's theorem involving all singularities in the momentum-resolved density, which naturally arises when mapping Landau levels on a cylinder to a fermion chain and deepens our understanding of non-Fermi liquids in 1D.

INTERNAL GRAVITY WAVES IN MASSIVE STARS: ANGULAR MOMENTUM TRANSPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, T. M.; Lin, D. N. C.; McElwaine, J. N.

2013-07-20

We present numerical simulations of internal gravity waves (IGW) in a star with a convective core and extended radiative envelope. We report on amplitudes, spectra, dissipation, and consequent angular momentum transport by such waves. We find that these waves are generated efficiently and transport angular momentum on short timescales over large distances. We show that, as in Earth's atmosphere, IGW drive equatorial flows which change magnitude and direction on short timescales. These results have profound consequences for the observational inferences of massive stars, as well as their long term angular momentum evolution. We suggest IGW angular momentum transport may explainmore » many observational mysteries, such as: the misalignment of hot Jupiters around hot stars, the Be class of stars, Ni enrichment anomalies in massive stars, and the non-synchronous orbits of interacting binaries.« less

Spectrum of Elementary Excitations in Galilean-Invariant Integrable Models

NASA Astrophysics Data System (ADS)

Petković, Aleksandra; Ristivojevic, Zoran

2018-04-01

The spectrum of elementary excitations in one-dimensional quantum liquids is generically linear at low momenta. It is characterized by the sound velocity that can be related to the ground-state energy. Here we study the spectrum at higher momenta in Galilean-invariant integrable models. Somewhat surprisingly, we show that the spectrum at arbitrary momentum is fully determined by the properties of the ground state. We find general exact relations for the coefficients of several terms in the expansion of the excitation energy at low momenta and arbitrary interaction and express them in terms of the Luttinger liquid parameter. We apply the obtained formulas to the Lieb-Liniger model and obtain several new results.

Gas kinematics, morphology and angular momentum in the FIRE simulations

NASA Astrophysics Data System (ADS)

El-Badry, Kareem; Quataert, Eliot; Wetzel, Andrew; Hopkins, Philip F.; Weisz, Daniel R.; Chan, T. K.; Fitts, Alex; Boylan-Kolchin, Michael; Kereš, Dušan; Faucher-Giguère, Claude-André; Garrison-Kimmel, Shea

2018-01-01

We study the z = 0 gas kinematics, morphology and angular momentum content of isolated galaxies in a suite of cosmological zoom-in simulations from the FIRE project spanning Mstar = 106-11 M⊙. Gas becomes increasingly rotationally supported with increasing galaxy mass. In the lowest mass galaxies (Mstar < 108 M⊙), gas fails to form a morphological disc and is primarily dispersion and pressure supported. At intermediate masses (Mstar = 108-10 M⊙), galaxies display a wide range of gas kinematics and morphologies, from thin, rotating discs to irregular spheroids with negligible net rotation. All the high-mass (Mstar = 1010-11 M⊙) galaxies form rotationally supported gas discs. Many of the haloes whose galaxies fail to form discs harbour high angular momentum gas in their circumgalactic medium. The ratio of the specific angular momentum of gas in the central galaxy to that of the dark matter halo increases significantly with galaxy mass, from 〈jgas〉/〈jDM〉 ∼ 0.1 at M_star=10^{6-7} M_{⊙} to 〈jgas〉/〈jDM〉 ∼ 2 at Mstar = 1010-11 M⊙. The reduced rotational support in the lowest mass galaxies owes to (a) stellar feedback and the UV background suppressing the accretion of high angular momentum gas at late times, and (b) stellar feedback driving large non-circular gas motions. We broadly reproduce the observed scaling relations between galaxy mass, gas rotation velocity, size and angular momentum, but may somewhat underpredict the incidence of disky, high angular momentum galaxies at the lowest observed masses (Mstar = (106-2 × 107) M⊙). Stars form preferentially from low angular momentum gas near the galactic centre and are less rotationally supported than gas. The common assumption that stars follow the same rotation curve as gas thus substantially overestimates the simulated galaxies' stellar angular momentum, particularly at low masses.

Fabrication of the planar angular rotator using the CMOS process

NASA Astrophysics Data System (ADS)

Dai, Ching-Liang; Chang, Chien-Liu; Chen, Hung-Lin; Chang, Pei-Zen

2002-05-01

In this investigation we propose a novel planar angular rotator fabricated by the conventional complementary metal-oxide semiconductor (CMOS) process. Following the 0.6 μm single poly triple metal (SPTM) CMOS process, the device is completed by a simple maskless, post-process etching step. The rotor of the planar angular rotator rotates around its geometric center with electrostatic actuation. The proposed design adopts an intelligent mechanism including the slider-crank system to permit simultaneous motion. The CMOS planar angular rotator could be driven with driving voltages of around 40 V. The design proposed here has a shorter response time and longer life, without problems of friction and wear, compared to the more common planar angular micromotor.

"Angular" plasma cell cheilitis.

PubMed

da Cunha Filho, Roberto Rheingantz; Tochetto, Lucas Baldissera; Tochetto, Bruno Baldissera; de Almeida, Hiram Larangeira; Lorencette, Nádia Aparecida; Netto, José Fillus

2014-03-17

Plasma cell cheilitis is an extremely rare disease, characterized by erythematous-violaceous, ulcerated and asymptomatic plaques, which evolve slowly. The histological characteristics include dermal infiltrate composed of mature plasmocytes. We report a case of Plasma cell angular cheilitis in a 58-year-old male, localized in the lateral oral commissure.

Exploration of particle production mechanisms via angular correlations of π, K, p, Λ with ALICE in pp collisions at √S = 7 TeV

NASA Astrophysics Data System (ADS)

Janik, Małgorzata Anna

2018-02-01

Two-particle correlations as a function of Δη and Δφ are used in many colliding systems to study a wide range of physical phenomena. Examples include the collective behavior of the quark-gluon plasma medium, jets, quantum statistics or Coulomb effects, conservation laws, and resonance decays. In this work, measurements of the correlations of identified particles and their antiparticles (for π, K, p, Λ) are reported in pp collisions at √s = 7 TeV at low transverse momenta. The analysis reveals differences in particle production between baryons and mesons. The correlation functions for mesons exhibit the expected peak dominated by the effects of mini-jet fragmentation and are reproduced well by general purpose Monte Carlo generators. For baryon pairs where both particles have the same baryon number, an anti-correlation structure is observed instead of a peak centered at (Δη, Δφ) = (0, 0); an observation which presents a challenge to models typically used to describe pp data (PYTHIA, PHOJET). This baryon anti-correlation is further interpreted in the context of baryon production mechanisms in the fragmentation processes.

Mass and angular-momentum inequalities for axi-symmetric initial data sets. II. Angular momentum

NASA Astrophysics Data System (ADS)

Chruściel, Piotr T.; Li, Yanyan; Weinstein, Gilbert

2008-10-01

We extend the validity of Dain's angular-momentum inequality to maximal, asymptotically flat, initial data sets on a simply connected manifold with several asymptotically flat ends which are invariant under a U(1) action and which admit a twist potential.

Temporal Evolution of Spectral and Angular Characteristics of SEP Particles during Several GLEs of Solar Cycle 23 Derived from NM Data

NASA Astrophysics Data System (ADS)

Mishev, Alexander; Usoskin, Ilya; Kocharov, Leon

High-energy charged particles of solar origin could represent a severe radiation risk for astronauts and air crew. In addition, they could disrupt technological systems. When a ground-based neutron monitor register abrupt increases in solar energetic particles (SEPs), we observe a special case of solar energetic particle event, a ground-level enhancement (GLE). In order to derive the spectral and angular characteristics of GLE particles a precise computation of solar energetic particle propagation in the Earth's magnetosphere and atmosphere is necessary. It consists of detailed computation of assymptotic cones for neutron monitors (NMs) and application of inverse method using the newly computed neutron monitor yield function. Assymptotic directions are computed using the Planetocosmics code and realistic magnetospheric models, namely IGRF as the internal model and Tsyganenko 89 with the corresponding Kp index as the external one. The inverse problem solution is performed on the basis of non-linear least squares method, namely Levenberg-Marqurdt. In the study presented here, we analyse several major GLEs of the solar cycle 23 as well as the first GLE event of the solar cycle 24, namely GLE69, GLE70 and GLE 71. The SEP spectra and pitch angle distribution are obtained at different momenta since the event's onset. The obtained characteristics are compared with previously reported results. The obtained results are briefly discussed.

Flows with fractional quantum circulation in Bose-Einstein condensates induced by nontopological phase defects

NASA Astrophysics Data System (ADS)

Kanai, Toshiaki; Guo, Wei; Tsubota, Makoto

2018-01-01

It is a common view that rotational motion in a superfluid can exist only in the presence of topological defects, i.e., quantized vortices. However, in our numerical studies on the merging of two concentric Bose-Einstein condensates with axial symmetry in two-dimensional space, we observe the emergence of a spiral dark soliton when one condensate has a nonzero initial angular momentum. This spiral dark soliton enables the transfer of angular momentum between the condensates and allows the merged condensate to rotate even in the absence of quantized vortices. Our examination of the flow field around the soliton strikingly reveals that its sharp endpoint can induce flow like a vortex point but with a fraction of a quantized circulation. This interesting nontopological "phase defect" may generate broad interest since rotational motion is essential in many quantum transport processes.

Statistical prescission point model of fission fragment angular distributions

NASA Astrophysics Data System (ADS)

John, Bency; Kataria, S. K.

1998-03-01

In light of recent developments in fission studies such as slow saddle to scission motion and spin equilibration near the scission point, the theory of fission fragment angular distribution is examined and a new statistical prescission point model is developed. The conditional equilibrium of the collective angular bearing modes at the prescission point, which is guided mainly by their relaxation times and population probabilities, is taken into account in the present model. The present model gives a consistent description of the fragment angular and spin distributions for a wide variety of heavy and light ion induced fission reactions.

Control of Angular Intervals for Angle-Multiplexed Holographic Memory

NASA Astrophysics Data System (ADS)

Kinoshita, Nobuhiro; Muroi, Tetsuhiko; Ishii, Norihiko; Kamijo, Koji; Shimidzu, Naoki

2009-03-01

In angle-multiplexed holographic memory, the full width at half maximum of the Bragg selectivity curves is dependent on the angle formed between the medium and incident laser beams. This indicates the possibility of high density and high multiplexing number by varying the angular intervals between adjacent holograms. We propose an angular interval scheduling for closely stacking holograms into medium even when the angle range is limited. We obtained bit error rates of the order of 10-4 under the following conditions: medium thickness of 1 mm, laser beam wavelength of 532 nm, and angular multiplexing number of 300.

Maximal power output by solar cells with angular confinement.

PubMed

Höhn, Oliver; Kraus, Tobias; Bauhuis, Gerard; Schwarz, Ulrich T; Bläsi, Benedikt

2014-05-05

Angularly selective filters can increase the efficiency of radiatively limited solar cells. A restriction of the acceptance angle is linked to the kind of utilizable solar spectrum (global or direct radiation). This has to be considered when calculating the potential enhancement of both the efficiency and the power output. In this paper, different concepts to realize angularly selective filters are compared regarding their limits for efficiency and power output per unit area. First experimental results of a promising system based on a thin-film filter as the angularly selective element are given to demonstrate the practical relevance of such systems.

Fourier transform of the multicenter product of 1s hydrogenic orbitals and Coulomb or Yukawa potentials and the analytically reduced form for subsequent integrals that include plane waves

NASA Technical Reports Server (NTRS)

Straton, Jack C.

1989-01-01

The Fourier transform of the multicenter product of N 1s hydrogenic orbitals and M Coulomb or Yukawa potentials is given as an (M+N-1)-dimensional Feynman integral with external momenta and shifted coordinates. This is accomplished through the introduction of an integral transformation, in addition to the standard Feynman transformation for the denominators of the momentum representation of the terms in the product, which moves the resulting denominator into an exponential. This allows the angular dependence of the denominator to be combined with the angular dependence in the plane waves.

Quantum chaos for nonstandard symmetry classes in the Feingold-Peres model of coupled tops

NASA Astrophysics Data System (ADS)

Fan, Yiyun; Gnutzmann, Sven; Liang, Yuqi

2017-12-01

We consider two coupled quantum tops with angular momentum vectors L and M . The coupling Hamiltonian defines the Feingold-Peres model, which is a known paradigm of quantum chaos. We show that this model has a nonstandard symmetry with respect to the Altland-Zirnbauer tenfold symmetry classification of quantum systems, which extends the well-known threefold way of Wigner and Dyson (referred to as "standard" symmetry classes here). We identify the nonstandard symmetry classes BD I0 (chiral orthogonal class with no zero modes), BD I1 (chiral orthogonal class with one zero mode), and C I (antichiral orthogonal class) as well as the standard symmetry class A I (orthogonal class). We numerically analyze the specific spectral quantum signatures of chaos related to the nonstandard symmetries. In the microscopic density of states and in the distribution of the lowest positive energy eigenvalue, we show that the Feingold-Peres model follows the predictions of the Gaussian ensembles of random-matrix theory in the appropriate symmetry class if the corresponding classical dynamics is chaotic. In a crossover to mixed and near-integrable classical dynamics, we show that these signatures disappear or strongly change.

Quantum chaos for nonstandard symmetry classes in the Feingold-Peres model of coupled tops.

PubMed

Fan, Yiyun; Gnutzmann, Sven; Liang, Yuqi

2017-12-01

We consider two coupled quantum tops with angular momentum vectors L and M. The coupling Hamiltonian defines the Feingold-Peres model, which is a known paradigm of quantum chaos. We show that this model has a nonstandard symmetry with respect to the Altland-Zirnbauer tenfold symmetry classification of quantum systems, which extends the well-known threefold way of Wigner and Dyson (referred to as "standard" symmetry classes here). We identify the nonstandard symmetry classes BDI_{0} (chiral orthogonal class with no zero modes), BDI_{1} (chiral orthogonal class with one zero mode), and CI (antichiral orthogonal class) as well as the standard symmetry class AI (orthogonal class). We numerically analyze the specific spectral quantum signatures of chaos related to the nonstandard symmetries. In the microscopic density of states and in the distribution of the lowest positive energy eigenvalue, we show that the Feingold-Peres model follows the predictions of the Gaussian ensembles of random-matrix theory in the appropriate symmetry class if the corresponding classical dynamics is chaotic. In a crossover to mixed and near-integrable classical dynamics, we show that these signatures disappear or strongly change.

Addition and Removal Energies via the In-Medium Similarity Renormalization Group Method

NASA Astrophysics Data System (ADS)

Yuan, Fei

The in-medium similarity renormalization group (IM-SRG) is an ab initio many-body method suitable for systems with moderate numbers of particles due to its polynomial scaling in computational cost. The formalism is highly flexible and admits a variety of modifications that extend its utility beyond the original goal of computing ground state energies of closed-shell systems. In this work, we present an extension of IM-SRG through quasidegenerate perturbation theory (QDPT) to compute addition and removal energies (single particle energies) near the Fermi level at low computational cost. This expands the range of systems that can be studied from closed-shell ones to nearby systems that differ by one particle. The method is applied to circular quantum dot systems and nuclei, and compared against other methods including equations-of-motion (EOM) IM-SRG and EOM coupled-cluster (CC) theory. The results are in good agreement for most cases. As part of this work, we present an open-source implementation of our flexible and easy-to-use J-scheme framework as well as the HF, IM-SRG, and QDPT codes built upon this framework. We include an overview of the overall structure, the implementation details, and strategies for maintaining high code quality and efficiency. Lastly, we also present a graphical application for manipulation of angular momentum coupling coefficients through a diagrammatic notation for angular momenta (Jucys diagrams). The tool enables rapid derivations of equations involving angular momentum coupling--such as in J-scheme--and significantly reduces the risk of human errors.

All joint moments significantly contribute to trunk angular acceleration

PubMed Central

Nott, Cameron R.; Zajac, Felix E.; Neptune, Richard R.; Kautz, Steven A.

2010-01-01

Computationally advanced biomechanical analyses of gait demonstrate the often counter intuitive roles of joint moments on various aspects of gait such as propulsion, swing initiation, and balance. Each joint moment can produce linear and angular acceleration of all body segments (including those on which the moment does not directly act) due to the dynamic coupling inherent in the interconnected musculoskeletal system. This study presents the quantitative relationships between individual joint moments and trunk control with respect to balance during gait to show that the ankle, knee, and hip joint moments all affect the angular acceleration of the trunk. We show that trunk angular acceleration is affected by all the joints in the leg with varying degrees of dependence during the gait cycle. Furthermore, it is shown that inter-planar coupling exists and a two dimensional analysis of trunk balance neglects important out-of-plane joint moments that affect trunk angular acceleration. PMID:20646711

The INCAS Project: An Innovative Contact-Less Angular Sensor

NASA Astrophysics Data System (ADS)

Ghislanzoni, L.; Di Cintio, A.; Solimando, M.; Parzianello, G.

2013-09-01

Angular Positions sensors are widely used in all spacecrafts, including re-entry vehicles and launchers, where mechanisms and pointing-scanning devices are required. The main applications are on mechanisms for TeleMeasure (TM) related to the release and deployment of devices, or on rotary mechanisms such as Solar Array Drive Mechanism (SADM) and Antenna Pointing Mechanism (APM). Longer lifetime (up to 7- 10 years) is becoming a new driver for the coming missions and contact technology sensors often incur in limitations due to the wear of the contacting parts [1].A Self-Compensating Absolute Angular Encoder was developed and tested in the frame of an ESA's ARTES 5.2 project, named INCAS (INnovative Contact-less Angular Sensor). More in particular, the INCAS sensor addresses a market need for contactless angular sensors aimed at replacing the more conventional rotary potentiometers, while featuring the same level of accuracy performances and extending the expected lifetime.

Angular displacement measuring device

NASA Technical Reports Server (NTRS)

Seegmiller, H. Lee B. (Inventor)

1992-01-01

A system for measuring the angular displacement of a point of interest on a structure, such as aircraft model within a wind tunnel, includes a source of polarized light located at the point of interest. A remote detector arrangement detects the orientation of the plane of the polarized light received from the source and compares this orientation with the initial orientation to determine the amount or rate of angular displacement of the point of interest. The detector arrangement comprises a rotating polarizing filter and a dual filter and light detector unit. The latter unit comprises an inner aligned filter and photodetector assembly which is disposed relative to the periphery of the polarizer so as to receive polarized light passing the polarizing filter and an outer aligned filter and photodetector assembly which receives the polarized light directly, i.e., without passing through the polarizing filter. The purpose of the unit is to compensate for the effects of dust, fog and the like. A polarization preserving optical fiber conducts polarized light from a remote laser source to the point of interest.

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Non-Abelian fractional quantum Hall states for hard-core bosons in one dimension

NASA Astrophysics Data System (ADS)

Paredes, Belén

2012-05-01

I present a family of one-dimensional bosonic liquids analogous to non-Abelian fractional quantum Hall states. A new quantum number is introduced to characterize these liquids, the chiral momentum, which differs from the usual angular or linear momentum in one dimension. As their two-dimensional counterparts, these liquids minimize a k-body hard-core interaction with the minimum total chiral momentum. They exhibit global order, with a hidden organization of the particles in k identical copies of a one-dimensional Laughlin state. For k=2 the state is a p-wave paired phase corresponding to the Pfaffian quantum Hall state. By imposing conservation of the total chiral momentum, an exact parent Hamiltonian is derived which involves long-range tunneling and interaction processes with an amplitude decaying with the chord distance. This family of non-Abelian liquids is shown to be in formal correspondence with a family of spin-(k)/(2) liquids which are total singlets made out of k indistinguishable resonating valence bond states. The corresponding spin Hamiltonians are obtained.

Geometric construction of quantum hall clustering Hamiltonians

DOE PAGES

Lee, Ching Hua; Papić, Zlatko; Thomale, Ronny

2015-10-08

In this study, many fractional quantum Hall wave functions are known to be unique highest-density zero modes of certain “pseudopotential” Hamiltonians. While a systematic method to construct such parent Hamiltonians has been available for the infinite plane and sphere geometries, the generalization to manifolds where relative angular momentum is not an exact quantum number, i.e., the cylinder or torus, remains an open problem. This is particularly true for non-Abelian states, such as the Read-Rezayi series (in particular, the Moore-Read and Read-Rezayi Z 3 states) and more exotic nonunitary (Haldane-Rezayi and Gaffnian) or irrational (Haffnian) states, whose parent Hamiltonians involve complicatedmore » many-body interactions. Here, we develop a universal geometric approach for constructing pseudopotential Hamiltonians that is applicable to all geometries. Our method straightforwardly generalizes to the multicomponent SU(n) cases with a combination of spin or pseudospin (layer, subband, or valley) degrees of freedom. We demonstrate the utility of our approach through several examples, some of which involve non-Abelian multicomponent states whose parent Hamiltonians were previously unknown, and we verify the results by numerically computing their entanglement properties.« less

Controlling orbital angular momentum of an optical vortex by varying its ellipticity

NASA Astrophysics Data System (ADS)

Kotlyar, Victor V.; Kovalev, Alexey A.

2018-03-01

An exact analytical expression is obtained for the orbital angular momentum (OAM) of a Gaussian optical vortex with a different degree of ellipticity. The OAM turned out to be proportional to the ratio of two Legendre polynomials of adjoining orders. It is shown that if an elliptical optical vortex is embedded into the center of the waist of a circularly symmetrical Gaussian beam, then the normalized OAM of such laser beam is fractional and it does not exceed the topological charge n. If, on the contrary, a circularly symmetrical optical vortex is embedded into the center of the waist of an elliptical Gaussian beam, then the OAM is equal to n. If the optical vortex and the Gaussian beam have the same (or matched) ellipticity degree, then the OAM of the laser beam is greater than n. Continuous varying of the OAM of a laser beam by varying its ellipticity degree can be used in optical trapping for accelerated motion of microscopic particles along an elliptical trajectory as well as in quantum informatics for detecting OAM-entangled photons.

A Bit of Quantum Mechanics

NASA Astrophysics Data System (ADS)

Oss, Stefano; Rosi, Tommaso

2015-04-01

We have developed an app for iOS-based smart-phones/tablets that allows a 3-D, complex phase-based colorful visualization of hydrogen atom wave functions. Several important features of the quantum behavior of atomic orbitals can easily be made evident, thus making this app a useful companion in introductory modern physics classes. There are many reasons why quantum mechanical systems and phenomena are difficult both to teach and deeply understand. They are described by equations that are generally hard to visualize, and they often oppose the so-called "common sense" based on the human perception of the world, which is built on mental images such as locality and causality. Moreover students cannot have direct experience of those systems and solutions, and generally do not even have the possibility to refer to pictures, videos, or experiments to fill this gap. Teachers often encounter quite serious troubles in finding out a sensible way to speak about the wonders of quantum physics at the high school level, where complex formalisms are not accessible at all. One should however consider that this is quite a common issue in physics and, more generally, in science education. There are plenty of natural phenomena whose models (not only at microscopic and atomic levels) are of difficult, if not impossible, visualization. Just think of certain kinds of waves, fields of forces, velocities, energy, angular momentum, and so on. One should also notice that physical reality is not the same as the images we make of it. Pictures (formal, abstract ones, as well as artists' views) are a convenient bridge between these two aspects.

Studying AGN Jets At Extreme Angular Resolution

NASA Astrophysics Data System (ADS)

Bruni, Gabriele

2016-10-01

RadioAstron is a 10m antenna orbiting on the Russian Speckt-R spacecraft, launched in 2011. Performing radio interferometry with a global array of ground telescopes, it is providing record angular resolution. The Key Science Project on AGN polarization is exploiting it to study in great detail the configuration of magnetic fields in AGN jets, and understand their formation and collimation. To date, the project has already achieved the highest angular resolution image ever obtained in Astronomy, and detected brightness temperatures exceeding the ones predicted by theory of AGN.

Analysis of angular momentum properties of photons emitted in fundamental atomic processes

NASA Astrophysics Data System (ADS)

Zaytsev, V. A.; Surzhykov, A. S.; Shabaev, V. M.; Stöhlker, Th.

2018-04-01

Many atomic processes result in the emission of photons. Analysis of the properties of emitted photons, such as energy and angular distribution as well as polarization, is regarded as a powerful tool for gaining more insight into the physics of corresponding processes. Another characteristic of light is the projection of its angular momentum upon propagation direction. This property has attracted a special attention over the past decades due to studies of twisted (or vortex) light beams. Measurements being sensitive to this projection may provide valuable information about the role of angular momentum in the fundamental atomic processes. Here we describe a simple theoretical method for determination of the angular momentum properties of the photons emitted in various atomic processes. This method is based on the evaluation of expectation value of the total angular momentum projection operator. To illustrate the method, we apply it to the textbook examples of plane-wave, spherical-wave, and Bessel light. Moreover, we investigate the projection of angular momentum for the photons emitted in the process of the radiative recombination with ionic targets. It is found that the recombination photons do carry a nonzero projection of the orbital angular momentum.

Angular momentum exchange in white dwarf binaries accreting through direct impact

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sepinsky, J. F.; Kalogera, V., E-mail: jeremy.sepinsky@scranton.edu, E-mail: vicky@northwestern.edu

We examine the exchange of angular momentum between the component spins and the orbit in semi-detached double white dwarf binaries undergoing mass transfer through direct impact of the transfer stream. We approximate the stream as a series of discrete massive particles ejected in the ballistic limit at the inner Lagrangian point of the donor toward the accretor. This work improves upon similar earlier studies in a number of ways. First, we self-consistently calculate the total angular momentum of the orbit at all times. This includes changes in the orbital angular momentum during the ballistic trajectory of the ejected mass, asmore » well as changes during the ejection/accretion due to the radial component of the particle's velocity. Second, we calculate the particle's ballistic trajectory for each system, which allows us to determine the precise position and velocity of the particle upon accretion. We can then include specific information about the radius of the accretor as well as the angle of impact. Finally, we ensure that the total angular momentum is conserved, which requires the donor star spin to vary self-consistently. With these improvements, we calculate the angular momentum change of the orbit and each binary component across the entire parameter space of direct impact double white dwarf binary systems. We find a significant decrease in the amount of angular momentum removed from the orbit during mass transfer, as well as cases where this process increases the angular momentum of the orbit at the expense of the spin angular momentum of the donor. We conclude that, unlike earlier claims in the literature, mass transfer through direct impact need not destabilize the binary and that the quantity and sign of the orbital angular momentum transfer depends on the binary properties, particularly the masses of the double white dwarf binary component stars. This stabilization may significantly impact the population synthesis calculations of the expected numbers

Angular Spacing Control for Segmented Data Pages in Angle-Multiplexed Holographic Memory

NASA Astrophysics Data System (ADS)

Kinoshita, Nobuhiro; Muroi, Tetsuhiko; Ishii, Norihiko; Kamijo, Koji; Kikuchi, Hiroshi; Shimidzu, Naoki; Ando, Toshio; Masaki, Kazuyoshi; Shimizu, Takehiro

2011-09-01

To improve the recording density of angle-multiplexed holographic memory, it is effective to increase the numerical aperture of the lens and to shorten the wavelength of the laser source as well as to increase the multiplexing number. The angular selectivity of a hologram, which determines the multiplexing number, is dependent on the incident angle of not only the reference beam but also the signal beam to the holographic recording medium. The actual signal beam, which is a convergent or divergent beam, is regarded as the sum of plane waves that have different propagation directions, angular selectivities, and optimal angular spacings. In this paper, focusing on the differences in the optimal angular spacing, we proposed a method to control the angular spacing for each segmented data page. We investigated the angular selectivity of a hologram and crosstalk for segmented data pages using numerical simulation. The experimental results showed a practical bit-error rate on the order of 10-3.

Coherent π-electron dynamics of (P)-2,2'-biphenol induced by ultrashort linearly polarized UV pulses: Angular momentum and ring current

NASA Astrophysics Data System (ADS)

Mineo, H.; Lin, S. H.; Fujimura, Y.

2013-02-01

The results of a theoretical investigation of coherent π-electron dynamics for nonplanar (P)-2,2'-biphenol induced by ultrashort linearly polarized UV pulses are presented. Expressions for the time-dependent coherent angular momentum and ring current are derived by using the density matrix method. The time dependence of these coherences is determined by the off-diagonal density matrix element, which can be obtained by solving the coupled equations of motion of the electronic-state density matrix. Dephasing effects on coherent angular momentum and ring current are taken into account within the Markov approximation. The magnitudes of the electronic angular momentum and current are expressed as the sum of expectation values of the corresponding operators in the two phenol rings (L and R rings). Here, L (R) denotes the phenol ring in the left (right)-hand side of (P)-2,2'-biphenol. We define the bond current between the nearest neighbor carbon atoms Ci and Cj as an electric current through a half plane perpendicular to the Ci-Cj bond. The bond current can be expressed in terms of the inter-atomic bond current. The inter-atomic bond current (bond current) depends on the position of the half plane on the bond and has the maximum value at the center. The coherent ring current in each ring is defined by averaging over the bond currents. Since (P)-2,2'-biphenol is nonplanar, the resultant angular momentum is not one-dimensional. Simulations of the time-dependent coherent angular momentum and ring current of (P)-2,2'-biphenol excited by ultrashort linearly polarized UV pulses are carried out using the molecular parameters obtained by the time-dependent density functional theory (TD-DFT) method. Oscillatory behaviors in the time-dependent angular momentum (ring current), which can be called angular momentum (ring current) quantum beats, are classified by the symmetry of the coherent state, symmetric or antisymmetric. The bond current of the bridge bond linking the L and R

The natural moon illusion: a multifactor angular account.

PubMed

Plug, C; Ross, H E

1994-01-01

It is argued that the failure to explain the celestial illusion results from conceptual confusion about perceived size and from disregard of the observational evidence relating to the natural moon illusion. The evidence shows that the illusion consists of a perceived angular size enlargement of horizon objects, by a factor of about 1.5-2.0 in diameter in comparison with elevated objects. Most measurements of the illusion have been made in terms of angular size, although in some proposed explanations an illusion of linear size is assumed. The magnitude of the illusion varies, particularly with the detail of the horizon scene. The illusion can be explained as the sum of several factors that affect perceived angular size: size contrast, vergence commands and eye or head position, aerial perspective, and colour. The relative contributions of these factors are assessed.

Initial angular momentum and flow in high energy nuclear collisions

NASA Astrophysics Data System (ADS)

Fries, Rainer J.; Chen, Guangyao; Somanathan, Sidharth

2018-03-01

We study the transfer of angular momentum in high energy nuclear collisions from the colliding nuclei to the region around midrapidity, using the classical approximation of the color glass condensate (CGC) picture. We find that the angular momentum shortly after the collision (up to times ˜1 /Qs , where Qs is the saturation scale) is carried by the "β -type" flow of the initial classical gluon field, introduced by some of us earlier. βi˜μ1∇iμ2-μ2∇iμ1 (i =1 ,2 ) describes the rapidity-odd transverse energy flow and emerges from Gauss's law for gluon fields. Here μ1 and μ2 are the averaged color charge fluctuation densities in the two nuclei, respectively. Interestingly, strong coupling calculations using anti-de Sitter/conformal field theory (AdS/CFT) techniques also find an energy flow term featuring this particular combination of nuclear densities. In classical CGC the order of magnitude of the initial angular momentum per rapidity in the reaction plane, at a time 1 /Qs , is |d L2/d η |≈ RAQs-3ɛ¯0/2 at midrapidity, where RA is the nuclear radius, and ɛ¯0 is the average initial energy density. This result emerges as a cancellation between a vortex of energy flow in the reaction plane aligned with the total angular momentum, and energy shear flow opposed to it. We discuss in detail the process of matching classical Yang-Mills results to fluid dynamics. We will argue that dissipative corrections should not be discarded to ensure that macroscopic conservation laws, e.g., for angular momentum, hold. Viscous fluid dynamics tends to dissipate the shear flow contribution that carries angular momentum in boost-invariant fluid systems. This leads to small residual angular momentum around midrapidity at late times for collisions at high energies.

Deformation dependence of proton decay rates and angular distributions in a time-dependent approach

NASA Astrophysics Data System (ADS)

Carjan, N.; Talou, P.; Strottman, D.

1998-12-01

A new, time-dependent, approach to proton decay from axially symmetric deformed nuclei is presented. The two-dimensional time-dependent Schrödinger equation for the interaction between the emitted proton and the rest of the nucleus is solved numerically for well defined initial quasi-stationary proton states. Applied to the hypothetical proton emission from excited states in deformed nuclei of 208Pb, this approach shows that the problem cannot be reduced to one dimension. There are in general more than one directions of emission with wide distributions around them, determined mainly by the quantum numbers of the initial wave function rather than by the potential landscape. The distribution of the "residual" angular momentum and its variation in time play a major role in the determination of the decay rate. In a couple of cases, no exponential decay was found during the calculated time evolution (2×10-21 sec) although more than half of the wave function escaped during that time.

Observation of new even-parity states of Sm I by resonance ionization mass spectrometry

NASA Astrophysics Data System (ADS)

Jayasekharan, T.; Razvi, M. A. N.; Bhale, G. L.

1996-04-01

Resonance ionization mass spectrometry is applied to investigate high-lying even-parity states of Sm I. Eighty-six even-parity states of Sm I are discovered in the region 32950-36000 cm -1 . Absolute energies of these states are measured with an uncertainty of +/- 0.3 cm -1 , and total angular momenta are uniquely assigned for most of them.

Optical evidence of quantum rotor orbital excitations in orthorhombic manganites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kovaleva, N. N., E-mail: nkovaleva@sci.lebedev.ru; Kugel, K. I.; Potůček, Z.

2016-05-15

In magnetic compounds with Jahn–Teller (JT) ions (such as Mn{sup 3+} or Cu{sup 2+}), the ordering of the electron or hole orbitals is associated with cooperative lattice distortions. There the role of JT effect, although widely recognized, is still elusive in the ground state properties. Here we discovered that, in these materials, there exist excitations whose energy spectrum is described in terms of the total angular momentum eigenstates and is quantized as in quantum rotors found in JT centers. We observed features originating from these excitations in the optical spectra of a model compound LaMnO{sub 3} using ellipsometry technique. Theymore » appear clearly as narrow sidebands accompanying the electron transition between the JT split orbitals at neighboring Mn{sup 3+} ions, displaying anomalous temperature behavior around the Néel temperature T{sub N} ≈ 140 K. We present these results together with new experimental data on photoluminescence found in LaMnO{sub 3}, which lend additional support to the ellipsometry implying the electronic-vibrational origin of the quantum rotor orbital excitations. We note that the discovered orbital excitations of quantum rotors may play an important role in many unusual properties observed in these materials upon doping, such as high-temperature superconductivity and colossal magnetoresistance.« less

Orbital-angular-momentum transfer to optically levitated microparticles in vacuum

NASA Astrophysics Data System (ADS)

Mazilu, Michael; Arita, Yoshihiko; Vettenburg, Tom; Auñón, Juan M.; Wright, Ewan M.; Dholakia, Kishan

2016-11-01

We demonstrate the transfer of orbital angular momentum to an optically levitated microparticle in vacuum. The microparticle is placed within a Laguerre-Gaussian beam and orbits the annular beam profile with increasing angular velocity as the air drag coefficient is reduced. We explore the particle dynamics as a function of the topological charge of the levitating beam. Our results reveal that there is a fundamental limit to the orbital angular momentum that may be transferred to a trapped particle, dependent upon the beam parameters and inertial forces present.

Orbital Angular Momentum Multiplexing over Visible Light Communication Systems

NASA Astrophysics Data System (ADS)

Tripathi, Hardik Rameshchandra

This thesis proposes and explores the possibility of using Orbital Angular Momentum multiplexing in Visible Light Communication system. Orbital Angular Momentum is mainly applied for laser and optical fiber transmissions, while Visible Light Communication is a technology using the light as a carrier for wireless communication. In this research, the study of the state of art and experiments showing some results on multiplexing based on Orbital Angular Momentum over Visible Light Communication system were done. After completion of the initial stage; research work and simulations were performed on spatial multiplexing over Li-Fi channel modeling. Simulation scenarios which allowed to evaluate the Signal-to-Noise Ratio, Received Power Distribution, Intensity and Illuminance were defined and developed.

Quantum Monte Carlo tunneling from quantum chemistry to quantum annealing

NASA Astrophysics Data System (ADS)

Mazzola, Guglielmo; Smelyanskiy, Vadim N.; Troyer, Matthias

2017-10-01

Quantum tunneling is ubiquitous across different fields, from quantum chemical reactions and magnetic materials to quantum simulators and quantum computers. While simulating the real-time quantum dynamics of tunneling is infeasible for high-dimensional systems, quantum tunneling also shows up in quantum Monte Carlo (QMC) simulations, which aim to simulate quantum statistics with resources growing only polynomially with the system size. Here we extend the recent results obtained for quantum spin models [Phys. Rev. Lett. 117, 180402 (2016), 10.1103/PhysRevLett.117.180402], and we study continuous-variable models for proton transfer reactions. We demonstrate that QMC simulations efficiently recover the scaling of ground-state tunneling rates due to the existence of an instanton path, which always connects the reactant state with the product. We discuss the implications of our results in the context of quantum chemical reactions and quantum annealing, where quantum tunneling is expected to be a valuable resource for solving combinatorial optimization problems.

Quantum rotor model for a Bose-Einstein condensate of dipolar molecules.

PubMed

Armaitis, J; Duine, R A; Stoof, H T C

2013-11-22

We show that a Bose-Einstein condensate of heteronuclear molecules in the regime of small and static electric fields is described by a quantum rotor model for the macroscopic electric dipole moment of the molecular gas cloud. We solve this model exactly and find the symmetric, i.e., rotationally invariant, and dipolar phases expected from the single-molecule problem, but also an axial and planar nematic phase due to many-body effects. Investigation of the wave function of the macroscopic dipole moment also reveals squeezing of the probability distribution for the angular momentum of the molecules.

Angular momentum transfer in low velocity oblique impacts - Implications for asteroids

NASA Technical Reports Server (NTRS)

Yanagisawa, Masahisa; Eluszkiewicz, Janusz; Ahrens, Thomas J.

1991-01-01

An experimental study has been conducted for the low-velocity oblique impact efficiency of angular momentum transfer, which is defined as that fraction of incident angular momentum that is transferred to the rotation of a target. The results obtained suggest that more energetic impacts are able to transfer angular momentum more efficiently. In the cases of ricochetted projectiles, the fraction of angular momentum carried off by the ejecta was noted to be less than 30 percent. It is suggested that, if asteroid spin rates are due to mutual noncatastrophic collisions and the taxonomic classes are indicative of bulk properties, the differences between corresponding spin rates will be smaller than expected from a consideration of relative strength and density alone.

Vestibular coriolis effect differences modeled with three-dimensional linear-angular interactions.

PubMed

Holly, Jan E

2004-01-01

The vestibular coriolis (or "cross-coupling") effect is traditionally explained by cross-coupled angular vectors, which, however, do not explain the differences in perceptual disturbance under different acceleration conditions. For example, during head roll tilt in a rotating chair, the magnitude of perceptual disturbance is affected by a number of factors, including acceleration or deceleration of the chair rotation or a zero-g environment. Therefore, it has been suggested that linear-angular interactions play a role. The present research investigated whether these perceptual differences and others involving linear coriolis accelerations could be explained under one common framework: the laws of motion in three dimensions, which include all linear-angular interactions among all six components of motion (three angular and three linear). The results show that the three-dimensional laws of motion predict the differences in perceptual disturbance. No special properties of the vestibular system or nervous system are required. In addition, simulations were performed with angular, linear, and tilt time constants inserted into the model, giving the same predictions. Three-dimensional graphics were used to highlight the manner in which linear-angular interaction causes perceptual disturbance, and a crucial component is the Stretch Factor, which measures the "unexpected" linear component.

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Quantum description of a field in macroscopic electrodynamics and photon properties in transparent media

NASA Astrophysics Data System (ADS)

Toptygin, I. N.

2017-12-01

Applying a quantum mechanical treatment to a high-frequency macroscopic electromagnetic field and radiative phenomena in a medium, we construct quantum operators for energy-momentum tensor components in dispersive media and find their eigenvalues, which are different in the Minkowski and Abraham representations. It is shown that the photon momentum in a medium resulting from the quantization of the vector potential differs from that defined from Abraham’s symmetric energy-momentum-tensor but is equal to the momentum defined from the Minkowski tensor. A similar result is obtained by calculating the intrinsic angular momentum (spin) of an electro-magnetic field in the medium. Only the Minkowski tensor leads to the experimentally confirmed spin values that are multiples of ħ, providing the grounds for choosing the Minkowski representation as the proper form for the momentum density of a transverse electromagnetic field in a transparent medium, in both classical and quantum descriptions of the field. The Abraham representation is unsuitable for this purpose and leads to contradictions. The conclusion drawn does not apply to quasistatic and static fields.

Angular width of the Cherenkov radiation with inclusion of multiple scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, Jian, E-mail: jzheng@ustc.edu.cn

2016-06-15

Visible Cherenkov radiation can offer a method of the measurement of the velocity of charged particles. The angular width of the radiation is important since it determines the resolution of the velocity measurement. In this article, the angular width of Cherenkov radiation with inclusion of multiple scattering is calculated through the path-integral method, and the analytical expressions are presented. The condition that multiple scattering processes dominate the angular distribution is obtained.

Two-dimensional angular transmission characterization of CPV modules.

PubMed

Herrero, R; Domínguez, C; Askins, S; Antón, I; Sala, G

2010-11-08

This paper proposes a fast method to characterize the two-dimensional angular transmission function of a concentrator photovoltaic (CPV) system. The so-called inverse method, which has been used in the past for the characterization of small optical components, has been adapted to large-area CPV modules. In the inverse method, the receiver cell is forward biased to produce a Lambertian light emission, which reveals the reverse optical path of the optics. Using a large-area collimator mirror, the light beam exiting the optics is projected on a Lambertian screen to create a spatially resolved image of the angular transmission function. An image is then obtained using a CCD camera. To validate this method, the angular transmission functions of a real CPV module have been measured by both direct illumination (flash CPV simulator and sunlight) and the inverse method, and the comparison shows good agreement.

Quantum games as quantum types

NASA Astrophysics Data System (ADS)

Delbecque, Yannick

In this thesis, we present a new model for higher-order quantum programming languages. The proposed model is an adaptation of the probabilistic game semantics developed by Danos and Harmer [DH02]: we expand it with quantum strategies which enable one to represent quantum states and quantum operations. Some of the basic properties of these strategies are established and then used to construct denotational semantics for three quantum programming languages. The first of these languages is a formalisation of the measurement calculus proposed by Danos et al. [DKP07]. The other two are new: they are higher-order quantum programming languages. Previous attempts to define a denotational semantics for higher-order quantum programming languages have failed. We identify some of the key reasons for this and base the design of our higher-order languages on these observations. The game semantics proposed in this thesis is the first denotational semantics for a lambda-calculus equipped with quantum types and with extra operations which allow one to program quantum algorithms. The results presented validate the two different approaches used in the design of these two new higher-order languages: a first one where quantum states are used through references and a second one where they are introduced as constants in the language. The quantum strategies presented in this thesis allow one to understand the constraints that must be imposed on quantum type systems with higher-order types. The most significant constraint is the fact that abstraction over part of the tensor product of many unknown quantum states must not be allowed. Quantum strategies are a new mathematical model which describes the interaction between classical and quantum data using system-environment dialogues. The interactions between the different parts of a quantum system are described using the rich structure generated by composition of strategies. This approach has enough generality to be put in relation with other

Professional tennis players' serve: correlation between segmental angular momentums and ball velocity.

PubMed

Martin, Caroline; Kulpa, Richard; Delamarche, Paul; Bideau, Benoit

2013-03-01

The purpose of the study was to identify the relationships between segmental angular momentum and ball velocity between the following events: ball toss, maximal elbow flexion (MEF), racket lowest point (RLP), maximal shoulder external rotation (MER), and ball impact (BI). Ten tennis players performed serves recorded with a real-time motion capture. Mean angular momentums of the trunk, upper arm, forearm, and the hand-racket were calculated. The anteroposterior axis angular momentum of the trunk was significantly related with ball velocity during the MEF-RLP, RLP-MER, and MER-BI phases. The strongest relationships between the transverse-axis angular momentums and ball velocity followed a proximal-to-distal timing sequence that allows the transfer of angular momentum from the trunk (MEF-RLP and RLP-MER phases) to the upper arm (RLP-MER phase), forearm (RLP-MER and MER-BI phases), and the hand-racket (MER-BI phase). Since sequence is crucial for ball velocity, players should increase angular momentums of the trunk during MEF-MER, upper arm during RLP-MER, forearm during RLP-BI, and the hand-racket during MER-BI.

Angular Rate Sensing with GyroWheel Using Genetic Algorithm Optimized Neural Networks.

PubMed

Zhao, Yuyu; Zhao, Hui; Huo, Xin; Yao, Yu

2017-07-22

GyroWheel is an integrated device that can provide three-axis control torques and two-axis angular rate sensing for small spacecrafts. Large tilt angle of its rotor and de-tuned spin rate lead to a complex and non-linear dynamics as well as difficulties in measuring angular rates. In this paper, the problem of angular rate sensing with the GyroWheel is investigated. Firstly, a simplified rate sensing equation is introduced, and the error characteristics of the method are analyzed. According to the analysis results, a rate sensing principle based on torque balance theory is developed, and a practical way to estimate the angular rates within the whole operating range of GyroWheel is provided by using explicit genetic algorithm optimized neural networks. The angular rates can be determined by the measurable values of the GyroWheel (including tilt angles, spin rate and torque coil currents), the weights and the biases of the neural networks. Finally, the simulation results are presented to illustrate the effectiveness of the proposed angular rate sensing method with GyroWheel.

Production of W + W - pairs via γ * γ * → W + W - subprocess with photon transverse momenta

NASA Astrophysics Data System (ADS)

Łuszczak, Marta; Schäfer, Wolfgang; Szczurek, Antoni

2018-05-01

We discuss production of W + W - pairs in proton-proton collisions induced by two-photon fusion including, for a first time, transverse momenta of incoming photons. The unintegrated inelastic fluxes (related to proton dissociation) of photons are calculated based on modern parametrizations of deep inelastic structure functions in a broad range of their arguments ( x and Q 2). In our approach we can get separate contributions of different W helicities states. Several one- and two-dimensional differential distributions are shown and discussed. The present results are compared to the results of previous calculations within collinear factorization approach. Similar results are found except of some observables such as e.g. transverse momentum of the pair of W + and W -. We find large contributions to the cross section from the region of large photon virtualities. We show decomposition of the total cross section as well as invariant mass distribution into the polarisation states of both W bosons. The role of the longitudinal F L structure function is quantified. Its inclusion leads to a 4-5% decrease of the cross section, almost independent of M WW .

Electron transfer in proton-hydrogen collisions under dense quantum plasma

NASA Astrophysics Data System (ADS)

Nayek, Sujay; Bhattacharya, Arka; Kamali, Mohd Zahurin Mohamed; Ghoshal, Arijit; Ratnavelu, Kurunathan

2017-09-01

The effects of dense quantum plasma on 1 s → nlm charge transfer, for arbitrary n,l,m, in proton-hydrogen collisions have been studied by employing a distorted wave approximation. The interactions among the charged particles in the plasma have been represented by modified Debye-Huckel potentials. A detailed study has been made to explore the effects of background plasma environment on the differential and total cross sections for electron capture into different angular momentum states for the incident energy in the range 10-1000 keV. For the unscreened case, our results agree well with some of the most accurate results available in the literature.

The Cosmology Large Angular Scale Surveyor

NASA Technical Reports Server (NTRS)

Harrington, Kathleen; Marriage, Tobias; Ali, Aamir; Appel, John; Bennett, Charles; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe;

2016-01-01

The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from inflation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad frequency range, large sky coverage, control over systematics, and high sensitivity, CLASS will observe the reionization and recombination peaks of the CMB E- and B-mode power spectra. CLASS will make a cosmic variance limited measurement of the optical depth to reionization and will measure or place upper limits on the tensor-to-scalar ratio, r, down to a level of 0.01 (95% C.L.).

The Cosmology Large Angular Scale Surveyor

NASA Astrophysics Data System (ADS)

Harrington, Kathleen; Marriage, Tobias; Ali, Aamir; Appel, John W.; Bennett, Charles L.; Boone, Fletcher; Brewer, Michael; Chan, Manwei; Chuss, David T.; Colazo, Felipe; Dahal, Sumit; Denis, Kevin; Dünner, Rolando; Eimer, Joseph; Essinger-Hileman, Thomas; Fluxa, Pedro; Halpern, Mark; Hilton, Gene; Hinshaw, Gary F.; Hubmayr, Johannes; Iuliano, Jeffrey; Karakla, John; McMahon, Jeff; Miller, Nathan T.; Moseley, Samuel H.; Palma, Gonzalo; Parker, Lucas; Petroff, Matthew; Pradenas, Bastián.; Rostem, Karwan; Sagliocca, Marco; Valle, Deniz; Watts, Duncan; Wollack, Edward; Xu, Zhilei; Zeng, Lingzhen

2016-07-01

The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from in ation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145/217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad frequency range, large sky coverage, control over systematics, and high sensitivity, CLASS will observe the reionization and recombination peaks of the CMB E- and B-mode power spectra. CLASS will make a cosmic variance limited measurement of the optical depth to reionization and will measure or place upper limits on the tensor-to-scalar ratio, r, down to a level of 0.01 (95% C.L.).

RadioAstron Maser Observations: a Record in Angular Resolution

NASA Astrophysics Data System (ADS)

Sobolev, A. M.; Shakhvorostova, N. N.; Alakoz, A. V.; Baan, W. A.; RadioAstron Maser Team

2017-06-01

Extremely long baselines of the space-ground interferometer RadioAstron allow to achieve ultra-high angular resolutions. The possibility of detection of a maser emission with resolutions about tens of micro-arcseconds was arguable before successful experiments reported in this paper. We present the results of the maser survey obtained by RadioAstron during first 5 years of operation. Extremely high angular resolution of 11 microarcseconds have been achieved in observations of the megamaser galaxy NGC 4258. For the galaxy at the distance about 7 Mpc this corresponds to linear resolution around 80 AU. Very compact features with angular sizes about 20 micro-arcseconds have been detected in star-forming regions of our Galaxy. Corresponding linear sizes are about 5-10 millions of kilometers.

Modification of the DSN radio frequency angular tropospheric refraction model

NASA Technical Reports Server (NTRS)

Berman, A. L.

1977-01-01

The previously derived DSN Radio Frequency Angular Tropospheric Refraction Model contained an assumption which was subsequently seen to be at a variance with the theoretical basis of angular refraction. The modification necessary to correct the model is minor in that the value of a constant is changed.

CONNECTING ANGULAR MOMENTUM AND GALACTIC DYNAMICS: THE COMPLEX INTERPLAY BETWEEN SPIN, MASS, AND MORPHOLOGY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teklu, Adelheid F.; Remus, Rhea-Silvia; Dolag, Klaus

The evolution and distribution of the angular momentum of dark matter (DM) halos have been discussed in several studies over the past decades. In particular, the idea arose that angular momentum conservation should allow us to infer the total angular momentum of the entire DM halo from measuring the angular momentum of the baryonic component, which is populating the center of the halo, especially for disk galaxies. To test this idea and to understand the connection between the angular momentum of the DM halo and its galaxy, we use a state-of-the-art, hydrodynamical cosmological simulation taken from the set of Magneticummore » Pathfinder simulations. Thanks to the inclusion of the relevant physical processes, the improved underlying numerical methods, and high spatial resolution, we successfully produce populations of spheroidal and disk galaxies self-consistently. Thus, we are able to study the dependence of galactic properties on their morphology. We find that (1) the specific angular momentum of stars in disk and spheroidal galaxies as a function of their stellar mass compares well with observational results; (2) the specific angular momentum of the stars in disk galaxies is slightly smaller compared to the specific angular momentum of the cold gas, in good agreement with observations; (3) simulations including the baryonic component show a dichotomy in the specific stellar angular momentum distribution when splitting the galaxies according to their morphological type (this dichotomy can also be seen in the spin parameter, where disk galaxies populate halos with slightly larger spin compared to spheroidal galaxies); (4) disk galaxies preferentially populate halos in which the angular momentum vector of the DM component in the central part shows a better alignment to the angular momentum vector of the entire halo; and (5) the specific angular momentum of the cold gas in disk galaxies is approximately 40% smaller than the specific angular momentum of the total

Nonreciprocal Transverse Photonic Spin and Magnetization-Induced Electromagnetic Spin-Orbit Coupling

PubMed Central

Levy, Miguel; Karki, Dolendra

2017-01-01

We present a formulation of electromagnetic spin-orbit coupling in magneto-optic media, and propose an alternative source of spin-orbit coupling to non-paraxial optics vortices. Our treatment puts forth a formulation of nonreciprocal transverse-spin angular-momentum-density shifts for evanescent waves in magneto-optic waveguide media. It shows that magnetization-induced electromagnetic spin-orbit coupling is possible, and that it leads to unequal spin to orbital angular momentum conversion in magneto-optic media evanescent waves in opposite propagation-directions. Generation of free-space helicoidal beams based on this conversion is shown to be spin-helicity- and magnetization-dependent. We show that transverse-spin to orbital angular momentum coupling into magneto-optic waveguide media engenders spin-helicity-dependent unidirectional propagation. This unidirectional effect produces different orbital angular momenta in opposite directions upon excitation-spin-helicity reversals. PMID:28059120

GALACTIC ANGULAR MOMENTUM IN THE ILLUSTRIS SIMULATION: FEEDBACK AND THE HUBBLE SEQUENCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Genel, Shy; Fall, S. Michael; Snyder, Gregory F.

We study the stellar angular momentum of thousands of galaxies in the Illustris cosmological simulation, which captures gravitational and gas dynamics within galaxies, as well as feedback from stars and black holes. We find that the angular momentum of the simulated galaxies matches observations well, and in particular two distinct relations are found for late-type versus early-type galaxies. The relation for late-type galaxies corresponds to the value expected from full conservation of the specific angular momentum generated by cosmological tidal torques. The relation for early-type galaxies corresponds to retention of only ∼30% of that, but we find that those early-typemore » galaxies with low angular momentum at z = 0 nevertheless reside at high redshift on the late-type relation. Some of them abruptly lose angular momentum during major mergers. To gain further insight, we explore the scaling relations in simulations where the galaxy formation physics is modified with respect to the fiducial model. We find that galactic winds with high mass-loading factors are essential for obtaining the high angular momentum relation typical for late-type galaxies, while active galactic nucleus feedback largely operates in the opposite direction. Hence, feedback controls the stellar angular momentum of galaxies, and appears to be instrumental for establishing the Hubble sequence.« less

A Missile-Borne Angular Velocity Sensor Based on Triaxial Electromagnetic Induction Coils.

PubMed

Li, Jian; Wu, Dan; Han, Yan

2016-09-30

Aiming to solve the problem of the limited measuring range for angular motion parameters of high-speed rotating projectiles in the field of guidance and control, a self-adaptive measurement method for angular motion parameters based on the electromagnetic induction principle is proposed. First, a framework with type bent "I-shape" is used to design triaxial coils in a mutually orthogonal way. Under the condition of high rotational speed of a projectile, the induction signal of the projectile moving across a geomagnetic field is acquired by using coils. Second, the frequency of the pulse signal is adjusted self-adaptively. Angular velocity and angular displacement are calculated in the form of periodic pulse counting and pulse accumulation, respectively. Finally, on the basis of that principle prototype of the sensor is researched and developed, performance of measuring angular motion parameters are tested on the sensor by semi-physical and physical simulation experiments, respectively. Experimental results demonstrate that the sensor has a wide measuring range of angular velocity from 1 rps to 100 rps with a measurement error of less than 0.3%, and the angular displacement measurement error is lower than 0.2°. The proposed method satisfies measurement requirements for high-speed rotating projectiles with an extremely high dynamic range of rotational speed and high precision, and has definite value to engineering applications in the fields of attitude determination and geomagnetic navigation.

Quantum space and quantum completeness

NASA Astrophysics Data System (ADS)

Jurić, Tajron

2018-05-01

Motivated by the question whether quantum gravity can "smear out" the classical singularity we analyze a certain quantum space and its quantum-mechanical completeness. Classical singularity is understood as a geodesic incompleteness, while quantum completeness requires a unique unitary time evolution for test fields propagating on an underlying background. Here the crucial point is that quantum completeness renders the Hamiltonian (or spatial part of the wave operator) to be essentially self-adjoint in order to generate a unique time evolution. We examine a model of quantum space which consists of a noncommutative BTZ black hole probed by a test scalar field. We show that the quantum gravity (noncommutative) effect is to enlarge the domain of BTZ parameters for which the relevant wave operator is essentially self-adjoint. This means that the corresponding quantum space is quantum complete for a larger range of BTZ parameters rendering the conclusion that in the quantum space one observes the effect of "smearing out" the singularity.

Prediction of Lunar Reconnaissance Orbiter Reaction Wheel Assembly Angular Momentum Using Regression Analysis

NASA Technical Reports Server (NTRS)

DeHart, Russell

2017-01-01

This study determines the feasibility of creating a tool that can accurately predict Lunar Reconnaissance Orbiter (LRO) reaction wheel assembly (RWA) angular momentum, weeks or even months into the future. LRO is a three-axis stabilized spacecraft that was launched on June 18, 2009. While typically nadir-pointing, LRO conducts many types of slews to enable novel science collection. Momentum unloads have historically been performed approximately once every two weeks with the goal of maintaining system total angular momentum below 70 Nms; however flight experience shows the models developed before launch are overly conservative, with many momentum unloads being performed before system angular momentum surpasses 50 Nms. A more accurate model of RWA angular momentum growth would improve momentum unload scheduling and decrease the frequency of these unloads. Since some LRO instruments must be deactivated during momentum unloads and in the case of one instrument, decontaminated for 24 hours there after a decrease in the frequency of unloads increases science collection. This study develops a new model to predict LRO RWA angular momentum. Regression analysis of data from October 2014 to October 2015 was used to develop relationships between solar beta angle, slew specifications, and RWA angular momentum growth. The resulting model predicts RWA angular momentum using input solar beta angle and mission schedule data. This model was used to predict RWA angular momentum from October 2013 to October 2014. Predictions agree well with telemetry; of the 23 momentum unloads performed from October 2013 to October 2014, the mean and median magnitude of the RWA total angular momentum prediction error at the time of the momentum unloads were 3.7 and 2.7 Nms, respectively. The magnitude of the largest RWA total angular momentum prediction error was 10.6 Nms. Development of a tool that uses the models presented herein is currently underway.

Tunable orbital angular momentum in high-harmonic generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gauthier, David; Ribič, P. Rebernik; Adhikary, G.

Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization. Here, we report on the generation of extreme-ultraviolet optical vortices with femtosecond duration carrying a controllable amount of OAM. From a basic physics viewpoint, our results help to resolve key questions such as the conservation of angular momentum in highly nonlinear light–matter interactions,more » and the disentanglement and independent control of the intrinsic and extrinsic components of the photon’s angular momentum at short-wavelengths. Finally, the methods developed here will allow testing some of the recently proposed concepts such as OAM-induced dichroism, magnetic switching in organic molecules and violation of dipolar selection rules in atoms.« less

Orbital and spin angular momentum in conical diffraction

NASA Astrophysics Data System (ADS)

Berry, M. V.; Jeffrey, M. R.; Mansuripur, M.

2005-11-01

The angular momentum Jinc of a light beam can be changed by passage through a slab of crystal. When the beam is incident along the optic axis of a biaxial crystal, which may also possess optical activity (chirality), the final angular momentum J can have both orbital (Jorb) and spin (Jsp) contributions, which we calculate paraxially exactly for arbitrary biaxiality and chirality and initially uniformly polarized beams with circular symmetry. For the familiar special case of a non-chiral crystal with fully developed conical-refraction rings, J is purely orbital and equal to Jinc/2, reflecting an interesting singularity structure in the beam. Explicit formulas and numerical computations are presented for a Gaussian incident beam. The change in angular momentum results in a torque on the crystal, along the axis of the incident beam. An additional, much larger, torque, about an axis lying in the slab, arises from the offset of the cone of conical refraction relative to the incident beam.

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