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Sample records for adiabatic pair creation

  1. On Adiabatic Pair Creation

    NASA Astrophysics Data System (ADS)

    Pickl, Peter; Dürr, Detlef

    2008-08-01

    We give here a rigorous proof of the well known prediction of pair creation as it arises from the Dirac equation with an external time dependent potential. Pair creation happens with probability one if the potential changes adiabatically in time and becomes overcritical, which means that an eigenvalue curve (as a function of time) bridges the gap between the negative and positive spectral continuum. The potential can be thought of as being zero at large negative and large positive times. The rigorous treatment of this effect has been lacking since the pioneering work of Beck, Steinwedel and Süßmann [1] in 1963 and Gershtein and Zeldovich [8] in 1970.

  2. Missing energies at pair creation

    NASA Technical Reports Server (NTRS)

    El-Ela, A. A.; Hassan, S.; Bagge, E. R.

    1985-01-01

    Wilson cloud chamber measurements of the separated spectra of positrons and electrons produced by gamma quanta of 6.14 MeV differ considerably from the theoretically predicted spectra by BETHE and HEITLER, but are in good agreement with those of a modified theory of pair creation.

  3. Pair creation and plasma oscillations.

    SciTech Connect

    Prozorkevich, A. V.; Vinnik, D. V.; Schmidt, S. M.; Hecht, M. B.; Roberts, C. D.

    2000-12-15

    We describe aspects of particle creation in strong fields using a quantum kinetic equation with a relaxation-time approximation to the collision term. The strong electric background field is determined by solving Maxwell's equation in tandem with the Vlasov equation. Plasma oscillations appear as a result of feedback between the background field and the field generated by the particles produced. The plasma frequency depends on the strength of the initial background fields and the collision frequency, and is sensitive to the necessary momentum-dependence of dressed-parton masses.

  4. Schwinger pair creation of Kaluza-Klein particles: Pair creation without tunneling

    SciTech Connect

    Friedmann, Tamar; Verlinde, Herman

    2005-03-15

    We study Schwinger pair creation of charged Kaluza-Klein (KK) particles from a static KK electric field. We find that the gravitational backreaction of the electric field on the geometry--which is incorporated via the electric KK-Melvin solution--prevents the electrostatic potential from overcoming the rest mass of the KK particles, thus impeding the tunneling mechanism which is often thought of as responsible for the pair creation. However, we find that pair creation still occurs with a finite rate formally similar to the classic Schwinger result, but via an apparently different mechanism, involving a combination of the Unruh effect and vacuum polarization due to the E-field.

  5. Pair creation: Back reactions and damping

    SciTech Connect

    Bloch, J. C. R.; Mizerny, V. A.; Prozorkevich, A. V.; Roberts, C. D.; Schmidt, S. M.; Smolyansky, S. A.; Vinnik, D. V.

    1999-12-01

    We solve the quantum Vlasov equation for fermions and bosons, incorporating spontaneous pair creation in the presence of back reactions and collisions. Pair creation is initiated by an external impulse field and the source term is non-Markovian. A simultaneous solution of Maxwell's equation in the presence of feedback yields an internal current and electric field that exhibit plasma oscillations with a period {tau}{sub pl}. Allowing for collisions, these oscillations are damped on a time scale {tau}{sub r} determined by the collision frequency. Plasma oscillations cannot affect the early stages of the formation of a quark-gluon plasma unless {tau}{sub r}>>{tau}{sub pl} and {tau}{sub pl}{approx}1/{lambda}{sub QCD}{approx}1 fm/c. (c) 1999 The American Physical Society.

  6. Pair Creation at Large Inherent Angles

    SciTech Connect

    Chen, P.; Tauchi, T.; Schroeder, D.V.; /SLAC

    2007-04-25

    In the next-generation linear colliders, the low-energy e{sup +}e{sup -} pairs created during the collision of high-energy e{sup +}e{sup -} beams would cause potential deleterious background problems to the detectors. At low collider energies, the pairs are made essentially by the incoherent process, where the pair is created by the interaction of beamstrahlung photons on the individual particles in the oncoming beam. This problem was first identified by Zolotarev, et al[1]. At energies where the beamstrahlung parameter {Upsilon} lies approximately in the range 0.6 {approx}< {Upsilon} {approx}< 100, pair creation from the beamstrahlung photons is dominated by a coherent process, first noted by Chen[2]. The seriousness of this pair creation problem lies in the transverse momenta that the pair particles carry when leaving the interaction point (IP) with large angles. One source of transverse momentum is from the kick by the field of the oncoming beam which results in an outcoming angle {theta} {proportional_to} 1/{radical}x, where x is the fractional energy of the particle relative to the initial beam particle energy[2,3]. As was shown in Ref. 131, there in fact exists an energy threshold for the coherent pairs, where x{sub th} {approx}> 1/2{Upsilon}. Thus within a tolerable exiting angle, there exists an upper limit for {Upsilon} where all coherent pairs would leave the detector through the exhaust port[4]. A somewhat different analysis has been done by Schroeder[5]. In the next generation of linear colliders, as it occurs, the coherent pairs can be exponentially suppressed[2] by properly choosing the {Upsilon}({approx}< 0.6). When this is achieved, the incoherent pairs becomes dominant. Since the central issue is the transverse momentum for particles with large angles, we notice that there is another source for it. Namely, when the pair particles are created at low energies, the intrinsic angles of these pairs when produced may already be large. This issue was

  7. Pair creation in noncommutative space-time

    NASA Astrophysics Data System (ADS)

    Hamil, B.; Chetouani, L.

    2016-09-01

    By taking two interactions, the Volkov plane wave and a constant electromagnetic field, the probability related to the process of pair creation from the vacuum is exactly and analytically determined via the Schwinger method in noncommutative space-time. For the plane wave, it is shown that the probability is simply null and for the electromagnetic wave it is found that the expression of the probability has a similar form to that obtained by Schwinger in a commutative space-time. For a certain critical value of H, the probability is simply equal to 1.

  8. Disruption, beamstrahlung, and beamstrahlung pair creation

    SciTech Connect

    Chen, P.

    1988-12-01

    The two major effects from the interaction of e/sup /minus//e/sup +/ beams---beamstrahlung and disruption---are reviewed, with emphasis on flat beam collisions. For the disruption effects we discuss the luminosity enhancement factor, the maximum and rms disruption angles, and the ''kink instability''. All the results are obtained from computer simulations, and scaling laws based on these are deduced whenever possible. For the beamstrahlung effects, we concentrate only on the final electron energy spectrum and the deflection angle associated with low energy particles. In addition to the generic studies on the beam-beam effects, we also list the relevant beam-beam parameters obtained from simulations on two sample designs: the TLC and the ILC. As an addendum, the newly discovered phenomenon of coherent beamstrahlung pair creation, together with the incoherent process, are discussed. 18 refs., 15 figs., 1 tab.

  9. Creation and Transfer of Coherence via Technique of Stimulated Raman Adiabatic Passage in Triple Quantum Dots.

    PubMed

    Tian, Si-Cong; Wan, Ren-Gang; Wang, Chun-Liang; Shu, Shi-Li; Wang, Li-Jie; Tong, Chun-Zhu

    2016-12-01

    We propose a scheme for creation and transfer of coherence among ground state and indirect exciton states of triple quantum dots via the technique of stimulated Raman adiabatic passage. Compared with the traditional stimulated Raman adiabatic passage, the Stokes laser pulse is replaced by the tunneling pulse, which can be controlled by the externally applied voltages. By varying the amplitudes and sequences of the pump and tunneling pulses, a complete coherence transfer or an equal coherence distribution among multiple states can be obtained. The investigations can provide further insight for the experimental development of controllable coherence transfer in semiconductor structure and may have potential applications in quantum information processing.

  10. Pair creation in heavy ion channeling

    NASA Astrophysics Data System (ADS)

    Belov, N. A.; Harman, Z.

    2016-04-01

    Heavy ions channeled through crystals with multi-GeV kinetic energies can create electron-positron pairs. In the framework of the ion, the energy of virtual photons arising from the periodic crystal potential may exceed the threshold 2mec2. The repeated periodic collisions with the crystal ions yield high pair production rates. When the virtual photon frequency matches a nuclear transition in the ion, the production rate can be resonantly increased. In this two-step excitation-pair conversion scheme, the excitation rates are coherently enhanced, and scale approximately quadratically with the number of crystal sites along the channel.

  11. Semiclassical fermion pair creation in de Sitter spacetime

    SciTech Connect

    Stahl, Clément Eckhard, Strobel

    2015-12-17

    We present a method to semiclassically compute the pair creation rate of bosons and fermions in de Sitter spacetime. The results in the bosonic case agree with the ones in the literature. We find that for the constant electric field the fermionic and bosonic pair creation rate are the same. This analogy of bosons and fermions in the semiclassical limit is known from several flat spacetime examples.

  12. Two-potential approach to pair creation from the vacuum

    NASA Astrophysics Data System (ADS)

    Lv, Q. Z.; Li, Y. T.; Su, Q.; Grobe, R.

    2017-02-01

    By applying a Foldy-Wouthuysen-like transformation and a low-momentum approximation to the usual quantum field theoretical Dirac Hamiltonian in one spatial dimension, we introduce a Hamiltonian for which the kinetic portion and the original potential are diagonal in the corresponding spinor space and a second potential occurs that is off diagonal. This two-potential Hamiltonian is applied to study the electron-positron pair creation process from the vacuum. Here the diagonal potential provides only the energy degeneracy of the lower and upper manifold of continuum states, which is one requirement for the permanent creation of particles. The off-diagonal potential actually triggers the creation process by providing the necessary coupling between the degenerate states. It also provides a concrete example of a model system for pair creation where the creation rate is perturbative in the coupling strength.

  13. Superrotations and black hole pair creation

    NASA Astrophysics Data System (ADS)

    Strominger, Andrew; Zhiboedov, Alexander

    2017-03-01

    Recent work has shown that the symmetries of classical gravitational scattering in asymptotically flat spacetimes include, at the linearized level, infinitesimal superrotations. These act like Virasoro generators on the celestial sphere at null infinity. However, due to the singularities in these generators, the physical status of finite superrotations has remained unclear. Here we address this issue in the context of the breaking of a cosmic string via quantum black hole pair nucleation. This process is described by a gravitational instanton known as the C-metric. After pair production, the black holes are pulled by the string to null infinity with a constant acceleration. At late times the string decays and the spacetime settles into a vacuum state. We show that the early and late spacetimes before and after string decay differ by a finite superrotation. This provides a physical interpretation of superrotations. They act on spacetimes which are asymptotically flat everywhere except at isolated singularities with cosmic string defects.

  14. Bosonic pair creation and the Schiff-Snyder-Weinberg effect

    NASA Astrophysics Data System (ADS)

    Lv, Q. Z.; Bauke, Heiko; Su, Q.; Keitel, C. H.; Grobe, R.

    2016-01-01

    Interactions between different bound states in bosonic systems can lead to pair creation. We study this process in detail by solving the Klein-Gordon equation on space-time grids in the framework of time-dependent quantum field theory. By choosing specific external field configurations, two bound states can become pseudodegenerate, which is commonly referred to as the Schiff-Snyder-Weinberg effect. These pseudodegenerate bound states, which have complex energy eigenvalues, are related to the pseudo-Hermiticity of the Klein-Gordon Hamiltonian. In this work, the influence of the Schiff-Snyder-Weinberg effect on pair production is studied. A generalized Schiff-Snyder-Weinberg effect, where several pairs of pseudodegenerate states appear, is found in combined electric and magnetic fields. The generalized Schiff-Snyder-Weinberg effect likewise triggers pair creation. The particle number in these situations obeys an exponential growth law in time enhancing the creation of bosons, which cannot be found in fermionic systems.

  15. Noncompeting channel approach to pair creation in supercritical fields.

    PubMed

    Lv, Q Z; Liu, Y; Li, Y J; Grobe, R; Su, Q

    2013-11-01

    The Dirac and Klein-Gordon equations are solved on a space-time grid to study the strong-field induced pair creation process for bosons and fermions from the vacuum. If the external field is sufficiently strong to induce bound states that are embedded in the negative energy continuum, a complex scaling technique of the Hamiltonian can predict the longtime behavior of the dynamics. In the case of multiple bound states this technique predicts the occurrence of a new collective time scale. The longtime behavior of the pair creation is not determined by a single (most important) channel, but collectively by the sum of all individual widths of the embedded states.

  16. Magnetic pair creation transparency in gamma-ray pulsars

    SciTech Connect

    Story, Sarah A.; Baring, Matthew G. E-mail: baring@rice.edu

    2014-07-20

    Magnetic pair creation, γ → e {sup +} e {sup –}, has been at the core of radio pulsar paradigms and central to polar cap models of gamma-ray pulsars for over three decades. The Fermi gamma-ray pulsar population now exceeds 140 sources and has defined an important part of Fermi's science legacy, providing rich information for the interpretation of young energetic pulsars and old millisecond pulsars. Among the population characteristics well established is the common occurrence of exponential turnovers in their spectra in the 1-10 GeV range. These turnovers are too gradual to arise from magnetic pair creation in the strong magnetic fields of pulsar inner magnetospheres. By demanding insignificant photon attenuation precipitated by such single-photon pair creation, the energies of these turnovers for Fermi pulsars can be used to compute lower bounds for the typical altitude of GeV band emission. This paper explores such pair transparency constraints below the turnover energy and updates earlier altitude bound determinations that have been deployed in various Fermi pulsar papers. For low altitude emission locales, general relativistic influences are found to be important, increasing cumulative opacity, shortening the photon attenuation lengths, and also reducing the maximum energy that permits escape of photons from a neutron star magnetosphere. Rotational aberration influences are also explored, and are found to be small at low altitudes, except near the magnetic pole. The analysis presented in this paper clearly demonstrates that including near-threshold physics in the pair creation rate is essential to deriving accurate attenuation lengths and escape energies. The altitude bounds are typically in the range of 2-7 stellar radii for the young Fermi pulsar population, and provide key information on the emission altitude in radio quiet pulsars that do not possess double-peaked pulse profiles. The bound for the Crab pulsar is at a much higher altitude, with the

  17. Pair creation in an electric flux tube and chiral anomaly

    SciTech Connect

    Iwazaki, Aiichi

    2009-11-15

    Using the chiral anomaly, we discuss the pair creation of massless fermions under the effect of a magnetic field B-vector when an electric flux tube E-vector parallel to B-vector is switched on. The tube is axially symmetric and infinitely long. For the constraint B>>E, we can analytically obtain the spatial and temporal behaviors of the number density of the fermions, the azimuthal magnetic field generated by the fermions, and so on. We find that the lifetime t{sub c} of the electric field becomes shorter as the width of the tube becomes narrower. Applying it to the plasma in high-energy heavy-ion collisions, we find that the color electric field decays quickly such that t{sub c}{approx_equal}Q{sub s}{sup -1}, in which Q{sub s} is the saturation momentum.

  18. Correlations in laser-induced electron-positron pair creation

    SciTech Connect

    Krajewska, K.; Kaminski, J. Z.

    2011-09-15

    Probability rates of electron-positron pair creation in head-on laser-beam-proton collisions are investigated, using an exact treatment of the colliding proton as a finite-mass particle. We observe that the recoil effects become more important when passing from the perturbative multiphoton regime to the nonperturbative above-threshold regime of laser-matter coupling. Thus we concentrate on the latter case. In this regime, our detailed analysis shows that energy supplied by the colliding proton makes the process more effective, and that the electrons and positrons that are created during the collision are more energetic than in the case when the momentum transfer from the proton is neglected. A number of similarities to above-threshold atomic ionization are also illustrated.

  19. Optical-vortex pair creation and annihilation and helical astigmatism of a nonplanar ring resonator

    SciTech Connect

    Heckenberg, N.R.; Vaupel, M.; Malos, J.T.; Weiss, C.O.

    1996-09-01

    The creation and annihilation of pairs of optical vortices have been studied in transitions between patterns produced in a photorefractive oscillator. Smooth metamorphosis between stable patterns occurs through pair creation or annihilation but can be modeled using superposition of modes taking into account lifting of degeneracy of helical modes by helical astigmatism of the resonator. {copyright} {ital 1996 The American Physical Society.}

  20. Pair Creation in QED-Strong Pulsed Laser Fields Interacting with Electron Beams

    SciTech Connect

    Sokolov, Igor V.; Naumova, Natalia M.; Nees, John A.; Mourou, Gerard A.

    2010-11-05

    QED effects are known to occur in a strong laser pulse interaction with a counterpropagating electron beam, among these effects being electron-positron pair creation. We discuss the range of laser pulse intensities of J{>=}5x10{sup 22} W/cm{sup 2} combined with electron beam energies of tens of GeV. In this regime multiple pairs may be generated from a single beam electron, some of the newborn particles being capable of further pair production. Radiation backreaction prevents avalanche development and limits pair creation. The system of integro-differential kinetic equations for electrons, positrons and {gamma} photons is derived and solved numerically.

  1. Pair creation in QED-strong pulsed laser fields interacting with electron beams.

    PubMed

    Sokolov, Igor V; Naumova, Natalia M; Nees, John A; Mourou, Gérard A

    2010-11-05

    QED effects are known to occur in a strong laser pulse interaction with a counterpropagating electron beam, among these effects being electron-positron pair creation. We discuss the range of laser pulse intensities of J≥5×10(22) W/cm2 combined with electron beam energies of tens of GeV. In this regime multiple pairs may be generated from a single beam electron, some of the newborn particles being capable of further pair production. Radiation backreaction prevents avalanche development and limits pair creation. The system of integro-differential kinetic equations for electrons, positrons and γ photons is derived and solved numerically.

  2. Monopole pair creation in energetic collisions: Is it possible

    SciTech Connect

    Drukier, A.K.; Nussinov, S.

    1982-07-12

    It is suggested that monopole-antimonopole pair production initiated by pointlike particles (electrons, quarks) has widely different cross sections in the two cases of ''pointlike'' and composite monopoles, respectively. Production of 't Hooft--Polyakov monopoles is expected to be suppressed by a hugh factor, > or =10/sup 30/. Furthermore, astrophysical evidence is presented suggesting that monopoles with m/sub m/roughly-equal10/sup 4/ GeV/c/sup 2/ cannot be pointlike.

  3. A homonuclear spin-pair filter for solid-state NMR based on adiabatic-passage techniques

    NASA Astrophysics Data System (ADS)

    Verel, René; Baldus, Marc; Ernst, Matthias; Meier, Beat H.

    1998-05-01

    A filtering scheme for the selection of spin pairs (and larger spin clusters) under fast magic-angle spinning is proposed. The scheme exploits the avoided level crossing in spin pairs during an adiabatic amplitude sweep through the so-called HORROR recoupling condition. The advantages over presently used double-quantum filters are twofold. (i) The maximum theoretical filter efficiency is, due to the adiabatic variation, 100% instead of 73% as for transient methods. (ii) Since the filter does not rely on the phase-cycling properties of the double-quantum coherence, there is no need to obtain the full double-quantum intensity for all spins in the sample at one single point in time. The only important requirement is that all coupled spins pass through a two-spin state during the amplitude sweep. This makes the pulse scheme robust with respect to rf-amplitude missetting, rf-field inhomogeneity and chemical-shift offset.

  4. Shortcuts to adiabaticity: suppression of pair production in driven Dirac dynamics

    NASA Astrophysics Data System (ADS)

    Deffner, Sebastian

    2016-01-01

    Achieving effectively adiabatic dynamics in finite time is a ubiquitous goal in virtually all areas of modern physics. So-called shortcuts to adiabaticity refer to a set of methods and techniques that allow us to produce in a short time the same final state that would result from an adiabatic, infinitely slow process. In this paper we generalize one of these methods—the fast-forward technique—to driven Dirac dynamics. As our main result we find that shortcuts to adiabaticity for the (1+1)-dimensional Dirac equation are facilitated by a combination of both scalar and pseudoscalar potentials. Our findings are illustrated for two analytically solvable examples, namely charged particles driven in spatially homogeneous and linear vector fields.

  5. Instantaneous rest-frame transformation method for temporally induced pair creation

    NASA Astrophysics Data System (ADS)

    Lv, Q. Z.; Vikartofsky, A.; Norris, S.; Li, Y. J.; Wagner, R.; Su, Q.; Grobe, R.

    2014-04-01

    We introduce a computational method to determine the rate of the electron-positron pair creation triggered by a time-dependent subcritical external field. It is based on constructing a Lorentz transformation to an instantaneous rest frame, for which the pair-creation rate can be determined by standard techniques. We will discuss the accuracy and efficiency of this method by comparing its predictions with exact time-dependent quantum field theoretical solutions to the Dirac and Klein-Gordon equations for various space-time dependent external fields.

  6. Robust conversion of singlet spin order in coupled spin-1/2 pairs by adiabatically ramped RF-fields.

    PubMed

    Pravdivtsev, Andrey N; Kiryutin, Alexey S; Yurkovskaya, Alexandra V; Vieth, Hans-Martin; Ivanov, Konstantin L

    2016-12-01

    We propose a robust and highly efficient NMR technique to create singlet spin order from longitudinal spin magnetization in coupled spin-½ pairs and to perform backward conversion (singlet order)→magnetization. In this method we exploit adiabatic ramping of an RF-field in order to drive transitions between the singlet state and the T± triplet states of a spin pair under study. We demonstrate that the method works perfectly for both strongly and weakly coupled spin pairs, providing a conversion efficiency between the singlet spin order and magnetization, which is equal to the theoretical maximum. We anticipate that the proposed technique is useful for generating long-lived singlet order, for preserving spin hyperpolarization and for analyzing singlet spin order in nearly equivalent spin pairs in specially designed molecules and in low-field NMR studies.

  7. Control of selective population transfer and creation of two orthogonal maximally superposition states via a pair of pump and chirped Stokes pulses

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenhua; Tian, Jin; Du, Juan

    2017-02-01

    We demonstrate a simple way to realize control of population transfer and creation of two orthogonal maximally superposition states in a Λ-type four-level system with closely spaced doublet target states via a pair of pump and chirped Stokes pulses. It is illustrated that the population in the initial state can be selectively, completely and robustly transferred to either of the doublet target states via chirped adiabatic passage with the suitable chirp rate and frequency detuning of the Stokes pulse. Besides, creation of two orthogonal maximally superposition states between the initial state and intermediate state with equal amplitude but inverse relative phases is also shown, which may have potential applications in the preparations of quantum bits.

  8. Black Hole Solutions and Pair Creation of Black Holes in Three, Four and Higher Dimensional Spacetimes

    NASA Astrophysics Data System (ADS)

    Dias, Oscar J. C.

    2004-10-01

    Black holes, first found as solutions of Einstein's General Relativity, are important in astrophysics, since they result from the gravitational collapse of a massive star or a cluster of stars, and in physics since they reveal properties of the fundamental physics, such as thermodynamic and quantum properties of gravitation. In order to better understand the black hole physics we need exact solutions that describe one or more black holes. In this thesis we study exact solutions in three, four and higher dimensional spacetimes. The study in 3-dimensions is important due to the simplification of the problem, while the discussion in higher dimensions is essential due to the fact that many theories indicate that extra dimensions exist in our universe. In this thesis, in any of the dimensions mentioned above, we study exact solutions with a single black hole and exact solutions that describe a pair of uniformly accelerated black holes (C-metric), with the acceleration source being well identified. This later solutions are then used to study in detail the quantum process of black hole pair creation in an external field. We also compute the gravitational radiation released during this pair creation process. KEYWORDS: Exact black hole solutions; Pair of accelerated black holes, C-metric, Ernst solution; Pair creation of black holes; Gravitational radiation; D-dimensional spacetimes; Cosmological constant backgrounds.

  9. Deterministic entanglement generation between a pair of atoms on different Rydberg states via chirped adiabatic passage

    NASA Astrophysics Data System (ADS)

    Qian, Jing; Zhang, Weiping

    2017-03-01

    We develop a scheme for deterministic generation of an entangled state between two atoms on different Rydberg states via a chirped adiabatic passage, which directly connects the initial ground and target entangled states and also does not request the normally needed blockade effect. The occupancy of intermediate states suffers from a strong reduction via two pulses with proper time-dependent detunings and the electromagnetically induced transparency condition. By solving the analytical expressions of eigenvalues and eigenstates of a two-atom system, we investigate the optimal parameters for guaranteeing the adiabatic condition. We present a detailed study for the effect of pulse duration, changing rate, different Rydberg interactions on the fidelity of the prepared entangled state with experimentally feasible parameters, which reveals a good agreement between the analytic and full numerical results.

  10. Ultra-Intense Short-Pulse Pair Creation Using the Texas Petawatt Laser

    NASA Astrophysics Data System (ADS)

    Liang, Edison; Henderson, Alexander; Clarke, Taylor; Taylor, Devin; Chaguine, Petr; Serratto, Kristina; Riley, Nathan; Dyer, Gilliss; Donovan, Michael; Ditmire, Todd

    2013-10-01

    We report results from the 2012 pair creation experiment using the Texas Petawatt Laser. Up to 1011 positrons per steradian were detected using 100 Joule pulses from the Texas Petawatt Laser to irradiate gold targets, with peak laser intensities up to 1.9 × 1021W/cm2 and pulse durations as short as 130 fs. Positron-to-electron ratios exceeding 20% were measured on some shots. The positron energy, positron yield per unit laser energy, and inferred positron density are significantly higher than those reported in previous experiments. This confirms that, for a given laser energy, higher intensity and shorter pulses irradiating thicker targets are more favorable for pair creation. Narrow-band high-energy positrons up to 23 MeV were observed from thin targets. Supported by DOE Grant DE-SC-0001481 and Rice FIF.

  11. Pair creation rates for one-dimensional fermionic and bosonic vacua

    NASA Astrophysics Data System (ADS)

    Ware, Matthew; Su, Q.; Grobe, R.

    2011-05-01

    We compare the creation rates for particle-antiparticle pairs produced by a supercritical force field for fermionic and bosonic model systems. The rates obtained from the Dirac and Klein-Gordon equations can be computed directly from the quantum mechanical transmission coefficients describing the scattering of an incoming particle with the supercritical potential barrier. We provide a unified framework that shows that the bosonic rates can exceed the fermionic ones, as one could expect from the Pauli exclusion principle for the fermion system. The predicted pair-creation rates also match the slopes of the time-dependent particle probabilities obtained from large-scale ab initio numerical simulations based on quantum field theory. This work has been supported by the NSF and Research Corporation.

  12. Pair creation rates for one-dimensional fermionic and bosonic vacua

    SciTech Connect

    Cheng, T.; Ware, M. R.; Su, Q.; Grobe, R.

    2009-12-15

    We compare the creation rates for particle-antiparticle pairs produced by a supercritical force field for fermionic and bosonic model systems. The rates obtained from the Dirac and Klein-Gordon equations can be computed directly from the quantum-mechanical transmission coefficients describing the scattering of an incoming particle with the supercritical potential barrier. We provide a unified framework that shows that the bosonic rates can exceed the fermionic ones, as one could expect from the Pauli-exclusion principle for the fermion system. This imbalance for small but supercritical forces is associated with the occurrence of negative bosonic transmission coefficients of arbitrary size for the Klein-Gordon system, while the Dirac coefficient is positive and bound by unity. We confirm the transmission coefficients with time-dependent scattering simulations. For large forces, however, the fermionic and bosonic pair-creation rates are surprisingly close to each other. The predicted pair creation rates also match the slopes of the time-dependent particle probabilities obtained from large-scale ab initio numerical simulations based on quantum field theory.

  13. Pair creation rates for one-dimensional fermionic and bosonic vacua

    NASA Astrophysics Data System (ADS)

    Cheng, T.; Ware, M. R.; Su, Q.; Grobe, R.

    2009-12-01

    We compare the creation rates for particle-antiparticle pairs produced by a supercritical force field for fermionic and bosonic model systems. The rates obtained from the Dirac and Klein-Gordon equations can be computed directly from the quantum-mechanical transmission coefficients describing the scattering of an incoming particle with the supercritical potential barrier. We provide a unified framework that shows that the bosonic rates can exceed the fermionic ones, as one could expect from the Pauli-exclusion principle for the fermion system. This imbalance for small but supercritical forces is associated with the occurrence of negative bosonic transmission coefficients of arbitrary size for the Klein-Gordon system, while the Dirac coefficient is positive and bound by unity. We confirm the transmission coefficients with time-dependent scattering simulations. For large forces, however, the fermionic and bosonic pair-creation rates are surprisingly close to each other. The predicted pair creation rates also match the slopes of the time-dependent particle probabilities obtained from large-scale ab initio numerical simulations based on quantum field theory.

  14. A Bayesian-based Method for Particle Track Identification in Low-energy Pair-creation Telescopes

    SciTech Connect

    Zoglauer, Andreas; Andritschke, Robert; Kanbach, Gottfried; Boggs, Steven E.

    2007-07-12

    A critical step during the data analysis of pair creation telescopes is the correct identification of the electron and positron tracks. For MEGA, an electron-tracking Compton and pair telescope optimized for energies up to 50 MeV, we describe a low-energy pair event reconstruction approach partly based on Bayesian statistics.

  15. Temperature effect on back electron-transfer reactions within a geminate radical pair: The influence of the solvent on the adiabaticity of the process

    NASA Astrophysics Data System (ADS)

    Vauthey, Eric; Suppan, Paul

    1989-12-01

    A study of the temperature dependence (from 233 to 353 K) of the rate of back electron-transfer reactions within geminate radical pairs by measurement of the free radical yield is reported. The radical pair is generated by photoinduced electron transfer with rhodamine 6G and oxazine 118 cations as electron acceptors and aromatic amines and methoxy-benzene derivatives as electron donors in acetonitrile, methanol and ethanol. In acetonitrile, the back electron transfer is non-adiabatic and apparent negative activation energies are observed for barrierless reactions. In alcohol solvents, an anomalously large temperature dependence is observed, which is attributed to a solvent-controlled adiabatic behaviour.

  16. Quantum entanglement of fermions-antifermions pair creation modes in noncommutative Bianchi I space-time

    NASA Astrophysics Data System (ADS)

    Ghiti, M. F.; Mebarki, N.; Aissaoui, H.

    2015-08-01

    The noncommutative Bianchi I curved space-time vierbeins and spin connections are derived. Moreover, the corresponding noncommutative Dirac equation as well as its solutions are presented. As an application within the quantum field theory approach using Bogoliubov transformations, the von Neumann fermion-antifermion pair creation quantum entanglement entropy is studied. It is shown that its behavior is strongly dependent on the value of the noncommutativity θ parameter, k⊥-modes frequencies and the structure of the curved space-time. Various discussions of the obtained features are presented.

  17. Dense gamma-ray and pair creation using ultra-intense lasers

    NASA Astrophysics Data System (ADS)

    Liang, Edison; Lo, Willie; Hasson, Hannah; Dyer, Gilliss; Clarke, Taylor; Fasanelli, Fabio; Yao, Kelly; Marchenka, Ilija; Henderson, Alexander; Dashko, Andriy; Zhang, Yuling; Ditmire, Todd

    2016-10-01

    We report recent results of gamma-ray and e +e- pair creation experiments using the Texas Petawatt laser (TPW) in Austin and the Trident laser at LANL irradiating solid high-Z targets. In addition to achieving record high densities of emerging gamma-rays and pairs at TPW, we measured in detail the spectra of hot electrons, positrons, and gamma-rays, and studied their spectral variation with laser and target parameters. A new type of gamma-ray spectrometer, called the scintillator attenuation spectrometer (SAS), was successfully demonstrated in Trident experiments in 2015. We will discuss the design and results of the SAS. Preliminary results of new experiments at TPW carried out in the summer of 2016 will also be presented.

  18. Multiloop Euler-Heisenberg Lagrangians, Schwinger Pair Creation, and the Photon S-Matrix

    NASA Astrophysics Data System (ADS)

    Huet, I.; de Traubenberg, M. R.; Schubert, C.

    2017-03-01

    Although the perturbation series in quantum electrodynamics has been studied for eighty years concerning its high-order behavior, our present understanding is still poorer than for many other field theories. An interesting case is Schwinger pair creation in a constant electric field, which may possibly provide a window to high loop orders; simple non-perturbative closed-form expressions have been conjectured for the pair creation rate in the weak field limit, for scalar QED in 1982 by Affleck, Alvarez, and Manton, and for spinor QED by Lebedev and Ritus in 1984. Using Borel analysis, these can be used to obtain non-perturbative information on the on-shell renormalized N-photon amplitudes at large N and low energy. This line of reasoning also leads to a number of nontrivial predictions for the effective QED Lagrangian in either four or two dimensions at any loop order, and preliminary results of a calculation of the three-loop Euler-Heisenberg Lagrangian in two dimensions are presented.

  19. A SEmi-Adiabatic Matched-phase Spin echo (SEAMS) PINS Pulse-pair for B1-insensitive Simultaneous Multi-slice Imaging

    PubMed Central

    Feldman, Rebecca E; Islam, Haisam M; Xu, Junqian; Balchandani, Priti

    2016-01-01

    Purpose Simultaneous multi-slice (SMS) imaging is a powerful technique that can reduce image acquisition time for anatomical, functional, and diffusion weighted magnetic resonance imaging. At higher magnetic fields, such as 7 Tesla, increased radiofrequency (RF) field inhomogeneity, power deposition, and changes in relaxation parameters make SMS spin echo imaging challenging. We designed an adiabatic 180° Power Independent of Number of Slices (PINS) pulse and a matched-phase 90° PINS pulse to generate a SEmi-Adiabatic Matched-phase Spin echo (SEAMS) PINS sequence to address these issues. Methods We used the adiabatic Shinnar Le-Roux (SLR) algorithm to generate a 180° pulse. The SLR polynomials for the 180° pulse were then used to create a matched-phase 90° pulse. The pulses were sub-sampled to produce a SEAMS PINS pulse-pair and the performance of this pulse-pair was validated in phantoms and in vivo. Results Simulations as well as phantom and in vivo results, demonstrate multi-slice capability and improved B1-insensitivity of the SEAMS PINS pulse-pair when operating at RF amplitudes of up to 40% above adiabatic threshold. Conclusion The SEAMS PINS approach presented here achieves multi-slice spin echo profiles with improved B1-insensitivity when compared to a conventional spin echo. PMID:25753055

  20. High e+/e– ratio dense pair creation with 1021W.cm–2 laser irradiating solid targets

    DOE PAGES

    Liang, E.; Clarke, T.; Henderson, A.; ...

    2015-09-14

    In this study, we report results of new pair creation experiments using ~100 Joule pulses of the Texas Petawatt Laser to irradiate solid gold and platinum targets, with intensities up to ~1.9 × 1021 W.cm–2 and pulse durations as short as ~130 fs. Positron to electron (e+/e–) ratios >15% were observed for many thick disk and rod targets, with the highest e+/e– ratio reaching ~50% for a Pt rod. The inferred pair yield was ~ few ×1010 with emerging pair density reaching ~1015/cm3 so that the pair skin depth becomes < pair jet transverse size. These results represent major milestonesmore » towards the goal of creating a significant quantity of dense pair-dominated plasmas with e+/e– approaching 100% and pair skin depth << pair plasma size, which will have wide-ranging applications to astrophysics and fundamental physics.« less

  1. High e+/e− Ratio Dense Pair Creation with 1021W.cm−2 Laser Irradiating Solid Targets

    PubMed Central

    Liang, E.; Clarke, T.; Henderson, A.; Fu, W.; Lo, W.; Taylor, D.; Chaguine, P.; Zhou, S.; Hua, Y.; Cen, X.; Wang, X.; Kao, J.; Hasson, H.; Dyer, G.; Serratto, K.; Riley, N.; Donovan, M.; Ditmire, T.

    2015-01-01

    We report results of new pair creation experiments using ~100 Joule pulses of the Texas Petawatt Laser to irradiate solid gold and platinum targets, with intensities up to ~1.9 × 1021 W.cm−2 and pulse durations as short as ~130 fs. Positron to electron (e+/e−) ratios >15% were observed for many thick disk and rod targets, with the highest e+/e− ratio reaching ~50% for a Pt rod. The inferred pair yield was ~ few ×1010 with emerging pair density reaching ~1015/cm3 so that the pair skin depth becomes < pair jet transverse size. These results represent major milestones towards the goal of creating a significant quantity of dense pair-dominated plasmas with e+/e− approaching 100% and pair skin depth ≪ pair plasma size, which will have wide-ranging applications to astrophysics and fundamental physics. PMID:26364764

  2. e{sup -}-e{sup +} pair creation by vacuum polarization around electromagnetic black holes

    SciTech Connect

    Cherubini, C.; Geralico, A.; Rueda H, J. A.; Ruffini, R.

    2009-06-15

    The concept of 'dyadotorus' was recently introduced to identify in the Kerr-Newman geometry the region where vacuum polarization processes may occur, leading to the creation of e{sup -}-e{sup +} pairs. This concept generalizes the original concept of ''dyadosphere'' initially introduced for Reissner-Nordstroem geometries. The topology of the axially symmetric dyadotorus is studied for selected values of the electric field and its electromagnetic energy is estimated by using three different methods all giving the same result. It is shown by a specific example the difference between a dyadotorus and a dyadosphere. The comparison is made for a Kerr-Newman black hole with the same total mass energy and the same charge to mass ratio of a Reissner-Nordstroem black hole. It turns out that the Kerr-Newman black hole leads to larger values of the electromagnetic field and energy when compared to the electric field and energy of the Reissner-Nordstroem one. The significance of these theoretical results for the realistic description of the process of gravitational collapse leading to black hole formation as well as the energy source of gamma ray bursts are also discussed.

  3. Observation of image pair creation and annihilation from superluminal scattering sources

    PubMed Central

    Clerici, Matteo; Spalding, Gabriel C.; Warburton, Ryan; Lyons, Ashley; Aniculaesei, Constantin; Richards, Joseph M.; Leach, Jonathan; Henderson, Robert; Faccio, Daniele

    2016-01-01

    The invariance of the speed of light is one of the foundational pillars of our current understanding of the universe. It implies a series of consequences related to our perception of simultaneity and, ultimately, of time itself. Whereas these consequences are experimentally well studied in the case of subluminal motion, the kinematics of superluminal motion lack direct evidence or even a clear experimental approach. We investigate kinematic effects associated with the superluminal motion of a light source. By using high-temporal-resolution imaging techniques, we directly demonstrate that if the source approaches an observer at superluminal speeds, the temporal ordering of events is inverted and its image appears to propagate backward. Moreover, for a source changing its speed and crossing the interface between subluminal and superluminal propagation regions, we observe image pair annihilation and creation, depending on the crossing direction. These results are very general and show that, regardless of the emitter speed, it is not possible to unambiguously determine the kinematics of an event from imaging and time-resolved measurements alone. This has implications not only for light, but also, for example, for sound and other wave phenomena. PMID:27152347

  4. Pair creation induced by transitions between electronic and positronic bound states

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Lv, Q. Z.; Li, Y. T.; Grobe, R.; Su, Q.

    2015-05-01

    We study the creation process of electron-positron pairs from the quantum electrodynamical vacuum under very strong electric fields by solving the quantum field theoretical Dirac equation on a space-time grid. We investigate the role of bound-bound state mixing in such a process, which can be studied if the external force can be modeled by a combination of a potential barrier and a potential well. By increasing the magnitude of the two potentials, discrete states that originate from the positive and negative energy continua can become quasidegenerate in the mass gap region (between -mc 2 and mc 2). We show that this bound-bound state mixing is quite different from the usual bound-continuum state mixing where the particles are created until the Pauli exclusion principle inhibits this process. In the case of bound-bound mixing the particle number exhibits a characteristic oscillatory behavior that in principle can last forever. These findings can be modeled by an effective two-state model.

  5. Natural versus artificial creation of base pairs in DNA: origin of nucleobases from the perspectives of unnatural base pair studies.

    PubMed

    Hirao, Ichiro; Kimoto, Michiko; Yamashige, Rie

    2012-12-18

    Since life began on Earth, the four types of bases (A, G, C, and T(U)) that form two sets of base pairs have remained unchanged as the components of nucleic acids that replicate and transfer genetic information. Throughout evolution, except for the U to T modification, the four base structures have not changed. This constancy within the genetic code raises the question of how these complicated nucleotides were generated from the molecules in a primordial soup on the early Earth. At some prebiotic stage, the complementarity of base pairs might have accelerated the generation and accumulation of nucleotides or oligonucleotides. We have no clues whether one pair of nucleobases initially appeared on the early Earth during this process or a set of two base pairs appeared simultaneously. Recently, researchers have developed new artificial pairs of nucleobases (unnatural base pairs) that function alongside the natural base pairs. Some unnatural base pairs in duplex DNA can be efficiently and faithfully amplified in a polymerase chain reaction (PCR) using thermostable DNA polymerases. The addition of unnatural base pair systems could expand the genetic alphabet of DNA, thus providing a new mechanism for the generation novel biopolymers by the site-specific incorporation of functional components into nucleic acids and proteins. Furthermore, the process of unnatural base pair development might provide clues to the origin of the natural base pairs in a primordial soup on the early Earth. In this Account, we describe the development of three representative types of unnatural base pairs that function as a third pair of nucleobases in PCR and reconsider the origin of the natural nucleic acids. As researchers developing unnatural base pairs, they use repeated "proof of concept" experiments. As researchers design new base pairs, they improve the structures that function in PCR and eliminate those that do not. We expect that this process is similar to the one functioning in the

  6. Effects of adiabatic, relativistic, and quantum electrodynamics interactions on the pair potential and thermophysical properties of helium.

    PubMed

    Cencek, Wojciech; Przybytek, Michał; Komasa, Jacek; Mehl, James B; Jeziorski, Bogumił; Szalewicz, Krzysztof

    2012-06-14

    The adiabatic, relativistic, and quantum electrodynamics (QED) contributions to the pair potential of helium were computed, fitted separately, and applied, together with the nonrelativistic Born-Oppenheimer (BO) potential, in calculations of thermophysical properties of helium and of the properties of the helium dimer. An analysis of the convergence patterns of the calculations with increasing basis set sizes allowed us to estimate the uncertainties of the total interaction energy to be below 50 ppm for interatomic separations R smaller than 4 bohrs and for the distance R = 5.6 bohrs. For other separations, the relative uncertainties are up to an order of magnitude larger (and obviously still larger near R = 4.8 bohrs where the potential crosses zero) and are dominated by the uncertainties of the nonrelativistic BO component. These estimates also include the contributions from the neglected relativistic and QED terms proportional to the fourth and higher powers of the fine-structure constant α. To obtain such high accuracy, it was necessary to employ explicitly correlated Gaussian expansions containing up to 2400 terms for smaller R (all R in the case of a QED component) and optimized orbital bases up to the cardinal number X = 7 for larger R. Near-exact asymptotic constants were used to describe the large-R behavior of all components. The fitted potential, exhibiting the minimum of -10.996 ± 0.004 K at R = 5.608 0 ± 0.000 1 bohr, was used to determine properties of the very weakly bound (4)He(2) dimer and thermophysical properties of gaseous helium. It is shown that the Casimir-Polder retardation effect, increasing the dimer size by about 2 Å relative to the nonrelativistic BO value, is almost completely accounted for by the inclusion of the Breit-interaction and the Araki-Sucher contributions to the potential, of the order α(2) and α(3), respectively. The remaining retardation effect, of the order of α(4) and higher, is practically negligible for the bound

  7. Simultaneous Creation of Electron-Positron Pairs and Photons in Robertson-Walker Universes with Statically Bounded Expansion

    NASA Astrophysics Data System (ADS)

    Lotze, K.-H.

    We present, based upon quantum electrodynamics in Robertson-Walker flat universes, a thorough analysis of the creation of mutually interacting electron-positron pairs and photons from vacuum. Therefore we discuss at least qualitatively all processes contributing to the number densities of created particles up to the second order in the coupling constant. For two particular expansion laws with Minkowskian in respectively in and out regions, we obtain exact solutions to the Dirac equation and investigate in detail the process of simultaneous creation of electron-positron pairs and photons and the related attenuation effect for fermionic particles. This is done for electrons and positrons which have nonrelativistic momenta at Compton time in rapidly expanding universes. The results are compared with the zeroth-order creation of electron-positron pairs. Despite being smaller by a factor of roughly e02 /4π ≈ 1 /137, the interacting-particle creation is important mainly as a source of photons even in conformally flat universes.

  8. Enhancement of electron-positron pair creation due to transient excitation of field-induced bound states

    NASA Astrophysics Data System (ADS)

    Jiang, M.; Lv, Q. Z.; Sheng, Z. M.; Grobe, R.; Su, Q.

    2013-04-01

    We study the creation of electron-positron pairs induced by two spatially separated electric fields that vary periodically in time. The results are based on large-scale computer simulations of the time-dependent Dirac equation in reduced spatial dimensions. When the separation of the fields is very large, the pair creation is caused by multiphoton transitions and mainly determined by the frequency of the fields. However, for small spatial separations a coherence effect can be observed that can enhance or reduce the particle yield compared to the case of two infinitely separated fields. If the travel time for a created electron or positron between both field locations becomes comparable to the period of the oscillating fields, we observe peaks in the energy spectrum which can be explained in terms of field-induced transient bound states.

  9. Ultra-intense Pair Creation using the Texas Petawatt Laser and Applications

    NASA Astrophysics Data System (ADS)

    Liang, Edison; Henderson, Alexander; Clarke, Taylor; Lo, Willie; Chaguine, Petr; Dyer, Gilliss; Riley, Nathan; Serratto, Kristina; Donovan, Michael; Ditmire, Todd

    2014-10-01

    Pair plasmas and intense gamma-ray sources are ubiquitous in the high-energy universe, from pulser winds to gamma-ray bursts (GRB). Their study can be greatly enhanced if such sources can be recreated in the laboratory under controlled conditions. In 2012 and 2013, a joint Rice-University of Texas team performed over 130 laser shots on thick gold and platinum targets using the 100 Joule Texas Petawatt Laser in Austin. The laser intensity of many shots exceeded 1021 W.cm-2 with pulses as short as 130 fs. These experiments probe a new extreme regime of ultra-intense laser - high-Z solid target interactions never achieved before. In addition to creating copious pairs with the highest density (>1015/cc) and emergent e +/e- ratio exceeding 20% in many shots, these experiments also created the highest density multi-MeV gamma-rays, comparable in absolute numbers to those found inside a gamma-ray burst (GRB). Potential applications of such intense pair and gamma-ray sources to laboratory astrophysics and innovative technologies will be discussed. Work supported by DOE HEDLP program.

  10. Chiral symmetry breaking and pair-creation mediated Walker breakdown in magnetic nanotubes

    NASA Astrophysics Data System (ADS)

    Yan, Ming; Andreas, Christian; Kákay, Attila; García-Sánchez, Felipe; Hertel, Riccardo

    2012-06-01

    Field-driven domain wall (DW) propagation in ferromagnetic nanotubes displays unusual effects, as revealed by a micromagnetic study. The left-right symmetry of the DW dynamics is broken, yielding markedly different DW mobilities for opposite propagation directions. This asymmetry arises from the tubular geometry and its impact on the DW structure. Also, the Walker breakdown field and velocity are found to be asymmetric for opposite directions. In certain cases, the breakdown can even be suppressed in one or both directions. Topological constraint requires a vortex-antivortex pair mediated breakdown, contrary to the single (anti)vortex in flat strips. This results in a higher breakdown velocity.

  11. Can nuclear physics explain the anomaly observed in the internal pair creation in Beryllium-8 nucleus?

    NASA Astrophysics Data System (ADS)

    Zhang, Xilin; Miller, Gerald A.

    2017-01-01

    Recently, the experimentalists in [Phys.Rev.Lett.116.042501(2016)] claimed seeing unexpected enhancement of the internal electron-positron pair (e+-e-) production in the large e+-e- relative angle region in the EM transition from the Beryllium-8 nucleus's second lowest 1+ state to its ground state. According to the experimentalists, the signal can be explained by a new neutral boson weighted around 17 MeV. This has stipulated significant interests in the particle physics community [e.g. Phys. Rev. Lett. 117, 071803 (2016)]. In this talk, I will present our latest study of the underlying nuclear physics, and emphasize several pieces of physics that haven't been well studied theoretically and not been included in the current experimental analysis, including the interferences between the dominant E1 and M1 transitions, two extra angular dependences, possible impact of E2 transition and its interferences with E1 and M1, and nuclear form factor. I will also point out that the previously measured on-shell photon production constrains the ratio between E1 and M1 contributions in the pair production, which however haven't been checked in the current experimental analysis. In the end, I will discuss the possibility of nuclear physics being the origin of the observed anomaly. The work is supported by the U.S. Department of Energy under Grant DE-FG02-97ER-41014.

  12. English semantic word-pair norms and a searchable Web portal for experimental stimulus creation.

    PubMed

    Buchanan, Erin M; Holmes, Jessica L; Teasley, Marilee L; Hutchison, Keith A

    2013-09-01

    As researchers explore the complexity of memory and language hierarchies, the need to expand normed stimulus databases is growing. Therefore, we present 1,808 words, paired with their features and concept-concept information, that were collected using previously established norming methods (McRae, Cree, Seidenberg, & McNorgan Behavior Research Methods 37:547-559, 2005). This database supplements existing stimuli and complements the Semantic Priming Project (Hutchison, Balota, Cortese, Neely, Niemeyer, Bengson, & Cohen-Shikora 2010). The data set includes many types of words (including nouns, verbs, adjectives, etc.), expanding on previous collections of nouns and verbs (Vinson & Vigliocco Journal of Neurolinguistics 15:317-351, 2008). We describe the relation between our and other semantic norms, as well as giving a short review of word-pair norms. The stimuli are provided in conjunction with a searchable Web portal that allows researchers to create a set of experimental stimuli without prior programming knowledge. When researchers use this new database in tandem with previous norming efforts, precise stimuli sets can be created for future research endeavors.

  13. Simulations On Pair Creation In Collision Of γ-Beams Produced With High Intensity Lasers

    NASA Astrophysics Data System (ADS)

    Jansen, Oliver; Ribeyre, Xavier; D'Humieres, Emmanuel; Lobet, Mathieu; Jequier, Sophie; Tikhonchuk, Vladimir

    2016-10-01

    Direct production of electron-positron pairs in two photon collisions, the Breit-Wheeler process, is one of the most basic processes in the universe. However, this process has never been directly observed in the laboratory due to the lack of high intensity γ sources. For a feasibility study and for the optimisation of experimental set-ups we developed a high-performance tree-code. Different possible set-ups with MeV photon sources were discussed and compared using collision detection for huge number of particles in a quantum-electrodynamic regime. The authors acknowledge the financial support from the French National Research Agency (ANR) in the framework of ''The Investments for the Future'' programme IdEx Bordeaux - LAPHIA (ANR-10IDEX-03-02)-Project TULIMA.

  14. Current flow and pair creation at low altitude in rotation-powered pulsars' force-free magnetospheres: space charge limited flow

    NASA Astrophysics Data System (ADS)

    Timokhin, A. N.; Arons, J.

    2013-02-01

    We report the results of an investigation of particle acceleration and electron-positron plasma generation at low altitude in the polar magnetic flux tubes of rotation-powered pulsars, when the stellar surface is free to emit whatever charges and currents are demanded by the force-free magnetosphere. We apply a new 1D hybrid plasma simulation code to the dynamical problem, using Particle-in-Cell methods for the dynamics of the charged particles, including a determination of the collective electrostatic fluctuations in the plasma, combined with a Monte Carlo treatment of the high-energy gamma-rays that mediate the formation of the electron-positron pairs. We assume the electric current flowing through the pair creation zone is fixed by the much higher inductance magnetosphere, and adopt the results of force-free magnetosphere models to provide the currents which must be carried by the accelerator. The models are spatially one dimensional, and designed to explore the physics, although of practical relevance to young, high-voltage pulsars. We observe novel behaviour (a) When the current density j is less than the Goldreich-Julian value (0 < j/jGJ < 1), space charge limited acceleration of the current carrying beam is mild, with the full Goldreich-Julian charge density comprising the charge densities of the beam and a cloud of electrically trapped particles with the same sign of charge as the beam. The voltage drops are of the order of mc2/e, and pair creation is absent. (b) When the current density exceeds the Goldreich-Julian value (j/jGJ > 1), the system develops high voltage drops (TV or greater), causing emission of curvature gamma-rays and intense bursts of pair creation. The bursts exhibit limit cycle behaviour, with characteristic time-scales somewhat longer than the relativistic fly-by time over distances comparable to the polar cap diameter (microseconds). (c) In return current regions, where j/jGJ < 0, the system develops similar bursts of pair creation

  15. Adiabatic capture and debunching

    SciTech Connect

    Ng, K.Y.; /Fermilab

    2012-03-01

    In the study of beam preparation for the g-2 experiment, adiabatic debunching and adiabatic capture are revisited. The voltage programs for these adiabbatic processes are derived and their properties discussed. Comparison is made with some other form of adiabatic capture program. The muon g-2 experiment at Fermilab calls for intense proton bunches for the creation of muons. A booster batch of 84 bunches is injected into the Recycler Ring, where it is debunched and captured into 4 intense bunches with the 2.5-MHz rf. The experiment requires short bunches with total width less than 100 ns. The transport line from the Recycler to the muon-production target has a low momentum aperture of {approx} {+-}22 MeV. Thus each of the 4 intense proton bunches required to have an emittance less than {approx} 3.46 eVs. The incoming booster bunches have total emittance {approx} 8.4 eVs, or each one with an emittance {approx} 0.1 eVs. However, there is always emittance increase when the 84 booster bunches are debunched. There will be even larger emittance increase during adiabatic capture into the buckets of the 2.5-MHz rf. In addition, the incoming booster bunches may have emittances larger than 0.1 eVs. In this article, we will concentrate on the analysis of the adiabatic capture process with the intention of preserving the beam emittance as much as possible. At this moment, beam preparation experiment is being performed at the Main Injector. Since the Main Injector and the Recycler Ring have roughly the same lattice properties, we are referring to adiabatic capture in the Main Injector instead in our discussions.

  16. Current Flow and Pair Creation at Low Altitude in Rotation-Powered Pulsars' Force-Free Magnetospheres: Space Charge Limited Flow

    NASA Technical Reports Server (NTRS)

    Timokhin, A. N.; Arons, J.

    2013-01-01

    We report the results of an investigation of particle acceleration and electron-positron plasma generation at low altitude in the polar magnetic flux tubes of rotation-powered pulsars, when the stellar surface is free to emit whatever charges and currents are demanded by the force-free magnetosphere. We apply a new 1D hybrid plasma simulation code to the dynamical problem, using Particle-in-Cell methods for the dynamics of the charged particles, including a determination of the collective electrostatic fluctuations in the plasma, combined with a Monte Carlo treatment of the high-energy gamma-rays that mediate the formation of the electron-positron pairs.We assume the electric current flowing through the pair creation zone is fixed by the much higher inductance magnetosphere, and adopt the results of force-free magnetosphere models to provide the currents which must be carried by the accelerator. The models are spatially one dimensional, and designed to explore the physics, although of practical relevance to young, high-voltage pulsars. We observe novel behaviour (a) When the current density j is less than the Goldreich-Julian value (0 < j/j(sub GJ) < 1), space charge limited acceleration of the current carrying beam is mild, with the full Goldreich-Julian charge density comprising the charge densities of the beam and a cloud of electrically trapped particles with the same sign of charge as the beam. The voltage drops are of the order of mc(sup 2)/e, and pair creation is absent. (b) When the current density exceeds the Goldreich-Julian value (j/j(sub GJ) > 1), the system develops high voltage drops (TV or greater), causing emission of curvature gamma-rays and intense bursts of pair creation. The bursts exhibit limit cycle behaviour, with characteristic time-scales somewhat longer than the relativistic fly-by time over distances comparable to the polar cap diameter (microseconds). (c) In return current regions, where j/j(sub GJ) < 0, the system develops similar

  17. High e+/e– ratio dense pair creation with 1021W.cm–2 laser irradiating solid targets

    SciTech Connect

    Liang, E.; Clarke, T.; Henderson, A.; Fu, W.; Lo, W.; Taylor, D.; Chaguine, P.; Zhou, S.; Hua, Y.; Cen, X.; Wang, X.; Kao, J.; Hasson, H.; Dyer, G.; Serratto, K.; Riley, N.; Donovan, M.; Ditmire, T.

    2015-09-14

    In this study, we report results of new pair creation experiments using ~100 Joule pulses of the Texas Petawatt Laser to irradiate solid gold and platinum targets, with intensities up to ~1.9 × 1021 W.cm–2 and pulse durations as short as ~130 fs. Positron to electron (e+/e–) ratios >15% were observed for many thick disk and rod targets, with the highest e+/e– ratio reaching ~50% for a Pt rod. The inferred pair yield was ~ few ×1010 with emerging pair density reaching ~1015/cm3 so that the pair skin depth becomes < pair jet transverse size. These results represent major milestones towards the goal of creating a significant quantity of dense pair-dominated plasmas with e+/e– approaching 100% and pair skin depth << pair plasma size, which will have wide-ranging applications to astrophysics and fundamental physics.

  18. Creation of targeted genomic deletions using TALEN or CRISPR/Cas nuclease pairs in one-cell mouse embryos

    PubMed Central

    Brandl, Christina; Ortiz, Oskar; Röttig, Bernhard; Wefers, Benedikt; Wurst, Wolfgang; Kühn, Ralf

    2014-01-01

    The use of TALEN and CRISPR/CAS nucleases is becoming increasingly popular as a means to edit single target sites in one-cell mouse embryos. Nevertheless, an area that has received less attention concerns the engineering of structural genome variants and the necessary religation of two distant double-strand breaks. Herein, we applied pairs of TALEN or sgRNAs and Cas9 to create deletions in the Rab38 gene. We found that the deletion of 3.2 or 9.3 kb, but not of 30 kb, occurs at a frequency of 6–37%. This is sufficient for the direct production of mutants by embryo microinjection. Therefore, deletions up to ∼10 kb can be readily achieved for modeling human disease alleles. This work represents an important step towards the establishment of new protocols that support the ligation of remote DSB ends to achieve even larger rearrangements. PMID:25685662

  19. Creation of electron-positron pairs at excited Landau levels by neutrino in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Kuznetsov, A. V.; Rumyantsev, D. A.; Savin, V. N.

    2014-10-01

    The process of neutrino production of electron-positron pairs in a magnetic field of arbitrary strength, where electrons and positrons can be created in the states corresponding to excited Landau levels, is analyzed. The mean value of the neutrino energy loss due to the process ν → νe-e+ is calculated. The result can be applied for calculating the efficiency of the electron-positron plasma production by neutrinos in the conditions of the Kerr black hole accretion disk considered by experts as the most possible source of a short cosmological gamma burst. The presented research can also be useful for further development of the calculation technique for an analysis of quantum processes in external active medium, and in part in the conditions of moderately strong magnetic field, when taking account of the ground Landau level appears to be insufficient.

  20. Optimizing Adiabaticity in NMR

    NASA Astrophysics Data System (ADS)

    Vandermause, Jonathan; Ramanathan, Chandrasekhar

    We demonstrate the utility of Berry's superadiabatic formalism for numerically finding control sequences that implement quasi-adiabatic unitary transformations. Using an iterative interaction picture, we design a shortcut to adiabaticity that reduces the time required to perform an adiabatic inversion pulse in liquid state NMR. We also show that it is possible to extend our scheme to two or more qubits to find adiabatic quantum transformations that are allowed by the control algebra, and demonstrate a two-qubit entangling operation in liquid state NMR. We examine the pulse lengths at which the fidelity of these adiabatic transitions break down and compare with the quantum speed limit.

  1. Wireless adiabatic power transfer

    SciTech Connect

    Rangelov, A.A.; Suchowski, H.; Silberberg, Y.; Vitanov, N.V.

    2011-03-15

    Research Highlights: > Efficient and robust mid-range wireless energy transfer between two coils. > The adiabatic energy transfer is analogous to adiabatic passage in quantum optics. > Wireless energy transfer is insensitive to any resonant constraints. > Wireless energy transfer is insensitive to noise in the neighborhood of the coils. - Abstract: We propose a technique for efficient mid-range wireless power transfer between two coils, by adapting the process of adiabatic passage for a coherently driven two-state quantum system to the realm of wireless energy transfer. The proposed technique is shown to be robust to noise, resonant constraints, and other interferences that exist in the neighborhood of the coils.

  2. Parallelizable adiabatic gate teleportation

    NASA Astrophysics Data System (ADS)

    Nakago, Kosuke; Hajdušek, Michal; Nakayama, Shojun; Murao, Mio

    2015-12-01

    To investigate how a temporally ordered gate sequence can be parallelized in adiabatic implementations of quantum computation, we modify adiabatic gate teleportation, a model of quantum computation proposed by Bacon and Flammia [Phys. Rev. Lett. 103, 120504 (2009), 10.1103/PhysRevLett.103.120504], to a form deterministically simulating parallelized gate teleportation, which is achievable only by postselection. We introduce a twisted Heisenberg-type interaction Hamiltonian, a Heisenberg-type spin interaction where the coordinates of the second qubit are twisted according to a unitary gate. We develop parallelizable adiabatic gate teleportation (PAGT) where a sequence of unitary gates is performed in a single step of the adiabatic process. In PAGT, numeric calculations suggest the necessary time for the adiabatic evolution implementing a sequence of L unitary gates increases at most as O (L5) . However, we show that it has the interesting property that it can map the temporal order of gates to the spatial order of interactions specified by the final Hamiltonian. Using this property, we present a controlled-PAGT scheme to manipulate the order of gates by a control qubit. In the controlled-PAGT scheme, two differently ordered sequential unitary gates F G and G F are coherently performed depending on the state of a control qubit by simultaneously applying the twisted Heisenberg-type interaction Hamiltonians implementing unitary gates F and G . We investigate why the twisted Heisenberg-type interaction Hamiltonian allows PAGT. We show that the twisted Heisenberg-type interaction Hamiltonian has an ability to perform a transposed unitary gate by just modifying the space ordering of the final Hamiltonian implementing a unitary gate in adiabatic gate teleportation. The dynamics generated by the time-reversed Hamiltonian represented by the transposed unitary gate enables deterministic simulation of a postselected event of parallelized gate teleportation in adiabatic

  3. Quantum adiabatic machine learning

    NASA Astrophysics Data System (ADS)

    Pudenz, Kristen L.; Lidar, Daniel A.

    2013-05-01

    We develop an approach to machine learning and anomaly detection via quantum adiabatic evolution. This approach consists of two quantum phases, with some amount of classical preprocessing to set up the quantum problems. In the training phase we identify an optimal set of weak classifiers, to form a single strong classifier. In the testing phase we adiabatically evolve one or more strong classifiers on a superposition of inputs in order to find certain anomalous elements in the classification space. Both the training and testing phases are executed via quantum adiabatic evolution. All quantum processing is strictly limited to two-qubit interactions so as to ensure physical feasibility. We apply and illustrate this approach in detail to the problem of software verification and validation, with a specific example of the learning phase applied to a problem of interest in flight control systems. Beyond this example, the algorithm can be used to attack a broad class of anomaly detection problems.

  4. Multiphoton adiabatic passage for atom optics applications

    SciTech Connect

    Demeter, Gabor; Djotyan, Gagik P.

    2009-04-15

    We study the force exerted on two-level atoms by short, counterpropagating laser pulses. When the counterpropagating pulses overlap each other partially, multiphoton adiabatic processes are possible in several configurations, which amplify the force exerted on the atoms. We investigate the practical usefulness of such multiphoton adiabatic transitions for the manipulation of the atoms' mechanical state. In particular, we compare the efficiency of a pair of constant frequency, oppositely detuned laser pulses and that of a pair of frequency-chirped pulses. We also consider the case of prolonged exposure to a sequence of laser pulses for a duration that is comparable to or much larger than the spontaneous lifetime of the atoms. We use numerical methods to calculate the reduction of the force and the heating of the atomic ensemble when spontaneous emission cannot be neglected during the interaction. In addition, we derive simple approximate formulas for the force and the heating, and compare them to the numerical results.

  5. Adiabatic gate teleportation.

    PubMed

    Bacon, Dave; Flammia, Steven T

    2009-09-18

    The difficulty in producing precisely timed and controlled quantum gates is a significant source of error in many physical implementations of quantum computers. Here we introduce a simple universal primitive, adiabatic gate teleportation, which is robust to timing errors and many control errors and maintains a constant energy gap throughout the computation above a degenerate ground state space. This construction allows for geometric robustness based upon the control of two independent qubit interactions. Further, our piecewise adiabatic evolution easily relates to the quantum circuit model, enabling the use of standard methods from fault-tolerance theory for establishing thresholds.

  6. Implementation of Pair Work and Group Work for Creation of Interaction Opportunities for Learners in Large Classes: The Viability of the Two Strategies

    ERIC Educational Resources Information Center

    Otienoh, Ruth O.

    2015-01-01

    This paper is based on an action research carried out in two Kenyan Primary schools in Nairobi. The purpose was to implement group work and pair work to improve teaching and learning in large classes by creating interaction opportunities for learners. This was a mixed method study of dominant/less dominant design where interviews and structured…

  7. Adiabatically implementing quantum gates

    SciTech Connect

    Sun, Jie; Lu, Songfeng Liu, Fang

    2014-06-14

    We show that, through the approach of quantum adiabatic evolution, all of the usual quantum gates can be implemented efficiently, yielding running time of order O(1). This may be considered as a useful alternative to the standard quantum computing approach, which involves quantum gates transforming quantum states during the computing process.

  8. Non-adiabatic effects in near-adiabatic mixed-field orientation and alignment

    NASA Astrophysics Data System (ADS)

    Maan, Anjali; Ahlawat, Dharamvir Singh; Prasad, Vinod

    2016-11-01

    We present a theoretical study of the impact of a pair of moderate electric fields tilted an angle with respect to one another on a molecule. As a prototype, we consider a molecule with large rotational constant (with corresponding small rotational period) and moderate dipole moment. Within rigid-rotor approximation, the time-dependent Schrodinger equation is solved using fourth-order Runge-Kutta method. We have analysed that lower rotational states are significantly influenced by variation in pulse durations, the tilt angle between the fields and also on the electric field strengths. We also suggest a control scheme of how the rotational dynamics, orientation and alignment of a molecule can be enhanced by a combination of near-adiabatic pulses in comparision to non-adiabatic or adiabatic pulses.

  9. Observations of persistent Leonid meteor trails: 4. Buoyant rise/vortex formation as mechanism for creation of parallel meteor train pairs

    NASA Astrophysics Data System (ADS)

    Zinn, John; Drummond, Jack

    2005-04-01

    In this paper we present numerical computations designed to demonstrate effects associated with the buoyant rise of persistent trails produced by large Leonid meteors in cases where the meteor velocity vector has a large horizontal component. We model the meteor trail as a hot cylindrical volume in an equilibrium atmosphere. The computed results show the hot cylinder first expanding radially and then rising because of buoyancy, while evolving into a pair of counterrotating linear vortices. These line vortex phenomena are offered as an explanation for the otherwise mysterious parallel pairs of trails that are often observed. We also show some high-resolution images of double meteor trails observed during the high Leonid meteor activity of 1998-2002. For the case of the Diamond Ring event we compare computed and measured luminosity profiles for the sodium 589 nm emission and for the red-near IR O2 atmospheric band (O2(b1Σg+) - O2(X3Σg-)) emission.

  10. Semiconductor adiabatic qubits

    DOEpatents

    Carroll, Malcolm S.; Witzel, Wayne; Jacobson, Noah Tobias; Ganti, Anand; Landahl, Andrew J.; Lilly, Michael; Nguyen, Khoi Thi; Bishop, Nathaniel; Carr, Stephen M.; Bussmann, Ezra; Nielsen, Erik; Levy, James Ewers; Blume-Kohout, Robin J.; Rahman, Rajib

    2016-12-27

    A quantum computing device that includes a plurality of semiconductor adiabatic qubits is described herein. The qubits are programmed with local biases and coupling terms between qubits that represent a problem of interest. The qubits are initialized by way of a tuneable parameter, a local tunnel coupling within each qubit, such that the qubits remain in a ground energy state, and that initial state is represented by the qubits being in a superposition of |0> and |1> states. The parameter is altered over time adiabatically or such that relaxation mechanisms maintain a large fraction of ground state occupation through decreasing the tunnel coupling barrier within each qubit with the appropriate schedule. The final state when tunnel coupling is effectively zero represents the solution state to the problem represented in the |0> and |1> basis, which can be accurately read at each qubit location.

  11. Geometry of the Adiabatic Theorem

    ERIC Educational Resources Information Center

    Lobo, Augusto Cesar; Ribeiro, Rafael Antunes; Ribeiro, Clyffe de Assis; Dieguez, Pedro Ruas

    2012-01-01

    We present a simple and pedagogical derivation of the quantum adiabatic theorem for two-level systems (a single qubit) based on geometrical structures of quantum mechanics developed by Anandan and Aharonov, among others. We have chosen to use only the minimum geometric structure needed for the understanding of the adiabatic theorem for this case.…

  12. Explaining the accelerated expansion of the Universe by particle creation

    NASA Astrophysics Data System (ADS)

    Singh, Ibotombi N.; Devi, Bembem Y.

    2016-04-01

    A spatially flat FRW Universe in the context of particle creation has been discussed by assuming a variable deceleration parameter which is a function of scale factor. A dust model in which creation of particles giving a negative creation pressure has been studied. Treating the Universe as an open adiabatic system, it is supposed that matter creation takes place out of gravitational energy. In this model, the Universe shows an accelerating phase of its expansion. Total number of particles increases while number of particle density decreases. Some physical implications of this model are investigated.

  13. Scalar current of created pairs by Schwinger mechanism in de Sitter spacetime

    NASA Astrophysics Data System (ADS)

    Bavarsad, Ehsan; Stahl, Clément; Xue, She-Sheng

    2016-11-01

    We consider a charged scalar field in a D -dimensional de Sitter spacetime and investigate pair creation by a Schwinger mechanism in a constant electric field background. Using a semiclassical approximation the current of the created pairs has been estimated. We find that the semiclassical current of the created pairs in the strong electric field limit responds as ED/2. Going further but restricting to D =3 dimensional de Sitter spacetime, the quantum expectation value of the spacelike component of the induced current has been computed in the in-vacuum state by applying an adiabatic subtraction scheme. We find that, in the strong electric field limit, the current responds as E3/2. In the weak electric field limit the current has a linear response in E and an inverse dependence on the mass of the scalar field. In the case of a massless scalar field, the current varies with E-1 which leads to a phenomenon of infrared hyperconductivity. A new relation between infrared hyperconductivity, tachyons, and conformality is discussed, and a scheme to avoid an infrared hyperconductivity regime is proposed. In D dimension, we eventually presented some first estimates of the backreaction of the Schwinger pairs to the gravitational field, and we find a decrease of the Hubble constant due to the pair creation.

  14. The Floquet Adiabatic Theorem revisited

    NASA Astrophysics Data System (ADS)

    Weinberg, Phillip; Bukov, Marin; D'Alessio, Luca; Kolodrubetz, Michael; Davidson, Shainen; Polkovnikov, Anatoli

    2015-03-01

    The existance of the adiabatic theorem for Floquet systems has been the subject of an active debate with different articles reaching opposite conclusions over the years. In this talk we clarify the situation by deriving a systematic expansion in the time-derivatives of a slow parameter for the occupation probabilities of the Floque states. Our analysis shows that the in a certain limit the transition between Floquet eigenstates are suppressed and it is possible to define an adiabatic theorem for Floquet systems. Crucially we observe however that the conditions for adiabaticity in ordinary and Floquet systems are different and that this difference can become important when the amplitude of the periodic driving is large. We illustrate our results with specific examples of a periodically driven harmonic oscillator and cold atoms in optical lattices which are relevant in current experiments.

  15. Adiabatic losses in Stirling refrigerators

    SciTech Connect

    Bauwens, L.

    1996-06-01

    The Stirling cycle has been used very effectively in cryocoolers; but efficiencies relative to the Carnot limit are typically observed to peak for absolute temperature ratios of about two, which makes it less suitable for low-life refrigeration. The adiabatic loss appears to be responsible for poor performance at small temperature differences. In this paper, adiabatic losses are evaluated, for a temperature ratio of 2/3, taking into account the effect of phase angle between pistons, of volume ratio, of the distribution of the dead volume necessary to reduce the volume ratio, and of the distribution of displacement between expansion and compression spaces. The study is carried out numerically, using an adiabatic Stirling engine model in which cylinder flow is assumed to be stratified. Results show that the best location for the cylinder dead volume is on the compression side. Otherwise, all strategies used to trade off refrigeration for coefficient of performance are found to be roughly equivalent.

  16. Adiabatic evolution of plasma equilibrium

    PubMed Central

    Grad, H.; Hu, P. N.; Stevens, D. C.

    1975-01-01

    A new theory of plasma equilibrium is introduced in which adiabatic constraints are specified. This leads to a mathematically nonstandard structure, as compared to the usual equilibrium theory, in which prescription of pressure and current profiles leads to an elliptic partial differential equation. Topologically complex configurations require further generalization of the concept of adiabaticity to allow irreversible mixing of plasma and magnetic flux among islands. Matching conditions across a boundary layer at the separatrix are obtained from appropriate conservation laws. Applications are made to configurations with planned islands (as in Doublet) and accidental islands (as in Tokamaks). Two-dimensional, axially symmetric, helically symmetric, and closed line equilibria are included. PMID:16578729

  17. Pressure Oscillations in Adiabatic Compression

    ERIC Educational Resources Information Center

    Stout, Roland

    2011-01-01

    After finding Moloney and McGarvey's modified adiabatic compression apparatus, I decided to insert this experiment into my physical chemistry laboratory at the last minute, replacing a problematic experiment. With insufficient time to build the apparatus, we placed a bottle between two thick textbooks and compressed it with a third textbook forced…

  18. Transitionless driving on adiabatic search algorithm

    SciTech Connect

    Oh, Sangchul; Kais, Sabre

    2014-12-14

    We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics.

  19. Transitionless driving on adiabatic search algorithm

    NASA Astrophysics Data System (ADS)

    Oh, Sangchul; Kais, Sabre

    2014-12-01

    We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics.

  20. Transitionless driving on adiabatic search algorithm.

    PubMed

    Oh, Sangchul; Kais, Sabre

    2014-12-14

    We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics.

  1. Digital waveguide adiabatic passage part 1: theory

    NASA Astrophysics Data System (ADS)

    Vaitkus, Jesse A.; Steel, M. J.; Greentree, Andrew D.

    2017-03-01

    Spatial adiabatic passage represents a new way to design integrated photonic devices. In conventional adiabatic passage designs require smoothly varying waveguide separations. Here we show modelling of adiabatic passage devices where the waveguide separation is varied digitally. Despite digitisation, our designs show robustness against variations in the input wavelength and refractive index contrast of the waveguides relative to the cladding. This approach to spatial adiabatic passage opens new design strategies and hence the potential for new photonics devices.

  2. Cloning Creationism in Turkey.

    ERIC Educational Resources Information Center

    Edis, Taner

    1999-01-01

    Defines how political balances and changes in Turkey effect creation-evolution relation. Describes the influences of Bilim Arastirma Vakfi (BAV) on these changes, which are directly targeted to public education, and discusses the content of creationism. Questions why Islamic creationism is a copy of that of the Institute for Creation Research…

  3. Invalidity of the quantitative adiabatic condition and general conditions for adiabatic approximations

    NASA Astrophysics Data System (ADS)

    Li, Dafa

    2016-05-01

    The adiabatic theorem was proposed about 90 years ago and has played an important role in quantum physics. The quantitative adiabatic condition constructed from eigenstates and eigenvalues of a Hamiltonian is a traditional tool to estimate adiabaticity and has proven to be the necessary and sufficient condition for adiabaticity. However, recently the condition has become a controversial subject. In this paper, we list some expressions to estimate the validity of the adiabatic approximation. We show that the quantitative adiabatic condition is invalid for the adiabatic approximation via the Euclidean distance between the adiabatic state and the evolution state. Furthermore, we deduce general necessary and sufficient conditions for the validity of the adiabatic approximation by different definitions.

  4. Adiabatic theory of solitons fed by dispersive waves

    NASA Astrophysics Data System (ADS)

    Pickartz, Sabrina; Bandelow, Uwe; Amiranashvili, Shalva

    2016-09-01

    We consider scattering of low-amplitude dispersive waves at an intense optical soliton which constitutes a nonlinear perturbation of the refractive index. Specifically, we consider a single-mode optical fiber and a group velocity matched pair: an optical soliton and a nearly perfectly reflected dispersive wave, a fiber-optical analog of the event horizon. By combining (i) an adiabatic approach that is used in soliton perturbation theory and (ii) scattering theory from quantum mechanics, we give a quantitative account of the evolution of all soliton parameters. In particular, we quantify the increase in the soliton peak power that may result in the spontaneous appearance of an extremely large, so-called champion soliton. The presented adiabatic theory agrees well with the numerical solutions of the pulse propagation equation. Moreover, we predict the full frequency band of the scattered dispersive waves and explain an emerging caustic structure in the space-time domain.

  5. Theory of Adiabatic Fountain Resonance

    NASA Astrophysics Data System (ADS)

    Williams, Gary A.

    2017-01-01

    The theory of "Adiabatic Fountain Resonance" with superfluid ^4{He} is clarified. In this geometry a film region between two silicon wafers bonded at their outer edge opens up to a central region with a free surface. We find that the resonance in this system is not a Helmholtz resonance as claimed by Gasparini et al., but in fact is a fourth sound resonance. We postulate that it occurs at relatively low frequency because the thin silicon wafers flex appreciably from the pressure oscillations of the sound wave.

  6. Adiabatic Wankel type rotary engine

    NASA Technical Reports Server (NTRS)

    Kamo, R.; Badgley, P.; Doup, D.

    1988-01-01

    This SBIR Phase program accomplished the objective of advancing the technology of the Wankel type rotary engine for aircraft applications through the use of adiabatic engine technology. Based on the results of this program, technology is in place to provide a rotor and side and intermediate housings with thermal barrier coatings. A detailed cycle analysis of the NASA 1007R Direct Injection Stratified Charge (DISC) rotary engine was performed which concluded that applying thermal barrier coatings to the rotor should be successful and that it was unlikely that the rotor housing could be successfully run with thermal barrier coatings as the thermal stresses were extensive.

  7. Ultrafast adiabatic second harmonic generation

    NASA Astrophysics Data System (ADS)

    Dahan, Asaf; Levanon, Assaf; Katz, Mordechai; Suchowski, Haim

    2017-03-01

    We introduce a generalization of the adiabatic frequency conversion method for an efficient conversion of ultrashort pulses in the full nonlinear regime. Our analysis takes into account dispersion as well as two-photon processes and Kerr effect, allowing complete analysis of any three waves with arbitrary phase mismatched design and any nonlinear optical process. We use this analysis to design an efficient and robust second harmonic generation, the most widely used nonlinear process for both fundamental and applied research. We experimentally show that such design not only allows for very efficient conversion of various of ultrashort pulses, but is also very robust to variations in the parameters of both the nonlinear crystal and the incoming light. These include variation of more than 100 °C in the crystal temperature, a wide bandwidth of up to 75 nm and a chirp variation of 300 fs to 3.5 ps of the incoming pulse. Also, we show the dependency of the adiabatic second harmonic generation design on the pump intensity and the crystal length. Our study shows that two photon absorption plays a critical role in such high influence nonlinear dynamics, and that it must be considered in order to achieve agreement with experimental results.

  8. Ultrafast adiabatic second harmonic generation.

    PubMed

    Dahan, Asaf; Levanon, Assaf; Katz, Mordechai; Suchowski, Haim

    2017-03-01

    We introduce a generalization of the adiabatic frequency conversion method for an efficient conversion of ultrashort pulses in the full nonlinear regime. Our analysis takes into account dispersion as well as two-photon processes and Kerr effect, allowing complete analysis of any three waves with arbitrary phase mismatched design and any nonlinear optical process. We use this analysis to design an efficient and robust second harmonic generation, the most widely used nonlinear process for both fundamental and applied research. We experimentally show that such design not only allows for very efficient conversion of various of ultrashort pulses, but is also very robust to variations in the parameters of both the nonlinear crystal and the incoming light. These include variation of more than 100 °C in the crystal temperature, a wide bandwidth of up to 75 nm and a chirp variation of 300 fs to 3.5 ps of the incoming pulse. Also, we show the dependency of the adiabatic second harmonic generation design on the pump intensity and the crystal length. Our study shows that two photon absorption plays a critical role in such high influence nonlinear dynamics, and that it must be considered in order to achieve agreement with experimental results.

  9. From Classical Nonlinear Integrable Systems to Quantum Shortcuts to Adiabaticity

    NASA Astrophysics Data System (ADS)

    Okuyama, Manaka; Takahashi, Kazutaka

    2016-08-01

    Using shortcuts to adiabaticity, we solve the time-dependent Schrödinger equation that is reduced to a classical nonlinear integrable equation. For a given time-dependent Hamiltonian, the counterdiabatic term is introduced to prevent nonadiabatic transitions. Using the fact that the equation for the dynamical invariant is equivalent to the Lax equation in nonlinear integrable systems, we obtain the counterdiabatic term exactly. The counterdiabatic term is available when the corresponding Lax pair exists and the solvable systems are classified in a unified and systematic way. Multisoliton potentials obtained from the Korteweg-de Vries equation and isotropic X Y spin chains from the Toda equations are studied in detail.

  10. Thermodynamics of cosmological matter creation

    PubMed Central

    Prigogine, I.; Geheniau, J.; Gunzig, E.; Nardone, P.

    1988-01-01

    A type of cosmological history that includes large-scale entropy production is proposed. These cosmologies are based on reinterpretation of the matter-energy stress tensor in Einstein's equations. This modifies the usual adiabatic energy conservation laws, thereby including irreversible matter creation. This creation corresponds to an irreversible energy flow from the gravitational field to the created matter constituents. This point of view results from consideration of the thermodynamics of open systems in the framework of cosmology. It is shown that the second law of thermodynamics requires that space-time transforms into matter, while the inverse transformation is forbidden. It appears that the usual initial singularity associated with the big bang is structurally unstable with respect to irreversible matter creation. The corresponding cosmological history therefore starts from an instability of the vacuum rather than from a singularity. This is exemplified in the framework of a simple phenomenological model that leads to a three-stage cosmology: the first drives the cosmological system from the initial instability to a de Sitter regime, and the last connects with the usual matter-radiation Robertson-Walker universe. Matter as well as entropy creation occurs during the first two stages, while the third involves the traditional cosmological evolution. A remarkable fact is that the de Sitter stage appears to be an attractor independent of the initial fluctuation. This is also the case for all the physical predictions involving the present Robertson-Walker universe. Most results obtained previously, in the framework of quantum field theory, can now be obtained on a macroscopic basis. It is shown that this description leads quite naturally to the introduction of primeval black holes as the intermediate stage between the Minkowski vacuum and the present matter-radiation universe. The instability at the origin of the universe is the result of fluctuations of the

  11. Thermodynamics of cosmological matter creation.

    PubMed

    Prigogine, I; Geheniau, J; Gunzig, E; Nardone, P

    1988-10-01

    A type of cosmological history that includes large-scale entropy production is proposed. These cosmologies are based on reinterpretation of the matter-energy stress tensor in Einstein's equations. This modifies the usual adiabatic energy conservation laws, thereby including irreversible matter creation. This creation corresponds to an irreversible energy flow from the gravitational field to the created matter constituents. This point of view results from consideration of the thermodynamics of open systems in the framework of cosmology. It is shown that the second law of thermodynamics requires that space-time transforms into matter, while the inverse transformation is forbidden. It appears that the usual initial singularity associated with the big bang is structurally unstable with respect to irreversible matter creation. The corresponding cosmological history therefore starts from an instability of the vacuum rather than from a singularity. This is exemplified in the framework of a simple phenomenological model that leads to a three-stage cosmology: the first drives the cosmological system from the initial instability to a de Sitter regime, and the last connects with the usual matter-radiation Robertson-Walker universe. Matter as well as entropy creation occurs during the first two stages, while the third involves the traditional cosmological evolution. A remarkable fact is that the de Sitter stage appears to be an attractor independent of the initial fluctuation. This is also the case for all the physical predictions involving the present Robertson-Walker universe. Most results obtained previously, in the framework of quantum field theory, can now be obtained on a macroscopic basis. It is shown that this description leads quite naturally to the introduction of primeval black holes as the intermediate stage between the Minkowski vacuum and the present matter-radiation universe. The instability at the origin of the universe is the result of fluctuations of the

  12. An interacting adiabatic quantum motor

    NASA Astrophysics Data System (ADS)

    Viola Kusminskiy, Silvia; Bruch, Anton; von Oppen, Felix

    We consider the effect of electron-electron interactions on the performance of an adiabatic quantum motor based on a Thouless pump operating in reverse. We model such a device by electrons in a 1d wire coupled to a slowly moving periodic potential associated with the classical mechanical degree of freedom of the motor. This periodic degree of freedom is set into motion by a bias voltage applied to the 1d electron channel. We investigate the Thouless motor with interacting leads modeled as Luttinger liquids. We show that interactions enhance the energy gap opened by the periodic potential and thus the robustness of the Thouless motor against variations in the chemical potential. We show that the motor degree of freedom can be described as a mobile impurity in a Luttinger liquid obeying Langevin dynamics with renormalized coefficients due to interactions, for which we give explicit expressions.

  13. Quantum and classical dynamics in adiabatic computation

    NASA Astrophysics Data System (ADS)

    Crowley, P. J. D.; Äńurić, T.; Vinci, W.; Warburton, P. A.; Green, A. G.

    2014-10-01

    Adiabatic transport provides a powerful way to manipulate quantum states. By preparing a system in a readily initialized state and then slowly changing its Hamiltonian, one may achieve quantum states that would otherwise be inaccessible. Moreover, a judicious choice of final Hamiltonian whose ground state encodes the solution to a problem allows adiabatic transport to be used for universal quantum computation. However, the dephasing effects of the environment limit the quantum correlations that an open system can support and degrade the power of such adiabatic computation. We quantify this effect by allowing the system to evolve over a restricted set of quantum states, providing a link between physically inspired classical optimization algorithms and quantum adiabatic optimization. This perspective allows us to develop benchmarks to bound the quantum correlations harnessed by an adiabatic computation. We apply these to the D-Wave Vesuvius machine with revealing—though inconclusive—results.

  14. Adiabatic heating in impulsive solar flares

    NASA Technical Reports Server (NTRS)

    Maetzler, C.; Bai, T.; Crannell, C. J.; Frost, K. J.

    1977-01-01

    The dynamic X-ray spectra of two simple, impulsive solar flares are examined together with H alpha, microwave and meter wave radio observations. X-ray spectra of both events were characteristic of thermal bremsstrahlung from single temperature plasmas. The symmetry between rise and fall was found to hold for the temperature and emission measure. The relationship between temperature and emission measure was that of an adiabatic compression followed by adiabatic expansion; the adiabatic index of 5/3 indicated that the electron distribution remained isotropic. Observations in H alpha provided further evidence for compressive energy transfer.

  15. Adiabatic fission barriers in superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Jachimowicz, P.; Kowal, M.; Skalski, J.

    2017-01-01

    Using the microscopic-macroscopic model based on the deformed Woods-Saxon single-particle potential and the Yukawa-plus-exponential macroscopic energy, we calculated static fission barriers Bf for 1305 heavy and superheavy nuclei 98 ≤Z ≤126 , including even-even, odd-even, even-odd and odd-odd systems. For odd and odd-odd nuclei, adiabatic potential-energy surfaces were calculated by a minimization over configurations with one blocked neutron or/and proton on a level from the 10th below to the 10th above the Fermi level. The parameters of the model that have been fixed previously by a fit to masses of even-even heavy nuclei were kept unchanged. A search for saddle points has been performed by the "imaginary water flow" method on a basic five-dimensional deformation grid, including triaxiality. Two auxiliary grids were used for checking the effects of the mass asymmetry and hexadecapole nonaxiality. The ground states (g.s.) were found by energy minimization over configurations and deformations. We find that the nonaxiality significantly changes first and second fission saddle in many nuclei. The effect of the mass asymmetry, known to lower the second, very deformed saddles in actinides, in the heaviest nuclei appears at the less deformed saddles in more than 100 nuclei. It happens for those saddles in which the triaxiality does not play any role, which suggests a decoupling between effects of the mass asymmetry and triaxiality. We studied also the influence of the pairing interaction strength on the staggering of Bf for odd- and even-particle numbers. Finally, we provide a comparison of our results with other theoretical fission barrier evaluations and with available experimental estimates.

  16. Experimental demonstration of composite adiabatic passage

    NASA Astrophysics Data System (ADS)

    Schraft, Daniel; Halfmann, Thomas; Genov, Genko T.; Vitanov, Nikolay V.

    2013-12-01

    We report an experimental demonstration of composite adiabatic passage (CAP) for robust and efficient manipulation of two-level systems. The technique represents a altered version of rapid adiabatic passage (RAP), driven by composite sequences of radiation pulses with appropriately chosen phases. We implement CAP with radio-frequency pulses to invert (i.e., to rephase) optically prepared spin coherences in a Pr3+:Y2SiO5 crystal. We perform systematic investigations of the efficiency of CAP and compare the results with conventional π pulses and RAP. The data clearly demonstrate the superior features of CAP with regard to robustness and efficiency, even under conditions of weakly fulfilled adiabaticity. The experimental demonstration of composite sequences to support adiabatic passage is of significant relevance whenever a high efficiency or robustness of coherent excitation processes need to be maintained, e.g., as required in quantum information technology.

  17. Adiabatic Quantum Search in Open Systems.

    PubMed

    Wild, Dominik S; Gopalakrishnan, Sarang; Knap, Michael; Yao, Norman Y; Lukin, Mikhail D

    2016-10-07

    Adiabatic quantum algorithms represent a promising approach to universal quantum computation. In isolated systems, a key limitation to such algorithms is the presence of avoided level crossings, where gaps become extremely small. In open quantum systems, the fundamental robustness of adiabatic algorithms remains unresolved. Here, we study the dynamics near an avoided level crossing associated with the adiabatic quantum search algorithm, when the system is coupled to a generic environment. At zero temperature, we find that the algorithm remains scalable provided the noise spectral density of the environment decays sufficiently fast at low frequencies. By contrast, higher order scattering processes render the algorithm inefficient at any finite temperature regardless of the spectral density, implying that no quantum speedup can be achieved. Extensions and implications for other adiabatic quantum algorithms will be discussed.

  18. Adiabatic Quantum Search in Open Systems

    NASA Astrophysics Data System (ADS)

    Wild, Dominik S.; Gopalakrishnan, Sarang; Knap, Michael; Yao, Norman Y.; Lukin, Mikhail D.

    2016-10-01

    Adiabatic quantum algorithms represent a promising approach to universal quantum computation. In isolated systems, a key limitation to such algorithms is the presence of avoided level crossings, where gaps become extremely small. In open quantum systems, the fundamental robustness of adiabatic algorithms remains unresolved. Here, we study the dynamics near an avoided level crossing associated with the adiabatic quantum search algorithm, when the system is coupled to a generic environment. At zero temperature, we find that the algorithm remains scalable provided the noise spectral density of the environment decays sufficiently fast at low frequencies. By contrast, higher order scattering processes render the algorithm inefficient at any finite temperature regardless of the spectral density, implying that no quantum speedup can be achieved. Extensions and implications for other adiabatic quantum algorithms will be discussed.

  19. General conditions for quantum adiabatic evolution

    SciTech Connect

    Comparat, Daniel

    2009-07-15

    Adiabaticity occurs when, during its evolution, a physical system remains in the instantaneous eigenstate of the Hamiltonian. Unfortunately, existing results, such as the quantum adiabatic theorem based on a slow down evolution [H({epsilon}t),{epsilon}{yields}0], are insufficient to describe an evolution driven by the Hamiltonian H(t) itself. Here we derive general criteria and exact bounds, for the state and its phase, ensuring an adiabatic evolution for any Hamiltonian H(t). As a corollary, we demonstrate that the commonly used condition of a slow Hamiltonian variation rate, compared to the spectral gap, is indeed sufficient to ensure adiabaticity but only when the Hamiltonian is real and nonoscillating (for instance, containing exponential or polynomial but no sinusoidal functions)

  20. Adiabatic limits on Riemannian Heisenberg manifolds

    SciTech Connect

    Yakovlev, A A

    2008-02-28

    An asymptotic formula is obtained for the distribution function of the spectrum of the Laplace operator, in the adiabatic limit for the foliation defined by the orbits of an invariant flow on a compact Riemannian Heisenberg manifold. Bibliography: 21 titles.

  1. Simulation of periodically focused, adiabatic thermal beams

    SciTech Connect

    Chen, C.; Akylas, T. R.; Barton, T. J.; Field, D. M.; Lang, K. M.; Mok, R. V.

    2012-12-21

    Self-consistent particle-in-cell simulations are performed to verify earlier theoretical predictions of adiabatic thermal beams in a periodic solenoidal magnetic focusing field [K.R. Samokhvalova, J. Zhou and C. Chen, Phys. Plasma 14, 103102 (2007); J. Zhou, K.R. Samokhvalova and C. Chen, Phys. Plasma 15, 023102 (2008)]. In particular, results are obtained for adiabatic thermal beams that do not rotate in the Larmor frame. For such beams, the theoretical predictions of the rms beam envelope, the conservations of the rms thermal emittances, the adiabatic equation of state, and the Debye length are verified in the simulations. Furthermore, the adiabatic thermal beam is found be stable in the parameter regime where the simulations are performed.

  2. Reconciling Evolution and Creation.

    ERIC Educational Resources Information Center

    Tax, Sol

    1983-01-01

    Proposes a way to reconcile evolution with creationism by hypothesizing that the universe was created when the scientific evidence shows, speculating that this was when God began the series of creations described in Genesis, and assuming that God gave humans intelligence to uncover the methods by which he ordained scientific evolution. (Author/MJL)

  3. Symmetry of the Adiabatic Condition in the Piston Problem

    ERIC Educational Resources Information Center

    Anacleto, Joaquim; Ferreira, J. M.

    2011-01-01

    This study addresses a controversial issue in the adiabatic piston problem, namely that of the piston being adiabatic when it is fixed but no longer so when it can move freely. It is shown that this apparent contradiction arises from the usual definition of adiabatic condition. The issue is addressed here by requiring the adiabatic condition to be…

  4. Coherent tunnelling adiabatic passage in optical fibres using superimposed long-period fiber gratings

    NASA Astrophysics Data System (ADS)

    Thyagarajan, K.; Gupta, Ruchi

    2016-08-01

    In this paper, we present the optical analogue of stimulated Raman adiabatic passage (STIRAP) technique for three level atomic system in optical fibre geometry. Considering linearly polarized modes of an optical fibre, it is shown that using a pair of superimposed long-period gratings with peak refractive index perturbation varying spatially along the propagation axis, light can be transferred adiabatically from one core mode to another core mode via an intermediate cladding mode which itself does not get appreciably excited; thus acting like a dark mode. We compare the transmission spectrum of superimposed long-period gratings involved in adiabatic transfer with the transmission spectrum of conventional long-period grating. The analogue output is further analysed for its tolerance to the changes in the ambient refractive index, temperature and other fabrication parameters.

  5. Assessment of total efficiency in adiabatic engines

    NASA Astrophysics Data System (ADS)

    Mitianiec, W.

    2016-09-01

    The paper presents influence of ceramic coating in all surfaces of the combustion chamber of SI four-stroke engine on working parameters mainly on heat balance and total efficiency. Three cases of engine were considered: standard without ceramic coating, fully adiabatic combustion chamber and engine with different thickness of ceramic coating. Consideration of adiabatic or semi-adiabatic engine was connected with mathematical modelling of heat transfer from the cylinder gas to the cooling medium. This model takes into account changeable convection coefficient based on the experimental formulas of Woschni, heat conductivity of multi-layer walls and also small effect of radiation in SI engines. The simulation model was elaborated with full heat transfer to the cooling medium and unsteady gas flow in the engine intake and exhaust systems. The computer program taking into account 0D model of engine processes in the cylinder and 1D model of gas flow was elaborated for determination of many basic engine thermodynamic parameters for Suzuki DR-Z400S 400 cc SI engine. The paper presents calculation results of influence of the ceramic coating thickness on indicated pressure, specific fuel consumption, cooling and exhaust heat losses. Next it were presented comparisons of effective power, heat losses in the cooling and exhaust systems, total efficiency in function of engine rotational speed and also comparison of temperature inside the cylinder for standard, semi-adiabatic and full adiabatic engine. On the basis of the achieved results it was found higher total efficiency of adiabatic engines at 2500 rpm from 27% for standard engine to 37% for full adiabatic engine.

  6. Pick a Pair. Pancake Pairs

    ERIC Educational Resources Information Center

    Miller, Pat

    2005-01-01

    Cold February weather and pancakes are a traditional pairing. Pancake Day began as a way to eat up the foods that were abstained from in Lent--traditionally meat, fat, eggs and dairy products. The best-known pancake event is The Pancake Day Race in Buckinghamshire, England, which has been run since 1445. This column describes pairs of books that…

  7. Diabatic Versus Adiabatic Calculation of Torsion-Vibration Interactions

    NASA Astrophysics Data System (ADS)

    Hougen, Jon T.

    2013-06-01

    The introductory part of this talk will deal briefly with two historical topics: (i) use of the words adiabatic, nonadiabatic, and diabatic in thermodynamics and quantum mechanics, and (ii) application of diabatic and adiabatic ideas to vibrational energy level calculations for a pair of diatomic-molecule potential energy curves exhibiting an avoided crossing. The main part of the talk will be devoted to recent work with Li-Hong Xu and Ron Lees on how ab initio projected frequency calculations for small-amplitude vibrations along the large-amplitude internal rotation path in methanol can best be used to help guide experimental assignments and fits in the IR vibrational spectrum. The three CH stretching vibrations for CH_{3}OH can conveniently be represented as coefficients multiplying three different types of basis vibrations, i.e., as coefficients of: (i) the local mode C-H_i bond displacements δr_{i} for hydrogens H_{1}, H_{2} and H_{3} of the methyl top, (ii) symmetrized linear combinations of the three δr_{i} of species A_{1} oplus E in the permutation-inversion group G_{6} = C_{3v} appropriate for methanol, or (iii) symmetrized linear combinations of the three δr_{i} of species 2A_{1} oplus A_{2} in the permutation-inversion group G_{6}. In this talk, we will focus on diabatic and adiabatic computations for the A_{1} oplus E basis vibrations of case (ii) above. We will briefly explain how Jahn-Teller-like and Renner-Teller-like torsion-vibration interaction terms occurring in the potential energy expression in the diabatic calculation become torsion-vibration Coriolis interaction terms occurring in the kinetic energy expression of the adiabatic calculations, and also show how, for algebraically solvable parameter choices, the same energy levels are obtained from either calculation. A final conclusion as to which approach is computationally superior for the numerical data given in a quantum chemistry output file has not yet been arrived at.

  8. Adiabatic optimization versus diffusion Monte Carlo methods

    NASA Astrophysics Data System (ADS)

    Jarret, Michael; Jordan, Stephen P.; Lackey, Brad

    2016-10-01

    Most experimental and theoretical studies of adiabatic optimization use stoquastic Hamiltonians, whose ground states are expressible using only real nonnegative amplitudes. This raises a question as to whether classical Monte Carlo methods can simulate stoquastic adiabatic algorithms with polynomial overhead. Here we analyze diffusion Monte Carlo algorithms. We argue that, based on differences between L1 and L2 normalized states, these algorithms suffer from certain obstructions preventing them from efficiently simulating stoquastic adiabatic evolution in generality. In practice however, we obtain good performance by introducing a method that we call Substochastic Monte Carlo. In fact, our simulations are good classical optimization algorithms in their own right, competitive with the best previously known heuristic solvers for MAX-k -SAT at k =2 ,3 ,4 .

  9. Nonadiabatic exchange dynamics during adiabatic frequency sweeps.

    PubMed

    Barbara, Thomas M

    2016-04-01

    A Bloch equation analysis that includes relaxation and exchange effects during an adiabatic frequency swept pulse is presented. For a large class of sweeps, relaxation can be incorporated using simple first order perturbation theory. For anisochronous exchange, new expressions are derived for exchange augmented rotating frame relaxation. For isochronous exchange between sites with distinct relaxation rate constants outside the extreme narrowing limit, simple criteria for adiabatic exchange are derived and demonstrate that frequency sweeps commonly in use may not be adiabatic with regard to exchange unless the exchange rates are much larger than the relaxation rates. Otherwise, accurate assessment of the sensitivity to exchange dynamics will require numerical integration of the rate equations. Examples of this situation are given for experimentally relevant parameters believed to hold for in-vivo tissue. These results are of significance in the study of exchange induced contrast in magnetic resonance imaging.

  10. Nonlinear Adiabatic Passage from Fermion Atoms to Boson Molecules

    SciTech Connect

    Pazy, E.; Tikhonenkov, I.; Band, Y.B.; Vardi, A.; Fleischhauer, M.

    2005-10-21

    We study the dynamics of an adiabatic sweep through a Feshbach resonance in a quantum gas of fermionic atoms. Analysis of the dynamical equations, supported by mean-field and many-body numerical results, shows that the dependence of the remaining atomic fraction {gamma} on the sweep rate {alpha} varies from exponential Landau-Zener behavior for a single pair of particles to a power-law dependence for large particle number N. The power law is linear, {gamma}{proportional_to}{alpha}, when the initial molecular fraction is smaller than the 1/N quantum fluctuations, and {gamma}{proportional_to}{alpha}{sup 1/3} when it is larger. Experimental data agree well with a linear dependence, but do not conclusively rule out the Landau-Zener model.

  11. Complexity of the Quantum Adiabatic Algorithm

    NASA Technical Reports Server (NTRS)

    Hen, Itay

    2013-01-01

    The Quantum Adiabatic Algorithm (QAA) has been proposed as a mechanism for efficiently solving optimization problems on a quantum computer. Since adiabatic computation is analog in nature and does not require the design and use of quantum gates, it can be thought of as a simpler and perhaps more profound method for performing quantum computations that might also be easier to implement experimentally. While these features have generated substantial research in QAA, to date there is still a lack of solid evidence that the algorithm can outperform classical optimization algorithms.

  12. On black hole spectroscopy via adiabatic invariance

    NASA Astrophysics Data System (ADS)

    Jiang, Qing-Quan; Han, Yan

    2012-12-01

    In this Letter, we obtain the black hole spectroscopy by combining the black hole property of adiabaticity and the oscillating velocity of the black hole horizon. This velocity is obtained in the tunneling framework. In particular, we declare, if requiring canonical invariance, the adiabatic invariant quantity should be of the covariant form Iadia = ∮pi dqi. Using it, the horizon area of a Schwarzschild black hole is quantized independently of the choice of coordinates, with an equally spaced spectroscopy always given by ΔA = 8 π lp2 in the Schwarzschild and Painlevé coordinates.

  13. On adiabatic invariant in generalized Galileon theories

    SciTech Connect

    Ema, Yohei; Jinno, Ryusuke; Nakayama, Kazunori; Mukaida, Kyohei E-mail: jinno@hep-th.phys.s.u-tokyo.ac.jp E-mail: kazunori@hep-th.phys.s.u-tokyo.ac.jp

    2015-10-01

    We consider background dynamics of generalized Galileon theories in the context of inflation, where gravity and inflaton are non-minimally coupled to each other. In the inflaton oscillation regime, the Hubble parameter and energy density oscillate violently in many cases, in contrast to the Einstein gravity with minimally coupled inflaton. However, we find that there is an adiabatic invariant in the inflaton oscillation regime in any generalized Galileon theory. This adiabatic invariant is useful in estimating the expansion law of the universe and also the particle production rate due to the oscillation of the Hubble parameter.

  14. Spontaneous emission in stimulated Raman adiabatic passage

    SciTech Connect

    Ivanov, P. A.; Vitanov, N. V.; Bergmann, K.

    2005-11-15

    This work explores the effect of spontaneous emission on the population transfer efficiency in stimulated Raman adiabatic passage (STIRAP). The approach uses adiabatic elimination of weakly coupled density matrix elements in the Liouville equation, from which a very accurate analytic approximation is derived. The loss of population transfer efficiency is found to decrease exponentially with the factor {omega}{sub 0}{sup 2}/{gamma}, where {gamma} is the spontaneous emission rate and {omega}{sub 0} is the peak Rabi frequency. The transfer efficiency increases with the pulse delay and reaches a steady value. For large pulse delay and large spontaneous emission rate STIRAP degenerates into optical pumping.

  15. Adiabatic Hyperspherical Analysis of Realistic Nuclear Potentials

    NASA Astrophysics Data System (ADS)

    Daily, K. M.; Kievsky, Alejandro; Greene, Chris H.

    2015-12-01

    Using the hyperspherical adiabatic method with the realistic nuclear potentials Argonne V14, Argonne V18, and Argonne V18 with the Urbana IX three-body potential, we calculate the adiabatic potentials and the triton bound state energies. We find that a discrete variable representation with the slow variable discretization method along the hyperradial degree of freedom results in energies consistent with the literature. However, using a Laguerre basis results in missing energy, even when extrapolated to an infinite number of basis functions and channels. We do not include the isospin T = 3/2 contribution in our analysis.

  16. Adiabatic cluster-state quantum computing

    SciTech Connect

    Bacon, Dave; Flammia, Steven T.

    2010-09-15

    Models of quantum computation (QC) are important because they change the physical requirements for achieving universal QC. For example, one-way QC requires the preparation of an entangled ''cluster'' state, followed by adaptive measurement on this state, a set of requirements which is different from the standard quantum-circuit model. Here we introduce a model based on one-way QC but without measurements (except for the final readout), instead using adiabatic deformation of a Hamiltonian whose initial ground state is the cluster state. Our results could help increase the feasibility of adiabatic schemes by using tools from one-way QC.

  17. Markovian quantum master equation beyond adiabatic regime.

    PubMed

    Yamaguchi, Makoto; Yuge, Tatsuro; Ogawa, Tetsuo

    2017-01-01

    By introducing a temporal change time scale τ_{A}(t) for the time-dependent system Hamiltonian, a general formulation of the Markovian quantum master equation is given to go well beyond the adiabatic regime. In appropriate situations, the framework is well justified even if τ_{A}(t) is faster than the decay time scale of the bath correlation function. An application to the dissipative Landau-Zener model demonstrates this general result. The findings are applicable to a wide range of fields, providing a basis for quantum control beyond the adiabatic regime.

  18. Markovian quantum master equation beyond adiabatic regime

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Makoto; Yuge, Tatsuro; Ogawa, Tetsuo

    2017-01-01

    By introducing a temporal change time scale τA(t ) for the time-dependent system Hamiltonian, a general formulation of the Markovian quantum master equation is given to go well beyond the adiabatic regime. In appropriate situations, the framework is well justified even if τA(t ) is faster than the decay time scale of the bath correlation function. An application to the dissipative Landau-Zener model demonstrates this general result. The findings are applicable to a wide range of fields, providing a basis for quantum control beyond the adiabatic regime.

  19. Landau-Zener transitions in frozen pairs of Rydberg atoms.

    PubMed

    Saquet, Nicolas; Cournol, Anne; Beugnon, Jérôme; Robert, Jacques; Pillet, Pierre; Vanhaecke, Nicolas

    2010-04-02

    We have induced adiabatic transitions in pairs of frozen Rydberg sodium atoms of a supersonic beam. The diatomic ns+ns-->np+(n-1)p transition takes place in a time-dependent electric field and originates from the adiabatic change of the internal state of the pair induced by the dipole-dipole interaction. This is experimentally achieved by sweeping an electric field across the energy degeneracy ns ns-np(n-1)p. Our results fully agree with a two-level Landau-Zener model in the diatom system.

  20. Landau-Zener Transitions in Frozen Pairs of Rydberg Atoms

    SciTech Connect

    Saquet, Nicolas; Cournol, Anne; Beugnon, Jerome; Robert, Jacques; Pillet, Pierre; Vanhaecke, Nicolas

    2010-04-02

    We have induced adiabatic transitions in pairs of frozen Rydberg sodium atoms of a supersonic beam. The diatomic ns+ns{yields}np+(n-1)p transition takes place in a time-dependent electric field and originates from the adiabatic change of the internal state of the pair induced by the dipole-dipole interaction. This is experimentally achieved by sweeping an electric field across the energy degeneracy ns ns-np(n-1)p. Our results fully agree with a two-level Landau-Zener model in the diatom system.

  1. Adiabatic Compression in a Fire Syringe.

    ERIC Educational Resources Information Center

    Hayn, Carl H.; Baird, Scott C.

    1985-01-01

    Suggests using better materials in fire syringes to obtain more effective results during demonstrations which show the elevation in temperature upon a very rapid (adiabatic) compression of air. Also describes an experiment (using ignition temperatures) which introduces students to the use of thermocouples for high temperature measurements. (DH)

  2. Apparatus to Measure Adiabatic and Isothermal Processes.

    ERIC Educational Resources Information Center

    Lamb, D. W.; White, G. M.

    1996-01-01

    Describes a simple manual apparatus designed to serve as an effective demonstration of the differences between isothermal and adiabatic processes for the general or elementary physics student. Enables students to verify Boyle's law for slow processes and identify the departure from this law for rapid processes and can also be used to give a clear…

  3. Adiabatic and Non-adiabatic quenches in a Spin-1 Bose Einstein Condensate

    NASA Astrophysics Data System (ADS)

    Boguslawski, Matthew; Hebbe Madhusudhana, Bharath; Anquez, Martin; Robbins, Bryce; Barrios, Maryrose; Hoang, Thai; Chapman, Michael

    2016-05-01

    A quantum phase transition (QPT) is observed in a wide range of phenomena. We have studied the dynamics of a spin-1 ferromagnetic Bose-Einstein condensate for both adiabatic and non-adiabatic quenches through a QPT. At the quantum critical point (QCP), finite size effects lead to a non-zero gap, which makes an adiabatic quench possible through the QPT. We experimentally demonstrate such a quench, which is forbidden at the mean field level. For faster quenches through the QCP, the vanishing energy gap causes the reaction timescale of the system to diverge, preventing the system from adiabatically following the ground state. We measure the temporal evolution of the spin populations for different quench speeds and determine the exponents characterizing the scaling of the onset of excitations, which are in good agreement with the predictions of Kibble-Zurek mechanism.

  4. Fixed-point adiabatic quantum search

    NASA Astrophysics Data System (ADS)

    Dalzell, Alexander M.; Yoder, Theodore J.; Chuang, Isaac L.

    2017-01-01

    Fixed-point quantum search algorithms succeed at finding one of M target items among N total items even when the run time of the algorithm is longer than necessary. While the famous Grover's algorithm can search quadratically faster than a classical computer, it lacks the fixed-point property—the fraction of target items must be known precisely to know when to terminate the algorithm. Recently, Yoder, Low, and Chuang [Phys. Rev. Lett. 113, 210501 (2014), 10.1103/PhysRevLett.113.210501] gave an optimal gate-model search algorithm with the fixed-point property. Previously, it had been discovered by Roland and Cerf [Phys. Rev. A 65, 042308 (2002), 10.1103/PhysRevA.65.042308] that an adiabatic quantum algorithm, operating by continuously varying a Hamiltonian, can reproduce the quadratic speedup of gate-model Grover search. We ask, can an adiabatic algorithm also reproduce the fixed-point property? We show that the answer depends on what interpolation schedule is used, so as in the gate model, there are both fixed-point and non-fixed-point versions of adiabatic search, only some of which attain the quadratic quantum speedup. Guided by geometric intuition on the Bloch sphere, we rigorously justify our claims with an explicit upper bound on the error in the adiabatic approximation. We also show that the fixed-point adiabatic search algorithm can be simulated in the gate model with neither loss of the quadratic Grover speedup nor of the fixed-point property. Finally, we discuss natural uses of fixed-point algorithms such as preparation of a relatively prime state and oblivious amplitude amplification.

  5. Adiabatic burst evaporation from bicontinuous nanoporous membranes.

    PubMed

    Ichilmann, Sachar; Rücker, Kerstin; Haase, Markus; Enke, Dirk; Steinhart, Martin; Xue, Longjian

    2015-05-28

    Evaporation of volatile liquids from nanoporous media with bicontinuous morphology and pore diameters of a few 10 nm is an ubiquitous process. For example, such drying processes occur during syntheses of nanoporous materials by sol-gel chemistry or by spinodal decomposition in the presence of solvents as well as during solution impregnation of nanoporous hosts with functional guests. It is commonly assumed that drying is endothermic and driven by non-equilibrium partial pressures of the evaporating species in the gas phase. We show that nearly half of the liquid evaporates in an adiabatic mode involving burst-like liquid-to-gas conversions. During single adiabatic burst evaporation events liquid volumes of up to 10(7) μm(3) are converted to gas. The adiabatic liquid-to-gas conversions occur if air invasion fronts get unstable because of the built-up of high capillary pressures. Adiabatic evaporation bursts propagate avalanche-like through the nanopore systems until the air invasion fronts have reached new stable configurations. Adiabatic cavitation bursts thus compete with Haines jumps involving air invasion front relaxation by local liquid flow without enhanced mass transport out of the nanoporous medium and prevail if the mean pore diameter is in the range of a few 10 nm. The results reported here may help optimize membrane preparation via solvent-based approaches, solution-loading of nanopore systems with guest materials as well as routine use of nanoporous membranes with bicontinuous morphology and may contribute to better understanding of adsorption/desorption processes in nanoporous media.

  6. Adiabatic circuits: converter for static CMOS signals

    NASA Astrophysics Data System (ADS)

    Fischer, J.; Amirante, E.; Bargagli-Stoffi, A.; Schmitt-Landsiedel, D.

    2003-05-01

    Ultra low power applications can take great advantages from adiabatic circuitry. In this technique a multiphase system is used which consists ideally of trapezoidal voltage signals. The input signals to be processed will often come from a function block realized in static CMOS. The static rectangular signals must be converted for the oscillating multiphase system of the adiabatic circuitry. This work shows how to convert the input signals to the proposed pulse form which is synchronized to the appropriate supply voltage. By means of adder structures designed for a 0.13µm technology in a 4-phase system there will be demonstrated, which additional circuits are necessary for the conversion. It must be taken into account whether the data arrive in parallel or serial form. Parallel data are all in one phase and therefore it is advantageous to use an adder structure with a proper input stage, e.g. a Carry Lookahead Adder (CLA). With a serial input stage it is possible to read and to process four signals during one cycle due to the adiabatic 4-phase system. Therefore input signals with a frequency four times higher than the adiabatic clock frequency can be used. This reduces the disadvantage of the slow clock period typical for adiabatic circuits. By means of an 8 bit Ripple Carry Adder (8 bit RCA) the serial reading will be introduced. If the word width is larger than 4 bits the word can be divided in 4 bit words which are processed in parallel. This is the most efficient way to minimize the number of input lines and pads. At the same time a high throughput is achieved.

  7. The dynamic instability of adiabatic blast waves

    NASA Technical Reports Server (NTRS)

    Ryu, Dongsu; Vishniac, Ethan T.

    1991-01-01

    Adiabatic blastwaves, which have a total energy injected from the center E varies as t(sup q) and propagate through a preshock medium with a density rho(sub E) varies as r(sup -omega) are described by a family of similarity solutions. Previous work has shown that adiabatic blastwaves with increasing or constant postshock entropy behind the shock front are susceptible to an oscillatory instability, caused by the difference between the nature of the forces on the two sides of the dense shell behind the shock front. This instability sets in if the dense postshock layer is sufficiently thin. The stability of adiabatic blastwaves with a decreasing postshock entropy is considered. Such blastwaves, if they are decelerating, always have a region behind the shock front which is subject to convection. Some accelerating blastwaves also have such region, depending on the values of q, omega, and gamma where gamma is the adiabatic index. However, since the shock interface stabilizes dynamically induced perturbations, blastwaves become convectively unstable only if the convective zone is localized around the origin or a contact discontinuity far from the shock front. On the other hand, the contact discontinuity of accelerating blastwaves is subject to a strong Rayleigh-Taylor instability. The frequency spectra of the nonradial, normal modes of adiabatic blastwaves have been calculated. The results have been applied to the shocks propagating through supernovae envelopes. It is shown that the metal/He and He/H interfaces are strongly unstable against the Rayleigh-Taylor instability. This instability will induce mixing in supernovae envelopes. In addition the implications of this work for the evolution of planetary nebulae is discussed.

  8. Evolution and dynamics of a matter creation model

    NASA Astrophysics Data System (ADS)

    Pan, S.; Haro, J. de; Paliathanasis, A.; Slagter, R. J.

    2016-08-01

    In a flat Friedmann-Lemaître-Robertson-Walker (FLRW) geometry, we consider the expansion of the universe powered by the gravitationally induced `adiabatic' matter creation. To demonstrate how matter creation works well with the expanding universe, we have considered a general creation rate and analysed this rate in the framework of dynamical analysis. The dynamical analysis hints the presence of a non-singular universe (without the big bang singularity) with two successive accelerated phases, one at the very early phase of the universe (i.e. inflation), and the other one describes the current accelerating universe, where this early, late accelerated phases are associated with an unstable fixed point (i.e. repeller) and a stable fixed point (attractor), respectively. We have described this phenomena by analytic solutions of the Hubble function and the scale factor of the FLRW universe. Using Jacobi last multiplier method, we have found a Lagrangian for this matter creation rate describing this scenario of the universe. To match with our early physics results, we introduce an equivalent dynamics driven by a single scalar field, discuss the associated observable parameters and compare them with the latest Planck data sets. Finally, introducing the teleparallel modified gravity, we have established an equivalent gravitational theory in the framework of matter creation.

  9. Creationism and Scientism.

    ERIC Educational Resources Information Center

    Howick, William H.

    The creationism evolution controversy has become a problem of major concern in many states, especially Arkansas and Louisiana, and is the basis for dispute in many courts. Creationists, sensing the need for a modern approach, have now become less concerned with the theological rationale for their argument and have turned to the scientific field as…

  10. Opposing Creationism: Scientists Organize.

    ERIC Educational Resources Information Center

    Saladin, Kenneth S.

    1982-01-01

    Describes the response of the scientific community to creationist activism. A symposium entitled "Science and Belief" was held at the annual meeting of the American Association for the Advancement of Science to debate creationism. A network was organized to facilitate communication and political efficiency among anticreationist citizen…

  11. Quantum-Classical Correspondence of Shortcuts to Adiabaticity

    NASA Astrophysics Data System (ADS)

    Okuyama, Manaka; Takahashi, Kazutaka

    2017-04-01

    We formulate the theory of shortcuts to adiabaticity in classical mechanics. For a reference Hamiltonian, the counterdiabatic term is constructed from the dispersionless Korteweg-de Vries (KdV) hierarchy. Then the adiabatic theorem holds exactly for an arbitrary choice of time-dependent parameters. We use the Hamilton-Jacobi theory to define the generalized action. The action is independent of the history of the parameters and is directly related to the adiabatic invariant. The dispersionless KdV hierarchy is obtained from the classical limit of the KdV hierarchy for the quantum shortcuts to adiabaticity. This correspondence suggests some relation between the quantum and classical adiabatic theorems.

  12. Adiabatic Quantum Simulation of Quantum Chemistry

    NASA Astrophysics Data System (ADS)

    Babbush, Ryan; Love, Peter J.; Aspuru-Guzik, Alán

    2014-10-01

    We show how to apply the quantum adiabatic algorithm directly to the quantum computation of molecular properties. We describe a procedure to map electronic structure Hamiltonians to 2-body qubit Hamiltonians with a small set of physically realizable couplings. By combining the Bravyi-Kitaev construction to map fermions to qubits with perturbative gadgets to reduce the Hamiltonian to 2-body, we obtain precision requirements on the coupling strengths and a number of ancilla qubits that scale polynomially in the problem size. Hence our mapping is efficient. The required set of controllable interactions includes only two types of interaction beyond the Ising interactions required to apply the quantum adiabatic algorithm to combinatorial optimization problems. Our mapping may also be of interest to chemists directly as it defines a dictionary from electronic structure to spin Hamiltonians with physical interactions.

  13. Ramsey numbers and adiabatic quantum computing.

    PubMed

    Gaitan, Frank; Clark, Lane

    2012-01-06

    The graph-theoretic Ramsey numbers are notoriously difficult to calculate. In fact, for the two-color Ramsey numbers R(m,n) with m, n≥3, only nine are currently known. We present a quantum algorithm for the computation of the Ramsey numbers R(m,n). We show how the computation of R(m,n) can be mapped to a combinatorial optimization problem whose solution can be found using adiabatic quantum evolution. We numerically simulate this adiabatic quantum algorithm and show that it correctly determines the Ramsey numbers R(3,3) and R(2,s) for 5≤s≤7. We then discuss the algorithm's experimental implementation, and close by showing that Ramsey number computation belongs to the quantum complexity class quantum Merlin Arthur.

  14. Comment on ``Adiabatic theory for the bipolaron''

    NASA Astrophysics Data System (ADS)

    Smondyrev, M. A.; Devreese, J. T.

    1996-05-01

    Comments are given on the application of the Bogoliubov-Tyablikov approach to the bipolaron problem in a recent paper by Lakhno [Phys. Rev. B 51, 3512 (1995)]. This author believes that his model (1) is the translation-invariant adiabatic theory of bipolarons and (2) gives asymptotically exact solutions in the adiabatic limit while the other approaches are considered as either phenomenological or variational in nature. Numerical results by Lakhno are in contradiction with all other papers published on the subject because his model leads to much lower energies. Thus, the author concludes that bipolarons ``are more stable than was considered before.'' We prove that both the analytical and the numerical results presented by Lakhno are wrong.

  15. Shortcuts to adiabaticity from linear response theory

    SciTech Connect

    Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian

    2015-10-23

    A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. Moreover, with the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. We finally propose a degenerate family of protocols, which facilitates shortcuts to adiabaticity for specific and very short driving times.

  16. Shortcuts to adiabaticity from linear response theory

    DOE PAGES

    Acconcia, Thiago V.; Bonança, Marcus V. S.; Deffner, Sebastian

    2015-10-23

    A shortcut to adiabaticity is a finite-time process that produces the same final state as would result from infinitely slow driving. We show that such shortcuts can be found for weak perturbations from linear response theory. Moreover, with the help of phenomenological response functions, a simple expression for the excess work is found—quantifying the nonequilibrium excitations. For two specific examples, i.e., the quantum parametric oscillator and the spin 1/2 in a time-dependent magnetic field, we show that finite-time zeros of the excess work indicate the existence of shortcuts. We finally propose a degenerate family of protocols, which facilitates shortcuts tomore » adiabaticity for specific and very short driving times.« less

  17. Adiabatic state preparation study of methylene

    SciTech Connect

    Veis, Libor Pittner, Jiří

    2014-06-07

    Quantum computers attract much attention as they promise to outperform their classical counterparts in solving certain type of problems. One of them with practical applications in quantum chemistry is simulation of complex quantum systems. An essential ingredient of efficient quantum simulation algorithms are initial guesses of the exact wave functions with high enough fidelity. As was proposed in Aspuru-Guzik et al. [Science 309, 1704 (2005)], the exact ground states can in principle be prepared by the adiabatic state preparation method. Here, we apply this approach to preparation of the lowest lying multireference singlet electronic state of methylene and numerically investigate preparation of this state at different molecular geometries. We then propose modifications that lead to speeding up the preparation process. Finally, we decompose the minimal adiabatic state preparation employing the direct mapping in terms of two-qubit interactions.

  18. Fast forward to the classical adiabatic invariant

    NASA Astrophysics Data System (ADS)

    Jarzynski, Christopher; Deffner, Sebastian; Patra, Ayoti; Subaşı, Yiǧit

    2017-03-01

    We show how the classical action, an adiabatic invariant, can be preserved under nonadiabatic conditions. Specifically, for a time-dependent Hamiltonian H =p2/2 m +U (q ,t ) in one degree of freedom, and for an arbitrary choice of action I0, we construct a so-called fast-forward potential energy function VFF(q ,t ) that, when added to H , guides all trajectories with initial action I0 to end with the same value of action. We use this result to construct a local dynamical invariant J (q ,p ,t ) whose value remains constant along these trajectories. We illustrate our results with numerical simulations. Finally, we sketch how our classical results may be used to design approximate quantum shortcuts to adiabaticity.

  19. Adiabatic invariance with first integrals of motion.

    PubMed

    Adib, Artur B

    2002-10-01

    The construction of a microthermodynamic formalism for isolated systems based on the concept of adiabatic invariance is an old but seldom appreciated effort in the literature, dating back at least to P. Hertz [Ann. Phys. (Leipzig) 33, 225 (1910)]. An apparently independent extension of such formalism for systems bearing additional first integrals of motion was recently proposed by Hans H. Rugh [Phys. Rev. E 64, 055101 (2001)], establishing the concept of adiabatic invariance even in such singular cases. After some remarks in connection with the formalism pioneered by Hertz, it will be suggested that such an extension can incidentally explain the success of a dynamical method for computing the entropy of classical interacting fluids, at least in some potential applications where the presence of additional first integrals cannot be ignored.

  20. Trapped Ion Quantum Computation by Adiabatic Passage

    SciTech Connect

    Feng Xuni; Wu Chunfeng; Lai, C. H.; Oh, C. H.

    2008-11-07

    We propose a new universal quantum computation scheme for trapped ions in thermal motion via the technique of adiabatic passage, which incorporates the advantages of both the adiabatic passage and the model of trapped ions in thermal motion. Our scheme is immune from the decoherence due to spontaneous emission from excited states as the system in our scheme evolves along a dark state. In our scheme the vibrational degrees of freedom are not required to be cooled to their ground states because they are only virtually excited. It is shown that the fidelity of the resultant gate operation is still high even when the magnitude of the effective Rabi frequency moderately deviates from the desired value.

  1. Adiabatic quantum simulation of quantum chemistry.

    PubMed

    Babbush, Ryan; Love, Peter J; Aspuru-Guzik, Alán

    2014-10-13

    We show how to apply the quantum adiabatic algorithm directly to the quantum computation of molecular properties. We describe a procedure to map electronic structure Hamiltonians to 2-body qubit Hamiltonians with a small set of physically realizable couplings. By combining the Bravyi-Kitaev construction to map fermions to qubits with perturbative gadgets to reduce the Hamiltonian to 2-body, we obtain precision requirements on the coupling strengths and a number of ancilla qubits that scale polynomially in the problem size. Hence our mapping is efficient. The required set of controllable interactions includes only two types of interaction beyond the Ising interactions required to apply the quantum adiabatic algorithm to combinatorial optimization problems. Our mapping may also be of interest to chemists directly as it defines a dictionary from electronic structure to spin Hamiltonians with physical interactions.

  2. Adiabatic quantum optimization for associative memory recall

    DOE PAGES

    Seddiqi, Hadayat; Humble, Travis S.

    2014-12-22

    Hopfield networks are a variant of associative memory that recall patterns stored in the couplings of an Ising model. Stored memories are conventionally accessed as fixed points in the network dynamics that correspond to energetic minima of the spin state. We show that memories stored in a Hopfield network may also be recalled by energy minimization using adiabatic quantum optimization (AQO). Numerical simulations of the underlying quantum dynamics allow us to quantify AQO recall accuracy with respect to the number of stored memories and noise in the input key. We investigate AQO performance with respect to how memories are storedmore » in the Ising model according to different learning rules. Our results demonstrate that AQO recall accuracy varies strongly with learning rule, a behavior that is attributed to differences in energy landscapes. Consequently, learning rules offer a family of methods for programming adiabatic quantum optimization that we expect to be useful for characterizing AQO performance.« less

  3. Adiabatic quantum optimization for associative memory recall

    SciTech Connect

    Seddiqi, Hadayat; Humble, Travis S.

    2014-12-22

    Hopfield networks are a variant of associative memory that recall patterns stored in the couplings of an Ising model. Stored memories are conventionally accessed as fixed points in the network dynamics that correspond to energetic minima of the spin state. We show that memories stored in a Hopfield network may also be recalled by energy minimization using adiabatic quantum optimization (AQO). Numerical simulations of the underlying quantum dynamics allow us to quantify AQO recall accuracy with respect to the number of stored memories and noise in the input key. We investigate AQO performance with respect to how memories are stored in the Ising model according to different learning rules. Our results demonstrate that AQO recall accuracy varies strongly with learning rule, a behavior that is attributed to differences in energy landscapes. Consequently, learning rules offer a family of methods for programming adiabatic quantum optimization that we expect to be useful for characterizing AQO performance.

  4. Adiabatic Quantum Simulation of Quantum Chemistry

    PubMed Central

    Babbush, Ryan; Love, Peter J.; Aspuru-Guzik, Alán

    2014-01-01

    We show how to apply the quantum adiabatic algorithm directly to the quantum computation of molecular properties. We describe a procedure to map electronic structure Hamiltonians to 2-body qubit Hamiltonians with a small set of physically realizable couplings. By combining the Bravyi-Kitaev construction to map fermions to qubits with perturbative gadgets to reduce the Hamiltonian to 2-body, we obtain precision requirements on the coupling strengths and a number of ancilla qubits that scale polynomially in the problem size. Hence our mapping is efficient. The required set of controllable interactions includes only two types of interaction beyond the Ising interactions required to apply the quantum adiabatic algorithm to combinatorial optimization problems. Our mapping may also be of interest to chemists directly as it defines a dictionary from electronic structure to spin Hamiltonians with physical interactions. PMID:25308187

  5. Many-body effects on adiabatic passage through Feshbach resonances

    SciTech Connect

    Tikhonenkov, I.; Pazy, E.; Band, Y. B.; Vardi, A.; Fleischhauer, M.

    2006-04-15

    We theoretically study the dynamics of an adiabatic sweep through a Feshbach resonance, thereby converting a degenerate quantum gas of fermionic atoms into a degenerate quantum gas of bosonic dimers. Our analysis relies on a zero temperature mean-field theory which accurately accounts for initial molecular quantum fluctuations, triggering the association process. The structure of the resulting semiclassical phase space is investigated, highlighting the dynamical instability of the system towards association, for sufficiently small detuning from resonance. It is shown that this instability significantly modifies the finite-rate efficiency of the sweep, transforming the single-pair exponential Landau-Zener behavior of the remnant fraction of atoms {gamma} on sweep rate {alpha}, into a power-law dependence as the number of atoms increases. The obtained nonadiabaticity is determined from the interplay of characteristic time scales for the motion of adiabatic eigenstates and for fast periodic motion around them. Critical slowing-down of these precessions near the instability leads to the power-law dependence. A linear power law {gamma}{proportional_to}{alpha} is obtained when the initial molecular fraction is smaller than the 1/N quantum fluctuations, and a cubic-root power law {gamma}{proportional_to}{alpha}{sup 1/3} is attained when it is larger. Our mean-field analysis is confirmed by exact calculations, using Fock-space expansions. Finally, we fit experimental low temperature Feshbach sweep data with a power-law dependence. While the agreement with the experimental data is well within experimental error bars, similar accuracy can be obtained with an exponential fit, making additional data highly desirable.

  6. Creationism and intelligent design.

    PubMed

    Pennock, Robert T

    2003-01-01

    Creationism, the rejection of evolution in favor of supernatural design, comes in many varieties besides the common young-earth Genesis version. Creationist attacks on science education have been evolving in the last few years through the alliance of different varieties. Instead of calls to teach "creation science," one now finds lobbying for "intelligent design" (ID). Guided by the Discovery Institute's "Wedge strategy," the ID movement aims to overturn evolution and what it sees as a pernicious materialist worldview and to renew a theistic foundation to Western culture, in which human beings are recognized as being created in the image of God. Common ID arguments involving scientific naturalism, "irreducible complexity," "complex specified information," and "icons of evolution," have been thoroughly examined and refuted. Nevertheless, from Kansas to Ohio to the U.S. Congress, ID continues lobbying to teach the controversy, and scientists need to be ready to defend good evolution education.

  7. Computer Code For Turbocompounded Adiabatic Diesel Engine

    NASA Technical Reports Server (NTRS)

    Assanis, D. N.; Heywood, J. B.

    1988-01-01

    Computer simulation developed to study advantages of increased exhaust enthalpy in adiabatic turbocompounded diesel engine. Subsytems of conceptual engine include compressor, reciprocator, turbocharger turbine, compounded turbine, ducting, and heat exchangers. Focus of simulation of total system is to define transfers of mass and energy, including release and transfer of heat and transfer of work in each subsystem, and relationship among subsystems. Written in FORTRAN IV.

  8. Adiabatic charging of nickel-hydrogen batteries

    NASA Technical Reports Server (NTRS)

    Lurie, Chuck; Foroozan, S.; Brewer, Jeff; Jackson, Lorna

    1995-01-01

    Battery management during prelaunch activities has always required special attention and careful planning. The transition from nickel-cadium to nickel-hydrogen batteries, with their high self discharge rate and lower charge efficiency, as well as longer prelaunch scenarios, has made this aspect of spacecraft battery management even more challenging. The AXAF-I Program requires high battery state of charge at launch. The use of active cooling, to ensure efficient charging, was considered and proved to be difficult and expensive. Alternative approaches were evaluated. Optimized charging, in the absence of cooling, appeared promising and was investigated. Initial testing was conducted to demonstrate the feasibility of the 'Adiabatic Charging' approach. Feasibility was demonstrated and additional testing performed to provide a quantitative, parametric data base. The assumption that the battery is in an adiabatic environment during prelaunch charging is a conservative approximation because the battery will transfer some heat to its surroundings by convective air cooling. The amount is small compared to the heat dissipated during battery overcharge. Because the battery has a large thermal mass, substantial overcharge can occur before the cells get too hot to charge efficiently. The testing presented here simulates a true adiabatic environment. Accordingly the data base may be slightly conservative. The adiabatic charge methodology used in this investigation begins with stabilizing the cell at a given starting temperature. The cell is then fully insulated on all sides. Battery temperature is carefully monitored and the charge terminated when the cell temperature reaches 85 F. Charging has been evaluated with starting temperatures from 55 to 75 F.

  9. Cooper pair splitting in parallel quantum dot Josephson junctions

    PubMed Central

    Deacon, R. S.; Oiwa, A.; Sailer, J.; Baba, S.; Kanai, Y.; Shibata, K.; Hirakawa, K.; Tarucha, S.

    2015-01-01

    Devices to generate on-demand non-local spin entangled electron pairs have potential application as solid-state analogues of the entangled photon sources used in quantum optics. Recently, Andreev entanglers that use two quantum dots as filters to adiabatically split and separate the quasi-particles of Cooper pairs have shown efficient splitting through measurements of the transport charge but the spin entanglement has not been directly confirmed. Here we report measurements on parallel quantum dot Josephson junction devices allowing a Josephson current to flow due to the adiabatic splitting and recombination of the Cooper pair between the dots. The evidence for this non-local transport is confirmed through study of the non-dissipative supercurrent while tuning independently the dots with local electrical gates. As the Josephson current arises only from processes that maintain the coherence, we can confirm that a current flows from the spatially separated entangled pair. PMID:26130172

  10. Aspects of adiabatic population transfer and control

    NASA Astrophysics Data System (ADS)

    Demirplak, Mustafa

    This thesis explores two different questions. The first question we answer is how to restore a given population transfer scenario given that it works efficiently in the adiabatic limit but fails because of lack of intensity and/or short duration. We derive a very simple algorithm to do this and apply it to both toy and realistic models. Two results emerge from this study. While the mathematical existence of the programme is certain it might not always be physically desirable. The restoration of adiabaticity is phase sensitive. The second question that is answered in this thesis is not how to invent new control paradigms, but rather what would happen to them in the presence of stochastic perturbers. We first use a phenomenological model to study the effect of stochastic dephasing on population transfer by stimulated Raman adiabatic passage. The results of this Monte Carlo calculation are qualitatively explained with a perturbation theoretical result in the dressed state basis. The reliability of our phenomenological model is questioned through a more rigorous hybrid quantal-classical simulation of controlled population transfer in HCl in Ar.

  11. Adiabatic graph-state quantum computation

    NASA Astrophysics Data System (ADS)

    Antonio, B.; Markham, D.; Anders, J.

    2014-11-01

    Measurement-based quantum computation (MBQC) and holonomic quantum computation (HQC) are two very different computational methods. The computation in MBQC is driven by adaptive measurements executed in a particular order on a large entangled state. In contrast in HQC the system starts in the ground subspace of a Hamiltonian which is slowly changed such that a transformation occurs within the subspace. Following the approach of Bacon and Flammia, we show that any MBQC on a graph state with generalized flow (gflow) can be converted into an adiabatically driven holonomic computation, which we call adiabatic graph-state quantum computation (AGQC). We then investigate how properties of AGQC relate to the properties of MBQC, such as computational depth. We identify a trade-off that can be made between the number of adiabatic steps in AGQC and the norm of \\dot{H} as well as the degree of H, in analogy to the trade-off between the number of measurements and classical post-processing seen in MBQC. Finally the effects of performing AGQC with orderings that differ from standard MBQC are investigated.

  12. Random matrix model of adiabatic quantum computing

    SciTech Connect

    Mitchell, David R.; Adami, Christoph; Lue, Waynn; Williams, Colin P.

    2005-05-15

    We present an analysis of the quantum adiabatic algorithm for solving hard instances of 3-SAT (an NP-complete problem) in terms of random matrix theory (RMT). We determine the global regularity of the spectral fluctuations of the instantaneous Hamiltonians encountered during the interpolation between the starting Hamiltonians and the ones whose ground states encode the solutions to the computational problems of interest. At each interpolation point, we quantify the degree of regularity of the average spectral distribution via its Brody parameter, a measure that distinguishes regular (i.e., Poissonian) from chaotic (i.e., Wigner-type) distributions of normalized nearest-neighbor spacings. We find that for hard problem instances - i.e., those having a critical ratio of clauses to variables - the spectral fluctuations typically become irregular across a contiguous region of the interpolation parameter, while the spectrum is regular for easy instances. Within the hard region, RMT may be applied to obtain a mathematical model of the probability of avoided level crossings and concomitant failure rate of the adiabatic algorithm due to nonadiabatic Landau-Zener-type transitions. Our model predicts that if the interpolation is performed at a uniform rate, the average failure rate of the quantum adiabatic algorithm, when averaged over hard problem instances, scales exponentially with increasing problem size.

  13. Stochastic Process Creation

    NASA Astrophysics Data System (ADS)

    Esparza, Javier

    In many areas of computer science entities can “reproduce”, “replicate”, or “create new instances”. Paramount examples are threads in multithreaded programs, processes in operating systems, and computer viruses, but many others exist: procedure calls create new incarnations of the callees, web crawlers discover new pages to be explored (and so “create” new tasks), divide-and-conquer procedures split a problem into subproblems, and leaves of tree-based data structures become internal nodes with children. For lack of a better name, I use the generic term systems with process creation to refer to all these entities.

  14. Creation of learning kits

    NASA Technical Reports Server (NTRS)

    Stow, D. A.; Estes, J. E.; Mertz, F. C.

    1981-01-01

    A learning kit is an essential part of any remote sensing workshop, course, or in-house training program to provide the "hands-on" experience of working with remotely sensed imagery. This is the objective of laboratory and field exercises as well as the reason behind the production of imagery/map kits. The way in which these learning kits (containing conventional remotely sensed and collateral data products) are put together is described and some concerns that influence the creation of learning kits are discussed. These include budgetary constraints, number of imagery types, and number of collateral data types.

  15. Bond selective chemistry beyond the adiabatic approximation

    SciTech Connect

    Butler, L.J.

    1993-12-01

    One of the most important challenges in chemistry is to develop predictive ability for the branching between energetically allowed chemical reaction pathways. Such predictive capability, coupled with a fundamental understanding of the important molecular interactions, is essential to the development and utilization of new fuels and the design of efficient combustion processes. Existing transition state and exact quantum theories successfully predict the branching between available product channels for systems in which each reaction coordinate can be adequately described by different paths along a single adiabatic potential energy surface. In particular, unimolecular dissociation following thermal, infrared multiphoton, or overtone excitation in the ground state yields a branching between energetically allowed product channels which can be successfully predicted by the application of statistical theories, i.e. the weakest bond breaks. (The predictions are particularly good for competing reactions in which when there is no saddle point along the reaction coordinates, as in simple bond fission reactions.) The predicted lack of bond selectivity results from the assumption of rapid internal vibrational energy redistribution and the implicit use of a single adiabatic Born-Oppenheimer potential energy surface for the reaction. However, the adiabatic approximation is not valid for the reaction of a wide variety of energetic materials and organic fuels; coupling between the electronic states of the reacting species play a a key role in determining the selectivity of the chemical reactions induced. The work described below investigated the central role played by coupling between electronic states in polyatomic molecules in determining the selective branching between energetically allowed fragmentation pathways in two key systems.

  16. Committees active against creationism

    NASA Astrophysics Data System (ADS)

    Weinberg, Stan

    In 1981 in Federal District Court, Judge William R. Overton held that the Arkansas law mandating equal time for the teaching of “scientific creationism” in the state's public schools was unconstitutional.The Overton decision was the latest in a series of legislative and judicial setbacks suffered by fundamentalists who advocate the introduction of creationism into schools, libraries, museums, and other public institutions. But rather than giving up the ghost, creationists are now switching their campaign into a series of local confrontations. In California the teaching of creationism in San Jose high schools is defended while the use of an evolution-oriented high school biology text is attacked. In Iowa an ambitious effort to introduce shoddy creationist paperbacks into the schools of 60 communities has just bogged down. In Michigan an exhibit on plant development in a modest, county-run museum is characterized as “blasphemous” because of the exhibit's evolutionary tone. So it goes across the United States and Canada.

  17. Quantized adiabatic transport in momentum space.

    PubMed

    Ho, Derek Y H; Gong, Jiangbin

    2012-07-06

    Though topological aspects of energy bands are known to play a key role in quantum transport in solid-state systems, the implications of Floquet band topology for transport in momentum space (i.e., acceleration) have not been explored so far. Using a ratchet accelerator model inspired by existing cold-atom experiments, here we characterize a class of extended Floquet bands of one-dimensional driven quantum systems by Chern numbers, reveal topological phase transitions therein, and theoretically predict the quantization of adiabatic transport in momentum space. Numerical results confirm our theory and indicate the feasibility of experimental studies.

  18. Adiabatic demagnetization refrigerator for space use

    NASA Technical Reports Server (NTRS)

    Serlemitsos, A. T.; Warner, B. A.; Castles, S.; Breon, S. R.; San Sebastian, M.; Hait, T.

    1990-01-01

    An Adiabatic Demagnetization Refrigerator (ADR) for space use is under development at NASA's Goddard Space Flight Center (GSFC). The breadboard ADR operated at 100 mK for 400 minutes. Some significant changes to that ADR, designed to eliminate shortcomings revealed during tests, are reported. To increase thermal contact, the ferric ammonium sulfate crystals were grown directly on gold-plated copper wires which serve as the thermal bus. The thermal link to the X-ray sensors was also markedly improved. To speed up the testing required to determine the best design parameters for the gas gap heat switch, the new heat switch has a modular design and is easy to disassemble.

  19. Shortcuts to adiabaticity for quantum annealing

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazutaka

    2017-01-01

    We study the Ising Hamiltonian with a transverse field term to simulate the quantum annealing. Using shortcuts to adiabaticity, we design the time dependence of the Hamiltonian. The dynamical invariant is obtained by the mean-field ansatz, and the Hamiltonian is designed by the inverse engineering. We show that the time dependence of physical quantities such as the magnetization is independent of the speed of the Hamiltonian variation in the infinite-range model. We also show that rotating transverse magnetic fields are useful to achieve the ideal time evolution.

  20. Phase avalanches in near-adiabatic evolutions

    SciTech Connect

    Vertesi, T.; Englman, R.

    2006-02-15

    In the course of slow, nearly adiabatic motion of a system, relative changes in the slowness can cause abrupt and high magnitude phase changes, ''phase avalanches,'' superimposed on the ordinary geometric phases. The generality of this effect is examined for arbitrary Hamiltonians and multicomponent (>2) wave packets and is found to be connected (through the Blaschke term in the theory of analytic signals) to amplitude zeros in the lower half of the complex time plane. Motion on a nonmaximal circle on the Poincare-sphere suppresses the effect. A spectroscopic transition experiment can independently verify the phase-avalanche magnitudes.

  1. Decoherence in a scalable adiabatic quantum computer

    SciTech Connect

    Ashhab, S.; Johansson, J. R.; Nori, Franco

    2006-11-15

    We consider the effects of decoherence on Landau-Zener crossings encountered in a large-scale adiabatic-quantum-computing setup. We analyze the dependence of the success probability--i.e., the probability for the system to end up in its new ground state--on the noise amplitude and correlation time. We determine the optimal sweep rate that is required to maximize the success probability. We then discuss the scaling of decoherence effects with increasing system size. We find that those effects can be important for large systems, even if they are small for each of the small building blocks.

  2. Cavity-state preparation using adiabatic transfer

    NASA Astrophysics Data System (ADS)

    Larson, Jonas; Andersson, Erika

    2005-05-01

    We show how to prepare a variety of cavity field states for multiple cavities. The state preparation technique used is related to the method of stimulated adiabatic Raman passage. The cavity modes are coupled by atoms, making it possible to transfer an arbitrary cavity field state from one cavity to another and also to prepare nontrivial cavity field states. In particular, we show how to prepare entangled states of two or more cavities, such as an Einstein-Podolsky-Rosen state and a W state, as well as various entangled superpositions of coherent states in different cavities, including Schrödinger cat states. The theoretical considerations are supported by numerical simulations.

  3. Generalized Ramsey numbers through adiabatic quantum optimization

    NASA Astrophysics Data System (ADS)

    Ranjbar, Mani; Macready, William G.; Clark, Lane; Gaitan, Frank

    2016-09-01

    Ramsey theory is an active research area in combinatorics whose central theme is the emergence of order in large disordered structures, with Ramsey numbers marking the threshold at which this order first appears. For generalized Ramsey numbers r( G, H), the emergent order is characterized by graphs G and H. In this paper we: (i) present a quantum algorithm for computing generalized Ramsey numbers by reformulating the computation as a combinatorial optimization problem which is solved using adiabatic quantum optimization; and (ii) determine the Ramsey numbers r({{T}}m,{{T}}n) for trees of order m,n = 6,7,8, most of which were previously unknown.

  4. Generating shortcuts to adiabaticity in quantum and classical dynamics

    NASA Astrophysics Data System (ADS)

    Jarzynski, Christopher

    2013-10-01

    Transitionless quantum driving achieves adiabatic evolution in a hurry, using a counterdiabatic Hamiltonian to stifle nonadiabatic transitions. Here this shortcut to adiabaticity is cast in terms of a generator of adiabatic transport. This yields a classical analog of transitionless driving, and provides a strategy for constructing quantal counterdiabatic Hamiltonians. As an application of this framework, exact classical and quantal counterdiabatic terms are obtained for a particle in a box and for even-power-law potentials in one degree of freedom.

  5. Numerical simulations of solar spicules: Adiabatic and non-adiabatic studies

    NASA Astrophysics Data System (ADS)

    Kuźma, B.; Murawski, K.; Zaqarashvili, T. V.; Konkol, P.; Mignone, A.

    2017-01-01

    Aims: We aim to study the formation and evolution of solar spicules using numerical simulations of a vertical velocity pulse that is launched from the upper chromosphere. Methods: With the use of the PLUTO code, we numerically solved adiabatic and non-adiabatic magnetohydrodynamic (MHD) equations in 2D cylindrical geometry. We followed the evolution of spicules triggered by pulses that are launched in a vertical velocity component from the upper chromosphere. Then we compared the results obtained with and without non-adiabatic terms in the MHD equations. Results: Our numerical results reveal that the velocity pulse is steepened into a shock that propagates upward into the corona. The chromospheric cold and dense plasma follows the shock and rises into the corona with the mean speed of 20-25 km s-1. The nonlinear wake behind the pulse in the stratified atmosphere leads to quasi-periodic rebound shocks, which lead to quasi-periodic rising of chromospheric plasma into the corona with a period close to the acoustic cut-off period of the chromosphere. We found that the effect of non-adiabatic terms on spicule evolution is minor; the general properties of spicules such as their heights and rising-time remain slightly affected by these terms. Conclusions: In the framework of the axisymmetric model we devised, we show that the solar spicules can be triggered by the vertical velocity pulses, and thermal conduction and radiative cooling terms do not exert any significant influence on the dynamics of these spicules.

  6. On the Role of Prior Probability in Adiabatic Quantum Algorithms

    NASA Astrophysics Data System (ADS)

    Sun, Jie; Lu, Songfeng; Yang, Liping

    2016-03-01

    In this paper, we study the role of prior probability on the efficiency of quantum local adiabatic search algorithm. The following aspects for prior probability are found here: firstly, only the probabilities of marked states affect the running time of the adiabatic evolution; secondly, the prior probability can be used for improving the efficiency of the adiabatic algorithm; thirdly, like the usual quantum adiabatic evolution, the running time for the case of multiple solution states where the number of marked elements are smaller enough than the size of the set assigned that contains them can be significantly bigger than that of the case where the assigned set only contains all the marked states.

  7. Adiabatic following for a three-state quantum system

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Shore, Bruce W.; Rangelov, Andon; Kyoseva, Elica

    2017-01-01

    Adiabatic time-evolution - found in various forms of adiabatic following and adiabatic passage - is often advantageous for controlled manipulation of quantum systems due to its insensitivity to deviations in the pulse shapes and timings. In this paper we discuss controlled adiabatic evolution of a three-state quantum system, a natural advance to the widespread use of two-state systems in numerous contemporary applications. We discuss, and illustrate, not only possibilities for population transfer but also for creating, with prescribed relative phase, 50:50 superpositions of two Zeeman sublevels in a letter-vee coupling linkage.

  8. Adiabatic approximation via hodograph translation and zero-curvature equations

    NASA Astrophysics Data System (ADS)

    Karasev, M. V.

    2014-04-01

    For quantum as well classical slow-fast systems, we develop a general method which allows one to compute the adiabatic invariant (approximate integral of motion), its symmetries, the adiabatic guiding center coordinates and the effective scalar Hamiltonian in all orders of a small parameter. The scheme does not exploit eigenvectors or diagonalization, but is based on the ideas of isospectral deformation and zero-curvature equations, where the role of "time" is played by the adiabatic (quantization) parameter. The algorithm includes the construction of the zero-curvature adiabatic connection and its splitting generated by averaging up to an arbitrary order in the small parameter.

  9. Quantum Adiabatic Algorithms and Large Spin Tunnelling

    NASA Technical Reports Server (NTRS)

    Boulatov, A.; Smelyanskiy, V. N.

    2003-01-01

    We provide a theoretical study of the quantum adiabatic evolution algorithm with different evolution paths proposed in this paper. The algorithm is applied to a random binary optimization problem (a version of the 3-Satisfiability problem) where the n-bit cost function is symmetric with respect to the permutation of individual bits. The evolution paths are produced, using the generic control Hamiltonians H (r) that preserve the bit symmetry of the underlying optimization problem. In the case where the ground state of H(0) coincides with the totally-symmetric state of an n-qubit system the algorithm dynamics is completely described in terms of the motion of a spin-n/2. We show that different control Hamiltonians can be parameterized by a set of independent parameters that are expansion coefficients of H (r) in a certain universal set of operators. Only one of these operators can be responsible for avoiding the tunnelling in the spin-n/2 system during the quantum adiabatic algorithm. We show that it is possible to select a coefficient for this operator that guarantees a polynomial complexity of the algorithm for all problem instances. We show that a successful evolution path of the algorithm always corresponds to the trajectory of a classical spin-n/2 and provide a complete characterization of such paths.

  10. The genesis of adiabatic shear bands

    PubMed Central

    Landau, P.; Osovski, S.; Venkert, A.; Gärtnerová, V.; Rittel, D.

    2016-01-01

    Adiabatic shear banding (ASB) is a unique dynamic failure mechanism that results in an unpredicted catastrophic failure due to a concentrated shear deformation mode. It is universally considered as a material or structural instability and as such, ASB is hardly controllable or predictable to some extent. ASB is modeled on the premise of stability analyses. The leading paradigm is that a competition between strain (rate) hardening and thermal softening determines the onset of the failure. It was recently shown that microstructural softening transformations, such as dynamic recrystallization, are responsible for adiabatic shear failure. These are dictated by the stored energy of cold work, so that energy considerations can be used to macroscopically model the failure mechanism. The initial mechanisms that lead to final failure are still unknown, as well as the ASB formation mechanism(s). Most of all - is ASB an abrupt instability or rather a gradual transition as would be dictated by microstructural evolutions? This paper reports thorough microstructural characterizations that clearly show the gradual character of the phenomenon, best described as a nucleation and growth failure mechanism, and not as an abrupt instability as previously thought. These observations are coupled to a simple numerical model that illustrates them. PMID:27849023

  11. Accurate Variational Description of Adiabatic Quantum Optimization

    NASA Astrophysics Data System (ADS)

    Carleo, Giuseppe; Bauer, Bela; Troyer, Matthias

    Adiabatic quantum optimization (AQO) is a quantum computing protocol where a system is driven by a time-dependent Hamiltonian. The initial Hamiltonian has an easily prepared ground-state and the final Hamiltonian encodes some desired optimization problem. An adiabatic time evolution then yields a solution to the optimization problem. Several challenges emerge in the theoretical description of this protocol: on one hand, the exact simulation of quantum dynamics is exponentially complex in the size of the optimization problem. On the other hand, approximate approaches such as tensor network states (TNS) are limited to small instances by the amount of entanglement that can be encoded. I will present here an extension of the time-dependent Variational Monte Carlo approach to problems in AQO. This approach is based on a general class of (Jastrow-Feenberg) entangled states, whose parameters are evolved in time according to a stochastic variational principle. We demonstrate this approach for optimization problems of the Ising spin-glass type. A very good accuracy is achieved when compared to exact time-dependent TNS on small instances. We then apply this approach to larger problems, and discuss the efficiency of the quantum annealing scheme in comparison with its classical counterpart.

  12. Nonadiabatic Transitions in Adiabatic Rapid Passage

    NASA Astrophysics Data System (ADS)

    Lu, T.; Miao, X.; Metcalf, H.

    2006-05-01

    Optical forces much larger than the ordinary radiative force can be achieved on a two-level atom by multiple repetitions of adiabatic rapid passage sweeps with counterpropagating light beams. Chirped light pulses drive the atom-laser system up a ladder of dressed state energy sheets on sequential trajectories, thereby decreasing the atomic kinetic energy. Nonadiabatic transitions between the energy sheets must be avoided for this process to be effective. We have calculated the nonadiabatic transition probability for various chirped light pulses numerically. These results were compared to the first Demkov-Kunike model and the well-known Landau-Zener model. In addition, an analytical form of the nonadiabatic transition probability has been found for linearly chirped pulses and an approximate form for generic symmetric finite-time pulses has been found for the entire parameter space using the technique of unitary integration. From this, the asymptotic transition probability in the adiabatic limit was derived. T. Lu, X. Miao, and H. Metcalf, Phys., Rev. A 71 061405(R) (2005). Yu. Demkov and M. Kunike, Vestn. Leningr. Univ. Fis. Khim., 16, 39 (1969); K.-A. Suominen and B. Garraway, Phys. Rev. A45, 374 (1992)

  13. The formation of multiple adiabatic shear bands

    NASA Astrophysics Data System (ADS)

    Zhou, F.; Wright, T. W.; Ramesh, K. T.

    2006-07-01

    In a previous paper, Zhou et al. [2006. A numerical methodology for investigating adiabatic shear band formation. J. Mech. Phys. Solids, 54, 904-926] developed a numerical method for analyzing one-dimensional deformation of thermoviscoplastic materials. The method uses a second order algorithm for integration along characteristic lines, and computes the plastic flow after complete localization with high resolution and efficiency. We apply this numerical scheme to analyze localization in a thermoviscoplastic material where multiple shear bands are allowed to form at random locations in a large specimen. As a shear band develops, it unloads neighboring regions and interacts with other bands. Beginning with a random distribution of imperfections, which might be imagined as arising qualitatively from the microstructure, we obtain the average spacing of shear bands through calculations and compare our results with previously existing theoretical estimates. It is found that the spacing between nucleating shear bands follows the perturbation theory due to Wright and Ockendon [1996. A scaling law for the effect of inertia on the formation of adiabatic shear bands. Int. J. Plasticity 12, 927-934], whereas the spacing between mature shear bands is closer to that predicted by the momentum diffusion theory of Grady and Kipp [1987. The growth of unstable thermoplastic shear with application to steady-wave shock compression in solids. J. Mech. Phys. Solids 35, 95-119]. Scaling laws for the dependence of band spacing on material parameters differ in many respects from either theory.

  14. Adiabatic cooling of solar wind electrons

    NASA Technical Reports Server (NTRS)

    Sandbaek, Ornulf; Leer, Egil

    1992-01-01

    In thermally driven winds emanating from regions in the solar corona with base electron densities of n0 not less than 10 exp 8/cu cm, a substantial fraction of the heat conductive flux from the base is transfered into flow energy by the pressure gradient force. The adiabatic cooling of the electrons causes the electron temperature profile to fall off more rapidly than in heat conduction dominated flows. Alfven waves of solar origin, accelerating the basically thermally driven solar wind, lead to an increased mass flux and enhanced adiabatic cooling. The reduction in electron temperature may be significant also in the subsonic region of the flow and lead to a moderate increase of solar wind mass flux with increasing Alfven wave amplitude. In the solar wind model presented here the Alfven wave energy flux per unit mass is larger than that in models where the temperature in the subsonic flow is not reduced by the wave, and consequently the asymptotic flow speed is higher.

  15. Non-adiabatic Rayleigh-Taylor instability

    NASA Astrophysics Data System (ADS)

    Canfield, Jesse; Denissen, Nicholas; Reisner, Jon

    2016-11-01

    Onset of Rayleigh-Taylor instability (RTI) in a non-adiabatic environment is investigated with the multi-physics numerical model, FLAG. This work was inspired by laboratory experiments of non-adiabatic RTI, where a glass vessel with a layer of tetrahyrdofuran (THF) below a layer of toluene was placed inside a microwave. THF, a polar solvent, readily absorbs electromagnetic energy from microwaves. Toluene, a non-polar solvent, is nearly transparent to microwave heating. The presence of a heat source in the THF layer produced convection and a time-dependent Atwood number (At). The system, initially in stable hydrostatic equilibrium At < 0 , was set into motion by microwave induced, volumetric heating of the THF. The point when At > 0 , indicates that the system is RTI unstable. The observed dominant mode at the onset of RTI was the horizontal length scale of the vessel. This scale is contrary to classical RTI, where the modes start small and increases in scale with time. It is shown that the dominant RTI mode observed in the experiments was determined by the THF length scale prior to RTI. The dominant length scale transitions from the THF to the toluene via the updrafts and downdrafts in the convective cells. This happens when At passes from negative to positive. This work was funded by the Advanced Simulation and Computing Program.

  16. Thermodynamic and spectral properties of adiabatic Peierls chains

    NASA Astrophysics Data System (ADS)

    Weber, Manuel; Assaad, Fakher F.; Hohenadler, Martin

    2016-10-01

    We present exact numerical results for the effects of thermal fluctuations on the experimentally relevant thermodynamic and spectral properties of Peierls chains. To this end, a combination of classical Monte Carlo sampling and exact diagonalization is used to study adiabatic half-filled Holstein and Su-Schrieffer-Heeger models. The classical nature of the lattice displacements in combination with parallel tempering permit simulations on large system sizes and a direct calculation of spectral functions in the frequency domain. Most notably, the long-range order and the associated Peierls gap give rise to a distinct low-temperature peak in the specific heat. The closing of the gap and suppression of order by thermal fluctuations involves in-gap excitations in the form of soliton-antisoliton pairs and is also reflected in the dynamic density and bond structure factors as well as in the optical conductivity. We compare our data to the widely used mean-field approximation and highlight relations to symmetry-protected topological phases and disorder problems.

  17. Experimental Progress Toward Multiple Adiabatic Rapid Passage Sequences

    NASA Astrophysics Data System (ADS)

    Miao, X.; Wertz, E.; Cohen, M. G.; Metcalf, H.

    2006-05-01

    Multiple repetitions of adiabatic rapid passage (ARP) sweeps with counterpropagating light beams can enable huge optical forces on atoms. The repetition rate of the ARP sweeps φsγ results in a force k φs/πk γ/2 ≡Frad where 1/γ≡τ is the excited state lifetime and Frad is the ordinary radiative force. This is because each pair of ARP-induced inversions can coherently transfer momentum ±2 k between the light beams, and thus 2 k to the atoms. In developing instruments for such experiments on the 2^3S1-> 2^3P2 transition at λ = 1083 nm in He, we exploit recent developments in the optical communications industry. We use commercial phase and intensity modulators of the LiNbO3 waveguide type having Vπ as low as 6 V and thus requiring relatively low rf power for the modulation. Synchronized driving of the two modulators can produce the necessary multiple ARP sequences of 10 ns chirped pulses that span several GHz, as needed for the experiment^3. We are also developing optical methods for characterizing these pulses. T. Lu, X. Miao, and H. Metcalf, Phys., Rev. A 71 061405(R) (2005).

  18. Adiabatic effects of electrons and ions on electro-acoustic solitary waves in an adiabatic dusty plasma

    NASA Astrophysics Data System (ADS)

    Tanjia, Fatema; Mamun, A. A.

    2009-02-01

    A dusty plasma consisting of negatively charged cold dust, adiabatic hot ions, and inertia-less adiabatic hot electrons has been considered. The adiabatic effects of electrons and ions on the basic properties of electro-acoustic solitary waves associated with different types of electro-acoustic (viz. ion-acoustic (IA), dust ion-acoustic (DIA), and dust acoustic (DA)) waves are thoroughly investigated by the reductive perturbation method. It is found that the basic properties of the IA, DIA, and DA waves are significantly modified by the adiabatic effects of ions and inertia-less electrons. The implications of our results in space and laboratory dusty plasmas are briefly discussed.

  19. Pairing Learners in Pair Work Activity

    ERIC Educational Resources Information Center

    Storch, Neomy; Aldosari, Ali

    2013-01-01

    Although pair work is advocated by major theories of second language (L2) learning and research findings suggest that pair work facilitates L2 learning, what is unclear is how to best pair students in L2 classes of mixed L2 proficiency. This study investigated the nature of pair work in an English as a Foreign Language (EFL) class in a college in…

  20. A Modified Adiabatic Quantum Algorithm for Evaluation of Boolean Functions

    NASA Astrophysics Data System (ADS)

    Sun, Jie; Lu, Songfeng; Liu, Fang

    2015-09-01

    In this paper, we propose a modified construction of the quantum adiabatic algorithm for Boolean functions studied by M. Andrecut et al. [13, 14]. Our algorithm has the time complexity O(1) for the evaluation of Boolean functions, without additional computational cost of implementing the driving Hamiltonian, which is required by the adiabatic evolution described in [13, 14].

  1. Adiabat-shaping in indirect drive inertial confinement fusion

    SciTech Connect

    Baker, K. L.; Robey, H. F.; Milovich, J. L.; Jones, O. S.; Smalyuk, V. A.; Casey, D. T.; MacPhee, A. G.; Pak, A.; Celliers, P. M.; Clark, D. S.; Landen, O. L.; Peterson, J. L.; Berzak-Hopkins, L. F.; Weber, C. R.; Haan, S. W.; Döppner, T. D.; Dixit, S.; Hamza, A. V.; Jancaitis, K. S.; Kroll, J. J.; and others

    2015-05-15

    Adiabat-shaping techniques were investigated in indirect drive inertial confinement fusion experiments on the National Ignition Facility as a means to improve implosion stability, while still maintaining a low adiabat in the fuel. Adiabat-shaping was accomplished in these indirect drive experiments by altering the ratio of the picket and trough energies in the laser pulse shape, thus driving a decaying first shock in the ablator. This decaying first shock is designed to place the ablation front on a high adiabat while keeping the fuel on a low adiabat. These experiments were conducted using the keyhole experimental platform for both three and four shock laser pulses. This platform enabled direct measurement of the shock velocities driven in the glow-discharge polymer capsule and in the liquid deuterium, the surrogate fuel for a DT ignition target. The measured shock velocities and radiation drive histories are compared to previous three and four shock laser pulses. This comparison indicates that in the case of adiabat shaping the ablation front initially drives a high shock velocity, and therefore, a high shock pressure and adiabat. The shock then decays as it travels through the ablator to pressures similar to the original low-adiabat pulses when it reaches the fuel. This approach takes advantage of initial high ablation velocity, which favors stability, and high-compression, which favors high stagnation pressures.

  2. The Adiabatic Invariance of the Action Variable in Classical Dynamics

    ERIC Educational Resources Information Center

    Wells, Clive G.; Siklos, Stephen T. C.

    2007-01-01

    We consider one-dimensional classical time-dependent Hamiltonian systems with quasi-periodic orbits. It is well known that such systems possess an adiabatic invariant which coincides with the action variable of the Hamiltonian formalism. We present a new proof of the adiabatic invariance of this quantity and illustrate our arguments by means of…

  3. Kinetic Theory Derivation of the Adiabatic Law for Ideal Gases.

    ERIC Educational Resources Information Center

    Sobel, Michael I.

    1980-01-01

    Discusses how the adiabatic law for ideal gases can be derived from the assumption of a Maxwell-Boltzmann (or any other) distribution of velocities--in contrast to the usual derivations from thermodynamics alone, and the higher-order effect that leads to one-body viscosity. An elementary derivation of the adiabatic law is given. (Author/DS)

  4. Quantum Adiabatic Optimization and Combinatorial Landscapes

    NASA Technical Reports Server (NTRS)

    Smelyanskiy, V. N.; Knysh, S.; Morris, R. D.

    2003-01-01

    In this paper we analyze the performance of the Quantum Adiabatic Evolution (QAE) algorithm on a variant of Satisfiability problem for an ensemble of random graphs parametrized by the ratio of clauses to variables, gamma = M / N. We introduce a set of macroscopic parameters (landscapes) and put forward an ansatz of universality for random bit flips. We then formulate the problem of finding the smallest eigenvalue and the excitation gap as a statistical mechanics problem. We use the so-called annealing approximation with a refinement that a finite set of macroscopic variables (verses only energy) is used, and are able to show the existence of a dynamic threshold gamma = gammad, beyond which QAE should take an exponentially long time to find a solution. We compare the results for extended and simplified sets of landscapes and provide numerical evidence in support of our universality ansatz.

  5. Number Partitioning via Quantum Adiabatic Computation

    NASA Technical Reports Server (NTRS)

    Smelyanskiy, Vadim N.; Toussaint, Udo; Clancy, Daniel (Technical Monitor)

    2002-01-01

    We study both analytically and numerically the complexity of the adiabatic quantum evolution algorithm applied to random instances of combinatorial optimization problems. We use as an example the NP-complete set partition problem and obtain an asymptotic expression for the minimal gap separating the ground and exited states of a system during the execution of the algorithm. We show that for computationally hard problem instances the size of the minimal gap scales exponentially with the problem size. This result is in qualitative agreement with the direct numerical simulation of the algorithm for small instances of the set partition problem. We describe the statistical properties of the optimization problem that are responsible for the exponential behavior of the algorithm.

  6. The HAWC and SAFIRE Adiabatic Demagnetization Refrigerators

    NASA Technical Reports Server (NTRS)

    Tuttle, Jim; Shirron, Peter; DiPirro, Michael; Jackson, Michael; Behr, Jason; Kunes, Evan; Hait, Tom; Krebs, Carolyn (Technical Monitor)

    2001-01-01

    The High-Resolution Airborne Wide-band Camera (HAWC) and Submillimeter and Far Infrared Experiment (SAFIRE) are far-infrared experiments which will fly on the Stratospheric Observatory for Infrared Astronomy (SOFIA) aircraft. HAWC's detectors will operate at 0.2 Kelvin, while those of SAFIRE will be at 0.1 Kelvin. Each instrument will include an adiabatic demagnetization refrigerator (ADR) to cool its detector stage from the liquid helium bath temperature (HAWC's at 4.2 Kelvin and SAFIRE's pumped to about 1.3 Kelvin) to its operating temperature. Except for the magnets used to achieve the cooling and a slight difference in the heat switch design, the two ADRs are nearly identical. We describe the ADR design and present the results of performance testing.

  7. Sliding seal materials for adiabatic engines

    NASA Technical Reports Server (NTRS)

    Lankford, J.

    1985-01-01

    The sliding friction coefficients and wear rates of promising carbide, oxide, and nitride materials were measured under temperature, environmental, velocity, loading conditions that are representative of the adiabatic engine environment. In order to provide guidance needed to improve materials for this application, the program stressed fundamental understanding of the mechanisms involved in friction and wear. Microhardness tests were performed on the candidate materials at elevated temperatures, and in atmospheres relevant to the piston seal application, and optical and electron microscopy were used to elucidate the micromechanisms of wear following wear testing. X-ray spectroscopy was used to evaluate interface/environment interactions which seemed to be important in the friction and wear process. Electrical effects in the friction and wear processes were explored in order to evaluate the potential usefulness of such effects in modifying the friction and wear rates in service. However, this factor was found to be of negligible significance in controlling friction and wear.

  8. An adiabatic demagnetization refrigerator for SIRTF

    NASA Astrophysics Data System (ADS)

    Timbie, P. T.; Bernstein, G. M.; Richards, P. L.

    1989-02-01

    An adiabatic demagnetization refrigerator (ADR) has been proposed to cool bolometric infrared detectors on the multiband imaging photometer of the Space Infrared Telescope Facility (SIRTF). One such refrigerator has been built which uses a ferric ammonium alum salt pill suspended by nylon threads in a 3-T solenoid. The resonant modes of this suspension are above 100 Hz. The heat leak to the salt pill is less than 0.5 microW. The system has a hold time at 0.1K of more than 12 h. The cold stage temperature is regulated with a feedback loop that controls the magnetic field. A second, similar refrigerator is being built at a SIRTF prototype to fly on a ballon-borne telescope. It will use a ferromagnetic shield. The possibility of using a high-Tc solenoid-actuated heat switch is also discussed.

  9. Design of a spaceworthy adiabatic demagnetization refrigerator

    NASA Astrophysics Data System (ADS)

    Serlemitsos, A. T.; Kunes, E.; Sansebastian, M.

    A spaceworthy adiabatic demagnetization refrigerator (ADR) under development at NASA-Goddard is presented. A baseline model heat switch was tested extensively with an on/off ratio of about 10,000 and a parasitic heat leak of 10 micro-W. Data obtained from the breadboard models were used to design an ADR with improved structural integrity. The core of the ADR is the salt pill which consists of the paramagnetic salt crystal and the thermal bus. When a magnetic field is applied to the salt it forces the alignment of the magnetic moments, thereby decreasing the entropy of the salt. Preliminary tests results showed a net crystal mass of 680 g instead of the expected 740 g, which indicate that there are gaps in the salt pill. A partial fix was accomplished by sealing helium gas in the salt pill at a pressure of 2 bar, which improved the thermal contact during salt magnetization, at about 2 K.

  10. On stress collapse in adiabatic shear bands

    NASA Astrophysics Data System (ADS)

    Wright, T. W.; Walter, J. W.

    T HE DYNAMICS of adiabatic shear band formation is considered making use of a simplified thermo/visco/plastic flow law. A new numerical solution is used to follow the growth of a perturbation from initiation, through early growth and severe localization, to a slowly varying terminal configuration. Asymptotic analyses predict the early and late stage patterns, but the timing and structure of the abrupt transition to severe localization can only be studied numerically, to date. A characteristic feature of the process is that temperature and plastic strain rate begin to localize immediately, but only slowly, whereas the stress first evolves almost as if there were no perturbation, but then collapses rapidly when severe localization occurs.

  11. Index Theory and Adiabatic Limit in QFT

    NASA Astrophysics Data System (ADS)

    Wawrzycki, Jarosław

    2013-08-01

    The paper has the form of a proposal concerned with the relationship between the three mathematically rigorous approaches to quantum field theory: (1) local algebraic formulation of Haag, (2) Wightman formulation and (3) the perturbative formulation based on the microlocal renormalization method. In this project we investigate the relationship between (1) and (3) and utilize the known relationships between (1) and (2). The main goal of the proposal lies in obtaining obstructions for the existence of the adiabatic limit ( confinement problem in the phenomenological standard model approach). We extend the method of deformation of Dütsch and Fredenhagen (in the Bordeman-Waldmann sense) and apply Fedosov construction of the formal index—an analog of the index for deformed symplectic manifolds, generalizing the Atiyah-Singer index. We present some first steps in realization of the proposal.

  12. An adiabatic demagnetization refrigerator for SIRTF

    NASA Technical Reports Server (NTRS)

    Timbie, P. T.; Bernstein, G. M.; Richards, P. L.

    1989-01-01

    An adiabatic demagnetization refrigerator (ADR) has been proposed to cool bolometric infrared detectors on the multiband imaging photometer of the Space Infrared Telescope Facility (SIRTF). One such refrigerator has been built which uses a ferric ammonium alum salt pill suspended by nylon threads in a 3-T solenoid. The resonant modes of this suspension are above 100 Hz. The heat leak to the salt pill is less than 0.5 microW. The system has a hold time at 0.1K of more than 12 h. The cold stage temperature is regulated with a feedback loop that controls the magnetic field. A second, similar refrigerator is being built at a SIRTF prototype to fly on a ballon-borne telescope. It will use a ferromagnetic shield. The possibility of using a high-Tc solenoid-actuated heat switch is also discussed.

  13. Design of a spaceworthy adiabatic demagnetization refrigerator

    NASA Technical Reports Server (NTRS)

    Serlemitsos, A. T.; Kunes, E.; Sansebastian, M.

    1992-01-01

    A spaceworthy adiabatic demagnetization refrigerator (ADR) under development at NASA-Goddard is presented. A baseline model heat switch was tested extensively with an on/off ratio of about 10,000 and a parasitic heat leak of 10 micro-W. Data obtained from the breadboard models were used to design an ADR with improved structural integrity. The core of the ADR is the salt pill which consists of the paramagnetic salt crystal and the thermal bus. When a magnetic field is applied to the salt it forces the alignment of the magnetic moments, thereby decreasing the entropy of the salt. Preliminary tests results showed a net crystal mass of 680 g instead of the expected 740 g, which indicate that there are gaps in the salt pill. A partial fix was accomplished by sealing helium gas in the salt pill at a pressure of 2 bar, which improved the thermal contact during salt magnetization, at about 2 K.

  14. Adiabatic connection at negative coupling strengths

    SciTech Connect

    Seidl, Michael; Gori-Giorgi, Paola

    2010-01-15

    The adiabatic connection of density functional theory (DFT) for electronic systems is generalized here to negative values of the coupling strength alpha (with attractive electrons). In the extreme limit alpha->-infinity a simple physical solution is presented and its implications for DFT (as well as its limitations) are discussed. For two-electron systems (a case in which the present solution can be calculated exactly), we find that an interpolation between the limit alpha->-infinity and the opposite limit of infinitely strong repulsion (alpha->+infinity) yields a rather accurate estimate of the second-order correlation energy E{sub c}{sup GL2}[rho] for several different densities rho, without using virtual orbitals. The same procedure is also applied to the Be isoelectronic series, analyzing the effects of near degeneracy.

  15. Adiabatic theory for anisotropic cold molecule collisions

    SciTech Connect

    Pawlak, Mariusz; Shagam, Yuval; Narevicius, Edvardas; Moiseyev, Nimrod

    2015-08-21

    We developed an adiabatic theory for cold anisotropic collisions between slow atoms and cold molecules. It enables us to investigate the importance of the couplings between the projection states of the rotational motion of the atom about the molecular axis of the diatom. We tested our theory using the recent results from the Penning ionization reaction experiment {sup 4}He(1s2s {sup 3}S) + HD(1s{sup 2}) → {sup 4}He(1s{sup 2}) + HD{sup +}(1s) + e{sup −} [Lavert-Ofir et al., Nat. Chem. 6, 332 (2014)] and demonstrated that the couplings have strong effect on positions of shape resonances. The theory we derived provides cross sections which are in a very good agreement with the experimental findings.

  16. An Integrated Development Environment for Adiabatic Quantum Programming

    SciTech Connect

    Humble, Travis S; McCaskey, Alex; Bennink, Ryan S; Billings, Jay Jay; D'Azevedo, Eduardo; Sullivan, Blair D; Klymko, Christine F; Seddiqi, Hadayat

    2014-01-01

    Adiabatic quantum computing is a promising route to the computational power afforded by quantum information processing. The recent availability of adiabatic hardware raises the question of how well quantum programs perform. Benchmarking behavior is challenging since the multiple steps to synthesize an adiabatic quantum program are highly tunable. We present an adiabatic quantum programming environment called JADE that provides control over all the steps taken during program development. JADE captures the workflow needed to rigorously benchmark performance while also allowing a variety of problem types, programming techniques, and processor configurations. We have also integrated JADE with a quantum simulation engine that enables program profiling using numerical calculation. The computational engine supports plug-ins for simulation methodologies tailored to various metrics and computing resources. We present the design, integration, and deployment of JADE and discuss its use for benchmarking adiabatic quantum programs.

  17. An integrated programming and development environment for adiabatic quantum optimization

    NASA Astrophysics Data System (ADS)

    Humble, T. S.; McCaskey, A. J.; Bennink, R. S.; Billings, J. J.; DʼAzevedo, E. F.; Sullivan, B. D.; Klymko, C. F.; Seddiqi, H.

    2014-01-01

    Adiabatic quantum computing is a promising route to the computational power afforded by quantum information processing. The recent availability of adiabatic hardware has raised challenging questions about how to evaluate adiabatic quantum optimization (AQO) programs. Processor behavior depends on multiple steps to synthesize an adiabatic quantum program, which are each highly tunable. We present an integrated programming and development environment for AQO called Jade Adiabatic Development Environment (JADE) that provides control over all the steps taken during program synthesis. JADE captures the workflow needed to rigorously specify the AQO algorithm while allowing a variety of problem types, programming techniques, and processor configurations. We have also integrated JADE with a quantum simulation engine that enables program profiling using numerical calculation. The computational engine supports plug-ins for simulation methodologies tailored to various metrics and computing resources. We present the design, integration, and deployment of JADE and discuss its potential use for benchmarking AQO programs by the quantum computer science community.

  18. Adiabatic theory, Liapunov exponents, and rotation number for quadratic Hamiltonians

    NASA Astrophysics Data System (ADS)

    Delyon, François; Foulon, Patrick

    1987-11-01

    We consider the adiabatic problem for general time-dependent quadratic Hamiltonians and develop a method quite different from WKB. In particular, we apply our results to the Schrödinger equation in a strip. We show that there exists a first regular step (avoiding resonance problems) providing one adiabatic invariant, bounds on the Liapunov exponents, and estimates on the rotation number at any order of the perturbation theory. The further step is shown to be equivalent to a quantum adiabatic problem, which, by the usual adiabatic techniques, provides the other possible adiabatic invariants. In the special case of the Schrödinger equation our method is simpler and more powerful than the WKB techniques.

  19. Adiabatic vs. non-adiabatic determination of specific absorption rate of ferrofluids

    NASA Astrophysics Data System (ADS)

    Natividad, Eva; Castro, Miguel; Mediano, Arturo

    2009-05-01

    The measurement of temperature variations in adiabatic conditions allows the determination of the specific absorption rate of magnetic nanoparticles and ferrofluids from the correct incremental expression, SAR=(1/ m MNP) C(Δ T/Δ t). However, when measurements take place in non-adiabatic conditions, one must approximate this expression by SAR≈ Cβ/ m MNP, where β is the initial slope of the temperature vs. time curve during alternating field application. The errors arising from the use of this approximation were estimated through several experiments with different isolating conditions, temperature sensors and sample-sensor contacts. It is concluded that small to appreciable errors can appear, which are difficult to infer or control.

  20. Non-adiabatic molecular dynamics with complex quantum trajectories. II. The adiabatic representation

    SciTech Connect

    Zamstein, Noa; Tannor, David J.

    2012-12-14

    We present a complex quantum trajectory method for treating non-adiabatic dynamics. Each trajectory evolves classically on a single electronic surface but with complex position and momentum. The equations of motion are derived directly from the time-dependent Schroedinger equation, and the population exchange arises naturally from amplitude-transfer terms. In this paper the equations of motion are derived in the adiabatic representation to complement our work in the diabatic representation [N. Zamstein and D. J. Tannor, J. Chem. Phys. 137, 22A517 (2012)]. We apply our method to two benchmark models introduced by John Tully [J. Chem. Phys. 93, 1061 (1990)], and get very good agreement with converged quantum-mechanical calculations. Specifically, we show that decoherence (spatial separation of wavepackets on different surfaces) is already contained in the equations of motion and does not require ad hoc augmentation.

  1. Energy decomposition analysis in an adiabatic picture.

    PubMed

    Mao, Yuezhi; Horn, Paul R; Head-Gordon, Martin

    2017-02-22

    Energy decomposition analysis (EDA) of electronic structure calculations has facilitated quantitative understanding of diverse intermolecular interactions. Nevertheless, such analyses are usually performed at a single geometry and thus decompose a "single-point" interaction energy. As a result, the influence of the physically meaningful EDA components on the molecular structure and other properties are not directly obtained. To address this gap, the absolutely localized molecular orbital (ALMO)-EDA is reformulated in an adiabatic picture, where the frozen, polarization, and charge transfer energy contributions are defined as energy differences between the stationary points on different potential energy surfaces (PESs), which are accessed by geometry optimizations at the frozen, polarized and fully relaxed levels of density functional theory (DFT). Other molecular properties such as vibrational frequencies can thus be obtained at the stationary points on each PES. We apply the adiabatic ALMO-EDA to different configurations of the water dimer, the water-Cl(-) and water-Mg(2+)/Ca(2+) complexes, metallocenes (Fe(2+), Ni(2+), Cu(2+), Zn(2+)), and the ammonia-borane complex. This method appears to be very useful for unraveling how physical effects such as polarization and charge transfer modulate changes in molecular properties induced by intermolecular interactions. As an example of the insight obtained, we find that a linear hydrogen bond geometry for the water dimer is preferred even without the presence of polarization and charge transfer, while the red shift in the OH stretch frequency is primarily a charge transfer effect; by contrast, a near-linear geometry for the water-chloride hydrogen bond is achieved only when charge transfer is allowed.

  2. Interpretation and creationism.

    PubMed

    Ahumada, J L

    1994-08-01

    This paper is an attempt to raise questions about certain underlying and implicit assumptions in some hermeneutic and narrative approaches to psychoanalysis. Starting from the view that Freud saw interpretation in the clinical setting as an attempt to unveil the analysand's psychic reality, it is argued that he envisaged that psychoanalysis aims to interpret what is real in the analysand's inner world--an empirical line of thought underpinned by the idea of analytic neutrality and an emphasis on the analysand's capacity to judge reality. By contrast, the tendency within the hermeneutic-narrative tradition is to demote psychic reality in favour of an emphasis on the analyst's capacity to interpret in order to help his analysand construct meaning. This approach may be said to put the analyst's words in the place of those of the Creator; in other words, it amounts to a 'verbal creationism', which the author argues is rooted in the idealistic philosophy of Hegel, Vico and Descartes and, further back, can be traced to the Book of Genesis--a conclusion causing the author to express some reservations.

  3. Anti-creationism in America

    NASA Astrophysics Data System (ADS)

    Park, Hee-Joo

    This thesis documents the development of organised anti-creationism in America. The revival of creationism culminated in the late 1970s with the success of creationists' national campaign for the introduction of legislation mandating "equal-time" for scientific creationism and evolution in the public schools. This prompted a proliferation of local protest groups which were eventually linked by the network called the Committees of Correspondence. This network became the political arm of the anti-creation movement at the grass-roots level. On the other hand, a small group of evolutionists responded to the creationist arguments by launching a journal, Creation/Evolution, which disseminated anti-creationism arguments. At the educational front, the National Association of Biology Teachers led the battle. These political, polemical and educational efforts were combined and evolved into the National Center for Science Education in 1986. With the NCSE, the evolution camp for the first time had its own full-time defenders to oppose large well-financed anti-evolution efforts. It appears, however, that the impact of organised anti-creationism was fairly limited. Evidence suggests that, despite anti-creationists' concerted efforts, the creationist movement in the nineties is as vigorous as ever and its influence on public beliefs about origins of the organic world remains strong. Gallup Polls have consistently shown that almost half of the adult population in the U.S. believes in the creation of humans about 10,000 years ago. Despite this dismal situation, major scientific bodies have failed to become directly engaged in the anti-creationism campaign due to their concern over public relation. Scientific organisations depend on public support for their research funds and therefore they generally do not want to offend the public by directly challenging its cherished beliefs such as creationism. Therefore, the ongoing battle has been largely left in the hands of individual

  4. On the General Class of Models of Adiabatic Evolution

    NASA Astrophysics Data System (ADS)

    Sun, Jie; Lu, Songfeng; Liu, Fang

    2016-10-01

    The general class of models of adiabatic evolution was proposed to speed up the usual adiabatic computation in the case of quantum search problem. It was shown [8] that, by temporarily increasing the ground state energy of a time-dependent Hamiltonian to a suitable quantity, the quantum computation can perform the calculation in time complexity O(1). But it is also known that if the overlap between the initial and final states of the system is zero, then the computation based on the generalized models of adiabatic evolution can break down completely. In this paper, we find another severe limitation for this class of adiabatic evolution-based algorithms, which should be taken into account in applications. That is, it is still possible that this kind of evolution designed to deal with the quantum search problem fails completely if the interpolating paths in the system Hamiltonian are chosen inappropriately, while the usual adiabatic evolutions can do the same job relatively effectively. This implies that it is not always recommendable to use nonlinear paths in adiabatic computation. On the contrary, the usual simple adiabatic evolution may be sufficient for effective use.

  5. Effects of EOS adiabat on hot spot dynamics

    NASA Astrophysics Data System (ADS)

    Cheng, Baolian; Kwan, Thomas; Wang, Yi-Ming; Batha, Steven

    2013-10-01

    Equation of state (EOS) and adiabat of the pusher play significant roles in the dynamics and formation of the hot spot of an ignition capsule. For given imploding energy, they uniquely determine the partition of internal energy, mass, and volume between the pusher and the hot spot. In this work, we apply the new scaling laws recently derived by Cheng et al. to the National Ignition Campaign (NIC) ignition capsules and study the impacts of EOS and adiabat of the pusher on the hot spot dynamics by using the EOS adiabat index as an adjustable model parameter. We compare our analysis with the NIC data, specifically, for shots N120321 and N120205, and with the numerical simulations of these shots. The predictions from our theoretical model are in good agreements with the NIC data when a hot adiabat was used for the pusher, and with code simulations when a cold adiabat was used for the pusher. Our analysis indicates that the actual adiabat of the pusher in NIC experiments may well be higher than the adiabat assumed in the simulations. This analysis provides a physical and systematic explanation to the ongoing disagreements between the NIC experimental results and the multi-dimensional numerical simulations. This work was performed under the auspices of the U.S. Department of Energy by the Los Alamos National Laboratory under contract number W-7405-ENG-36.

  6. Non-adiabatic perturbations in Ricci dark energy model

    SciTech Connect

    Karwan, Khamphee; Thitapura, Thiti E-mail: nanodsci2523@hotmail.com

    2012-01-01

    We show that the non-adiabatic perturbations between Ricci dark energy and matter can grow both on superhorizon and subhorizon scales, and these non-adiabatic perturbations on subhorizon scales can lead to instability in this dark energy model. The rapidly growing non-adiabatic modes on subhorizon scales always occur when the equation of state parameter of dark energy starts to drop towards -1 near the end of matter era, except that the parameter α of Ricci dark energy equals to 1/2. In the case where α = 1/2, the rapidly growing non-adiabatic modes disappear when the perturbations in dark energy and matter are adiabatic initially. However, an adiabaticity between dark energy and matter perturbations at early time implies a non-adiabaticity between matter and radiation, this can influence the ordinary Sachs-Wolfe (OSW) effect. Since the amount of Ricci dark energy is not small during matter domination, the integrated Sachs-Wolfe (ISW) effect is greatly modified by density perturbations of dark energy, leading to a wrong shape of CMB power spectrum. The instability in Ricci dark energy is difficult to be alleviated if the effects of coupling between baryon and photon on dark energy perturbations are included.

  7. MICROSTRUCTURE IN ADIABATIC SHEAR BANDS IN A PEARLITIC ULTRAHIGH CARBON STEEL

    SciTech Connect

    Syn, C K; Lesuer, D R; Sherby, O D

    2003-09-22

    Adiabatic shear bands, obtained in compression deformation at a strain rate of 4000 s{sup -1}, in a pearlitic 1.3%C steel, were investigated. Shear-bands initiated at 55% compression deformation with the width of the band equal to 14 {micro}m. Nano-indentor hardness of the shear band was 11.5 GPa in contrast to the initial matrix hardness of 3.5 GPa. The high strength of the shear band is attributed to its creation from two sequential events. First, large strain deformation, at a high strain rate, accompanied by adiabatic heating, led to phase transformation to austenite. Second, retransformation upon rapid cooling occurred by a divorced eutectoid transformation. The result is a predicted microstructure consisting of nano-size carbide particles within a matrix of fine ferrite grains. It is proposed that the divorced eutectoid transformation occurs in iron-carbon steels during high rate deformation in ball milling, ball drop tests and in commercial wire drawing.

  8. Statistical mechanics of Roskilde liquids: Configurational adiabats, specific heat contours, and density dependence of the scaling exponent

    SciTech Connect

    Bailey, Nicholas P.; Bøhling, Lasse; Veldhorst, Arno A.; Schrøder, Thomas B.; Dyre, Jeppe C.

    2013-11-14

    We derive exact results for the rate of change of thermodynamic quantities, in particular, the configurational specific heat at constant volume, C{sub V}, along configurational adiabats (curves of constant excess entropy S{sub ex}). Such curves are designated isomorphs for so-called Roskilde liquids, in view of the invariance of various structural and dynamical quantities along them. The slope of the isomorphs in a double logarithmic representation of the density-temperature phase diagram, γ, can be interpreted as one third of an effective inverse power-law potential exponent. We show that in liquids where γ increases (decreases) with density, the contours of C{sub V} have smaller (larger) slope than configurational adiabats. We clarify also the connection between γ and the pair potential. A fluctuation formula for the slope of the C{sub V}-contours is derived. The theoretical results are supported with data from computer simulations of two systems, the Lennard-Jones fluid, and the Girifalco fluid. The sign of dγ/dρ is thus a third key parameter in characterizing Roskilde liquids, after γ and the virial-potential energy correlation coefficient R. To go beyond isomorph theory we compare invariance of a dynamical quantity, the self-diffusion coefficient, along adiabats and C{sub V}-contours, finding it more invariant along adiabats.

  9. Dual origin of pairing in nuclei

    NASA Astrophysics Data System (ADS)

    Idini, A.; Potel, G.; Barranco, F.; Vigezzi, E.; Broglia, R. A.

    2016-11-01

    The pairing correlations of the nucleus 120Sn are calculated by solving the Nambu-Gor'kov equations, including medium polarization effects resulting from the interweaving of quasiparticles, spin and density vibrations, taking into account, within the framework of nuclear field theory (NFT), processes leading to self-energy and vertex corrections and to the induced pairing interaction. From these results one can not only demonstrate the inevitability of the dual origin of pairing in nuclei, but also extract information which can be used at profit to quantitatively disentangle the contributions to the pairing gap Δ arising from the bare and from the induced pairing interaction. The first is the strong 1 S 0 short-range NN potential resulting from meson exchange between nucleons moving in time reversal states within an energy range of hundreds of MeV from the Fermi energy. The second results from the exchange of vibrational modes between nucleons moving within few MeV from the Fermi energy. Short- ( v p bare) and long-range ( v p ind) pairing interactions contribute essentially equally to nuclear Cooper pair stability. That is to the breaking of gauge invariance in open-shell superfluid nuclei and thus to the order parameter, namely to the ground state expectation value of the pair creation operator. In other words, to the emergent property of generalized rigidity in gauge space, and associated rotational bands and Cooper pair tunneling between members of these bands.

  10. Dynamics of Charged Particles in an Adiabatic Thermal Beam Equilibrium

    NASA Astrophysics Data System (ADS)

    Chen, Chiping; Wei, Haofei

    2010-11-01

    Charged-particle motion is studied in the self-electric and self-magnetic fields of a well-matched, intense charged-particle beam and an applied periodic solenoidal magnetic focusing field. The beam is assumed to be in a state of adiabatic thermal equilibrium. The phase space is analyzed and compared with that of the well-known Kapchinskij-Vladimirskij (KV)-type beam equilibrium. It is found that the widths of nonlinear resonances in the adiabatic thermal beam equilibrium are narrower than those in the KV-type beam equilibrium. Numerical evidence is presented, indicating almost complete elimination of chaotic particle motion in the adiabatic thermal beam equilibrium.

  11. Quantum adiabatic optimization and combinatorial landscapes

    NASA Astrophysics Data System (ADS)

    Smelyanskiy, V. N.; Knysh, S.; Morris, R. D.

    2004-09-01

    In this paper we analyze the performance of the Quantum Adiabatic Evolution algorithm on a variant of the satisfiability problem for an ensemble of random graphs parametrized by the ratio of clauses to variables, γ=M/N . We introduce a set of macroscopic parameters (landscapes) and put forward an ansatz of universality for random bit flips. We then formulate the problem of finding the smallest eigenvalue and the excitation gap as a statistical mechanics problem. We use the so-called annealing approximation with a refinement that a finite set of macroscopic variables (instead of only energy) is used, and are able to show the existence of a dynamic threshold γ=γd starting with some value of K —the number of variables in each clause. Beyond the dynamic threshold, the algorithm should take an exponentially long time to find a solution. We compare the results for extended and simplified sets of landscapes and provide numerical evidence in support of our universality ansatz. We have been able to map the ensemble of random graphs onto another ensemble with fluctuations significantly reduced. This enabled us to obtain tight upper bounds on the satisfiability transition and to recompute the dynamical transition using the extended set of landscapes.

  12. Design of the PIXIE adiabatic demagnetization refrigerators

    NASA Astrophysics Data System (ADS)

    Shirron, Peter J.; Kimball, Mark O.; Fixsen, Dale J.; Kogut, Alan J.; Li, Xiaoyi; DiPirro, Michael J.

    2012-04-01

    The Primordial Inflation Explorer (PIXIE) is a proposed mission to densely map the polarization of the cosmic microwave background. It will operate in a scanning mode from a sun-synchronous orbit, using low temperature detectors (at 0.1 K) and located inside a telescope that is cooled to approximately 2.73 K - to match the background temperature. A mechanical cryocooler operating at 4.5 K establishes a low base temperature from which two adiabatic demagnetization refrigerator (ADR) assemblies will cool the telescope and detectors. To achieve continuous scanning capability, the ADRs must operate continuously. Complicating the design are two factors: (1) the need to systematically vary the temperature of various telescope components in order to separate the small polarization signal variations from those that may arise from temperature drifts and changing gradients within the telescope, and (2) the orbital and monthly variations in lunar irradiance into the telescope barrels. These factors require the telescope ADR to reject quasi-continuous heat loads of 2-3 mW, while maintaining a peak heat reject rate of less than 12 mW. The detector heat load at 0.1 K is comparatively small at 1-2 μW. This paper will describe the 3-stage and 2-stage continuous ADRs that will be used to meet the cooling power and temperature stability requirements of the PIXIE detectors and telescope.

  13. Adiabatic quantum algorithm for search engine ranking.

    PubMed

    Garnerone, Silvano; Zanardi, Paolo; Lidar, Daniel A

    2012-06-08

    We propose an adiabatic quantum algorithm for generating a quantum pure state encoding of the PageRank vector, the most widely used tool in ranking the relative importance of internet pages. We present extensive numerical simulations which provide evidence that this algorithm can prepare the quantum PageRank state in a time which, on average, scales polylogarithmically in the number of web pages. We argue that the main topological feature of the underlying web graph allowing for such a scaling is the out-degree distribution. The top-ranked log(n) entries of the quantum PageRank state can then be estimated with a polynomial quantum speed-up. Moreover, the quantum PageRank state can be used in "q-sampling" protocols for testing properties of distributions, which require exponentially fewer measurements than all classical schemes designed for the same task. This can be used to decide whether to run a classical update of the PageRank.

  14. Adiabatic Quantum Algorithm for Search Engine Ranking

    NASA Astrophysics Data System (ADS)

    Garnerone, Silvano; Zanardi, Paolo; Lidar, Daniel A.

    2012-06-01

    We propose an adiabatic quantum algorithm for generating a quantum pure state encoding of the PageRank vector, the most widely used tool in ranking the relative importance of internet pages. We present extensive numerical simulations which provide evidence that this algorithm can prepare the quantum PageRank state in a time which, on average, scales polylogarithmically in the number of web pages. We argue that the main topological feature of the underlying web graph allowing for such a scaling is the out-degree distribution. The top-ranked log⁡(n) entries of the quantum PageRank state can then be estimated with a polynomial quantum speed-up. Moreover, the quantum PageRank state can be used in “q-sampling” protocols for testing properties of distributions, which require exponentially fewer measurements than all classical schemes designed for the same task. This can be used to decide whether to run a classical update of the PageRank.

  15. On the persistence of adiabatic shear bands

    NASA Astrophysics Data System (ADS)

    Boakye-Yiadom, S.; Bassim, M. N.; Al-Ameeri, S.

    2012-08-01

    It is generally agreed that the initiation and development of adiabatic shear bands (ASBs) are manifestations of damage in metallic materials subjected to high strain rates and large strains as those due to impact in a Hopkinson Bar system. Models for evolution of these bands have been described in the literature. One question that has not received attention is how persistent these bands are and whether their presence and effect can be reversed or eliminated by using a process of thermal (heat treatment) or thermo-mechanical treatment that would relieve the material from the high strain associated with ASBs and their role as precursors to crack initiation and subsequent failure. Since ASBs are more prevalent and more defined in BCC metals including steels, a study was conducted to investigate the best conditions of generating ASBs in a heat treatable steel, followed by determining the best conditions for heat treatment of specimens already damaged by the presence of ASBs in order to relieve the strains due to ASBs and restore the material to an apparent microstructure without the "scars" due to the previous presence of ASBs. It was found that heat treatment achieves the curing from ASBs. This presentation documents the process undertaken to achieve this objective.

  16. Adiabatic Spin Pumping with Quantum Dots

    NASA Astrophysics Data System (ADS)

    Mucciolo, Eduardo R.

    Electronic transport in mesoscopic systems has been intensively studied for more the last three decades. While there is a substantial understanding of the stationary regime, much less is know about phase-coherent nonequilibrium transport when pulses or ac perturbations are used to drive electrons at low temperatures and at small length scales. However, about 20 years ago Thouless proposed to drive nondissipative currents in quantum systems by applying simultaneously two phase-locked external perturbations. The so-called adiabatic pumping mechanism has been revived in the last few years, both theoretically and experimentally, in part because of the development of lateral semiconductor quantum dots. Here we will explain how open dots can be used to create spin-polarized currents with little or no net charge transfer. The pure spin pump we propose is the analog of a charge battery in conventional electronics and may provide a needed circuit element for spin-based electronics. We will also discuss other relevant issues such as rectification and decoherence and point out possible extensions of the mechanism to closed dots.

  17. 'Ethos' Enabling Organisational Knowledge Creation

    NASA Astrophysics Data System (ADS)

    Matsudaira, Yoshito

    This paper examines knowledge creation in relation to improvements on the production line in the manufacturing department of Nissan Motor Company and aims to clarify embodied knowledge observed in the actions of organisational members who enable knowledge creation will be clarified. For that purpose, this study adopts an approach that adds a first, second, and third-person's viewpoint to the theory of knowledge creation. Embodied knowledge, observed in the actions of organisational members who enable knowledge creation, is the continued practice of 'ethos' (in Greek) founded in Nissan Production Way as an ethical basis. Ethos is knowledge (intangible) assets for knowledge creating companies. Substantiated analysis classifies ethos into three categories: the individual, team and organisation. This indicates the precise actions of the organisational members in each category during the knowledge creation process. This research will be successful in its role of showing the indispensability of ethos - the new concept of knowledge assets, which enables knowledge creation -for future knowledge-based management in the knowledge society.

  18. Acceleration of adiabatic quantum dynamics in electromagnetic fields

    SciTech Connect

    Masuda, Shumpei; Nakamura, Katsuhiro

    2011-10-15

    We show a method to accelerate quantum adiabatic dynamics of wave functions under electromagnetic field (EMF) by developing the preceding theory [Masuda and Nakamura, Proc. R. Soc. London Ser. A 466, 1135 (2010)]. Treating the orbital dynamics of a charged particle in EMF, we derive the driving field which accelerates quantum adiabatic dynamics in order to obtain the final adiabatic states in any desired short time. The scheme is consolidated by describing a way to overcome possible singularities in both the additional phase and driving potential due to nodes proper to wave functions under EMF. As explicit examples, we exhibit the fast forward of adiabatic squeezing and transport of excited Landau states with nonzero angular momentum, obtaining the result consistent with the transitionless quantum driving applied to the orbital dynamics in EMF.

  19. Adiabatic shear bands localization in materials undergoing deformations

    NASA Astrophysics Data System (ADS)

    Ryabov, P. N.; Kudryashov, N. A.; Muratov, R. V.

    2017-01-01

    We consider the adiabatic shear banding phenomenon in composite materials undergoing the high speed shear deformations. The mathematical model of adiabatic shear banding in thermo-visco-plastic material is given. New two step numerical algorithm which is based on the Courant-Isaacson-Rees scheme that allows one to simulate fully localized plastic flow from initial stage of localization is proposed. To test this numerical algorithm we use three benchmark problems. The testing results show the accuracy and efficiency of proposed algorithm. The features of adiabatic shear bands formation in composites are studied. The existence of characteristic depth of localization in composites is shown. Influence of initial temperature distribution on the processes of adiabatic shear bands formation in composites is considered.

  20. Adiabaticity and spectral splits in collective neutrino transformations

    SciTech Connect

    Raffelt, Georg G.; Smirnov, Alexei Yu.

    2007-12-15

    Neutrinos streaming off a supernova core transform collectively by neutrino-neutrino interactions, leading to 'spectral splits' where an energy E{sub split} divides the transformed spectrum sharply into parts of almost pure but different flavors. We present a detailed description of the spectral-split phenomenon which is conceptually and quantitatively understood in an adiabatic treatment of neutrino-neutrino effects. Central to this theory is a self-consistency condition in the form of two sum rules (integrals over the neutrino spectra that must equal certain conserved quantities). We provide explicit analytic and numerical solutions for various neutrino spectra. We introduce the concept of the adiabatic reference frame and elaborate on the relative adiabatic evolution. Violating adiabaticity leads to the spectral split being 'washed out'. The sharpness of the split appears to be represented by a surprisingly universal function.

  1. Adiabatic and isocurvature perturbation projections in multi-field inflation

    SciTech Connect

    Gordon, Chris; Saffin, Paul M. E-mail: Paul.Saffin@nottingham.ac.uk

    2013-08-01

    Current data are in good agreement with the predictions of single field inflation. However, the hemispherical asymmetry, seen in the cosmic microwave background data, may hint at a potential problem. Generalizing to multi-field models may provide one possible explanation. A useful way of modeling perturbations in multi-field inflation is to investigate the projection of the perturbation along and perpendicular to the background fields' trajectory. These correspond to the adiabatic and isocurvature perturbations. However, it is important to note that in general there are no corresponding adiabatic and isocurvature fields. The purpose of this article is to highlight the distinction between a field redefinition and a perturbation projection. We provide a detailed derivation of the evolution of the isocurvature perturbation to show that no assumption of an adiabatic or isocurvature field is needed. We also show how this evolution equation is consistent with the field covariant evolution equations for the adiabatic perturbation in the flat field space limit.

  2. Ultrafast stimulated Raman parallel adiabatic passage by shaped pulses

    SciTech Connect

    Dridi, G.; Guerin, S.; Hakobyan, V.; Jauslin, H. R.; Eleuch, H.

    2009-10-15

    We present a general and versatile technique of population transfer based on parallel adiabatic passage by femtosecond shaped pulses. Their amplitude and phase are specifically designed to optimize the adiabatic passage corresponding to parallel eigenvalues at all times. We show that this technique allows the robust adiabatic population transfer in a Raman system with the total pulse area as low as 3{pi}, corresponding to a fluence of one order of magnitude below the conventional stimulated Raman adiabatic passage process. This process of short duration, typically picosecond and subpicosecond, is easily implementable with the modern pulse shaper technology and opens the possibility of ultrafast robust population transfer with interesting applications in quantum information processing.

  3. Shortcuts to adiabaticity for non-Hermitian systems

    SciTech Connect

    Ibanez, S.; Martinez-Garaot, S.; Torrontegui, E.; Muga, J. G.; Chen Xi

    2011-08-15

    Adiabatic processes driven by non-Hermitian, time-dependent Hamiltonians may be sped up by generalizing inverse engineering techniques based on counter-diabatic (transitionless driving) algorithms or on dynamical invariants. We work out the basic theory and examples described by two-level Hamiltonians: the acceleration of rapid adiabatic passage with a decaying excited level and of the dynamics of a classical particle on an expanding harmonic oscillator.

  4. Nonadiabatic transitions in finite-time adiabatic rapid passage

    NASA Astrophysics Data System (ADS)

    Lu, T.; Miao, X.; Metcalf, H.

    2007-06-01

    To apply the adiabatic rapid passage process repetitively [T. Lu, X. Miao, and H. Metcalf, Phys. Rev. A 71, 061405(R) (2005)], the nonadiabatic transition probability of a two-level atom subject to chirped light pulses over a finite period of time needs to be calculated. Using a unitary first-order perturbation method in the rotating adiabatic frame, an approximate formula has been derived for such transition probabilities in the entire parameter space of the pulses.

  5. ENTROPY-VORTEX WAVES IN NON-ADIABATIC FLOWS

    SciTech Connect

    Ibáñez S, Miguel H.

    2016-02-20

    The Ertel theorem on the vorticity along the flow of adiabatic fluids is generalized for non-adiabatic flows. Several limiting cases are analyzed and the results are applied to flows behind different hydrodynamics fronts, particularly to thermal fronts (heat and cooling fronts). An important conclusion of the present analysis is that vorticity is inherent in the condensation’s (or hot spots) formation by thermal instabilities in plasma flows. Implications for several astrophysical plasmas are outlined.

  6. Vacuum vessel eddy current modeling for TFTR adiabatic compression experiments

    SciTech Connect

    DeLucia, J.; Bell, M.; Wong, K.L.

    1985-07-01

    A relatively simple current filament model of the TFTR vacuum vessel is described. It is used to estimate the three-dimensional structure of magnetic field perturbations in the vicinity of the plasma that arise from vacuum vessel eddy currents induced during adiabatic compression. Eddy currents are calculated self-consistently with the plasma motion. The Shafranov formula and adiabatic scaling laws are used to model the plasma. Although the specific application is to TFTR, the present model is of generation applicability.

  7. A connection between mix and adiabat in ICF capsules

    NASA Astrophysics Data System (ADS)

    Cheng, Baolian; Kwan, Thomas; Wang, Yi-Ming; Yi, Sunghuan (Austin); Batha, Steven

    2016-10-01

    We study the relationship between instability induced mix, preheat and the adiabat of the deuterium-tritium (DT) fuel in fusion capsule experiments. Our studies show that hydrodynamic instability not only directly affects the implosion, hot spot shape and mix, but also affects the thermodynamics of the capsule, such as, the adiabat of the DT fuel, and, in turn, affects the energy partition between the pusher shell (cold DT) and the hot spot. It was found that the adiabat of the DT fuel is sensitive to the amount of mix caused by Richtmyer-Meshkov (RM) and Rayleigh-Taylor (RT) instabilities at the material interfaces due to its exponential dependence on the fuel entropy. An upper limit of mix allowed maintaining a low adiabat of DT fuel is derived. Additionally we demonstrated that the use of a high adiabat for the DT fuel in theoretical analysis and with the aid of 1D code simulations could explain some aspects of the 3D effects and mix in the capsule experiments. Furthermore, from the observed neutron images and our physics model, we could infer the adiabat of the DT fuel in the capsule and determine the possible amount of mix in the hot spot (LA-UR-16-24880). This work was conducted under the auspices of the U.S. Department of Energy by the Los Alamos National Laboratory under Contract No. W-7405-ENG-36.

  8. Adiabatic and non-adiabatic charge pumping in a single-level molecular motor

    NASA Astrophysics Data System (ADS)

    Napitu, B. D.; Thijssen, J. M.

    2015-07-01

    We propose a design for realizing quantum charge pump based on a recent proposal for a molecular motor (Seldenthuis J S et al 2010 ACS Nano 4 6681). Our design is based on the presence of a moiety with a permanent dipole moment which can rotate, thereby modulating the couplings to metallic contacts at both ends of the molecule. Using the non-equilibrium Keldysh Green’s function formalism (NEGF), we show that our design indeed generates a pump current. In the non-interacting pump, the variation of frequency from adiabatic to non-adiabatic regime, can be used to control the direction as well as the amplitude of the average current. The effect of Coulomb interaction is considered within the first- and the second- order perturbation. The numerical implementation of the scheme is quite demanding, and we develop an analytical approximation to obtain a speed-up giving results within a reasonable time. We find that the amplitude of the average pumped current can be controlled by both the driving frequency and the Coulomb interaction. The direction of of pumped current is shown to be determined by the phase difference between left and right anchoring groups.

  9. Adiabatic and non-adiabatic charge pumping in a single-level molecular motor.

    PubMed

    Napitu, B D; Thijssen, J M

    2015-07-15

    We propose a design for realizing quantum charge pump based on a recent proposal for a molecular motor (Seldenthuis J S et al 2010 ACS Nano 4 6681). Our design is based on the presence of a moiety with a permanent dipole moment which can rotate, thereby modulating the couplings to metallic contacts at both ends of the molecule. Using the non-equilibrium Keldysh Green's function formalism (NEGF), we show that our design indeed generates a pump current. In the non-interacting pump, the variation of frequency from adiabatic to non-adiabatic regime, can be used to control the direction as well as the amplitude of the average current. The effect of Coulomb interaction is considered within the first- and the second- order perturbation. The numerical implementation of the scheme is quite demanding, and we develop an analytical approximation to obtain a speed-up giving results within a reasonable time. We find that the amplitude of the average pumped current can be controlled by both the driving frequency and the Coulomb interaction. The direction of of pumped current is shown to be determined by the phase difference between left and right anchoring groups.

  10. Color, light, and altruistic creation

    NASA Astrophysics Data System (ADS)

    Charnay, Yves

    2002-06-01

    It seems necessary to me to combine a certain technical inventivity with plastic creation, a particular poetry arises from this relation. The sources of inspiration for works, especially works in which color plays a pre-eminent role, do not only come from nature. The fantasy of the creators evolves and changes thanks to discoveries and technological inventions. My work as a painter has made me particularly sensitive to the diversity of the plastic writings in general and to the chromatic writings in particular. (1) Environmental creation imposes a renewal of the means of creation. Conducting experimental works, I study the particularities of light, mainly its incidence on materials (transmission, reflection, colors, textures, etc.) and its mobility. These works are a source of inspiration for my architectural works and nurture my lectures at the Ecole Nationale Superieure des Arts Decoratifs (National College of Decorative Arts). Environmental creation also imposes some qualities on the artist since he, whether he serves a social entity or a person, serves the whole collectivity. Environmental creation has to be envisaged as an altruistic approach.

  11. Geometrized Instantons and the Creation of the Universe

    NASA Astrophysics Data System (ADS)

    Novello, M.; Oliveira, L. A. R.; Salim, J. M.; Elbaz, E.

    A nonsingular cosmological scenario is presented in which the currently observed Riemannian configuration of spacetime originates from a primordial Weylian “stiff matter” phase driven by a geometrized inflaton-like field. In the particular case of a Friedman-Robertson-Walker line element, it is shown that an unstable original Minkowski vacuum starts to collapse adiabatically at a remote past and bounces when a minimum radius is attained. Throughout the collapsing stage, this matter-free Universe is accelerated (or “inflationary”). As in models of spontaneous quantum creation, the bouncing phase can be shown to correspond to the propagation of a Weyl instanton in an Euclideanized, classically forbidden region. In the course of the bouncing period, concurrent to the maximal deviation of the Riemannian configuration, a geometry-driven amplification mechanism operates causing the exponential increase of entropy and matter fluctuations. Once the environment temperature is always bounded, this nonadiabatical process stands for a “ Big — but finite — Bang” creation event, followed by a standard radiation-dominated era. The model describes an eternal, Friedman-like open Universe, free of many problems that hinder standard cosmology; the observed existence of a baryon excess also fits naturally within the proposed scheme.

  12. Evolutionary Creation: Moving beyond the Evolution versus Creation Debate

    ERIC Educational Resources Information Center

    Lamoureux, Denis O.

    2010-01-01

    Evolutionary creation offers a conservative Christian approach to evolution. It explores biblical faith and evolutionary science through a Two Divine Books model and proposes a complementary relationship between Scripture and science. The Book of God's Words discloses the spiritual character of the world, while the Book of God's Works reveals the…

  13. LETTERS AND COMMENTS: Adiabatic process reversibility: microscopic and macroscopic views

    NASA Astrophysics Data System (ADS)

    Anacleto, Joaquim; Pereira, Mário G.

    2009-05-01

    The reversibility of adiabatic processes was recently addressed by two publications. In the first (Miranda 2008 Eur. J. Phys. 29 937-43), an equation was derived relating the initial and final volumes and temperatures for adiabatic expansions of an ideal gas, using a microscopic approach. In that relation the parameter r accounts for the process reversibility, ranging between 0 and 1, which corresponds to the free and reversible expansion, respectively. In the second (Anacleto and Pereira 2009 Eur. J. Phys. 30 177-83), the authors have shown that thermodynamics can effectively and efficiently be used to obtain the general law for adiabatic processes carried out by an ideal gas, including compressions, for which r \\ge 1. The present work integrates and extends the aforementioned studies, providing thus further insights into the analysis of the adiabatic process. It is shown that Miranda's work is wholly valid for compressions. In addition, it is demonstrated that the adiabatic reversibility coefficient given in terms of the piston velocity and the root mean square velocity of the gas particles is equivalent to the macroscopic description, given just by the quotient between surroundings and system pressure values.

  14. Experiencing Collaborative Knowledge Creation Processes

    ERIC Educational Resources Information Center

    Jakubik, Maria

    2008-01-01

    Purpose: How people learn and create knowledge together through interactions in communities of practice (CoPs) is not fully understood. The purpose of this paper is to create and apply a model that could increase participants' consciousness about knowledge creation processes. Design/methodology/approach: This four-month qualitative research was…

  15. Creationism, Evolution and the Courts.

    ERIC Educational Resources Information Center

    O'Connor, Karen; Ivers, Gregg

    1988-01-01

    Discusses the continuing controversy over evolution and creationism and the role that the courts have played. Examines the effects that result from this controversy, such as the overly cautious selection of textbooks by adoption committees and publishers' reluctance to include "questionable" materials in new books. (GEA)

  16. Can Teachers Cope with Creationism?

    ERIC Educational Resources Information Center

    Pearson, Craig

    1981-01-01

    The creation/evolution controversy has gained renewed popularity in the last few years. This has resulted in serious implications for science teachers. All classroom teachers need to protect themselves by learning the distinctions between scientific law and theory and to acquire knowledge of the various theories of evolution. (JN)

  17. Evolution versus Creationism in Education

    ERIC Educational Resources Information Center

    Apple, Michael W.

    2008-01-01

    As part of the continuing series of the Reviewing Policy section, this article examines some of the recent literature on the creation-evolution controversy. These controversies are placed within a larger analysis of the growth of authoritarian populist movements in the United States. The article then focuses attention on debates both over a number…

  18. Knowledge Creation in Constructivist Learning

    ERIC Educational Resources Information Center

    Jaleel, Sajna; Verghis, Alie Molly

    2015-01-01

    In today's competitive global economy characterized by knowledge acquisition, the concept of knowledge management has become increasingly prevalent in academic and business practices. Knowledge creation is an important factor and remains a source of competitive advantage over knowledge management. Constructivism holds that learners learn actively…

  19. Uprising of Creation in Education

    ERIC Educational Resources Information Center

    Hatamleh, Habes Mohamed

    2015-01-01

    This research (Uprising of Creation in Education) aims at defining the importance of creativity in education, and its reflection on the elements of the educational process. Creativity is regarded an important element in the nations progress, which depends on the minds of their sons. Creativity became the language of the present age, after the…

  20. Shortcuts to adiabaticity in a time-dependent box

    PubMed Central

    Campo, A. del; Boshier, M. G.

    2012-01-01

    A method is proposed to drive an ultrafast non-adiabatic dynamics of an ultracold gas trapped in a time-dependent box potential. The resulting state is free from spurious excitations associated with the breakdown of adiabaticity, and preserves the quantum correlations of the initial state up to a scaling factor. The process relies on the existence of an adiabatic invariant and the inversion of the dynamical self-similar scaling law dictated by it. Its physical implementation generally requires the use of an auxiliary expulsive potential. The method is extended to a broad family of interacting many-body systems. As illustrative examples we consider the ultrafast expansion of a Tonks-Girardeau gas and of Bose-Einstein condensates in different dimensions, where the method exhibits an excellent robustness against different regimes of interactions and the features of an experimentally realizable box potential. PMID:22970340

  1. Adiabatic circular polarizer based on chiral fiber grating.

    PubMed

    Yang, Li; Xue, Lin-Lin; Li, Cheng; Su, Jue; Qian, Jing-Ren

    2011-01-31

    Based on the adiabatic coupling principle, a new scheme of a broadband circular polarizer formed by twisting a high-birefringence (Hi-Bi) fiber with a slowly varying twist rate is proposed. The conditions of adiabatic coupling for the adiabatic polarizer are first identified through analytical derivations. These conditions are easily realized by choosing a reasonable variation of the twist rate. Moreover, the bandwidth of the polarizer is able to be directly determined by the twist rates at the two ends. Finally, the broadband characteristics of the polarizer are demonstrated by simulations. It is also shown that the performance of the polarizer can be remarkably improved by accomplishing a multi-mode phase-matching along the grating or by using of the couplings of the core mode to lossy modes.

  2. Effect of dephasing on stimulated Raman adiabatic passage

    SciTech Connect

    Ivanov, P.A.; Vitanov, N.V.; Bergmann, K.

    2004-12-01

    This work explores the effect of phase relaxation on the population transfer efficiency in stimulated Raman adiabatic passage (STIRAP). The study is based on the Liouville equation, which is solved analytically in the adiabatic limit. The transfer efficiency of STIRAP is found to decrease exponentially with the dephasing rate; this effect is stronger for shorter pulse delays and weaker for larger delays, since the transition time is found to be inversely proportional to the pulse delay. Moreover, it is found that the transfer efficiency of STIRAP in the presence of dephasing does not depend on the peak Rabi frequencies at all, as long as they are sufficiently large to enforce adiabatic evolution; hence increasing the field intensity cannot reduce the dephasing losses. It is shown also that for any dephasing rate, the final populations of the initial state and the intermediate state are equal. For strong dephasing all three populations tend to (1/3)

  3. Applications of chirped Raman adiabatic rapid passage to atom interferometry

    NASA Astrophysics Data System (ADS)

    Kotru, Krish; Butts, David L.; Kinast, Joseph M.; Johnson, David M. S.; Radojevic, Antonije M.; Timmons, Brian P.; Stoner, Richard E.

    2012-02-01

    We present robust atom optics, based on chirped Raman adiabatic rapid passage (ARP), in the context of atom interferometry. Such ARP light pulses drive coherent population transfer between two hyperfine ground states by sweeping the frequency difference of two fixed-intensity optical fields with large single photon detunings. Since adiabatic transfer is less sensitive to atom temperature and non-uniform Raman beam intensity than standard Raman pulses, this approach should improve the stability of atom interferometers operating in dynamic environments. In such applications, chirped Raman ARP may also provide advantages over the previously demonstrated stimulated Raman adiabatic passage (STIRAP) technique, which requires precise modulation of beam intensity and zeroing of the single photon detuning. We demonstrate a clock interferometer with chirped Raman ARP pulses, and compare its stability to that of a conventional Raman pulse interferometer. We also discuss potential improvements to inertially sensitive atom interferometers. Copyright 2011 by The Charles Stark Draper Laboratory, Inc. All rights reserved.

  4. Adiabatic Pseudospectral Technique: Applications to Four Atom Molecules

    NASA Astrophysics Data System (ADS)

    Antikainen, Jyrki Tapio

    1995-01-01

    After the introduction, in chapter 2 we review some of the well established techniques used to solve the Schrodinger equation. The following methods are discussed: the Finite Basis Representation, the Discrete Variable Representation, the Basic Light basis set truncation, and the Lanczos tridiagonalization. After reviewing the previous techniques we present the main features of our Adiabatic Pseudospectral (APS) technique. The Adiabatic Pseudospectral technique is a synthesis of several powerful computational methods such as the sequential adiabatic basis set reduction, the iterative Lanczos diagonalization, the collocation techniques, and a careful implementation of the matrix -vector product for the Hamiltonian in the reduced adiabatic representation. In chapter 3 we use our adiabatic pseudospectral method (APS) to calculate energy levels of the H _2O_2 molecule up to 5000 cm ^{-1}. Reasonably high accuracy (a few wavenumbers) is achieved for a fully six dimensional calculation in a few hours of CPU time on an IBM 580 workstation. These results are a great improvement over previous calculations on the same system which required 50-100 times more computational effort for a similar level of accuracy. The method presented here is both general and robust. It will allow for routine studies of six dimensional potential surfaces and the associated spectroscopy, while making calculations on still larger systems feasible. In chapter 4 the adiabatic pseudospectral method is used to study the high energy vibrational levels of the H_2C_2 molecule. We calculate stimulated emission pumping spectra initialized by the excited electronic state vibrational trans-bent state ~ A_sp{u}{1 }3_{nu}_3 . The calculations show that with the APS-method we can easily investigate energy regions in the excess of 15,000 cm^{-1}; these high energy regions have been previously unattainable by computational techniques.

  5. The quantum and thermodynamical characteristics of fission taking into account adiabatic and nonadiabatic modes of motion

    SciTech Connect

    Kadmensky, S. G.

    2007-09-15

    In the framework of the quantum theory of spontaneous and low-energy induced fission, the nature of quantum and thermodynamical properties of a fissioning system is analyzed taking into account adiabatic and nonadiabatic modes of motion for different fission stages. It is shown that, owing to the influence of the Coriolis interaction, the states of the fissile nucleus and of primary fission products are cold and strongly nonequilibrium. The important role of superfluid and pairing nucleon-nucleon correlations for binary and ternary fission is demonstrated. The mechanism of pumping of high values of relative orbital momenta and spins of fission fragments for binary and ternary fission and the nonevaporation mechanism of formation of third particles for ternary fission are investigated. The anisotropies and P-odd, P-even, and T-odd asymmetries for angular distributions of fission products are analyzed.

  6. Control of Diabatic versus Adiabatic Field Dissociation in a Heavy Rydberg System

    SciTech Connect

    Shiell, R.C.; Reinhold, E.; Ubachs, W.; Magnus, F.

    2005-11-18

    A novel phenomenon is observed in the dynamics of laser-prepared coherent wave packets, bound by the Coulombic 1/r potential of an ion-pair system. After exciting weakly bound ({approx_equal}3 meV) H{sup +}F{sup -} wave packets in a Stark field, and permitting them to evolve in time, control of field dissociation via adiabatic and diabatic routes is demonstrated by applying delayed pulsed-electric fields, involving a zero-field crossing. Control manifests itself through the production of ions from each pathway at a different instant in time. This phenomenon is applied to map the oscillatory behavior of an angular momentum wave packet in a heavy Rydberg system. The characteristic frequencies of the observed Stark oscillations verify predicted mass-scaling laws for heavy Rydberg systems.

  7. Spatial adiabatic passage: a review of recent progress

    NASA Astrophysics Data System (ADS)

    Menchon-Enrich, R.; Benseny, A.; Ahufinger, V.; Greentree, A. D.; Busch, Th; Mompart, J.

    2016-07-01

    Adiabatic techniques are known to allow for engineering quantum states with high fidelity. This requirement is currently of large interest, as applications in quantum information require the preparation and manipulation of quantum states with minimal errors. Here we review recent progress on developing techniques for the preparation of spatial states through adiabatic passage, particularly focusing on three state systems. These techniques can be applied to matter waves in external potentials, such as cold atoms or electrons, and to classical waves in waveguides, such as light or sound.

  8. Quantum dynamics by the constrained adiabatic trajectory method

    SciTech Connect

    Leclerc, A.; Jolicard, G.; Guerin, S.; Killingbeck, J. P.

    2011-03-15

    We develop the constrained adiabatic trajectory method (CATM), which allows one to solve the time-dependent Schroedinger equation constraining the dynamics to a single Floquet eigenstate, as if it were adiabatic. This constrained Floquet state (CFS) is determined from the Hamiltonian modified by an artificial time-dependent absorbing potential whose forms are derived according to the initial conditions. The main advantage of this technique for practical implementation is that the CFS is easy to determine even for large systems since its corresponding eigenvalue is well isolated from the others through its imaginary part. The properties and limitations of the CATM are explored through simple examples.

  9. Adiabatic regularisation of power spectra in k-inflation

    SciTech Connect

    Alinea, Allan L.; Kubota, Takahiro; Nakanishi, Yukari; Naylor, Wade E-mail: kubota@celas.osaka-u.ac.jp E-mail: naylor@phys.sci.osaka-u.ac.jp

    2015-06-01

    We look at the question posed by Parker et al. about the effect of UV regularisation on the power spectrum for inflation. Focusing on the slow-roll k-inflation, we show that up to second order in the Hubble and sound flow parameters, the adiabatic regularisation of such model leads to no difference in the power spectrum apart from certain cases that violate near scale-invariant power spectra. Furthermore, extending to non-minimal k-inflation, we establish the equivalence of the subtraction terms in the adiabatic regularisation of the power spectrum in Jordan and Einstein frames.

  10. Dynamics with the effective adiabatic theory: The Bloch equations

    NASA Astrophysics Data System (ADS)

    Carmeli, Benny; Chandler, David

    1988-07-01

    This paper extends our earlier work on the effective adiabatic theory [J. Chem. Phys. 82, 3400 (1985)] to study relaxation of a two-level system coupled to a Gaussian dissipative bath—the spin-boson problem. Bloch equations are derived which, under the limited circumstances described herein, treat the role of bath fluctuations omitted in the equilibrium effective adiabatic reference system. Applications to the Lorentzian dissipative bath show that the theory agrees closely with numerical simulation results. Application to an Ohmic bath shows that the theory is in agreement with currently accepted results concerned with the problem of macroscopic quantum coherence.

  11. Adiabatic State Conversion and Pulse Transmission in Optomechanical Systems

    NASA Astrophysics Data System (ADS)

    Tian, Lin

    2012-04-01

    Optomechanical systems with strong coupling can be a powerful medium for quantum state engineering of the cavity modes. Here, we show that quantum state conversion between cavity modes of distinctively different wavelengths can be realized with high fidelity by adiabatically varying the effective optomechanical couplings. The conversion fidelity for Gaussian states is derived by solving the Langevin equation in the adiabatic limit. Meanwhile, we also show that traveling photon pulses can be transmitted between different input and output channels with high fidelity and the output pulse can be engineered via the optomechanical couplings.

  12. Gravitational Chern-Simons and the adiabatic limit

    SciTech Connect

    McLellan, Brendan

    2010-12-15

    We compute the gravitational Chern-Simons term explicitly for an adiabatic family of metrics using standard methods in general relativity. We use the fact that our base three-manifold is a quasiregular K-contact manifold heavily in this computation. Our key observation is that this geometric assumption corresponds exactly to a Kaluza-Klein Ansatz for the metric tensor on our three-manifold, which allows us to translate our problem into the language of general relativity. Similar computations have been performed by Guralnik et al.[Ann. Phys. 308, 222 (2008)], although not in the adiabatic context.

  13. Creationism, Evolution, and Science Education

    SciTech Connect

    Scott, Eugenie C.

    2005-06-22

    Many topics in the curriculum of American schools are controversial, but perhaps the one with the longest tenure is evolution. Three arguments are made against evolution: that it is allegedly weak science ('evolution is a theory in crisis'); that it is incompatible with religion; and that it is only 'fair' to 'balance' evolution with creationism. Regardless of the appropriateness of their application to science education, all three of the arguments are made to try to restrict the teaching of evolution. Variants of the fairness argument such as balancing evolution with 'scientific alternatives to evolution' or balancing evolution with 'arguments against evolution' have in fact become the current predominant antievolutionist strategy. Current events in the creationism/evolution controversy will be reviewed, and suggestions made for how to promote sound science education in the schools.

  14. Network testbed creation and validation

    DOEpatents

    Thai, Tan Q.; Urias, Vincent; Van Leeuwen, Brian P.; Watts, Kristopher K.; Sweeney, Andrew John

    2017-03-21

    Embodiments of network testbed creation and validation processes are described herein. A "network testbed" is a replicated environment used to validate a target network or an aspect of its design. Embodiments describe a network testbed that comprises virtual testbed nodes executed via a plurality of physical infrastructure nodes. The virtual testbed nodes utilize these hardware resources as a network "fabric," thereby enabling rapid configuration and reconfiguration of the virtual testbed nodes without requiring reconfiguration of the physical infrastructure nodes. Thus, in contrast to prior art solutions which require a tester manually build an emulated environment of physically connected network devices, embodiments receive or derive a target network description and build out a replica of this description using virtual testbed nodes executed via the physical infrastructure nodes. This process allows for the creation of very large (e.g., tens of thousands of network elements) and/or very topologically complex test networks.

  15. Geometric creation of quantum vorticity

    NASA Astrophysics Data System (ADS)

    Good, Michael R. R.; Xiong, Chi; Chua, Alvin J. K.; Huang, Kerson

    2016-11-01

    We consider superfluidity and quantum vorticity in rotating spacetimes. The system is described by a complex scalar satisfying a nonlinear Klein-Gordon equation. Rotation terms are identified and found to lead to the transfer of angular momentum of the spacetime to the scalar field. The scalar field responds by rotating, physically behaving as a superfluid, through the creation of quantized vortices. We demonstrate vortex nucleation through numerical simulation.

  16. Ion pair receptors†

    PubMed Central

    Kim, Sung Kuk

    2010-01-01

    Compared with simple ion receptors, which are able to bind either a cation or an anion, ion pair receptors bearing both a cation and an anion recognition site offer the promise of binding ion pairs or pairs of ions strongly as the result of direct or indirect cooperative interactions between co-bound ions. This critical review focuses on the recent progress in the design of ion pair receptors and summarizes the various binding modes that have been used to accommodate ion pairs (110 references). PMID:20737073

  17. Kinetic Description of Vacuum Creation of Massive Vector Bosons

    SciTech Connect

    Blaschke, D.B.; Prozorkevich, A.V.; Smolyansky, S.A.; Reichel, A.V.

    2005-06-01

    In the simple model of massive vector field in a flat spacetime, we derive the kinetic equation of non-Markovian type describing the vacuum pair creation under action of external fields of different nature. We use for this aim the nonperturbative methods of kinetic theory in combination with a new element when the transition of the instantaneous quasiparticle representation is realized within the oscillator (holomorphic) representation. We study in detail the process of vacuum creation of vector bosons generated by a time-dependent boson mass in accordance with the framework of a conformal-invariant scalar-tensor gravitational theory and its cosmological application. It is indicated that the choice of the equation of state allows one to obtain a number density of vector bosons that is sufficient to explain the observed number density of photons in the cosmic microwave background radiation.

  18. Adiabatic frequency conversion with a sign flip in the coupling

    NASA Astrophysics Data System (ADS)

    Hristova, H. S.; Rangelov, A. A.; Montemezzani, G.; Vitanov, N. V.

    2016-09-01

    Adiabatic frequency conversion is a method recently developed in nonlinear optics [H. Suchowski, D. Oron, A. Arie, and Y. Silberberg, Phys. Rev. A 78, 063821 (2008), 10.1103/PhysRevA.78.063821], using ideas from the technique of rapid adiabatic passage (RAP) via a level crossing in quantum physics. In this method, the coupling coefficients are constant and the phase mismatch is chirped adiabatically. In this work, we propose another method for adiabatic frequency conversion, in which the phase mismatch is constant and the coupling is a pulse-shaped function with a sign flip (i.e., a phase step of π ) at its maximum. Compared to the RAP method, our technique has comparable efficiency but it is simpler to implement for it only needs two bulk crystals with opposite χ(2 ) nonlinearity. Moreover, because our technique requires constant nonzero frequency mismatch and has zero conversion efficiency on exact frequency matching, it can be used as a frequency filter.

  19. Failure of geometric electromagnetism in the adiabatic vector Kepler problem

    SciTech Connect

    Anglin, J.R.; Schmiedmayer, J.

    2004-02-01

    The magnetic moment of a particle orbiting a straight current-carrying wire may precess rapidly enough in the wire's magnetic field to justify an adiabatic approximation, eliminating the rapid time dependence of the magnetic moment and leaving only the particle position as a slow degree of freedom. To zeroth order in the adiabatic expansion, the orbits of the particle in the plane perpendicular to the wire are Keplerian ellipses. Higher-order postadiabatic corrections make the orbits precess, but recent analysis of this 'vector Kepler problem' has shown that the effective Hamiltonian incorporating a postadiabatic scalar potential ('geometric electromagnetism') fails to predict the precession correctly, while a heuristic alternative succeeds. In this paper we resolve the apparent failure of the postadiabatic approximation, by pointing out that the correct second-order analysis produces a third Hamiltonian, in which geometric electromagnetism is supplemented by a tensor potential. The heuristic Hamiltonian of Schmiedmayer and Scrinzi is then shown to be a canonical transformation of the correct adiabatic Hamiltonian, to second order. The transformation has the important advantage of removing a 1/r{sup 3} singularity which is an artifact of the adiabatic approximation.

  20. Fast Quasi-Adiabatic Gas Cooling: An Experiment Revisited

    ERIC Educational Resources Information Center

    Oss, S.; Gratton, L. M.; Calza, G.; Lopez-Arias, T.

    2012-01-01

    The well-known experiment of the rapid expansion and cooling of the air contained in a bottle is performed with a rapidly responsive, yet very cheap thermometer. The adiabatic, low temperature limit is approached quite closely and measured with our apparatus. A straightforward theoretical model for this process is also presented and discussed.…

  1. Adiabatic compression and radiative compression of magnetic fields

    SciTech Connect

    Woods, C.H.

    1980-02-12

    Flux is conserved during mechanical compression of magnetic fields for both nonrelativistic and relativistic compressors. However, the relativistic compressor generates radiation, which can carry up to twice the energy content of the magnetic field compressed adiabatically. The radiation may be either confined or allowed to escape.

  2. Digitized adiabatic quantum computing with a superconducting circuit.

    PubMed

    Barends, R; Shabani, A; Lamata, L; Kelly, J; Mezzacapo, A; Las Heras, U; Babbush, R; Fowler, A G; Campbell, B; Chen, Yu; Chen, Z; Chiaro, B; Dunsworth, A; Jeffrey, E; Lucero, E; Megrant, A; Mutus, J Y; Neeley, M; Neill, C; O'Malley, P J J; Quintana, C; Roushan, P; Sank, D; Vainsencher, A; Wenner, J; White, T C; Solano, E; Neven, H; Martinis, John M

    2016-06-09

    Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.

  3. Cosmological solutions in spatially curved universes with adiabatic particle production

    NASA Astrophysics Data System (ADS)

    Aresté Saló, Llibert; de Haro, Jaume

    2017-03-01

    We perform a qualitative and thermodynamic study of two models when one takes into account adiabatic particle production. In the first one, there is a constant particle production rate, which leads to solutions depicting the current cosmic acceleration but without inflation. The other one has solutions that unify the early and late time acceleration. These solutions converge asymptotically to the thermal equilibrium.

  4. A Kinetic Study of the Adiabatic Polymerization of Acrylamide.

    ERIC Educational Resources Information Center

    Thomson, R. A. M.

    1986-01-01

    Discusses theory, procedures, and results for an experiment which demonstrates the application of basic physics to chemical problems. The experiment involves the adiabatic process, in which polymerization carried out in a vacuum flask is compared to the theoretical prediction of the model with the temperature-time curve obtained in practice. (JN)

  5. Reversibility and energy dissipation in adiabatic superconductor logic.

    PubMed

    Takeuchi, Naoki; Yamanashi, Yuki; Yoshikawa, Nobuyuki

    2017-12-01

    Reversible computing is considered to be a key technology to achieve an extremely high energy efficiency in future computers. In this study, we investigated the relationship between reversibility and energy dissipation in adiabatic superconductor logic. We analyzed the evolution of phase differences of Josephson junctions in the reversible quantum-flux-parametron (RQFP) gate and confirmed that the phase differences can change time reversibly, which indicates that the RQFP gate is physically, as well as logically, reversible. We calculated energy dissipation required for the RQFP gate to perform a logic operation and numerically demonstrated that the energy dissipation can fall below the thermal limit, or the Landauer bound, by lowering operation frequencies. We also investigated the 1-bit-erasure gate as a logically irreversible gate and the quasi-RQFP gate as a physically irreversible gate. We calculated the energy dissipation of these irreversible gates and showed that the energy dissipation of these gate is dominated by non-adiabatic state changes, which are induced by unwanted interactions between gates due to logical or physical irreversibility. Our results show that, in reversible computing using adiabatic superconductor logic, logical and physical reversibility are required to achieve energy dissipation smaller than the Landauer bound without non-adiabatic processes caused by gate interactions.

  6. Adiabatic State Conversion and Photon Transmission in Optomechanical Systems

    NASA Astrophysics Data System (ADS)

    Tian, Lin

    2012-02-01

    Light-matter interaction in optomechanical systems in the strong coupling regime can be explored as a tool to transfer cavity states and to transmit photon pulses. Here, we show that quantum state conversion between cavity modes with different wavelengths can be realized with high fidelity by adiabatically varying the effective optomechanical couplings. During this adiabatic process, the quantum state is preserved in the dark mode of the cavities, similar to the adiabatic transfer schemes in EIT systems. The fidelity for gaussian states is derived by solving the Langevin equation in the adiabatic limit and shows negligible dependence on the mechanical noise. We also show that an input pulse can be transmitted to an output channel with a different wavelength via the effective optomechanical couplings. The condition for optimal transmission is derived in the frequency domain. Input pulses with a narrow spectral width can be transmitted with high fidelity. For input pulses with a large spectral width, the shape of the output pulses can be manipulated by applying time-dependent effective couplings. (1) L. Tian, arXiv:1111.2119. (2) L. Tian and H. L. Wang, Phys. Rev. A 82, 053806 (2010).

  7. When an Adiabatic Irreversible Expansion or Compression Becomes Reversible

    ERIC Educational Resources Information Center

    Anacleto, Joaquim; Ferreira, J. M.; Soares, A. A.

    2009-01-01

    This paper aims to contribute to a better understanding of the concepts of a "reversible process" and "entropy". For this purpose, an adiabatic irreversible expansion or compression is analysed, by considering that an ideal gas is expanded (compressed), from an initial pressure P[subscript i] to a final pressure P[subscript f], by being placed in…

  8. Dark energy and dark matter from an additional adiabatic fluid

    NASA Astrophysics Data System (ADS)

    Dunsby, Peter K. S.; Luongo, Orlando; Reverberi, Lorenzo

    2016-10-01

    The dark sector is described by an additional barotropic fluid which evolves adiabatically during the Universe's history and whose adiabatic exponent γ is derived from the standard definitions of specific heats. Although in general γ is a function of the redshift, the Hubble parameter and its derivatives, we find that our assumptions lead necessarily to solutions with γ =constant in a Friedmann-Lemaître-Robertson-Walker universe. The adiabatic fluid acts effectively as the sum of two distinct components, one evolving like nonrelativistic matter and the other depending on the value of the adiabatic index. This makes the model particularly interesting as a way of simultaneously explaining the nature of both dark energy and dark matter, at least at the level of the background cosmology. The Λ CDM model is included in this family of theories when γ =0 . We fit our model to supernovae Ia, H (z ) and baryonic acoustic oscillation data, discussing the model selection criteria. The implications for the early Universe and the growth of small perturbations in this model are also discussed.

  9. Non-adiabatic transition probability dependence on conical intersection topography

    NASA Astrophysics Data System (ADS)

    Malhado, João Pedro; Hynes, James T.

    2016-11-01

    We derive a closed form analytical expression for the non-adiabatic transition probability for a distribution of trajectories passing through a generic conical intersection (CI), based on the Landau-Zener equation for the non-adiabatic transition probability for a single straight-line trajectory in the CI's vicinity. We investigate the non-adiabatic transition probability's variation with topographical features and find, for the same crossing velocity, no intrinsic difference in efficiency at promoting non-adiabatic decay between peaked and sloped CIs, a result in contrast to the commonly held view. Any increased efficiency of peaked over sloped CIs is thus due to dynamical effects rather than to any increased transition probability of topographical origin. It is also shown that the transition probability depends in general on the direction of approach to the CI, and that the coordinates' reduced mass can affect the transition probability via its influence on the CI topography in mass-scaled coordinates. The resulting predictions compare well with surface hopping simulation results.

  10. Non-adiabatic transition probability dependence on conical intersection topography.

    PubMed

    Malhado, João Pedro; Hynes, James T

    2016-11-21

    We derive a closed form analytical expression for the non-adiabatic transition probability for a distribution of trajectories passing through a generic conical intersection (CI), based on the Landau-Zener equation for the non-adiabatic transition probability for a single straight-line trajectory in the CI's vicinity. We investigate the non-adiabatic transition probability's variation with topographical features and find, for the same crossing velocity, no intrinsic difference in efficiency at promoting non-adiabatic decay between peaked and sloped CIs, a result in contrast to the commonly held view. Any increased efficiency of peaked over sloped CIs is thus due to dynamical effects rather than to any increased transition probability of topographical origin. It is also shown that the transition probability depends in general on the direction of approach to the CI, and that the coordinates' reduced mass can affect the transition probability via its influence on the CI topography in mass-scaled coordinates. The resulting predictions compare well with surface hopping simulation results.

  11. Digitized adiabatic quantum computing with a superconducting circuit

    NASA Astrophysics Data System (ADS)

    Barends, R.; Shabani, A.; Lamata, L.; Kelly, J.; Mezzacapo, A.; Heras, U. Las; Babbush, R.; Fowler, A. G.; Campbell, B.; Chen, Yu; Chen, Z.; Chiaro, B.; Dunsworth, A.; Jeffrey, E.; Lucero, E.; Megrant, A.; Mutus, J. Y.; Neeley, M.; Neill, C.; O'Malley, P. J. J.; Quintana, C.; Roushan, P.; Sank, D.; Vainsencher, A.; Wenner, J.; White, T. C.; Solano, E.; Neven, H.; Martinis, John M.

    2016-06-01

    Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.

  12. Creationism in 20th-Century America.

    ERIC Educational Resources Information Center

    Numbers, Ronald L.

    1982-01-01

    As the crusade to outlaw the teaching of evolution changed to a battle for equal time for creationism, the ideological defenses of that doctrine also shifted, from biblical to scientific grounds. The development of "scientific creationism" is described, focusing on the intellectual leaders of creationism, particularly those claiming scientific…

  13. Creation operators for Cartesian and circular beams.

    PubMed

    Siguenza-Torres, Anibal; Gutiérrez-Vega, Julio C

    2016-05-01

    Creation operators of fractional order, to derive the general Cartesian beams and circular beams from the lowest-order Gaussian beam, are introduced and discussed. Finding the creation operator for these general cases is a way to find the creation operator of all the special cases of Cartesian and circular beams.

  14. Sub-adiabatic perpendicular electron heating across high-Mach number collisionless shocks

    NASA Astrophysics Data System (ADS)

    Sundkvist, D. J.; Mozer, F.

    2012-12-01

    Spacecraft observations of a high Mach number quasi-perpendicular bow shock with high plasma beta have revealed electrons that were sub-adiabatic through the shock ramp because they were less heated than expected from conservation of the first adiabatic invariant. This stands out in contrast to existing theories of electron heating at collisionless shocks in which the electrons are adiabatically heated through compression or more-than-adiabatically heated due to additional effects such as anomalous resistivity induced by microinstabilites.

  15. Ultrabright source of entangled photon pairs.

    PubMed

    Dousse, Adrien; Suffczyński, Jan; Beveratos, Alexios; Krebs, Olivier; Lemaître, Aristide; Sagnes, Isabelle; Bloch, Jacqueline; Voisin, Paul; Senellart, Pascale

    2010-07-08

    A source of triggered entangled photon pairs is a key component in quantum information science; it is needed to implement functions such as linear quantum computation, entanglement swapping and quantum teleportation. Generation of polarization entangled photon pairs can be obtained through parametric conversion in nonlinear optical media or by making use of the radiative decay of two electron-hole pairs trapped in a semiconductor quantum dot. Today, these sources operate at a very low rate, below 0.01 photon pairs per excitation pulse, which strongly limits their applications. For systems based on parametric conversion, this low rate is intrinsically due to the Poissonian statistics of the source. Conversely, a quantum dot can emit a single pair of entangled photons with a probability near unity but suffers from a naturally very low extraction efficiency. Here we show that this drawback can be overcome by coupling an optical cavity in the form of a 'photonic molecule' to a single quantum dot. Two coupled identical pillars-the photonic molecule-were etched in a semiconductor planar microcavity, using an optical lithography method that ensures a deterministic coupling to the biexciton and exciton energy states of a pre-selected quantum dot. The Purcell effect ensures that most entangled photon pairs are emitted into two cavity modes, while improving the indistinguishability of the two optical recombination paths. A polarization entangled photon pair rate of 0.12 per excitation pulse (with a concurrence of 0.34) is collected in the first lens. Our results open the way towards the fabrication of solid state triggered sources of entangled photon pairs, with an overall (creation and collection) efficiency of 80%.

  16. Pumping Electron-Positron Pairs from a Well Potential

    PubMed Central

    Wang, Qiang; Liu, Jie; Fu, Li-bin

    2016-01-01

    In the presence of very deep well potential, electrons will spontaneously occupy the empty embedded bound states and electron-positron pairs are created by means of a non-perturbative tunneling process. In this work, by slowly oscillating the width or depth, the population transfer channels are opened and closed periodically. We find and clearly show that by the non-synchronous ejections of particles, the saturation of pair number in a static super-critical well can be broken, and electrons and positrons can be pumped inexhaustibly from vacuum with a constant production rate. In the adiabatic limit, final pair number after a single cycle has quantized values as a function of the upper boundary of the oscillating, and the critical upper boundaries indicate the diving points of the bound states. PMID:27125998

  17. Pumping Electron-Positron Pairs from a Well Potential

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Liu, Jie; Fu, Li-Bin

    2016-04-01

    In the presence of very deep well potential, electrons will spontaneously occupy the empty embedded bound states and electron-positron pairs are created by means of a non-perturbative tunneling process. In this work, by slowly oscillating the width or depth, the population transfer channels are opened and closed periodically. We find and clearly show that by the non-synchronous ejections of particles, the saturation of pair number in a static super-critical well can be broken, and electrons and positrons can be pumped inexhaustibly from vacuum with a constant production rate. In the adiabatic limit, final pair number after a single cycle has quantized values as a function of the upper boundary of the oscillating, and the critical upper boundaries indicate the diving points of the bound states.

  18. Matched-pair classification

    SciTech Connect

    Theiler, James P

    2009-01-01

    Following an analogous distinction in statistical hypothesis testing, we investigate variants of machine learning where the training set comes in matched pairs. We demonstrate that even conventional classifiers can exhibit improved performance when the input data has a matched-pair structure. Online algorithms, in particular, converge quicker when the data is presented in pairs. In some scenarios (such as the weak signal detection problem), matched pairs can be generated from independent samples, with the effect not only doubling the nominal size of the training set, but of providing the structure that leads to better learning. A family of 'dipole' algorithms is introduced that explicitly takes advantage of matched-pair structure in the input data and leads to further performance gains. Finally, we illustrate the application of matched-pair learning to chemical plume detection in hyperspectral imagery.

  19. Dealing with Creationism in Astronomy

    NASA Astrophysics Data System (ADS)

    Bridgman, W. T.

    2005-12-01

    In recent years, the battle to force some form of pseudo-science into American science classrooms has intensified. In court cases and Boards of Education, the sides have formed between religious groups claiming to desire a `balanced' treatment and scientific groups insisting on a total ban on the topics. But there is a third option which has not been explored. Many claims of `Creation Science' and other pseudosciences can be explored and refuted at the level of introductory physics and astronomy classes. I will present a few claims of Young-Earth Creationists (YECs) pertaining to cosmology and illustrate some methods for refuting them.

  20. Pairing-induced speedup of nuclear spontaneous fission

    SciTech Connect

    Sadhukhan, Jhilam; Dobaczewski, J.; Nazarewicz, W.; Sheikh, J. A.; Baran, A.

    2014-12-22

    Collective inertia is strongly influenced at the level crossing at which the quantum system changes its microscopic configuration diabatically. Pairing correlations tend to make the large-amplitude nuclear collective motion more adiabatic by reducing the effect of these configuration changes. Competition between pairing and level crossing is thus expected to have a profound impact on spontaneous fission lifetimes. To elucidate the role of nucleonic pairing on spontaneous fission, we study the dynamic fission trajectories of 264Fm and 240Pu using the state-of-the-art self-consistent framework. We employ the superfluid nuclear density functional theory with the Skyrme energy density functional SkM* and a density-dependent pairing interaction. Along with shape variables, proton and neutron pairing correlations are taken as collective coordinates. The collective inertia tensor is calculated within the nonperturbative cranking approximation. The fission paths are obtained by using the least action principle in a four-dimensional collective space of shape and pairing coordinates. Pairing correlations are enhanced along the minimum-action fission path. For the symmetric fission of 264Fm, where the effect of triaxiality on the fission barrier is large, the geometry of the fission pathway in the space of the shape degrees of freedom is weakly impacted by pairing. This is not the case for 240Pu, where pairing fluctuations restore the axial symmetry of the dynamic fission trajectory. The minimum-action fission path is strongly impacted by nucleonic pairing. In some cases, the dynamical coupling between shape and pairing degrees of freedom can lead to a dramatic departure from the static picture. As a result, in the dynamical description of nuclear fission, particle-particle correlations should be considered on the same footing as those associated with shape degrees of freedom.

  1. Pairing-induced speedup of nuclear spontaneous fission

    DOE PAGES

    Sadhukhan, Jhilam; Dobaczewski, J.; Nazarewicz, W.; ...

    2014-12-22

    Collective inertia is strongly influenced at the level crossing at which the quantum system changes its microscopic configuration diabatically. Pairing correlations tend to make the large-amplitude nuclear collective motion more adiabatic by reducing the effect of these configuration changes. Competition between pairing and level crossing is thus expected to have a profound impact on spontaneous fission lifetimes. To elucidate the role of nucleonic pairing on spontaneous fission, we study the dynamic fission trajectories of 264Fm and 240Pu using the state-of-the-art self-consistent framework. We employ the superfluid nuclear density functional theory with the Skyrme energy density functional SkM* and a density-dependentmore » pairing interaction. Along with shape variables, proton and neutron pairing correlations are taken as collective coordinates. The collective inertia tensor is calculated within the nonperturbative cranking approximation. The fission paths are obtained by using the least action principle in a four-dimensional collective space of shape and pairing coordinates. Pairing correlations are enhanced along the minimum-action fission path. For the symmetric fission of 264Fm, where the effect of triaxiality on the fission barrier is large, the geometry of the fission pathway in the space of the shape degrees of freedom is weakly impacted by pairing. This is not the case for 240Pu, where pairing fluctuations restore the axial symmetry of the dynamic fission trajectory. The minimum-action fission path is strongly impacted by nucleonic pairing. In some cases, the dynamical coupling between shape and pairing degrees of freedom can lead to a dramatic departure from the static picture. As a result, in the dynamical description of nuclear fission, particle-particle correlations should be considered on the same footing as those associated with shape degrees of freedom.« less

  2. Relativistic thermal plasmas - Pair processes and equilibria

    NASA Technical Reports Server (NTRS)

    Lightman, A. P.

    1982-01-01

    The work of Bisnovatyi-Kogan, Zel'dovich and Sunyaev (1971) is extended and generalized, through the inclusion of pair-producing photon processes and effects due to the finite size of the plasma, in an investigation of the equilibria of relativistic thermal plasmas which takes into account electron-positron creation and annihilation and photons produced within the plasma. It is shown that the bridge between an effectively thin plasma and an effectively thick plasma occurs in the transrelativistic region, where the dimensionless temperature value is between 0.1 and 1.0 and the temperature remains in this region over a great luminosity range.

  3. Vortex pairs on surfaces

    SciTech Connect

    Koiller, Jair

    2009-05-06

    A pair of infinitesimally close opposite vortices moving on a curved surface moves along a geodesic, according to a conjecture by Kimura. We outline a proof. Numerical simulations are presented for a pair of opposite vortices at a close but nonzero distance on a surface of revolution, the catenoid. We conjecture that the vortex pair system on a triaxial ellipsoid is a KAM perturbation of Jacobi's geodesic problem. We outline some preliminary calculations required for this study. Finding the surfaces for which the vortex pair system is integrable is in order.

  4. Knowledge Creation in Nursing Education

    PubMed Central

    Hassanian, Zahra Marzieh; Ahanchian, Mohammad Reza; Ahmadi, Suleiman; Gholizadeh, Rezvan Hossein; Karimi-Moonaghi, Hossein

    2015-01-01

    In today’s society, knowledge is recognized as a valuable social asset and the educational system is in search of a new strategy that allows them to construct their knowledge and experience. The purpose of this study was to explore the process of knowledge creation in nursing education. In the present study, the grounded theory approach was used. This method provides a comprehensive approach to collecting, organizing, and analyzing data. Data were obtained through 17 semi-structured interviews with nursing faculties and nursing students. Purposeful and theoretical sampling was conducted. Based on the method of Strauss and Corbin, the data were analyzed using fragmented, deep, and constant-comparative methods. The main categories included striving for growth and reduction of ambiguity, use of knowledge resources, dynamism of mind and social factors, converting knowledge, and creating knowledge. Knowledge was converted through mind processes, individual and group reflection, praxis and research, and resulted in the creation of nursing knowledge. Discrete nursing knowledge is gained through disconformity research in order to gain more individual advantages. The consequence of this analysis was gaining new knowledge. Knowledge management must be included in the mission and strategic planning of nursing education, and it should be planned through operational planning in order to create applicable knowledge. PMID:25716383

  5. Sideband excitation of trapped ions by rapid adiabatic passage for manipulation of motional states

    SciTech Connect

    Watanabe, T.; Nomura, S.; Toyoda, K.; Urabe, S.

    2011-09-15

    We describe an analysis and experimental results of the manipulation of motional states of a single trapped {sup 40}Ca{sup +} ion based on sideband excitation by rapid adiabatic passage. When the sideband transition is excited by rapid adiabatic passage, adiabaticity may be affected by ac Stark shifts. We investigate the influence of ac Stark shifts and compensate for these shifts with an additional laser field. This makes the population transfer by rapid adiabatic passage more robust with respect to experimental parameters. Finally, we manipulate the motional states and generate motional Fock states of a single {sup 40}Ca{sup +} ion by rapid adiabatic passage with ac Stark compensation.

  6. Relativistic and quantum electrodynamics effects in the helium pair potential.

    PubMed

    Przybytek, M; Cencek, W; Komasa, J; Łach, G; Jeziorski, B; Szalewicz, K

    2010-05-07

    The helium pair potential was computed including relativistic and quantum electrodynamics contributions as well as improved accuracy adiabatic ones. Accurate asymptotic expansions were used for large distances R. Error estimates show that the present potential is more accurate than any published to date. The computed dissociation energy and the average R for the (4)He(2) bound state are 1.62+/-0.03 mK and 47.1+/-0.5 A. These values can be compared with the measured ones: 1.1(-0.2)(+0.3) mK and 52+/-4 A [R. E. Grisenti, Phys. Rev. Lett. 85, 2284 (2000)].

  7. Nuclear inertia from the time dependent pairing equations

    NASA Astrophysics Data System (ADS)

    Mirea, M.

    2016-10-01

    In a dynamical system, the momenta of inertia and the effective masses are not adiabatic quantities, but are dynamical ones that depend on the dissipated energy accumulated during motion. However, these parameters are calculated for adiabatic nuclear systems, leaving no room for dissipated energy. In this work, a formalism is elaborated in order to derive simultaneously the nuclear momenta of inertia and the effective masses by taking into account the appearance of dissipated energy for large amplitude motion of the nuclear system. The expressions that define the inertia are obtained from the variational principle. The same principle manages the time dependent pairing equations, offering estimations of the averaged dissipation energy for large amplitude motions. The model is applied to 232Th fission. The fission barrier was calculated along the least action trajectory. The dissipation energy, effective mass and moment of inertia are determined for different values of the collective velocities. The dissipation increases with the internuclear velocity in binary disintegration processes and modifies the effective mass parameters. We observed that the inertia decreases as long as the collective velocity increases to some moderate values and begins to grow for larger collective velocities. So, a dependence between the cranking mass parameters and the intrinsic excitation energy is evidenced. In order to investigate the overall effect, the half-lives are predicted for adiabatic and dynamics simulations.

  8. Cooper pairs and bipolarons

    NASA Astrophysics Data System (ADS)

    Lakhno, Victor

    2016-11-01

    It is shown that Cooper pairs are a solution of the bipolaron problem for model Fröhlich Hamiltonian. The total energy of a pair for the initial Fröhlich Hamiltonian is found. Differences between the solutions for the model and initial two-particle problems are discussed.

  9. Cooper Pairs in Insulators?!

    ScienceCinema

    James Valles

    2016-07-12

    Nearly 50 years elapsed between the discovery of superconductivity and the emergence of the microscopic theory describing this zero resistance state. The explanation required a novel phase of matter in which conduction electrons joined in weakly bound pairs and condensed with other pairs into a single quantum state. Surprisingly, this Cooper pair formation has also been invoked to account for recently uncovered high-resistance or insulating phases of matter. To address this possibility, we have used nanotechnology to create an insulating system that we can probe directly for Cooper pairs. I will present the evidence that Cooper pairs exist and dominate the electrical transport in these insulators and I will discuss how these findings provide new insight into superconductor to insulator quantum phase transitions. 

  10. Non-adiabatic dynamics of molecules in optical cavities

    NASA Astrophysics Data System (ADS)

    Kowalewski, Markus; Bennett, Kochise; Mukamel, Shaul

    2016-02-01

    Strong coupling of molecules to the vacuum field of micro cavities can modify the potential energy surfaces thereby opening new photophysical and photochemical reaction pathways. While the influence of laser fields is usually described in terms of classical field, coupling to the vacuum state of a cavity has to be described in terms of dressed photon-matter states (polaritons) which require quantized fields. We present a derivation of the non-adiabatic couplings for single molecules in the strong coupling regime suitable for the calculation of the dressed state dynamics. The formalism allows to use quantities readily accessible from quantum chemistry codes like the adiabatic potential energy surfaces and dipole moments to carry out wave packet simulations in the dressed basis. The implications for photochemistry are demonstrated for a set of model systems representing typical situations found in molecules.

  11. Non-adiabatic dynamics of molecules in optical cavities

    SciTech Connect

    Kowalewski, Markus Bennett, Kochise; Mukamel, Shaul

    2016-02-07

    Strong coupling of molecules to the vacuum field of micro cavities can modify the potential energy surfaces thereby opening new photophysical and photochemical reaction pathways. While the influence of laser fields is usually described in terms of classical field, coupling to the vacuum state of a cavity has to be described in terms of dressed photon-matter states (polaritons) which require quantized fields. We present a derivation of the non-adiabatic couplings for single molecules in the strong coupling regime suitable for the calculation of the dressed state dynamics. The formalism allows to use quantities readily accessible from quantum chemistry codes like the adiabatic potential energy surfaces and dipole moments to carry out wave packet simulations in the dressed basis. The implications for photochemistry are demonstrated for a set of model systems representing typical situations found in molecules.

  12. Adiabatic far-field sub-diffraction imaging.

    PubMed

    Cang, Hu; Salandrino, Alessandro; Wang, Yuan; Zhang, Xiang

    2015-08-10

    The limited resolution of a conventional optical imaging system stems from the fact that the fine feature information of an object is carried by evanescent waves, which exponentially decays in space and thus cannot reach the imaging plane. We introduce here an adiabatic lens, which utilizes a geometrically conformal surface to mediate the interference of slowly decompressed electromagnetic waves at far field to form images. The decompression is satisfying an adiabatic condition, and by bridging the gap between far field and near field, it allows far-field optical systems to project an image of the near-field features directly. Using these designs, we demonstrated the magnification can be up to 20 times and it is possible to achieve sub-50 nm imaging resolution in visible. Our approach provides a means to extend the domain of geometrical optics to a deep sub-wavelength scale.

  13. Engineering adiabaticity at an avoided crossing with optimal control

    NASA Astrophysics Data System (ADS)

    Chasseur, T.; Theis, L. S.; Sanders, Y. R.; Egger, D. J.; Wilhelm, F. K.

    2015-04-01

    We investigate ways to optimize adiabaticity and diabaticity in the Landau-Zener model with nonuniform sweeps. We show how diabaticity can be engineered with a pulse consisting of a linear sweep augmented by an oscillating term. We show that the oscillation leads to jumps in populations whose value can be accurately modeled using a model of multiple, photon-assisted Landau-Zener transitions, which generalizes work by Wubs et al. [New J. Phys. 7, 218 (2005)], 10.1088/1367-2630/7/1/218. We extend the study on diabaticity using methods derived from optimal control. We also show how to preserve adiabaticity with optimal pulses at limited time, finding a nonuniform quantum speed limit.

  14. Adiabatic molecular-dynamics-simulation-method studies of kinetic friction

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Sokoloff, J. B.

    2005-06-01

    An adiabatic molecular-dynamics method is developed and used to study the Muser-Robbins model for dry friction (i.e., nonzero kinetic friction in the slow sliding speed limit). In this model, dry friction between two crystalline surfaces rotated with respect to each other is due to mobile molecules (i.e., dirt particles) adsorbed at the interface. Our adiabatic method allows us to quickly locate interface potential-well minima, which become unstable during sliding of the surfaces. Since dissipation due to friction in the slow sliding speed limit results from mobile molecules dropping out of such unstable wells, our method provides a way to calculate dry friction, which agrees extremely well with results found by conventional molecular dynamics for the same system, but our method is more than a factor of 10 faster.

  15. Steam bottoming cycle for an adiabatic diesel engine

    NASA Technical Reports Server (NTRS)

    Poulin, E.; Demier, R.; Krepchin, I.; Walker, D.

    1984-01-01

    Steam bottoming cycles using adiabatic diesel engine exhaust heat which projected substantial performance and economic benefits for long haul trucks were studied. Steam cycle and system component variables, system cost, size and performance were analyzed. An 811 K/6.90 MPa state of the art reciprocating expander steam system with a monotube boiler and radiator core condenser was selected for preliminary design. The costs of the diesel with bottoming system (TC/B) and a NASA specified turbocompound adiabatic diesel with aftercooling with the same total output were compared, the annual fuel savings less the added maintenance cost was determined to cover the increase initial cost of the TC/B system in a payback period of 2.3 years. Steam bottoming system freeze protection strategies were developed, technological advances required for improved system reliability are considered and the cost and performance of advanced systes are evaluated.

  16. Adiabatic approximation and fluctuations in exciton-polariton condensates

    NASA Astrophysics Data System (ADS)

    Bobrovska, Nataliya; Matuszewski, Michał

    2015-07-01

    We study the relation between the models commonly used to describe the dynamics of nonresonantly pumped exciton-polariton condensates, namely the ones described by the complex Ginzburg-Landau equation, and by the open-dissipative Gross-Pitaevskii equation including a separate equation for the reservoir density. In particular, we focus on the validity of the adiabatic approximation and small density fluctuations approximation that allow one to reduce the coupled condensate-reservoir dynamics to a single partial differential equation. We find that the adiabatic approximation consists of three independent analytical conditions that have to be fulfilled simultaneously. By investigating stochastic versions of the two corresponding models, we verify that the breakdown of these approximations can lead to discrepancies in correlation lengths and distributions of fluctuations. Additionally, we consider the phase diffusion and number fluctuations of a condensate in a box, and show that self-consistent description requires treatment beyond the typical Bogoliubov approximation.

  17. Confinement loss in adiabatic photonic crystal fiber tapers

    NASA Astrophysics Data System (ADS)

    Kuhlmey, Boris T.; Nguyen, Hong C.; Steel, M. J.; Eggleton, Benjamin J.

    2006-09-01

    We numerically study confinement loss in photonic crystal fiber (PCF) tapers and compare our results with previously published experimental data. Agreement between theory and experiment requires taking into account hole shrinkage during the tapering process, which we measure by using a noninvasive technique. We show that losses are fully explained within the adiabatic approximation and that they are closely linked to the existence of a fundamental core-mode cutoff. This cutoff is equivalent to the core-mode cutoff in depressed-cladding fibers, so that losses in PCF tapers can be obtained semiquantitatively from an equivalent depressed-cladding fiber model. Finally, we discuss the definition of adiabaticity in this open boundary problem.

  18. Adiabatic far-field sub-diffraction imaging

    PubMed Central

    Cang, Hu; Salandrino, Alessandro; Wang, Yuan; Zhang, Xiang

    2015-01-01

    The limited resolution of a conventional optical imaging system stems from the fact that the fine feature information of an object is carried by evanescent waves, which exponentially decays in space and thus cannot reach the imaging plane. We introduce here an adiabatic lens, which utilizes a geometrically conformal surface to mediate the interference of slowly decompressed electromagnetic waves at far field to form images. The decompression is satisfying an adiabatic condition, and by bridging the gap between far field and near field, it allows far-field optical systems to project an image of the near-field features directly. Using these designs, we demonstrated the magnification can be up to 20 times and it is possible to achieve sub-50 nm imaging resolution in visible. Our approach provides a means to extend the domain of geometrical optics to a deep sub-wavelength scale. PMID:26258769

  19. Multidimensional Study of High-Adiabat OMEGA Cryogenic Experiments

    NASA Astrophysics Data System (ADS)

    Collins, T. J. B.; Betti, R.; Bose, A.; Christopherson, A. R.; Knauer, J. P.; Marozas, J. A.; Maximov, A. V.; Mora, A.; Radha, P. B.; Shang, W.; Shvydky, A.; Stoeckl, C.; Woo, K. M.; Varchas, G.

    2016-10-01

    Despite recent advances in modeling laser direct-drive inertial confinement fusion (ICF) experiments, there remains a predictability gap. This is particularly shown by the shortfall in hot-spot pressures inferred from OMEGA cryogenic implosions. To address this, a series of high-adiabat, cryogenic implosions were performed on OMEGA. These shots were performed with and without single-beam smoothing by spectral dispersion, at low and high drive intensities. These shots represent a regime where good agreement with simulation is expected because of the high adiabat. Multidimensional simulations of these shots will be presented with an emphasis on comparison with experimental indicators of departure from spherical symmetry (``1-D-ness''). The roles of short- and long-wavelength perturbations are considered. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  20. Breaking of dynamical adiabaticity in direct laser acceleration of electrons

    NASA Astrophysics Data System (ADS)

    Robinson, A. P. L.; Arefiev, A. V.

    2017-02-01

    The interaction of an electron oscillating in an ion channel and irradiated by a plane electromagnetic wave is considered. It is shown that the interaction qualitatively changes with the increase of electron energy, as the oscillations across the channel become relativistic. The "square-wave-like" profile of the transverse velocity in the relativistic case enables breaking of the adiabaticity that precludes electron energy retention in the non-relativistic case. For an electron with a relativistic factor γ0, the adiabaticity breaks if ωL/ωp0≪√{γ0 } . Under these conditions, the kinetic energy acquired by the electron is retained once the interaction with the laser field ceases. This mechanism notably enables electron heating in regimes that do not require a resonant interaction between the initially oscillating electron and the laser electric field.

  1. Fluctuations of work in nearly adiabatically driven open quantum systems.

    PubMed

    Suomela, S; Salmilehto, J; Savenko, I G; Ala-Nissila, T; Möttönen, M

    2015-02-01

    We extend the quantum jump method to nearly adiabatically driven open quantum systems in a way that allows for an accurate account of the external driving in the system-environment interaction. Using this framework, we construct the corresponding trajectory-dependent work performed on the system and derive the integral fluctuation theorem and the Jarzynski equality for nearly adiabatic driving. We show that such identities hold as long as the stochastic dynamics and work variable are consistently defined. We numerically study the emerging work statistics for a two-level quantum system and find that the conventional diabatic approximation is unable to capture some prominent features arising from driving, such as the continuity of the probability density of work. Our results reveal the necessity of using accurate expressions for the drive-dressed heat exchange in future experiments probing jump time distributions.

  2. Reverse engineering of a nonlossy adiabatic Hamiltonian for non-Hermitian systems

    NASA Astrophysics Data System (ADS)

    Wu, Qi-Cheng; Chen, Ye-Hong; Huang, Bi-Hua; Xia, Yan; Song, Jie

    2016-11-01

    We generalize the quantum adiabatic theorem to the non-Hermitian system and build a strict adiabaticity condition to make the adiabatic evolution nonlossy when taking into account the effect of the adiabatic phase. According to the strict adiabaticity condition, the nonadiabatic couplings and the effect of the imaginary part of adiabatic phase should be eliminated as much as possible. Also, the non-Hermitian Hamiltonian reverse-engineering method is proposed for adiabatically driving an artificial quantum state. A concrete two-level system is adopted to show the usefulness of the reverse-engineering method. We obtain the desired target state by adjusting extra rotating magnetic fields at a predefined time. Furthermore, the numerical simulation shows that certain noise and dissipation in the systems are no longer undesirable but play a positive role in the scheme. Therefore, the scheme is quite useful for quantum information processing in some dissipative systems.

  3. Experimental Adiabatic Quantum Factorization under Ambient Conditions Based on a Solid-State Single Spin System.

    PubMed

    Xu, Kebiao; Xie, Tianyu; Li, Zhaokai; Xu, Xiangkun; Wang, Mengqi; Ye, Xiangyu; Kong, Fei; Geng, Jianpei; Duan, Changkui; Shi, Fazhan; Du, Jiangfeng

    2017-03-31

    The adiabatic quantum computation is a universal and robust method of quantum computing. In this architecture, the problem can be solved by adiabatically evolving the quantum processor from the ground state of a simple initial Hamiltonian to that of a final one, which encodes the solution of the problem. Adiabatic quantum computation has been proved to be a compatible candidate for scalable quantum computation. In this Letter, we report on the experimental realization of an adiabatic quantum algorithm on a single solid spin system under ambient conditions. All elements of adiabatic quantum computation, including initial state preparation, adiabatic evolution (simulated by optimal control), and final state read-out, are realized experimentally. As an example, we found the ground state of the problem Hamiltonian S_{z}I_{z} on our adiabatic quantum processor, which can be mapped to the factorization of 35 into its prime factors 5 and 7.

  4. Geometric Phase for Adiabatic Evolutions of General Quantum States

    SciTech Connect

    Wu, Biao; Liu, Jie; Niu, Qian; Singh, David J

    2005-01-01

    The concept of a geometric phase (Berry's phase) is generalized to the case of noneigenstates, which is applicable to both linear and nonlinear quantum systems. This is particularly important to nonlinear quantum systems, where, due to the lack of the superposition principle, the adiabatic evolution of a general state cannot be described in terms of eigenstates. For linear quantum systems, our new geometric phase reduces to a statistical average of Berry's phases. Our results are demonstrated with a nonlinear two-level model.

  5. Stellar oscillations - II - The non-adiabatic case

    NASA Astrophysics Data System (ADS)

    Samadi, R.; Belkacem, K.; Sonoi, T.

    2015-02-01

    A leap forward has been performed due to the space-borne missions, MOST, CoRoT and Kepler. They provided a wealth of observational data, and more precisely oscillation spectra, which have been (and are still) exploited to infer the internal structure of stars. While an adiabatic approach is often sufficient to get information on the stellar equilibrium structures it is not sufficient to get a full understanding of the physics of the oscillation. Indeed, it does not permit one to answer some fundamental questions about the oscillations, such as: What are the physical mechanisms responsible for the pulsations inside stars? What determines the amplitudes? To what extent the adiabatic approximation is valid? All these questions can only be addressed by considering the energy exchanges between the oscillations and the surrounding medium. This lecture therefore aims at considering the energetical aspects of stellar pulsations with particular emphasis on the driving and damping mechanisms. To this end, the full non-adiabatic equations are introduced and thoroughly discussed. Two types of pulsation are distinguished, namely the self-excited oscillations that result from an instability and the solar-like oscillations that result from a balance between driving and damping by turbulent convection. For each type, the main physical principles are presented and illustrated using recent observations obtained with the ultra-high precision photometry space-borne missions (MOST, CoRoT and Kepler). Finally, we consider in detail the physics of scaling relations, which relates the seismic global indices with the global stellar parameters and gave birth to the development of statistical (or ensemble) asteroseismology. Indeed, several of these relations rely on the same cause: the physics of non-adiabatic oscillations.

  6. Adiabatic modulation of cnoidal wave by Kuznetsov - Ma soliton

    NASA Astrophysics Data System (ADS)

    Makarov, V. A.; Petnikova, V. M.; Shuvalov, V. V.

    2016-08-01

    The problem of nonlinear interaction of a cnoidal wave (a “fast” component of vector light field) with localized in time and periodic in space control signal in the form of Kuznetsov-Ma soliton (a "slow" component of the same field) is analytically solved in the adiabatic approximation. The conditions which must be fulfilled for stable propagation of the obtained solution with amplitude and frequency modulation are determined.

  7. Adiabatic pipelining: a key to ternary computing with quantum dots.

    PubMed

    Pečar, P; Ramšak, A; Zimic, N; Mraz, M; Lebar Bajec, I

    2008-12-10

    The quantum-dot cellular automaton (QCA), a processing platform based on interacting quantum dots, was introduced by Lent in the mid-1990s. What followed was an exhilarating period with the development of the line, the functionally complete set of logic functions, as well as more complex processing structures, however all in the realm of binary logic. Regardless of these achievements, it has to be acknowledged that the use of binary logic is in computing systems mainly the end result of the technological limitations, which the designers had to cope with in the early days of their design. The first advancement of QCAs to multi-valued (ternary) processing was performed by Lebar Bajec et al, with the argument that processing platforms of the future should not disregard the clear advantages of multi-valued logic. Some of the elementary ternary QCAs, necessary for the construction of more complex processing entities, however, lead to a remarkable increase in size when compared to their binary counterparts. This somewhat negates the advantages gained by entering the ternary computing domain. As it turned out, even the binary QCA had its initial hiccups, which have been solved by the introduction of adiabatic switching and the application of adiabatic pipeline approaches. We present here a study that introduces adiabatic switching into the ternary QCA and employs the adiabatic pipeline approach to successfully solve the issues of elementary ternary QCAs. What is more, the ternary QCAs presented here are sizewise comparable to binary QCAs. This in our view might serve towards their faster adoption.

  8. Competing adiabatic Thouless pumps in enlarged parameter spaces

    NASA Astrophysics Data System (ADS)

    Lopes, Pedro L. e. S.; Ghaemi, Pouyan; Ryu, Shinsei; Hughes, Taylor L.

    2016-12-01

    The transfer of conserved charges through insulating matter via smooth deformations of the Hamiltonian is known as quantum adiabatic, or Thouless, pumping. Central to this phenomenon are Hamiltonians whose insulating gap is controlled by a multidimensional (usually two-dimensional) parameter space in which paths can be defined for adiabatic changes in the Hamiltonian, i.e., without closing the gap. Here, we extend the concept of Thouless pumps of band insulators by considering a larger, three-dimensional parameter space. We show that the connectivity of this parameter space is crucial for defining quantum pumps, demonstrating that, as opposed to the conventional two-dimensional case, pumped quantities depend not only on the initial and final points of Hamiltonian evolution but also on the class of the chosen path and preserved symmetries. As such, we distinguish the scenarios of closed/open paths of Hamiltonian evolution, finding that different closed cycles can lead to the pumping of different quantum numbers, and that different open paths may point to distinct scenarios for surface physics. As explicit examples, we consider models similar to simple models used to describe topological insulators, but with doubled degrees of freedom compared to a minimal topological insulator model. The extra fermionic flavors from doubling allow for extra gapping terms/adiabatic parameters—besides the usual topological mass which preserves the topology-protecting discrete symmetries—generating an enlarged adiabatic parameter space. We consider cases in one and three spatial dimensions, and our results in three dimensions may be realized in the context of crystalline topological insulators, as we briefly discuss.

  9. Adiabatic Compression Sensitivity of Liquid Fuels and Monopropellants

    DTIC Science & Technology

    2007-11-02

    Sensitivity of Liquid Fuels and Monopropellants " 46’b Internat’I Instrumentation Syrup (Bellevue, WA, 30 Apr- 04 May 00) (Statement A) (Deadline: 30 Dec...99) Adiabatic Compression Sensitivity of Liquid Fuels and Monopropellants Ismail M. K. Ismail Tom W. Hawkins Senior Engineer/Scientist Group Leader...hazard sensitivity, propellants, fuels, oxidizers ABSTRACT Liquid rocket fuels and monopropellants can be sensitive to rapid compression. Such liquids

  10. On optimal methods for adiabatic quantum state transformations

    NASA Astrophysics Data System (ADS)

    Somma, Rolando

    2013-03-01

    Many problems in science could be solved by preparing the low-energy quantum state (or any eigenstate) of a Hamiltonian. A common example is the Boolean satisfiability problem, where each clause can be mapped to the energy of an interacting many-body system, and the problem reduces to minimizing the energy. In quantum computing, adiabatic quantum state transformations (ASTs) provide a tool for preparing the quantum state. ASTs are conventionally implemented via slow or adiabatic perturbations to the Hamiltonian, relying on the quantum adiabatic theorem. Nevertheless, more efficient implementations of ASTs exist. In this talk I will review recently developed methods for ASTs that are more efficient and require less assumptions on the Hamiltonians than the conventional implementation. Such methods involve measurements of the states along the evolution path and have a best-case implementation cost of L/G, where L is the length of the (evolved) state path and G is a lower bound to the spectral gap of the Hamiltonians. I will show that this cost is optimal and comment on results of the gap amplification problem, where the goal is to reduce the cost by increasing G. We acknowledge support from NSF through the CCF program and the LDRD programs at Los Alamos National Laboratory and Sandia National Laboratories.

  11. Non-adiabatic molecular dynamics by accelerated semiclassical Monte Carlo

    SciTech Connect

    White, Alexander J.; Gorshkov, Vyacheslav N.; Tretiak, Sergei; Mozyrsky, Dmitry

    2015-07-07

    Non-adiabatic dynamics, where systems non-radiatively transition between electronic states, plays a crucial role in many photo-physical processes, such as fluorescence, phosphorescence, and photoisomerization. Methods for the simulation of non-adiabatic dynamics are typically either numerically impractical, highly complex, or based on approximations which can result in failure for even simple systems. Recently, the Semiclassical Monte Carlo (SCMC) approach was developed in an attempt to combine the accuracy of rigorous semiclassical methods with the efficiency and simplicity of widely used surface hopping methods. However, while SCMC was found to be more efficient than other semiclassical methods, it is not yet as efficient as is needed to be used for large molecular systems. Here, we have developed two new methods: the accelerated-SCMC and the accelerated-SCMC with re-Gaussianization, which reduce the cost of the SCMC algorithm up to two orders of magnitude for certain systems. In many cases shown here, the new procedures are nearly as efficient as the commonly used surface hopping schemes, with little to no loss of accuracy. This implies that these modified SCMC algorithms will be of practical numerical solutions for simulating non-adiabatic dynamics in realistic molecular systems.

  12. Dynamics of Quantum Adiabatic Evolution Algorithm for Number Partitioning

    NASA Technical Reports Server (NTRS)

    Smelyanskiy, Vadius; vonToussaint, Udo V.; Timucin, Dogan A.; Clancy, Daniel (Technical Monitor)

    2002-01-01

    We have developed a general technique to study the dynamics of the quantum adiabatic evolution algorithm applied to random combinatorial optimization problems in the asymptotic limit of large problem size n. We use as an example the NP-complete Number Partitioning problem and map the algorithm dynamics to that of an auxiliary quantum spin glass system with the slowly varying Hamiltonian. We use a Green function method to obtain the adiabatic eigenstates and the minimum exitation gap, gmin = O(n2(sup -n/2)), corresponding to the exponential complexity of the algorithm for Number Partitioning. The key element of the analysis is the conditional energy distribution computed for the set of all spin configurations generated from a given (ancestor) configuration by simultaneous flipping of a fixed number of spins. For the problem in question this distribution is shown to depend on the ancestor spin configuration only via a certain parameter related to the energy of the configuration. As the result, the algorithm dynamics can be described in terms of one-dimensional quantum diffusion in the energy space. This effect provides a general limitation of a quantum adiabatic computation in random optimization problems. Analytical results are in agreement with the numerical simulation of the algorithm.

  13. Dynamics of Quantum Adiabatic Evolution Algorithm for Number Partitioning

    NASA Technical Reports Server (NTRS)

    Smelyanskiy, V. N.; Toussaint, U. V.; Timucin, D. A.

    2002-01-01

    We have developed a general technique to study the dynamics of the quantum adiabatic evolution algorithm applied to random combinatorial optimization problems in the asymptotic limit of large problem size n. We use as an example the NP-complete Number Partitioning problem and map the algorithm dynamics to that of an auxiliary quantum spin glass system with the slowly varying Hamiltonian. We use a Green function method to obtain the adiabatic eigenstates and the minimum excitation gap. g min, = O(n 2(exp -n/2), corresponding to the exponential complexity of the algorithm for Number Partitioning. The key element of the analysis is the conditional energy distribution computed for the set of all spin configurations generated from a given (ancestor) configuration by simultaneous flipping of a fixed number of spins. For the problem in question this distribution is shown to depend on the ancestor spin configuration only via a certain parameter related to 'the energy of the configuration. As the result, the algorithm dynamics can be described in terms of one-dimensional quantum diffusion in the energy space. This effect provides a general limitation of a quantum adiabatic computation in random optimization problems. Analytical results are in agreement with the numerical simulation of the algorithm.

  14. The performance of the quantum adiabatic algorithm on spike Hamiltonians

    NASA Astrophysics Data System (ADS)

    Kong, Linghang; Crosson, Elizabeth

    Spike Hamiltonians arise from optimization instances for which the adiabatic algorithm provably out performs classical simulated annealing. In this work, we study the efficiency of the adiabatic algorithm for solving the “the Hamming weight with a spike” problem by analyzing the scaling of the spectral gap at the critical point for various sizes of the barrier. Our main result is a rigorous lower bound on the minimum spectral gap for the adiabatic evolution when the bit-symmetric cost function has a thin but polynomially high barrier, which is based on a comparison argument and an improved variational ansatz for the ground state. We also adapt the discrete WKB method for the case of abruptly changing potentials and compare it with the predictions of the spin coherent instanton method which was previously used by Farhi, Goldstone and Gutmann. Finally, our improved ansatz for the ground state leads to a method for predicting the location of avoided crossings in the excited energy states of the thin spike Hamiltonian, and we use a recursion relation to understand the ordering of some of these avoided crossings as a step towards analyzing the previously observed diabatic cascade phenomenon.

  15. Adiabatic shear mechanisms for the hard cutting process

    NASA Astrophysics Data System (ADS)

    Yue, Caixu; Wang, Bo; Liu, Xianli; Feng, Huize; Cai, Chunbin

    2015-05-01

    The most important consequence of adiabatic shear phenomenon is formation of sawtooth chip. Lots of scholars focused on the formation mechanism of sawtooth, and the research often depended on experimental approach. For the present, the mechanism of sawtooth chip formation still remains some ambiguous aspects. This study develops a combined numerical and experimental approach to get deeper understanding of sawtooth chip formation mechanism for Polycrystalline Cubic Boron Nitride (PCBN) tools orthogonal cutting hard steel GCr15. By adopting the Johnson-Cook material constitutive equations, the FEM simulation model established in this research effectively overcomes serious element distortions and cell singularity in high strain domain caused by large material deformation, and the adiabatic shear phenomenon is simulated successfully. Both the formation mechanism and process of sawtooth are simulated. Also, the change features regarding the cutting force as well as its effects on temperature are studied. More specifically, the contact of sawtooth formation frequency with cutting force fluctuation frequency is established. The cutting force and effect of cutting temperature on mechanism of adiabatic shear are investigated. Furthermore, the effects of the cutting condition on sawtooth chip formation are researched. The researching results show that cutting feed has the most important effect on sawtooth chip formation compared with cutting depth and speed. This research contributes a better understanding of mechanism, feature of chip formation in hard turning process, and supplies theoretical basis for the optimization of hard cutting process parameters.

  16. Irreconcilable difference between quantum walks and adiabatic quantum computing

    NASA Astrophysics Data System (ADS)

    Wong, Thomas G.; Meyer, David A.

    2016-06-01

    Continuous-time quantum walks and adiabatic quantum evolution are two general techniques for quantum computing, both of which are described by Hamiltonians that govern their evolutions by Schrödinger's equation. In the former, the Hamiltonian is fixed, while in the latter, the Hamiltonian varies with time. As a result, their formulations of Grover's algorithm evolve differently through Hilbert space. We show that this difference is fundamental; they cannot be made to evolve along each other's path without introducing structure more powerful than the standard oracle for unstructured search. For an adiabatic quantum evolution to evolve like the quantum walk search algorithm, it must interpolate between three fixed Hamiltonians, one of which is complex and introduces structure that is stronger than the oracle for unstructured search. Conversely, for a quantum walk to evolve along the path of the adiabatic search algorithm, it must be a chiral quantum walk on a weighted, directed star graph with structure that is also stronger than the oracle for unstructured search. Thus, the two techniques, although similar in being described by Hamiltonians that govern their evolution, compute by fundamentally irreconcilable means.

  17. Non-adiabatic molecular dynamics by accelerated semiclassical Monte Carlo

    DOE PAGES

    White, Alexander J.; Gorshkov, Vyacheslav N.; Tretiak, Sergei; ...

    2015-07-07

    Non-adiabatic dynamics, where systems non-radiatively transition between electronic states, plays a crucial role in many photo-physical processes, such as fluorescence, phosphorescence, and photoisomerization. Methods for the simulation of non-adiabatic dynamics are typically either numerically impractical, highly complex, or based on approximations which can result in failure for even simple systems. Recently, the Semiclassical Monte Carlo (SCMC) approach was developed in an attempt to combine the accuracy of rigorous semiclassical methods with the efficiency and simplicity of widely used surface hopping methods. However, while SCMC was found to be more efficient than other semiclassical methods, it is not yet as efficientmore » as is needed to be used for large molecular systems. Here, we have developed two new methods: the accelerated-SCMC and the accelerated-SCMC with re-Gaussianization, which reduce the cost of the SCMC algorithm up to two orders of magnitude for certain systems. In many cases shown here, the new procedures are nearly as efficient as the commonly used surface hopping schemes, with little to no loss of accuracy. This implies that these modified SCMC algorithms will be of practical numerical solutions for simulating non-adiabatic dynamics in realistic molecular systems.« less

  18. Adiabatic dynamics with classical noise in optical lattice

    NASA Astrophysics Data System (ADS)

    Xu, Guanglei; Daley, Andrew

    2016-05-01

    The technique of adiabatic state preparation is an interesting potential tool for the realisation of sensitive many-body states with ultra-cold atoms at low temperatures. However, questions remain regarding the influence of classical noise in these adiabatic dynamics. We investigate such dynamics in a situation where a level dressing scheme can make amplitude noise in an optical lattice proportional to the Hamiltonian, leading to a quantum Zeno effect for non-adiabatic transitions. We compute the dynamics using stochastic many-body Schrödinger equation and master equation approaches. Taking the examples of 1D Bose-Hubbard model from Mott insulator phase to superfluid phase and comparing with analytical calculations for a two-level system, we demonstrate that when the total time for the process is limited, properly transformed noise can lead to an increased final fidelity in the state preparation. We consider the dynamics also in the presence of imperfections, studying the resulting heating and dephasing for the many-body states, and identifying optimal regimes for future experiments.

  19. Adiabatic invariants for the regular region of the Dicke model

    NASA Astrophysics Data System (ADS)

    Bastarrachea-Magnani, M. A.; Relaño, A.; Lerma-Hernández, S.; López-del-Carpio, B.; Chávez-Carlos, J.; Hirsch, J. G.

    2017-04-01

    Adiabatic invariants for the non-integrable Dicke model are introduced. They are shown to provide approximate second integrals of motion in the energy region where the system exhibits a regular dynamics. This low-energy region, present for any set of values of the Hamiltonian parameters is described both with a semiclassical and a full quantum analysis in a broad region of the parameter space. Peres lattices in this region exhibit that many observables vary smoothly with energy, along distinct lines which beg for a formal description. It is demonstrated how the adiabatic invariants provide a rationale to their presence in many cases. They are built employing the Born–Oppenheimer approximation, valid when a fast system is coupled to a much slower one. As the Dicke model has one bosonic and one fermionic degree of freedom, two versions of the approximation are used, depending on which one is the faster. In both cases a noticeably accord with exact numerical results is obtained. The employment of the adiabatic invariants provides a simple and clear theoretical framework to study the physical phenomenology associated to these regimes, far beyond the energies where a quadratic approximation around the minimal energy configuration can be used.

  20. Experimental implementation of an adiabatic quantum optimization algorithm

    NASA Astrophysics Data System (ADS)

    Steffen, Matthias; van Dam, Wim; Hogg, Tad; Breyta, Greg; Chuang, Isaac

    2003-03-01

    A novel quantum algorithm using adiabatic evolution was recently presented by Ed Farhi [1] and Tad Hogg [2]. This algorithm represents a remarkable discovery because it offers new insights into the usefulness of quantum resources. An experimental demonstration of an adiabatic algorithm has remained beyond reach because it requires an experimentally accessible Hamiltonian which encodes the problem and which must also be smoothly varied over time. We present tools to overcome these difficulties by discretizing the algorithm and extending average Hamiltonian techniques [3]. We used these techniques in the first experimental demonstration of an adiabatic optimization algorithm: solving an instance of the MAXCUT problem using three qubits and nuclear magnetic resonance techniques. We show that there exists an optimal run-time of the algorithm which can be predicted using a previously developed decoherence model. [1] E. Farhi et al., quant-ph/0001106 (2000) [2] T. Hogg, PRA, 61, 052311 (2000) [3] W. Rhim, A. Pines, J. Waugh, PRL, 24,218 (1970)

  1. Analysis of a High-Adiabat Cryogenic Implosion on OMEGA

    NASA Astrophysics Data System (ADS)

    Christopherson, A. R.; Betti, R.; Nora, R.; Epstein, R.; Marshall, F. J.; Forrest, C. J.; Stoeckl, C.; Delettrez, J. A.; Radha, P. B.; Howard, J.

    2014-10-01

    The performance of high-adiabat implosions >~ 10 is marginally affected by nonuniformities because of the strong ablative stabilization. To test the validity of the one-dimensional (1-D) physics included in existing hydrocodes, a study of high-adiabat cryogenic DT implosions is carried out by comparing the results of 1-D simulations with several measured quantities. It is found that after including nonlocal transport, cross-beam energy transfer, and hot electrons, 1-D simulations reproduce most of the observables with reasonable accuracy. Since the analysis is applied to the only high-adiabat DT implosion fielded on OMEGA, these results do not fully validate the 1-D physics of current hydrocodes. However, this work shows the framework for establishing a validation capability of the 1-D physics of inertial confinement fusion implosions. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and the Office of Fusion Energy Sciences Number DE-FG02-04ER54786.

  2. Skyrmion creation and annihilation by spin waves

    SciTech Connect

    Liu, Yizhou Yin, Gen; Lake, Roger K.; Zang, Jiadong; Shi, Jing

    2015-10-12

    Single skyrmion creation and annihilation by spin waves in a crossbar geometry are theoretically analyzed. A critical spin-wave frequency is required both for the creation and the annihilation of a skyrmion. The minimum frequencies for creation and annihilation are similar, but the optimum frequency for creation is below the critical frequency for skyrmion annihilation. If a skyrmion already exists in the cross bar region, a spin wave below the critical frequency causes the skyrmion to circulate within the central region. A heat assisted creation process reduces the spin-wave frequency and amplitude required for creating a skyrmion. The effective field resulting from the Dzyaloshinskii-Moriya interaction and the emergent field of the skyrmion acting on the spin wave drive the creation and annihilation processes.

  3. Iconicity can ground the creation of vocal symbols

    PubMed Central

    Perlman, Marcus; Dale, Rick; Lupyan, Gary

    2015-01-01

    Studies of gestural communication systems find that they originate from spontaneously created iconic gestures. Yet, we know little about how people create vocal communication systems, and many have suggested that vocalizations do not afford iconicity beyond trivial instances of onomatopoeia. It is unknown whether people can generate vocal communication systems through a process of iconic creation similar to gestural systems. Here, we examine the creation and development of a rudimentary vocal symbol system in a laboratory setting. Pairs of participants generated novel vocalizations for 18 different meanings in an iterative ‘vocal’ charades communication game. The communicators quickly converged on stable vocalizations, and naive listeners could correctly infer their meanings in subsequent playback experiments. People's ability to guess the meanings of these novel vocalizations was predicted by how close the vocalization was to an iconic ‘meaning template’ we derived from the production data. These results strongly suggest that the meaningfulness of these vocalizations derived from iconicity. Our findings illuminate a mechanism by which iconicity can ground the creation of vocal symbols, analogous to the function of iconicity in gestural communication systems. PMID:26361547

  4. Strangeness suppression of qq¯ creation observed in exclusive reactions

    DOE PAGES

    Mestayer, M. D.; Park, K.; Adhikari, K. P.; ...

    2014-10-10

    In this study, we measured the ratios of electroproduction cross sections from a proton target for three exclusive meson-baryon final states: ΛK+, pπ0, and nπ+, with the CLAS detector at Jefferson Lab. Using a simple model of quark hadronization, we extract qq¯ creation probabilities for the first time in exclusive two-body production, in which only a single qq¯ pair is created. We observe a sizable suppression of strange quark-antiquark pairs compared to nonstrange pairs, similar to that seen in high-energy production.

  5. Paired Straight Hearth Furnace

    SciTech Connect

    2009-04-01

    This factsheet describes a research project whose goals are to design, develop, and evaluate the scalability and commercial feasibility of the PSH Paired Straight Hearth Furnace alternative ironmaking process.

  6. Cooper Pair Insulators

    NASA Astrophysics Data System (ADS)

    Valles, James

    One of the recent advances in the field of the Superconductor to Insulator Transition (SIT) has been the discovery and characterization of the Cooper Pair Insulator phase. This bosonic insulator, which consists of localized Cooper pairs, exhibits activated transport and a giant magneto-resistance peak. These features differ markedly from the weakly localized transport that emerges as pairs break at a ``fermionic'' SIT. I will describe how our experiments on films nano-patterned with a nearly triangular array of holes have enabled us to 1) distinguish bosonic insulators from fermionic insulators, 2) show that Cooper pairs, rather than quasi-particles dominate the transport in the Cooper Pair insulator phase, 3) demonstrate that very weak, sub nano-meter thickness inhomogeneities control whether a bosonic or fermionic insulator forms at an SIT and 4) reveal that Cooper pairs disintegrate rather than becoming more tightly bound deep in the localized phase. We have also developed a method, using a magnetic field, to tune flux disorder reversibly in these films. I will present our latest results on the influence of magnetic flux disorder and random gauge fields on phenomena near bosonic SITs. This work was performed in collaboration with M. D. Stewart, Jr., Hung Q. Nguyen, Shawna M. Hollen, Jimmy Joy, Xue Zhang, Gustavo Fernandez, Jeffrey Shainline and Jimmy Xu. It was supported by NSF Grants DMR 1307290 and DMR-0907357.

  7. Concept Papers: Relationships between Vocational Education and Job Creation. Job Creation Project.

    ERIC Educational Resources Information Center

    Illinois Univ., Champaign.

    This publication contains ten papers designed to show relationships between job creation and vocational education. Information is presented regarding three areas: (1) national and state perspectives of job creation, (2) examples of how specific vocational education disciplines impact in the job creation process, and (3) case studies of job…

  8. Crowdsourcing Content Creation in the Classroom

    ERIC Educational Resources Information Center

    Hills, Thomas T.

    2015-01-01

    The recent growth in crowdsourcing technologies offers a new way of envisioning student involvement in the classroom. This article describes a participatory action research approach to combining crowdsourced content creation with the student as producer model, whereby students' interests are used to drive the identification and creation of…

  9. Creation Stories: Windows to Cultural Values.

    ERIC Educational Resources Information Center

    Hodges, David H.

    1995-01-01

    Maintains that a difficulty in teaching humanities survey courses is coordinating data from the various disciplines of cultural history. Recommends the use of creation stories as "windows" on the cultures of the Egyptians, Mesopotamians, and the Hebrews. Provides an overview of each culture's creation stories and a bibliography of…

  10. Evolution, Creationism, and the Courts: 20 Questions

    ERIC Educational Resources Information Center

    Moore, Randy; Miksch, Karen L.

    2003-01-01

    The teaching of evolution and creationism is controversial to many people in the United States. Knowledge of the many important court-decisions about the teaching of evolution and creationism in the United States can be used not only to resist anti-evolution activities of creationists, but also to help teachers address questions about the teaching…

  11. Does Teaching Creationism Facilitate Student Autonomy?

    ERIC Educational Resources Information Center

    Warnick, Bryan R.; Fooce, C. David

    2007-01-01

    The teaching of evolution in US public schools continues to generate controversy. One argument for including creationism in science classrooms is based on the goal of facilitating student autonomy. Autonomy requires that students be exposed to significant alternatives, it is argued, and religious creation stories offer a significant alternative to…

  12. History Forum Addresses Creation/Evolution Controversy.

    ERIC Educational Resources Information Center

    Schweinsberg, John

    1997-01-01

    A series of programs entitled Creationism and Evolution: The History of a Controversy was presented at the University of Alabama in Huntsville. The controversy was addressed from an historical and sociological, rather than a scientific perspective. Speakers addressed the evolution of scientific creationism, ancient texts versus sedimentary rocks…

  13. Science and Creation: Geological, Theological & Educational Perspectives.

    ERIC Educational Resources Information Center

    Hanson, Robert W., Ed.

    This book provides working examples of how different teachers, scientists, and theologians have dealt with problems of "creation science" versus evolutionary concepts. A 1982 symposia on the topic of science and creation was so well received that the participants were asked to submit formal presentations; this book is a collection of these papers.…

  14. Atom-Pair Kinetics with Strong Electric-Dipole Interactions.

    PubMed

    Thaicharoen, N; Gonçalves, L F; Raithel, G

    2016-05-27

    Rydberg-atom ensembles are switched from a weakly to a strongly interacting regime via adiabatic transformation of the atoms from an approximately nonpolar into a highly dipolar quantum state. The resultant electric dipole-dipole forces are probed using a device akin to a field ion microscope. Ion imaging and pair-correlation analysis reveal the kinetics of the interacting atoms. Dumbbell-shaped pair-correlation images demonstrate the anisotropy of the binary dipolar force. The dipolar C_{3} coefficient, derived from the time dependence of the images, agrees with the value calculated from the permanent electric-dipole moment of the atoms. The results indicate many-body dynamics akin to disorder-induced heating in strongly coupled particle systems.

  15. Shortcuts to adiabaticity by counterdiabatic driving for trapped-ion displacement in phase space

    PubMed Central

    An, Shuoming; Lv, Dingshun; del Campo, Adolfo; Kim, Kihwan

    2016-01-01

    The application of adiabatic protocols in quantum technologies is severely limited by environmental sources of noise and decoherence. Shortcuts to adiabaticity by counterdiabatic driving constitute a powerful alternative that speed up time-evolution while mimicking adiabatic dynamics. Here we report the experimental implementation of counterdiabatic driving in a continuous variable system, a shortcut to the adiabatic transport of a trapped ion in phase space. The resulting dynamics is equivalent to a ‘fast-motion video' of the adiabatic trajectory. The robustness of this protocol is shown to surpass that of competing schemes based on classical local controls and Fourier optimization methods. Our results demonstrate that shortcuts to adiabaticity provide a robust speedup of quantum protocols of wide applicability in quantum technologies. PMID:27669897

  16. Shear Faulting and Adiabatic Heating: Experimental Results from Ice

    NASA Astrophysics Data System (ADS)

    Golding, N.; Schulson, E. M.; Renshaw, C. E.

    2011-12-01

    Ice exhibits two distinct modes of shear faulting (Golding et al. Acta Materialia, 2010;58:5043), namely frictional or Coulombic (C) faulting under moderate levels of confinement and non-frictional or plastic (P) faulting under high levels of confinement. The mechanisms governing C-faulting have previously been discussed in connection with the comb-crack model (Renshaw & Schulson Nature, 2001;412:897). Here we examine the physical process[es] that trigger P-faulting. Systematic experiments on laboratory grown granular and columnar polycrystalline ice loaded triaxially under a high degree of confinement at -10 oC to -40 oC at applied strain rates 10-5 s-1 to 10-1 s-1 trace the micro-mechanical evolution of P-faulting. Terminal failure is characterized by a sudden brittle-like loss in load bearing capacity, the development of a narrow shear band, comprised of recrystallized grains and oriented on a plane of maximum shear, and localized heating. Possible mechanisms considered to account for the localization include: 1) adiabatic heating, 2) localized material softening through a reduction in dislocation density caused by dynamic recrystallization and 3) a transition from power-law creep to grain-size-dependent diffusional creep as a result of grain refinement caused by dynamic recrystallization. Our results indicate that, although recrystallization develops dynamically during loading, microstructural development does not significantly affect shear localization in ice. Nor does it affect the character of the fault. The minimum levels of deformation required to generate faulting are found to be consistent with those predicted for adiabatic shear instability. The present observations suggest that under specific conditions adiabatic heating, rather than dynamic recrystallization, may lead to material instability and shear faulting.

  17. Adiabatic quantum computing with spin qubits hosted by molecules.

    PubMed

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

    2015-01-28

    A molecular spin quantum computer (MSQC) requires electron spin qubits, which pulse-based electron spin/magnetic resonance (ESR/MR) techniques can afford to manipulate for implementing quantum gate operations in open shell molecular entities. Importantly, nuclear spins, which are topologically connected, particularly in organic molecular spin systems, are client qubits, while electron spins play a role of bus qubits. Here, we introduce the implementation for an adiabatic quantum algorithm, suggesting the possible utilization of molecular spins with optimized spin structures for MSQCs. We exemplify the utilization of an adiabatic factorization problem of 21, compared with the corresponding nuclear magnetic resonance (NMR) case. Two molecular spins are selected: one is a molecular spin composed of three exchange-coupled electrons as electron-only qubits and the other an electron-bus qubit with two client nuclear spin qubits. Their electronic spin structures are well characterized in terms of the quantum mechanical behaviour in the spin Hamiltonian. The implementation of adiabatic quantum computing/computation (AQC) has, for the first time, been achieved by establishing ESR/MR pulse sequences for effective spin Hamiltonians in a fully controlled manner of spin manipulation. The conquered pulse sequences have been compared with the NMR experiments and shown much faster CPU times corresponding to the interaction strength between the spins. Significant differences are shown in rotational operations and pulse intervals for ESR/MR operations. As a result, we suggest the advantages and possible utilization of the time-evolution based AQC approach for molecular spin quantum computers and molecular spin quantum simulators underlain by sophisticated ESR/MR pulsed spin technology.

  18. Optical force on atoms with periodic adiabatic rapid passage sequences

    NASA Astrophysics Data System (ADS)

    Miao, Xiyue

    Adiabatic Rapid Passage (ARP) is a long-existing method to invert the population of a two-level nuclear spin system. Its extension to the optical domain necessitates a frequency chirped light pulse to interact with a two-level atom through dipole interaction. In this dissertation ARP processes for various pulse schemes and pulse parameters have been studied theoretically and experimentally. The non-adiabatic transition probability of ARP was quantified to characterize the efficiency of ARP for population transfer. Unanticipated regularities were found in the pulse parameter space. ARP sequences in periodic phase coherent counter-propagating light pulses can be used to produce large optical forces on atoms. The magnitude of the force is proportional to the pulse repetition rate. So the force can be much larger than the usual radiative force if the pulse repetition rate is much higher than the spontaneous emission rate. The behavior of the atoms in such periodic ARP fields without spontaneous emission is well described by a periodic Hamiltonian. By investigating the evolution of the Bloch vector on the Bloch sphere, we related the average optical force on atoms to the non-adiabatic transition probability of a single pulse. Syncopation time has to be introduced in the pulsing scheme to produce a directional force in the presence of spontaneous emission. Experimentally, we observed the force on He* atoms by the deflection of the atomic beam with periodic chirped pulses from counter-propagating pulse trains. The chirped pulse train was realized by synchronized phase and amplitude modulation of the light from a cw diode laser. The Fourier spectrum of the modulated light was monitored to guarantee the quality of the chirped pulses. The measured ARP forces are about half of the theoretical predictions. Not only have we shown that such forces are huge and robust, but we have also been able to map the forces in the two dimensional pulse parameter space. The force

  19. Major Steps in the Discovery of Adiabatic Shear Bands

    NASA Astrophysics Data System (ADS)

    Dodd, Bradley; Walley, Stephen M.; Yang, Rong; Nesterenko, Vitali F.

    2015-10-01

    The standard story of the discovery of adiabatic shear bands is that it began with the American researchers Zener and Hollomon's famous 1944 paper where the phenomenon was first reported and named. However, a recent discovery by one of us (SMW) in the Cambridge University Library has shown that the phenomenon was discovered and described by a Russian researcher, V.P. Kravz-Tarnavskii, in 1928. A follow-up paper was published by two of his colleagues in 1935. Translations of the 1928 and 1935 papers may be found at http://arxiv.org/abs/1410.1353.

  20. Adiabatic transport of qubits around a black hole

    NASA Astrophysics Data System (ADS)

    Viennot, David; Moro, Olivia

    2017-03-01

    We consider localized qubits evolving around a black hole following a quantum adiabatic dynamics. We develop a geometric structure (based on fibre bundles) permitting to describe the quantum states of a qubit and the spacetime geometry in a single framework. The quantum decoherence induced by the black hole on the qubit is analysed in this framework (the role of the dynamical and geometric phases in this decoherence is treated), especially for the quantum teleportation protocol when one qubit falls to the event horizon. A simple formula to compute the fidelity of the teleportation is derived. The case of a Schwarzschild black hole is analysed.

  1. Relativistic blast waves in two dimensions. I - The adiabatic case

    NASA Technical Reports Server (NTRS)

    Shapiro, P. R.

    1979-01-01

    Approximate solutions are presented for the dynamical evolution of strong adiabatic relativistic blast waves which result from a point explosion in an ambient gas in which the density varies both with distance from the explosion center and with polar angle in axisymmetry. Solutions are analytical or quasi-analytical for the extreme relativistic case and numerical for the arbitrarily relativistic case. Some general properties of nonplanar relativistic shocks are also discussed, including the incoherence of spherical ultrarelativistic blast-wave fronts on angular scales greater than the reciprocal of the shock Lorentz factor, as well as the conditions for producing blast-wave acceleration.

  2. Magnetic shielding for a spaceborne adiabatic demagnetization refrigerator (ADR)

    NASA Technical Reports Server (NTRS)

    Warner, Brent A.; Shirron, Peter J.; Castles, Stephen H.; Serlemitsos, Aristides T.

    1991-01-01

    The Goddard Space Flight Center has studied magnetic shielding for an adiabatic demagnetization refrigerator. Four types of shielding were studied: active coils, passive ferromagnetic shells, passive superconducting coils, and passive superconducting shells. The passive superconducting shells failed by allowing flux penetration. The other three methods were successful, singly or together. Experimental studies of passive ferromagnetic shielding are compared with calculations made using the Poisson Group of programs, distributed by the Los Alamos Accelerator Code Group of the Los Alamos National Laboratory. Agreement between calculation and experiment is good. The ferromagnetic material is a silicon iron alloy.

  3. More bang for your buck: Super-adiabatic quantum engines

    PubMed Central

    Campo, A. del; Goold, J.; Paternostro, M.

    2014-01-01

    The practical untenability of the quasi-static assumption makes any realistic engine intrinsically irreversible and its operating time finite, thus implying friction effects at short cycle times. An important technological goal is thus the design of maximally efficient engines working at the maximum possible power. We show that, by utilising shortcuts to adiabaticity in a quantum engine cycle, one can engineer a thermodynamic cycle working at finite power and zero friction. Our findings are illustrated using a harmonic oscillator undergoing a quantum Otto cycle. PMID:25163421

  4. Non-Adiabatic Holonomic Quantum Gates in an atomic system

    NASA Astrophysics Data System (ADS)

    Azimi Mousolou, Vahid; Canali, Carlo M.; Sjoqvist, Erik

    2012-02-01

    Quantum computation is essentially the implementation of a universal set of quantum gate operations on a set of qubits, which is reliable in the presence of noise. We propose a scheme to perform robust gates in an atomic four-level system using the idea of non-adiabatic holonomic quantum computation proposed in [1]. The gates are realized by applying sequences of short laser pulses that drive transitions between the four energy levels in such a way that the dynamical phases vanish. [4pt] [1] E. Sjoqvist, D.M. Tong, B. Hessmo, M. Johansson, K. Singh, arXiv:1107.5127v2 [quant-ph

  5. Metallization of nanofilms in strong adiabatic electric fields.

    PubMed

    Durach, Maxim; Rusina, Anastasia; Kling, Matthias F; Stockman, Mark I

    2010-08-20

    We introduce an effect of metallization of dielectric nanofilms by strong, adiabatically varying electric fields. The metallization causes optical properties of a dielectric film to become similar to those of a plasmonic metal (strong absorption and negative permittivity at low optical frequencies). This is a quantum effect, which is exponentially size-dependent, occurring at fields on the order of 0.1 V/Å and pulse durations ranging from ∼1 fs to ∼10 ns for a film thickness of 3-10 nm.

  6. Metallization of Nanofilms in Strong Adiabatic Electric Fields

    NASA Astrophysics Data System (ADS)

    Durach, Maxim; Rusina, Anastasia; Kling, Matthias F.; Stockman, Mark I.

    2010-08-01

    We introduce an effect of metallization of dielectric nanofilms by strong, adiabatically varying electric fields. The metallization causes optical properties of a dielectric film to become similar to those of a plasmonic metal (strong absorption and negative permittivity at low optical frequencies). This is a quantum effect, which is exponentially size-dependent, occurring at fields on the order of 0.1V/Å and pulse durations ranging from ˜1fs to ˜10ns for a film thickness of 3-10 nm.

  7. Salt materials testing for a spacecraft adiabatic demagnetization refrigerator

    NASA Astrophysics Data System (ADS)

    Savage, M. L.; Kittel, P.; Roellig, T.

    As part of a technology development effort to qualify adiabatic demagnetization refrigerators for use in a NASA spacecraft, such as the Space Infrared Telescope Facility, a study of low temperature characteristics, heat capacity and resistance to dehydration was conducted for different salt materials. This report includes results of testing with cerrous metaphosphate, several synthetic rubies, and chromic potassium alum (CPA). Preliminary results show that CPA may be suitable for long-term spacecraft use, provided that the salt is property encapsulated. Methods of salt pill construction and testing for all materials are discussed, as well as reliability tests. Also, the temperature regulation scheme and the test cryostat design are briefly discussed.

  8. Non-adiabatic pumping in an oscillating-piston model

    NASA Astrophysics Data System (ADS)

    Chuchem, Maya; Dittrich, Thomas; Cohen, Doron

    2012-05-01

    We consider the prototypical "piston pump" operating on a ring, where a circulating current is induced by means of an AC driving. This can be regarded as a generalized Fermi-Ulam model, incorporating a finite-height moving wall (piston) and non-trivial topology (ring). The amount of particles transported per cycle is determined by a layered structure of phase space. Each layer is characterized by a different drift velocity. We discuss the differences compared with the adiabatic and Boltzmann pictures, and highlight the significance of the "diabatic" contribution that might lead to a counter-stirring effect.

  9. Optimized sympathetic cooling of atomic mixtures via fast adiabatic strategies

    SciTech Connect

    Choi, Stephen; Sundaram, Bala; Onofrio, Roberto

    2011-11-15

    We discuss fast frictionless cooling techniques in the framework of sympathetic cooling of cold atomic mixtures. It is argued that optimal cooling of an atomic species--in which the deepest quantum degeneracy regime is achieved--may be obtained by means of sympathetic cooling with another species whose trapping frequency is dynamically changed to maintain constancy of the Lewis-Riesenfeld adiabatic invariant. Advantages and limitations of this cooling strategy are discussed, with particular regard to the possibility of cooling Fermi gases to a deeper degenerate regime.

  10. Salt materials testing for a spacecraft adiabatic demagnetization refrigerator

    NASA Technical Reports Server (NTRS)

    Savage, M. L.; Kittel, P.; Roellig, T.

    1990-01-01

    As part of a technology development effort to qualify adiabatic demagnetization refrigerators for use in a NASA spacecraft, such as the Space Infrared Telescope Facility, a study of low temperature characteristics, heat capacity and resistance to dehydration was conducted for different salt materials. This report includes results of testing with cerrous metaphosphate, several synthetic rubies, and chromic potassium alum (CPA). Preliminary results show that CPA may be suitable for long-term spacecraft use, provided that the salt is property encapsulated. Methods of salt pill construction and testing for all materials are discussed, as well as reliability tests. Also, the temperature regulation scheme and the test cryostat design are briefly discussed.

  11. Propagation of laser pulses under conditions of adiabatic population transfer

    SciTech Connect

    Arkhipkin, V G; Manushkin, D V; Timofeev, V P

    1998-12-31

    A medium of three-level absorbing atoms is considered under conditions of adiabatic population transfer. A study is made of the characteristics of spatial propagation of two delayed (relative to one another) Gaussian pulses. It is shown that selective excitation of a two-photon resonant state with a near-unity probability is conserved over the length of a medium, which is considerably greater than the absorption length of a weak probe pulse in the absence of the second field. (physical basis of quantum electronics)

  12. Stimulated Raman adiabatic passage in Tm{sup 3+}:YAG

    SciTech Connect

    Alexander, A. L.; Lauro, R.; Louchet, A.; Chaneliere, T.; Le Goueet, J. L.

    2008-10-01

    We report on the experimental demonstration of stimulated Raman adiabatic passage in a Tm{sup 3+}:YAG crystal. Tm{sup 3+}:YAG is a promising material for use in quantum information processing applications, but as yet there are few experimental investigations of coherent Raman processes in this material. We investigate the effect of inhomogeneous broadening and Rabi frequency on the transfer efficiency and the width of the two-photon spectrum. Simulations of the complete Tm{sup 3+}:YAG system are presented along with the corresponding experimental results.

  13. Adiabatic invariants in stellar dynamics. 2: Gravitational shocking

    NASA Technical Reports Server (NTRS)

    Weinberg, Martin D.

    1994-01-01

    A new theory of gravitational shocking based on time-dependent perturbation theory shows that the changes in energy and angular momentum due to a slowly varying disturbance are not exponentially small for stellar dynamical systems in general. It predicts significant shock heating by slowly varying perturbations previously thought to be negligible according to the adiabatic criterion. The theory extends the scenarios traditionally computed only with the impulse approximation and is applicable to a wide class of disturbances. The approach is applied specifically to the problem of disk shocking of star clusters.

  14. Modeling of the Adiabatic and Isothermal Methanation Process

    NASA Astrophysics Data System (ADS)

    Porubova, Jekaterina; Bazbauers, Gatis; Markova, Darja

    2011-01-01

    Increased use of biomass offers one of the ways to reduce anthropogenic impact on the environment. Using various biomass conversion processes, it is possible to obtain different types of fuels: • solid, e.g. bio-carbon; • liquid, e.g. biodiesel and ethanol; • gaseous, e.g. biomethane. Biomethane can be used in the transport and energy sector, and the total methane production efficiency can reach 65%. By modeling adiabatic and isothermal methanation processes, the most effective one from the methane production point of view is defined. Influence of the process parameters on the overall efficiency of the methane production is determined.

  15. Control of adiabatic light transfer in coupled waveguides with longitudinally varying detuning

    NASA Astrophysics Data System (ADS)

    Oukraou, Hassan; Vittadello, Laura; Coda, Virginie; Ciret, Charles; Alonzo, Massimo; Rangelov, Andon A.; Vitanov, Nikolay V.; Montemezzani, Germano

    2017-02-01

    We study adiabatic light transfer in systems of two coupled waveguides with spatially varying detuning of the propagation constants, providing an analogy to the quantum phenomena of rapid adiabatic passage (RAP) and two-state stimulated Raman adiabatic passage (two-state STIRAP). Experimental demonstration using a photoinduction technique confirms the robust and broadband character of the structures that act as broadband directional couplers and broadband beam splitters, respectively.

  16. Shortcut to Adiabatic Passage in Two- and Three-Level Atoms

    SciTech Connect

    Chen Xi; Lizuain, I.; Muga, J. G.; Ruschhaupt, A.; Guery-Odelin, D.

    2010-09-17

    We propose a method to speed up adiabatic passage techniques in two-level and three-level atoms extending to the short-time domain their robustness with respect to parameter variations. It supplements or substitutes the standard laser beam setups with auxiliary pulses that steer the system along the adiabatic path. Compared to other strategies, such as composite pulses or the original adiabatic techniques, it provides a fast and robust approach to population control.

  17. Determining the Complexity of the Quantum Adiabatic Algorithm using Quantum Monte Carlo Simulations

    DTIC Science & Technology

    2012-12-18

    efficiently a quantum computer could solve optimization problems using the quantum adiabatic algorithm (QAA). Comparisons were made with a classical...Park, NC 27709-2211 15. SUBJECT TERMS Quantum Adiabatic Algorithm , Optimization, Monte Carlo, quantum computer, satisfiability problems, spin glass... quantum adiabatic algorithm (QAA). Comparisons were made with a classical heuristic algorithm , WalkSAT. A preliminary study was also made to see if the

  18. Shortcut to adiabatic control of soliton matter waves by tunable interaction

    PubMed Central

    Li, Jing; Sun, Kun; Chen, Xi

    2016-01-01

    We propose a method for shortcut to adiabatic control of soliton matter waves in harmonic traps. The tunable interaction controlled by Feshbach resonance is inversely designed to achieve fast and high-fidelity compression of soliton matter waves as compared to the conventional adiabatic compression. These results pave the way to control the nonlinear dynamics for matter waves and optical solitons by using shortcuts to adiabaticity. PMID:28009007

  19. Particle creation in bouncing cosmologies

    NASA Astrophysics Data System (ADS)

    Celani, Diogo C. F.; Pinto-Neto, Nelson; Vitenti, Sandro D. P.

    2017-01-01

    We investigate scalar particle creation in a set of bouncing models where the bounce occurs due to quantum cosmological effects described by the Wheeler-DeWitt equation. The scalar field can be either conformally or minimally coupled to gravity, and it can be massive or massless, without self-interaction. The analysis is made for models containing a single radiation fluid and for the more realistic case of models containing the usual observed radiation and dust fluids, which can fit most of the observed features of our universe, including an almost scale invariant power spectrum of scalar cosmological perturbations. In the conformal coupling case, the particle production is negligible. In the minimal coupling case, for massive particles, the results point to the same physical conclusion within observational constraints: particle production is most important at the bounce energy scale, and it is not sensitive either to its mass or to whether there is dust in the background model. The only caveat is the case where the particle mass is larger than the bounce energy scale. On the other hand, the energy density of produced massive particles depend on their masses and the energy scale of the bounce. For very large masses and deep bounces, this energy density may overcome that of the background. In the case of massless particles, the energy density of produced particles can become comparable to the background energy density only for bounces occurring at energy scales comparable to the Planck scale or above, which lies beyond the scope of this paper: we expect that the simple Wheeler-DeWitt approach we are using should be valid only at scales a few orders of magnitude below the Planck energy. Nevertheless, in the case in which dust is present, there is an infrared divergence, which becomes important only for scales much larger than today's Hubble radius.

  20. Singularity of the time-energy uncertainty in adiabatic perturbation and cycloids on a Bloch sphere.

    PubMed

    Oh, Sangchul; Hu, Xuedong; Nori, Franco; Kais, Sabre

    2016-02-26

    Adiabatic perturbation is shown to be singular from the exact solution of a spin-1/2 particle in a uniformly rotating magnetic field. Due to a non-adiabatic effect, its quantum trajectory on a Bloch sphere is a cycloid traced by a circle rolling along an adiabatic path. As the magnetic field rotates more and more slowly, the time-energy uncertainty, proportional to the length of the quantum trajectory, calculated by the exact solution is entirely different from the one obtained by the adiabatic path traced by the instantaneous eigenstate. However, the non-adiabatic Aharonov-Anandan geometric phase, measured by the area enclosed by the exact path, approaches smoothly the adiabatic Berry phase, proportional to the area enclosed by the adiabatic path. The singular limit of the time-energy uncertainty and the regular limit of the geometric phase are associated with the arc length and arc area of the cycloid on a Bloch sphere, respectively. Prolate and curtate cycloids are also traced by different initial states outside and inside of the rolling circle, respectively. The axis trajectory of the rolling circle, parallel to the adiabatic path, is shown to be an example of transitionless driving. The non-adiabatic resonance is visualized by the number of cycloid arcs.

  1. Fast adiabatic quantum state transfer and entanglement generation between two atoms via dressed states

    PubMed Central

    Wu, Jin-Lei; Ji, Xin; Zhang, Shou

    2017-01-01

    We propose a dressed-state scheme to achieve shortcuts to adiabaticity in atom-cavity quantum electrodynamics for speeding up adiabatic two-atom quantum state transfer and maximum entanglement generation. Compared with stimulated Raman adiabatic passage, the dressed-state scheme greatly shortens the operation time in a non-adiabatic way. By means of some numerical simulations, we determine the parameters which can guarantee the feasibility and efficiency both in theory and experiment. Besides, numerical simulations also show the scheme is robust against the variations in the parameters, atomic spontaneous emissions and the photon leakages from the cavity.

  2. Singularity of the time-energy uncertainty in adiabatic perturbation and cycloids on a Bloch sphere

    PubMed Central

    Oh, Sangchul; Hu, Xuedong; Nori, Franco; Kais, Sabre

    2016-01-01

    Adiabatic perturbation is shown to be singular from the exact solution of a spin-1/2 particle in a uniformly rotating magnetic field. Due to a non-adiabatic effect, its quantum trajectory on a Bloch sphere is a cycloid traced by a circle rolling along an adiabatic path. As the magnetic field rotates more and more slowly, the time-energy uncertainty, proportional to the length of the quantum trajectory, calculated by the exact solution is entirely different from the one obtained by the adiabatic path traced by the instantaneous eigenstate. However, the non-adiabatic Aharonov- Anandan geometric phase, measured by the area enclosed by the exact path, approaches smoothly the adiabatic Berry phase, proportional to the area enclosed by the adiabatic path. The singular limit of the time-energy uncertainty and the regular limit of the geometric phase are associated with the arc length and arc area of the cycloid on a Bloch sphere, respectively. Prolate and curtate cycloids are also traced by different initial states outside and inside of the rolling circle, respectively. The axis trajectory of the rolling circle, parallel to the adiabatic path, is shown to be an example of transitionless driving. The non-adiabatic resonance is visualized by the number of cycloid arcs. PMID:26916031

  3. Synthesizing skyrmion bound pairs in Fe-Gd thin films

    NASA Astrophysics Data System (ADS)

    Lee, J. C. T.; Chess, J. J.; Montoya, S. A.; Shi, X.; Tamura, N.; Mishra, S. K.; Fischer, P.; McMorran, B. J.; Sinha, S. K.; Fullerton, E. E.; Kevan, S. D.; Roy, S.

    2016-07-01

    We show that properly engineered amorphous Fe-Gd alloy thin films with perpendicular magnetic anisotropy exhibit bound pairs of like-polarity, opposite helicity skyrmions at room temperature. Magnetic mirror symmetry planes present in the stripe phase, instead of chiral exchange, determine the internal skyrmion structure and the net achirality of the skyrmion phase. Our study shows that stripe domain engineering in amorphous alloy thin films may enable the creation of skyrmion phases with technologically desirable properties.

  4. Synthesizing skyrmion bound pairs in Fe-Gd thin films

    DOE PAGES

    Lee, J. C. T.; Chess, J. J.; Montoya, S. A.; ...

    2016-07-11

    Here, we show that properly engineered amorphous Fe-Gd alloy thin films with perpendicular magnetic anisotropy exhibit bound pairs of like-polarity, opposite helicity skyrmions at room temperature. Magnetic mirror symmetry planes present in the stripe phase, instead of chiral exchange, determine the internal skyrmion structure and the net achirality of the skyrmion phase. Our study shows that stripe domain engineering in amorphous alloy thin films may enable the creation of skyrmion phases with technologically desirable properties.

  5. Robust quantum logic in neutral atoms via adiabatic Rydberg dressing

    SciTech Connect

    Keating, Tyler; Cook, Robert L.; Hankin, Aaron M.; Jau, Yuan -Yu; Biedermann, Grant W.; Deutsch, Ivan H.

    2015-01-28

    We study a scheme for implementing a controlled-Z (CZ) gate between two neutral-atom qubits based on the Rydberg blockade mechanism in a manner that is robust to errors caused by atomic motion. By employing adiabatic dressing of the ground electronic state, we can protect the gate from decoherence due to random phase errors that typically arise because of atomic thermal motion. In addition, the adiabatic protocol allows for a Doppler-free configuration that involves counterpropagating lasers in a σ+- orthogonal polarization geometry that further reduces motional errors due to Doppler shifts. The residual motional error is dominated by dipole-dipole forces acting on doubly-excited Rydberg atoms when the blockade is imperfect. As a result, for reasonable parameters, with qubits encoded into the clock states of 133Cs, we predict that our protocol could produce a CZ gate in < 10 μs with error probability on the order of 10-3.

  6. Sliding Seal Materials for Adiabatic Engines, Phase 2

    NASA Technical Reports Server (NTRS)

    Lankford, J.; Wei, W.

    1986-01-01

    An essential task in the development of the heavy-duty adiabatic diesel engine is identification and improvements of reliable, low-friction piston seal materials. In the present study, the sliding friction coefficients and wear rates of promising carbide, oxide, and nitride materials were measured under temperature, environmental, velocity, and loading conditions that are representative of the adiabatic engine environment. In addition, silicon nitride and partially stabilized zirconia disks were ion implanted with TiNi, Ni, Co, and Cr, and subsequently run against carbide pins, with the objective of producing reduced friction via solid lubrication at elevated temperature. In order to provide guidance needed to improve materials for this application, the program stressed fundamental understanding of the mechanisms involved in friction and wear. Electron microscopy was used to elucidate the micromechanisms of wear following wear testing, and Auger electron spectroscopy was used to evaluate interface/environment interactions which seemed to be important in the friction and wear process. Unmodified ceramic sliding couples were characterized at all temperatures by friction coefficients of 0.24 and above. The coefficient at 800 C in an oxidizing environment was reduced to below 0.1, for certain material combinations, by the ion implanation of TiNi or Co. This beneficial effect was found to derive from lubricious Ti, Ni, and Co oxides.

  7. Breakdown of adiabatic electron behavior in expanding magnetic fields

    NASA Astrophysics Data System (ADS)

    Lichko, Emily; Egedal, Jan; Daughton, William

    2015-11-01

    During magnetic reconnection the incoming magnetic flux tubes expand in the inflow region. If this expansion is sufficiently slow the results are well described by a previously developed adiabatic model. Using kinetic simulations in a simple geometry and applying rapid magnetic perturbations, this study investigates the point at which the adiabatic assumption fails. To this end a 2D VPIC simulation was constructed, where the magnetic field in a uniform plasma is perturbed by externally driven currents. By varying the onset speed of the magnetic perturbation and the electron thermal speed, we found a sharp threshold at which this model breaks down. We believe that this point is determined by the time of the magnetic pumping compared to the electron transit time through the region, i.e. ω ~ Ḃ / B ~vthe / L . This threshold was also characterized by the launching of Whistler waves and with time domain structures, such as electron holes and double layers, which agree with those seen during magnetic reconnection and may relate to similar structures in the Van Allen Belts. NSF GEM award 1405166 and NASA grant NNX14AC68G.

  8. Robust quantum logic in neutral atoms via adiabatic Rydberg dressing

    DOE PAGES

    Keating, Tyler; Cook, Robert L.; Hankin, Aaron M.; ...

    2015-01-28

    We study a scheme for implementing a controlled-Z (CZ) gate between two neutral-atom qubits based on the Rydberg blockade mechanism in a manner that is robust to errors caused by atomic motion. By employing adiabatic dressing of the ground electronic state, we can protect the gate from decoherence due to random phase errors that typically arise because of atomic thermal motion. In addition, the adiabatic protocol allows for a Doppler-free configuration that involves counterpropagating lasers in a σ+/σ- orthogonal polarization geometry that further reduces motional errors due to Doppler shifts. The residual motional error is dominated by dipole-dipole forces actingmore » on doubly-excited Rydberg atoms when the blockade is imperfect. As a result, for reasonable parameters, with qubits encoded into the clock states of 133Cs, we predict that our protocol could produce a CZ gate in < 10 μs with error probability on the order of 10-3.« less

  9. Schedule path optimization for adiabatic quantum computing and optimization

    NASA Astrophysics Data System (ADS)

    Zeng, Lishan; Zhang, Jun; Sarovar, Mohan

    2016-04-01

    Adiabatic quantum computing and optimization have garnered much attention recently as possible models for achieving a quantum advantage over classical approaches to optimization and other special purpose computations. Both techniques are probabilistic in nature and the minimum gap between the ground state and first excited state of the system during evolution is a major factor in determining the success probability. In this work we investigate a strategy for increasing the minimum gap and success probability by introducing intermediate Hamiltonians that modify the evolution path between initial and final Hamiltonians. We focus on an optimization problem relevant to recent hardware implementations and present numerical evidence for the existence of a purely local intermediate Hamiltonian that achieve the optimum performance in terms of pushing the minimum gap to one of the end points of the evolution. As a part of this study we develop a convex optimization formulation of the search for optimal adiabatic schedules that makes this computation more tractable, and which may be of independent interest. We further study the effectiveness of random intermediate Hamiltonians on the minimum gap and success probability, and empirically find that random Hamiltonians have a significant probability of increasing the success probability, but only by a modest amount.

  10. The effect of adiabaticity on strongly quenched Bose Einstein Condensates

    NASA Astrophysics Data System (ADS)

    Ling, Hong; Kain, Ben

    2015-05-01

    We study the properties of a Bose-Einstein condensate following a deep quench to a large scattering length during which the condensate fraction nc changes with time. We construct a closed set of equations that highlight the role of the adiabaticity or equivalently, dnc/dt, the rate change of nc, which is to induce an (imaginary) effective interaction between quasiparticles. We show analytically that such a system supports a steady state characterized by a constant condensate density and a steady but periodically changing momentum distribution, whose time average is described exactly by the generalized Gibbs ensemble. We discuss how the nc -induced effective interaction, which cannot be ignored on the grounds of the adiabatic approximation for modes near the gapless Goldstone mode, can significantly affect condensate populations and Tan's contact for a Bose gas that has undergone a deep quench. In particular, we find that even when the Bose gas is quenched to unitarity, nc(t) does not completely deplete, approaching, instead, to a steady state with a finite condensate fraction. ITAMP, Harvard-Smithsonian Center for Astrophysics; KITP, University of Santa Barbara.

  11. Highly parallel implementation of non-adiabatic Ehrenfest molecular dynamics

    NASA Astrophysics Data System (ADS)

    Kanai, Yosuke; Schleife, Andre; Draeger, Erik; Anisimov, Victor; Correa, Alfredo

    2014-03-01

    While the adiabatic Born-Oppenheimer approximation tremendously lowers computational effort, many questions in modern physics, chemistry, and materials science require an explicit description of coupled non-adiabatic electron-ion dynamics. Electronic stopping, i.e. the energy transfer of a fast projectile atom to the electronic system of the target material, is a notorious example. We recently implemented real-time time-dependent density functional theory based on the plane-wave pseudopotential formalism in the Qbox/qb@ll codes. We demonstrate that explicit integration using a fourth-order Runge-Kutta scheme is very suitable for modern highly parallelized supercomputers. Applying the new implementation to systems with hundreds of atoms and thousands of electrons, we achieved excellent performance and scalability on a large number of nodes both on the BlueGene based ``Sequoia'' system at LLNL as well as the Cray architecture of ``Blue Waters'' at NCSA. As an example, we discuss our work on computing the electronic stopping power of aluminum and gold for hydrogen projectiles, showing an excellent agreement with experiment. These first-principles calculations allow us to gain important insight into the the fundamental physics of electronic stopping.

  12. Enhanced Diffusion Weighting Generated by Selective Adiabatic Pulse Trains

    PubMed Central

    Sun, Ziqi; Bartha, Robert

    2007-01-01

    A theoretical description and experimental validation of the enhanced diffusion weighting generated by selective adiabatic full passage (AFP) pulse trains is provided. Six phantoms (Ph-1 to Ph-6) were studied on a 4T Varian/Siemens whole body MRI system. Phantoms consisted of 2.8 cm diameter plastic tubes containing a mixture of 10 μm ORGASOL polymer beads and 2 mM Gd-DTPA dissolved in 5% agar (Ph-1) or nickel(II) ammonium sulphate hexahydrate doped (56.3 mM – 0.8 mM) water solutions (Ph-2 to Ph-6). A customized localization by adiabatic selective refocusing (LASER) sequence containing slice selective AFP pulse trains and pulsed diffusion gradients applied in the phase encoding direction was used to measure 1H2O diffusion. The b-value associated with the LASER sequence was derived using the Bloch-Torrey equation. The apparent diffusion coefficients measured by LASER were comparable to those measured by a conventional pulsed gradient spin-echo (PGSE) sequence for all phantoms. Image signal intensity increased in Ph-1 and decreased in Ph-2 – Ph-6 as AFP pulse train length increased while maintaining a constant echo-time. These experimental results suggest that such AFP pulse trains can enhance contrast between regions containing microscopic magnetic susceptibility variations and homogeneous regions in which dynamic dephasing relaxation mechanisms are dominant. PMID:17600741

  13. The 0.1K bolometers cooled by adiabatic demagnetization

    NASA Technical Reports Server (NTRS)

    Roellig, T.; Lesyna, L.; Kittel, P.; Werner, M.

    1983-01-01

    The most straightforward way of reducing the noise equivalent power of bolometers is to lower their operating temperature. We have been exploring the possibility of using conventionally constructed bolometers at ultra-low temperatures to achieve NEP's suitable to the background environment of cooled space telescopes. We have chosen the technique of adiabatic demagnetization of a paramagnetic salt as a gravity independent, compact, and low power way to achieve temperatures below pumped He-3 (0.3 K). The demagnetization cryostat we used was capable of reaching temperatures below 0.08 K using Chromium Potassium Alum as a salt from a starting temperature of 1.5 K and a starting magnetic field of 30,000 gauss. Computer control of the magnetic field decay allowed a temperature of 0.2 K to be maintained to within 0.5 mK over a time period exceeding 14 hours. The refrigerator duty cycle was over 90 percent at this temperature. The success of these tests has motivated us to construct a more compact portable adiabatic demagnetization cryostat capable of bolometer optical tests and use at the 5m Hale telescope at 1mm wavelengths.

  14. Conditions for super-adiabatic droplet growth after entrainment mixing

    DOE PAGES

    Yang, Fan; Shaw, Raymond; Xue, Huiwen

    2016-07-29

    Cloud droplet response to entrainment and mixing between a cloud and its environment is considered, accounting for subsequent droplet growth during adiabatic ascent following a mixing event. The vertical profile for liquid water mixing ratio after a mixing event is derived analytically, allowing the reduction to be predicted from the mixing fraction and from the temperature and humidity for both the cloud and environment. It is derived for the limit of homogeneous mixing. The expression leads to a critical height above the mixing level: at the critical height the cloud droplet radius is the same for both mixed and unmixedmore » parcels, and the critical height is independent of the updraft velocity and mixing fraction. Cloud droplets in a mixed parcel are larger than in an unmixed parcel above the critical height, which we refer to as the “super-adiabatic” growth region. Analytical results are confirmed with a bin microphysics cloud model. Using the model, we explore the effects of updraft velocity, aerosol source in the environmental air, and polydisperse cloud droplets. Results show that the mixed parcel is more likely to reach the super-adiabatic growth region when the environmental air is humid and clean. It is also confirmed that the analytical predictions are matched by the volume-mean cloud droplet radius for polydisperse size distributions. The findings have implications for the origin of large cloud droplets that may contribute to onset of collision–coalescence in warm clouds.« less

  15. Adiabatic cooling of the artificial Porcupine plasma jet

    NASA Astrophysics Data System (ADS)

    Ruizhin, Iu. Ia.; Treumann, R. A.; Bauer, O. H.; Moskalenko, A. M.

    1987-01-01

    Measurements of the plasma density obtained during the interaction of the artificial plasma jet, fired into the ionosphere with the body of the Porcupine main payload, have been analyzed for times when there was a well-developed wake effect. Using wake theory, the maximum temperature of the quasi-neutral xenon ion beam has been determined for an intermediate distance from the ion beam source when the beam has left the diamagnetic region but is still much denser than the ionospheric background plasma. The beam temperature is found to be about 4 times less than the temperature at injection. This observation is very well explained by adiabatic cooling of the beam during its initial diamagnetic and current-buildup phases at distances r smaller than 10 m. Outside this region, the beam conserves the temperature achieved. The observation proves that the artificial plasma jet passes through an initial gas-like diamagnetic phase restricted to the vicinity of the beam source, where it expands adiabatically. Partial cooling also takes place outside the diamagnetic region where the beam current still builds up. The observations also support a recently developed current-closure model of the quasi-neutral ion beam.

  16. AB INITIO SIMULATIONS FOR MATERIAL PROPERTIES ALONG THE JUPITER ADIABAT

    SciTech Connect

    French, Martin; Becker, Andreas; Lorenzen, Winfried; Nettelmann, Nadine; Bethkenhagen, Mandy; Redmer, Ronald; Wicht, Johannes

    2012-09-15

    We determine basic thermodynamic and transport properties of hydrogen-helium-water mixtures for the extreme conditions along Jupiter's adiabat via ab initio simulations, which are compiled in an accurate and consistent data set. In particular, we calculate the electrical and thermal conductivity, the shear and longitudinal viscosity, and diffusion coefficients of the nuclei. We present results for associated quantities like the magnetic and thermal diffusivity and the kinematic shear viscosity along an adiabat that is taken from a state-of-the-art interior structure model. Furthermore, the heat capacities, the thermal expansion coefficient, the isothermal compressibility, the Grueneisen parameter, and the speed of sound are calculated. We find that the onset of dissociation and ionization of hydrogen at about 0.9 Jupiter radii marks a region where the material properties change drastically. In the deep interior, where the electrons are degenerate, many of the material properties remain relatively constant. Our ab initio data will serve as a robust foundation for applications that require accurate knowledge of the material properties in Jupiter's interior, e.g., models for the dynamo generation.

  17. Adiabatic-nuclei calculations of positron scattering from molecular hydrogen

    NASA Astrophysics Data System (ADS)

    Zammit, Mark C.; Fursa, Dmitry V.; Savage, Jeremy S.; Bray, Igor; Chiari, Luca; Zecca, Antonio; Brunger, Michael J.

    2017-02-01

    The single-center adiabatic-nuclei convergent close-coupling method is used to investigate positron collisions with molecular hydrogen (H2) in the ground and first vibrationally excited states. Cross sections are presented over the energy range from 1 to 1000 eV for elastic scattering, vibrational excitation, total ionization, and the grand total cross section. The present adiabatic-nuclei positron-H2 scattering length is calculated as A =-2.70 a0 for the ground state and A =-3.16 a0 for the first vibrationally excited state. The present elastic differential cross sections are also used to "correct" the low-energy grand total cross-section measurements of the Trento group [A. Zecca et al., Phys. Rev. A 80, 032702 (2009), 10.1103/PhysRevA.80.032702] for the forward-angle-scattering effect. In general, the comparison with experiment is good. By performing convergence studies, we estimate that our Rm=1.448 a0 fixed-nuclei results are converged to within ±5 % for the major scattering integrated cross sections.

  18. Breakdown of the adiabatic Born-Oppenheimer approximation in graphene

    NASA Astrophysics Data System (ADS)

    Pisana, Simone; Lazzeri, Michele; Casiraghi, Cinzia; Novoselov, Kostya S.; Geim, A. K.; Ferrari, Andrea C.; Mauri, Francesco

    2007-03-01

    The adiabatic Born-Oppenheimer approximation (ABO) has been the standard ansatz to describe the interaction between electrons and nuclei since the early days of quantum mechanics. ABO assumes that the lighter electrons adjust adiabatically to the motion of the heavier nuclei, remaining at any time in their instantaneous ground state. ABO is well justified when the energy gap between ground and excited electronic states is larger than the energy scale of the nuclear motion. In metals, the gap is zero and phenomena beyond ABO (such as phonon-mediated superconductivity or phonon-induced renormalization of the electronic properties) occur. The use of ABO to describe lattice motion in metals is, therefore, questionable. In spite of this, ABO has proved effective for the accurate determination of chemical reactions, molecular dynamics and phonon frequencies in a wide range of metallic systems. Here, we show that ABO fails in graphene. Graphene, recently discovered in the free state, is a zero-bandgap semiconductor that becomes a metal if the Fermi energy is tuned applying a gate voltage, Vg. This induces a stiffening of the Raman G peak that cannot be described within ABO.

  19. Ultra-Flexible Thermal Bus for Use in the Astro-H Adiabatic Demagnetization Refrigerator

    NASA Technical Reports Server (NTRS)

    Kimball, Mark O.; Shirron, Peter J.

    2015-01-01

    The adiabatic demagnetization refrigerator (ADR) developed for the Astro-H Soft-X-ray Spectrometer (SXS) is a multi-stage solid-state cooler. It is capable of holding the SXS detector array at 0.050 K for greater than 24 hours with a recycle time of less than one hour. This quick recycle time relies upon high-conductivity thermal straps to couple the individual stages to a pair of heat switches without imposing a lateral load on the paramagnetic salt pills. To accomplish this we construct thermal straps using a technique of diffusion bonding together the ends of high-purity copper straps leaving the length between as individual foils. A thermal bus created this way has a thermal conductivity comparable to a solid strap of the equivalent thickness but with much-increased flexibility. The technique for selecting the base material, machining, cleaning, forming into final shape, and finally bonding together individual foils will be discussed along with examples of complete straps in various geometries.

  20. Adiabatic manipulations of Majorana fermions in a three-dimensional network of quantum wires

    NASA Astrophysics Data System (ADS)

    Halperin, Bertrand I.; Oreg, Yuval; Stern, Ady; Refael, Gil; Alicea, Jason; von Oppen, Felix

    2012-04-01

    It has been proposed that localized zero-energy Majorana states can be realized in a two-dimensional network of quasi-one-dimensional semiconductor wires that are proximity coupled to a bulk superconductor. The wires should have strong spin-orbit coupling with appropriate symmetry, and their electrons should be partially polarized by a strong Zeeman field. Then, if the Fermi level is in an appropriate range, the wire can be in a topological superconducting phase, with Majorana states that occur at wire ends and at Y junctions, where three topological superconductor segments may be joined. Here we generalize these ideas to consider a three-dimensional network. The positions of Majorana states can be manipulated, and their non-Abelian properties made visible, by using external gates to selectively deplete portions of the network or by physically connecting and redividing wire segments. Majorana states can also be manipulated by reorientations of the Zeeman field on a wire segment, by physically rotating the wire about almost any axis, or by evolution of the phase of the order parameter in the proximity-coupled superconductor. We show how to keep track of sign changes in the zero-energy Hilbert space during adiabatic manipulations by monitoring the evolution of each Majorana state separately, rather than keeping track of the braiding of all possible pairs. This has conceptual advantages in the case of a three-dimensional network, and may be computationally useful even in two dimensions, if large numbers of Majorana sites are involved.

  1. Minimal Pairs: Minimal Importance?

    ERIC Educational Resources Information Center

    Brown, Adam

    1995-01-01

    This article argues that minimal pairs do not merit as much attention as they receive in pronunciation instruction. There are other aspects of pronunciation that are of greater importance, and there are other ways of teaching vowel and consonant pronunciation. (13 references) (VWL)

  2. Tunneling-assisted coherent population transfer and creation of coherent superposition states in triple quantum dots

    NASA Astrophysics Data System (ADS)

    Tian, Si-Cong; Wan, Ren-Gang; Wang, Li-Jie; Shu, Shi-Li; Tong, Cun-Zhu; Wang, Li-Jun

    2016-12-01

    A scheme is proposed for coherent population transfer and creation of coherent superposition states assisted by one time-dependent tunneling pulse and one time-independent tunneling pulse in triple quantum dots. Time-dependent tunneling, which is similar to the Stokes laser pulse used in traditional stimulated Raman adiabatic passage, can lead to complete population transfer from the ground state to the indirect exciton states. Time-independent tunneling can also create double dark states, resulting in the distribution of the population and arbitrary coherent superposition states. Such a scheme can also be extended to multiple quantum dots assisted by one time-dependent tunneling pulse and more time-independent tunneling pulses.

  3. Universe creation on a computer

    NASA Astrophysics Data System (ADS)

    McCabe, Gordon

    The purpose of this paper is to provide an account of the epistemology and metaphysics of universe creation on a computer. The paper begins with F.J. Tipler's argument that our experience is indistinguishable from the experience of someone embedded in a perfect computer simulation of our own universe, hence we cannot know whether or not we are part of such a computer program ourselves. Tipler's argument is treated as a special case of epistemological scepticism, in a similar vein to 'brain-in-a-vat' arguments. It is argued that Tipler's hypothesis that our universe is a program running on a digital computer in another universe, generates empirical predictions, and is therefore a falsifiable hypothesis. The computer program hypothesis is also treated as a hypothesis about what exists beyond the physical world, and is compared with Kant's metaphysics of noumena. It is argued that if our universe is a program running on a digital computer, then our universe must have compact spatial topology, and the possibilities of observationally testing this prediction are considered. The possibility of testing the computer program hypothesis with the value of the density parameter Ω0 is also analysed. The informational requirements for a computer to represent a universe exactly and completely are considered. Consequent doubt is thrown upon Tipler's claim that if a hierarchy of computer universes exists, we would not be able to know which 'level of implementation' our universe exists at. It is then argued that a digital computer simulation of a universe, or any other physical system, does not provide a realisation of that universe or system. It is argued that a digital computer simulation of a physical system is not objectively related to that physical system, and therefore cannot exist as anything else other than a physical process occurring upon the components of the computer. It is concluded that Tipler's sceptical hypothesis, and a related hypothesis from Bostrom, cannot be

  4. Hysteresis loops and adiabatic Landau-Zener-Stückelberg transitions in the magnetic molecule {V6}.

    PubMed

    Rousochatzakis, I; Ajiro, Y; Mitamura, H; Kögerler, P; Luban, M

    2005-04-15

    We have observed hysteresis loops and abrupt magnetization steps in the magnetic molecule {V(6)}, where each molecule comprises a pair of identical spin triangles, in the temperature range 1-5 K for external magnetic fields B with sweep rates of several Tesla per millisecond executing a variety of closed cycles. The hysteresis loops are accurately reproduced using a generalization of the Bloch equation based on direct one-phonon transitions between the instantaneous Zeeman-split levels of the ground state (an S=1/2 doublet) of each spin triangle. The magnetization steps occur for B approximately 0, and they are explained in terms of adiabatic Landau-Zener-Stückelberg transitions between the lowest magnetic energy levels as modified by an intertriangle anisotropic exchange of order 0.4 K.

  5. Evolution, Creation, and the Scientific Method

    ERIC Educational Resources Information Center

    Moore, John N.

    1973-01-01

    Doubts about the validity of the general theory of evolution are raised. Evidence in favor of evolution is circumstantial and not reproducible. Teachers should explain the theory of creation proposed in the Bible when discussing evolution. (PS)

  6. Evolution and Creationism: One Long Argument.

    ERIC Educational Resources Information Center

    Good, Ron

    2003-01-01

    Discusses the dilemma between evolution and creationism in biology teaching. Explains the position of the Louisiana House Education Committee and presents an example from the Louisiana State University (LSU). (Author/SOE)

  7. Evolution vs. Creationism, 1973-1981.

    ERIC Educational Resources Information Center

    Pratt, Donald L.

    Various aspects of the current evolution/creationism controversy are reviewed including the impact of attempting to remove evolutionary material from textbooks and including creationist material. A number of viewpoints, opinions, and references from current literature are cited. (DS)

  8. New Approaches to Arteriovenous Fistula Creation.

    PubMed

    Rajan, Dheeraj K

    2016-03-01

    An autogenous arteriovenous fistula is considered the ideal access for hemodialysis delivery. However, surgical creation of an arteriovenous fistula is associated with less than optimal technical success, and multiple interventions are often required to assist maturation or maintain early patency. Given these shortcomings, multiple new approaches are now under investigation that possibly improve on surgical techniques and/or outcomes. Minimally invasive methods of creation with novel devices are under investigation, with preliminary published results available.

  9. Interplay between Rashba spin-orbit coupling and adiabatic rotation in a two-dimensional Fermi gas

    NASA Astrophysics Data System (ADS)

    Doko, E.; Subaşı, A. L.; Iskin, M.

    2017-01-01

    We explore the trap profiles of a two-dimensional atomic Fermi gas in the presence of a Rashba spin-orbit coupling and under an adiabatic rotation. We first consider a noninteracting gas and show that the competition between the effects of Rashba coupling on the local density of single-particle states and the Coriolis effects caused by rotation gives rise to a characteristic ring-shaped density profile that survives at experimentally accessible temperatures. Furthermore, Rashba splitting of the Landau levels gives the density profiles a ziggurat shape in the rapid-rotation limit. We then consider an interacting gas under the BCS mean-field approximation for local pairing, and study the pair-breaking mechanism that is induced by the Coriolis effects on superfluidity, where we calculate the critical rotation frequencies both for the onset of pair breaking and for the complete destruction of superfluidity in the system. In particular, by comparing the results of a fully-quantum-mechanical Bogoliubov-de Gennes approach with those of a semiclassical local-density approximation, we construct extensive phase diagrams for a wide range of parameter regimes in the trap where the aforementioned competition may, e.g., favor an outer normal edge that is completely phase separated from the central superfluid core by vacuum.

  10. Simple proof of equivalence between adiabatic quantum computation and the circuit model.

    PubMed

    Mizel, Ari; Lidar, Daniel A; Mitchell, Morgan

    2007-08-17

    We prove the equivalence between adiabatic quantum computation and quantum computation in the circuit model. An explicit adiabatic computation procedure is given that generates a ground state from which the answer can be extracted. The amount of time needed is evaluated by computing the gap. We show that the procedure is computationally efficient.

  11. Protected Flux Pairing Qubit

    NASA Astrophysics Data System (ADS)

    Bell, Matthew; Zhang, Wenyuan; Ioffe, Lev; Gershenson, Michael

    2014-03-01

    We have studied the coherent flux tunneling in a qubit containing two submicron Josephson junctions shunted by a superinductor (a dissipationless inductor with an impedance much greater than the resistance quantum). The two low energy quantum states of this device, 0 and 1, are represented by even and odd number of fluxes in the loop, respectively. This device is dual to the charge pairing Josephson rhombi qubit. The spectrum of the device, studied by microwave spectroscopy, reflects the interference between coherent quantum phase slips in the two junctions (the Aharonov-Casher effect). The time domain measurements demonstrate the suppression of the qubit's energy relaxation in the protected regime, which illustrates the potential of this flux pairing device as a protected quantum circuit. Templeton Foundation, NSF, and ARO.

  12. Junctionless Cooper pair transistor

    NASA Astrophysics Data System (ADS)

    Arutyunov, K. Yu.; Lehtinen, J. S.

    2017-02-01

    Quantum phase slip (QPS) is the topological singularity of the complex order parameter of a quasi-one-dimensional superconductor: momentary zeroing of the modulus and simultaneous 'slip' of the phase by ±2π. The QPS event(s) are the dynamic equivalent of tunneling through a conventional Josephson junction containing static in space and time weak link(s). Here we demonstrate the operation of a superconducting single electron transistor (Cooper pair transistor) without any tunnel junctions. Instead a pair of thin superconducting titanium wires in QPS regime was used. The current-voltage characteristics demonstrate the clear Coulomb blockade with magnitude of the Coulomb gap modulated by the gate potential. The Coulomb blockade disappears above the critical temperature, and at low temperatures can be suppressed by strong magnetic field.

  13. Quantum Decay of the 'False Vacuum' and Pair Creation of Soliton Domain Walls

    SciTech Connect

    Miller, John H. Jr.

    2011-03-28

    Quantum decay of metastable states ('false vacua') has been proposed as a mechanism for bubble nucleation of new universes and phase transitions in the early universe. Experiments indicate the occurrence of false vacuum decay, within a region bounded by soliton domain walls that nucleate via quantum tunneling, in a highly anisotropic condensed matter system. This phenomenon provides a compelling example of false vacuum decay in the laboratory.

  14. ON THE POLAR CAP CASCADE PAIR MULTIPLICITY OF YOUNG PULSARS

    SciTech Connect

    Timokhin, A. N.; Harding, A. K.

    2015-09-10

    We study the efficiency of pair production in polar caps of young pulsars under a variety of conditions to estimate the maximum possible multiplicity of pair plasma in pulsar magnetospheres. We develop a semi-analytic model for calculation of cascade multiplicity which allows efficient exploration of the parameter space and corroborate it with direct numerical simulations. Pair creation processes are considered separately from particle acceleration in order to assess different factors affecting cascade efficiency, with acceleration of primary particles described by recent self-consistent non-stationary model of pair cascades. We argue that the most efficient cascades operate in the curvature radiation/synchrotron regime, the maximum multiplicity of pair plasma in pulsar magnetospheres is ∼few × 10{sup 5}. The multiplicity of pair plasma in magnetospheres of young energetic pulsars weakly depends on the strength of the magnetic field and the radius of curvature of magnetic field lines and has a stronger dependence on pulsar inclination angle. This result questions assumptions about very high pair plasma multiplicity in theories of pulsar wind nebulae.

  15. Controlled Rapid Adiabatic Passage in a V-Type System

    NASA Astrophysics Data System (ADS)

    Song, Yunheung; Lee, Han-Gyeol; Jo, Hanlae; Ahn, Jaewook

    2016-05-01

    In chirped rapid adiabatic passage (RAP), chirp sign determines the final state to which the complete population transfer (CPT) occurs in a three-level V-type system. In this study, we show that laser intensity can be alternatively used as a control means in RAP, when the laser pulse is chirped and of a spectral hole resonant to one of the excited states. We verified such excitation selectivity in the experiment performed as-shaped femtosecond laser pulses interacting with the lowest three levels (5S, 5 P1/2, and 5 P3/2) of atomic rubidium. The successful demonstration implies that this intensity-dependent RAP in conjunction with laser beam profile programming may allow excitation selectivity for atoms or ions arranged in space.

  16. Multiphoton Raman Atom Optics with Frequency-Swept Adiabatic Passage

    NASA Astrophysics Data System (ADS)

    Kotru, Krish; Butts, David; Kinast, Joseph; Stoner, Richard

    2016-05-01

    Light-pulse atom interferometry is a promising candidate for future inertial navigators, gravitational wave detectors, and measurements of fundamental physical constants. The sensitivity of this technique, however, is often limited by the small momentum separations created between interfering atom wave packets (typically ~ 2 ℏk) . We address this issue using light-pulse atom optics derived from stimulated Raman transitions and frequency-swept adiabatic rapid passage (ARP). In experiments, these Raman ARP atom optics have generated up to 30 ℏk photon recoil momenta in an acceleration-sensitive atom interferometer, thereby enhancing the phase shift per unit acceleration by a factor of 15. Since this approach forgoes evaporative cooling and velocity selection, it could enable large-area atom interferometry at higher data rates, while also lowering the atom shot-noise-limited measurement uncertainty.

  17. Adiabatic photo-steering theory in topological insulators

    PubMed Central

    Inoue, Jun-ichi

    2014-01-01

    Feasible external control of material properties is a crucial issue in condensed matter physics. A new approach to achieving this aim, named adiabatic photo-steering, is reviewed. The core principle of this scheme is that several material constants are effectively turned into externally tunable variables by irradiation of monochromatic laser light. Two-dimensional topological insulators are selected as the optimal systems that exhibit a prominent change in their properties following the application of this method. Two specific examples of photo-steered quantum phenomena, which reflect topological aspects of the electronic systems at hand, are presented. One is the integer quantum Hall effect described by the Haldane model, and the other is the quantum spin Hall effect described by the Kane–Mele model. The topological quantities associated with these phenomena are the conventional Chern number and spin Chern number, respectively. A recent interesting idea, time-reversal symmetry breaking via a temporary periodic external stimulation, is also discussed. PMID:27877726

  18. Investigating the adiabatic beam grouping at the NICA accelerator complex

    NASA Astrophysics Data System (ADS)

    Brovko, O. I.; Butenko, A. V.; Grebentsov, A. Yu.; Eliseev, A. V.; Meshkov, I. N.; Svetov, A. L.; Sidorin, A. O.; Slepnev, V. M.

    2016-12-01

    The NICA complex comprises the Booster and Nuclotron synchrotrons for accelerating particle beams to the required energy and the Collider machine, in which particle collisions are investigated. The experimental heavy-ion program deals with ions up to Au+79. The light-ion program deals with polarized deuterons and protons. Grouping of a beam coasting in an ion chamber is required in many parts of the complex. Beam grouping may effectively increase the longitudinal emittance and particle losses. To avoid these negative effects, various regimes of adiabatic grouping have been simulated and dedicated experiments with a deuteron beam have been conducted at the Nuclotron machine. As a result, we are able to construct and optimize the beam-grouping equipment, which provides a capture efficiency near 100% either retaining or varying the harmonic multiplicity of the HF system.

  19. Adiabatic approximation for the Rabi model with broken inversion symmetry

    NASA Astrophysics Data System (ADS)

    Shen, Li-Tuo; Yang, Zhen-Biao; Wu, Huai-Zhi

    2017-01-01

    We study the properties and behavior of the Rabi model with broken inversion symmetry. Using an adiabatic approximation approach, we explore the high-frequency qubit and oscillator regimes, and obtain analytical solutions for the qubit-oscillator system. We demonstrate that, due to broken inversion symmetry, the positions of two potentials and zero-point energies in the oscillators become asymmetric and have a quadratic dependence on the mean dipole moments within the high-frequency oscillator regime. Furthermore, we find that there is a critical point above which the qubit-oscillator system becomes unstable, and the position of this critical point has a quadratic dependence on the mean dipole moments within the high-frequency qubit regime. Finally, we verify this critical point based on the method of semiclassical approximation.

  20. Shortcut to Adiabaticity for an Anisotropic Gas Containing Quantum Defects.

    PubMed

    Papoular, D J; Stringari, S

    2015-07-10

    We present a shortcut to adiabaticity (STA) protocol applicable to 3D unitary Fermi gases and 2D weakly interacting Bose gases containing defects such as vortices or solitons. Our protocol relies on a new class of exact scaling solutions in the presence of anisotropic time-dependent harmonic traps. It connects stationary states in initial and final traps having the same frequency ratios. The resulting scaling laws exhibit a universal form and also apply to the classical Boltzmann gas. The duration of the STA can be made very short so as to realize a quantum quench from one stationary state to another. When applied to an anisotropically trapped superfluid gas, the STA conserves the shape of the quantum defects hosted by the cloud, thereby acting like a perfect microscope, which sharply contrasts with their strong distortion occurring during the free expansion of the cloud.

  1. Novel latch for adiabatic quantum-flux-parametron logic

    SciTech Connect

    Takeuchi, Naoki Yamanashi, Yuki; Yoshikawa, Nobuyuki; Ortlepp, Thomas

    2014-03-14

    We herein propose the quantum-flux-latch (QFL) as a novel latch for adiabatic quantum-flux-parametron (AQFP) logic. A QFL is very compact and compatible with AQFP logic gates and can be read out in one clock cycle. Simulation results revealed that the QFL operates at 5 GHz with wide parameter margins of more than ±22%. The calculated energy dissipation was only ∼0.1 aJ/bit, which yields a small energy delay product of 20 aJ·ps. We also designed shift registers using QFLs to demonstrate more complex circuits with QFLs. Finally, we experimentally demonstrated correct operations of the QFL and a 1-bit shift register (a D flip-flop)

  2. Passive gas-gap heat switch for adiabatic demagnetization refrigerator

    NASA Technical Reports Server (NTRS)

    Shirron, Peter J. (Inventor); Di Pirro, Michael J. (Inventor)

    2005-01-01

    A passive gas-gap heat switch for use with a multi-stage continuous adiabatic demagnetization refrigerator (ADR). The passive gas-gap heat switch turns on automatically when the temperature of either side of the switch rises above a threshold value and turns off when the temperature on either side of the switch falls below this threshold value. One of the heat switches in this multistage process must be conductive in the 0.25? K to 0.3? K range. All of the heat switches must be capable of switching off in a short period of time (1-2 minutes), and when off to have a very low thermal conductance. This arrangement allows cyclic cooling cycles to be used without the need for separate heat switch controls.

  3. Some properties of adiabatic blast waves in preexisting cavities

    NASA Technical Reports Server (NTRS)

    Cox, D. P.; Franco, J.

    1981-01-01

    Cox and Anderson (1982) have conducted an investigation regarding an adiabatic blast wave in a region of uniform density and finite external pressure. In connection with an application of the results of the investigation to a study of interstellar blast waves in the very hot, low-density matrix, it was found that it would be desirable to examine situations with a positive radial density gradient in the ambient medium. Information concerning such situations is needed to learn about the behavior of blast waves occurring within preexisting, presumably supernova-induced cavities in the interstellar mass distribution. The present investigation is concerned with the first steps of a study conducted to obtain the required information. A review is conducted of Sedov's (1959) similarity solutions for the dynamical structure of any explosion in a medium with negligible pressure and power law density dependence on radius.

  4. Quasi-adiabatic compression heating of selected foods

    NASA Astrophysics Data System (ADS)

    Landfeld, Ales; Strohalm, Jan; Halama, Radek; Houska, Milan

    2011-03-01

    The quasi-adiabatic temperature increase due to compression heating, during high-pressure (HP) processing (HPP), was studied using specially designed equipment. The temperature increase was evaluated as the difference in temperature, during compression, between atmospheric pressure and nominal pressure. The temperature was measured using a thermocouple in the center of a polyoxymethylene cup, which contained the sample. Fresh meat balls, pork meat pate, and tomato purée temperature increases were measured at three initial temperature levels between 40 and 80 °C. Nominal pressure was either 400 or 500 MPa. Results showed that the fat content had a positive effect on temperature increases. Empirical equations were developed to calculate the temperature increase during HPP at different initial temperatures for pressures of 400 and 500 MPa. This thermal effect data can be used for numerical modeling of temperature histories of foods during HP-assisted pasteurization or sterilization processes.

  5. Adiabatic nucleation in the liquid-vapor phase transition

    NASA Astrophysics Data System (ADS)

    de Sá, Elon M.; Meyer, Erich; Soares, Vitorvani

    2001-05-01

    The fundamental difference between classical (isothermal) nucleation theory (CNT) and adiabatic nucleation theory (ANT) is discussed. CNT uses the concept of isothermal heterophase fluctuations, while ANT depends on common fluctuations of the thermodynamic variables. Applications to the nonequilibrium liquid to vapor transition are shown. However, we cannot yet calculate nucleation frequencies. At present, we can only indicate at what temperatures and pressures copious homogeneous nucleation is expected in the liquid to vapor phase transition. It is also explained why a similar general indication cannot be made for the inverse vapor to liquid transition. Simultaneously, the validity of Peng-Robinson's equation of state [D.-Y. Peng and D. B. Robinson, Ind. Eng. Chem. Fundam. 15, 59 (1976)] is confirmed for highly supersaturated liquids.

  6. Adiabatic rotation of effective spin. II. Spin-rotational relaxation

    NASA Astrophysics Data System (ADS)

    Serebrennikov, Yu. A.; Steiner, U. E.

    1994-05-01

    The theory of electron spin-rotational (SR) relaxation in systems with an effective spin Seff=1/2 is formulated in terms of the adiabatic rotation of effective spin (ARES) approach. It is shown that SR relaxation results from the orientational random walk of the axes of the intramolecular electric field potential (ligand field) to which a spin-bearing atomic center is exposed. The validity of the stochastic treatment presented here is not limited by the Redfield conditions. The general expression obtained for the time constant of electron spin relaxation in liquid phase reproduces the well-known result of Hubbard-Atkins-Kivelson theory if it is specialized to the case of systems with weak spin-orbit coupling.

  7. Perspective: Stimulated Raman adiabatic passage: The status after 25 years

    NASA Astrophysics Data System (ADS)

    Bergmann, Klaas; Vitanov, Nikolay V.; Shore, Bruce W.

    2015-05-01

    The first presentation of the STIRAP (stimulated Raman adiabatic passage) technique with proper theoretical foundation and convincing experimental data appeared 25 years ago, in the May 1st, 1990 issue of The Journal of Chemical Physics. By now, the STIRAP concept has been successfully applied in many different fields of physics, chemistry, and beyond. In this article, we comment briefly on the initial motivation of the work, namely, the study of reaction dynamics of vibrationally excited small molecules, and how this initial idea led to the documented success. We proceed by providing a brief discussion of the physics of STIRAP and how the method was developed over the years, before discussing a few examples from the amazingly wide range of applications which STIRAP now enjoys, with the aim to stimulate further use of the concept. Finally, we mention some promising future directions.

  8. Crossover from adiabatic to antiadiabatic quantum pumping with dissipation.

    PubMed

    Pellegrini, Franco; Negri, C; Pistolesi, F; Manini, Nicola; Santoro, Giuseppe E; Tosatti, Erio

    2011-08-05

    Quantum pumping, in its different forms, is attracting attention from different fields, from fundamental quantum mechanics, to nanotechnology, to superconductivity. We investigate the crossover of quantum pumping from the adiabatic to the antiadiabatic regime in the presence of dissipation, and find general and explicit analytical expressions for the pumped current in a minimal model describing a system with the topology of a ring forced by a periodic modulation of frequency ω. The solution allows following in a transparent way the evolution of pumped dc current from much smaller to much larger ω values than the other relevant energy scale, the energy splitting introduced by the modulation. We find and characterize a temperature-dependent optimal value of the frequency for which the pumped current is maximal.

  9. Properties of a two stage adiabatic demagnetization refrigerator

    NASA Astrophysics Data System (ADS)

    Fukuda, H.; Ueda, S.; Arai, R.; Li, J.; Saito, A. T.; Nakagome, H.; Numazawa, T.

    2015-12-01

    Currently, many space missions using cryogenic temperatures are being planned. In particular, high resolution sensors such as Transition Edge Sensors need very low temperatures, below 100 mK. It is well known that the adiabatic demagnetization refrigerator (ADR) is one of most useful tools for producing ultra-low temperatures in space because it is gravity independent. We studied a continuous ADR system consisting of 4 stages and demonstrated it could provide continuous temperatures around 100 mK. However, there was some heat leakage from the power leads which resulted in reduced cooling power. Our efforts to upgrade our ADR system are presented. We show the effect of using the HTS power leads and discuss a cascaded Carnot cycle consisting of 2 ADR units.

  10. Planar prism spectrometer based on adiabatically connected waveguiding slabs

    NASA Astrophysics Data System (ADS)

    Civitci, F.; Hammer, M.; Hoekstra, H. J. W. M.

    2016-04-01

    The device principle of a prism-based on-chip spectrometer for TE polarization is introduced. The spectrometer exploits the modal dispersion in planar waveguides in a layout with slab regions having two different thicknesses of the guiding layer. The set-up uses parabolic mirrors, for the collimation of light of the input waveguide and focusing of the light to the receiver waveguides, which relies on total internal reflection at the interface between two such regions. These regions are connected adiabatically to prevent unwanted mode conversion and loss at the edges of the prism. The structure can be fabricated with two wet etching steps. The paper presents basic theory and a general approach for device optimization. The latter is illustrated with a numerical example assuming SiON technology.

  11. Microwave photon Fock state generation by stimulated Raman adiabatic passage

    NASA Astrophysics Data System (ADS)

    Premaratne, Shavindra P.; Wellstood, F. C.; Palmer, B. S.

    2017-01-01

    The deterministic generation of non-classical states of light, including squeezed states, Fock states and Bell states, plays an important role in quantum information processing and exploration of the physics of quantum entanglement. Preparation of these non-classical states in resonators is non-trivial due to their inherent harmonicity. Here we use stimulated Raman adiabatic passage to generate microwave photon Fock states in a superconducting circuit quantum electrodynamics system comprised of a fixed-frequency transmon qubit in a three-dimensional microwave cavity at 20 mK. A two-photon process is employed to overcome a first order forbidden transition and the first, second and third Fock states are demonstrated. We also demonstrate how this all-microwave technique can be used to generate an arbitrary superposition of Fock states. Simulations of the system are in excellent agreement with the data and fidelities of 89%, 68% and 43% are inferred for the first three Fock states respectively.

  12. Design of an adiabatic demagnetization refrigerator for studies in astrophysics

    NASA Technical Reports Server (NTRS)

    Castles, S.

    1983-01-01

    An adiabatic demagnetization refrigerator was designed for cooling infrared bolometers for studies in astrophysics and aeronomy. The design was tailored to the requirements of a Shuttle sortie experiment. The refrigerator should be capable of maintaining three bolometers at 0.1 K with a 90% cycle. The advantage are of operations the bolometer at 0.1K. greater sensitivity, faster response time, and the ability to use larger bolometer elements without compromising the response time. The design presented is the first complete design of an ADR intended for use in space. The most important of these specifications are to survive a Shuttle launch, to operate with 1.5 K - 2.0 K space-pumped liquid helium as a heat sink, to have a 90% duty cycle, and to be highly efficient.

  13. Robust entanglement via optomechanical dark mode: adiabatic scheme

    NASA Astrophysics Data System (ADS)

    Tian, Lin; Wang, Ying-Dan; Huang, Sumei; Clerk, Aashish

    2013-03-01

    Entanglement is a powerful resource for studying quantum effects in macroscopic objects and for quantum information processing. Here, we show that robust entanglement between cavity modes with distinct frequencies can be generated via a mechanical dark mode in an optomechanical quantum interface. Due to quantum interference, the effect of the mechanical noise is cancelled in a way that is similar to the electromagnetically induced transparency. We derive the entanglement in the strong coupling regime by solving the quantum Langevin equation using a perturbation theory approach. The entanglement in the adiabatic scheme is then compared with the entanglement in the stationary state scheme. Given the robust entanglement schemes and our previous schemes on quantum wave length conversion, the optomechanical interface hence forms an effective building block for a quantum network. This work is supported by DARPA-ORCHID program, NSF-DMR-0956064, NSF-CCF-0916303, and NSF-COINS.

  14. Broadband electrically detected magnetic resonance using adiabatic pulses

    NASA Astrophysics Data System (ADS)

    Hrubesch, F. M.; Braunbeck, G.; Voss, A.; Stutzmann, M.; Brandt, M. S.

    2015-05-01

    We present a broadband microwave setup for electrically detected magnetic resonance (EDMR) based on microwave antennae with the ability to apply arbitrarily shaped pulses for the excitation of electron spin resonance (ESR) and nuclear magnetic resonance (NMR) of spin ensembles. This setup uses non-resonant stripline structures for on-chip microwave delivery and is demonstrated to work in the frequency range from 4 MHz to 18 GHz. π pulse times of 50 ns and 70 μs for ESR and NMR transitions, respectively, are achieved with as little as 100 mW of microwave or radiofrequency power. The use of adiabatic pulses fully compensates for the microwave magnetic field inhomogeneity of the stripline antennae, as demonstrated with the help of BIR4 unitary rotation pulses driving the ESR transition of neutral phosphorus donors in silicon and the NMR transitions of ionized phosphorus donors as detected by electron nuclear double resonance (ENDOR).

  15. Broadband electrically detected magnetic resonance using adiabatic pulses.

    PubMed

    Hrubesch, F M; Braunbeck, G; Voss, A; Stutzmann, M; Brandt, M S

    2015-05-01

    We present a broadband microwave setup for electrically detected magnetic resonance (EDMR) based on microwave antennae with the ability to apply arbitrarily shaped pulses for the excitation of electron spin resonance (ESR) and nuclear magnetic resonance (NMR) of spin ensembles. This setup uses non-resonant stripline structures for on-chip microwave delivery and is demonstrated to work in the frequency range from 4 MHz to 18 GHz. π pulse times of 50 ns and 70 μs for ESR and NMR transitions, respectively, are achieved with as little as 100 mW of microwave or radiofrequency power. The use of adiabatic pulses fully compensates for the microwave magnetic field inhomogeneity of the stripline antennae, as demonstrated with the help of BIR4 unitary rotation pulses driving the ESR transition of neutral phosphorus donors in silicon and the NMR transitions of ionized phosphorus donors as detected by electron nuclear double resonance (ENDOR).

  16. Differential geometric treewidth estimation in adiabatic quantum computation

    NASA Astrophysics Data System (ADS)

    Wang, Chi; Jonckheere, Edmond; Brun, Todd

    2016-10-01

    The D-Wave adiabatic quantum computing platform is designed to solve a particular class of problems—the Quadratic Unconstrained Binary Optimization (QUBO) problems. Due to the particular "Chimera" physical architecture of the D-Wave chip, the logical problem graph at hand needs an extra process called minor embedding in order to be solvable on the D-Wave architecture. The latter problem is itself NP-hard. In this paper, we propose a novel polynomial-time approximation to the closely related treewidth based on the differential geometric concept of Ollivier-Ricci curvature. The latter runs in polynomial time and thus could significantly reduce the overall complexity of determining whether a QUBO problem is minor embeddable, and thus solvable on the D-Wave architecture.

  17. Comments on adiabatic modifications to plasma turbulence theory

    SciTech Connect

    Krommes, J.A.

    1980-11-01

    Catto earlier introduced an interesting and plausible modification of the usual resonance-broadening prescription for obtaining the nonlinear dielectric function. He argued reasonably that one should employ that prescription only for the nonadiabatic response, and that one should treat the adiabatic response essentially exactly. However, Misguich, in a recent Comment on Catto's work, found an apparent divergence in a form for the renormalized dielectric which he argued was equivalent to Catto's. Misguich was thus led to conclude that, at least for stationary turbulence, Catto's form was suspect, and that a more intricate renormalization might have to be used to obtain a sensible, convergent result. It is argued that this conclusion is incorrect, at least for the reasons Misguich gives.

  18. Adiabatic invariants in stellar dynamics. 1: Basic concepts

    NASA Technical Reports Server (NTRS)

    Weinberg, Martin D.

    1994-01-01

    The adiabatic criterion, widely used in astronomical dynamics, is based on the harmonic oscillator. It asserts that the change in action under a slowly varying perturbation is exponentially small. Recent mathematical results that precisely define the conditions for invariance show that this model does not apply in general. In particular, a slowly varying perturbation may cause significant evolution stellar dynamical systems even if its time scale is longer than any internal orbital time scale. This additional 'heating' may have serious implications for the evolution of star clusters and dwarf galaxies which are subject to long-term environmental forces. The mathematical developments leading to these results are reviewed, and the conditions for applicability to and further implications for stellar systems are discussed. Companion papers present a computational method for a general time-dependent disturbance and detailed example.

  19. Effect of Poisson noise on adiabatic quantum control

    NASA Astrophysics Data System (ADS)

    Kiely, A.; Muga, J. G.; Ruschhaupt, A.

    2017-01-01

    We present a detailed derivation of the master equation describing a general time-dependent quantum system with classical Poisson white noise and outline its various properties. We discuss the limiting cases of Poisson white noise and provide approximations for the different noise strength regimes. We show that using the eigenstates of the noise superoperator as a basis can be a useful way of expressing the master equation. Using this, we simulate various settings to illustrate different effects of Poisson noise. In particular, we show a dip in the fidelity as a function of noise strength where high fidelity can occur in the strong-noise regime for some cases. We also investigate recent claims [J. Jing et al., Phys. Rev. A 89, 032110 (2014), 10.1103/PhysRevA.89.032110] that this type of noise may improve rather than destroy adiabaticity.

  20. Optical waveguide device with an adiabatically-varying width

    DOEpatents

    Watts; Michael R. , Nielson; Gregory N.

    2011-05-10

    Optical waveguide devices are disclosed which utilize an optical waveguide having a waveguide bend therein with a width that varies adiabatically between a minimum value and a maximum value of the width. One or more connecting members can be attached to the waveguide bend near the maximum value of the width thereof to support the waveguide bend or to supply electrical power to an impurity-doped region located within the waveguide bend near the maximum value of the width. The impurity-doped region can form an electrical heater or a semiconductor junction which can be activated with a voltage to provide a variable optical path length in the optical waveguide. The optical waveguide devices can be used to form a tunable interferometer (e.g. a Mach-Zehnder interferometer) which can be used for optical modulation or switching. The optical waveguide devices can also be used to form an optical delay line.

  1. Adiabatic quantum-flux-parametron cell library adopting minimalist design

    SciTech Connect

    Takeuchi, Naoki; Yamanashi, Yuki; Yoshikawa, Nobuyuki

    2015-05-07

    We herein build an adiabatic quantum-flux-parametron (AQFP) cell library adopting minimalist design and a symmetric layout. In the proposed minimalist design, every logic cell is designed by arraying four types of building block cells: buffer, NOT, constant, and branch cells. Therefore, minimalist design enables us to effectively build and customize an AQFP cell library. The symmetric layout reduces unwanted parasitic magnetic coupling and ensures a large mutual inductance in an output transformer, which enables very long wiring between logic cells. We design and fabricate several logic circuits using the minimal AQFP cell library so as to test logic cells in the library. Moreover, we experimentally investigate the maximum wiring length between logic cells. Finally, we present an experimental demonstration of an 8-bit carry look-ahead adder designed using the minimal AQFP cell library and demonstrate that the proposed cell library is sufficiently robust to realize large-scale digital circuits.

  2. Quantum and classical non-adiabatic dynamics of Li_{2}^{+}Ne photodissociation

    NASA Astrophysics Data System (ADS)

    Pouilly, Brigitte; Monnerville, Maurice; Zanuttini, David; Gervais, Benoît

    2015-01-01

    The 3D photodissociation dynamics of Li2+Ne system is investigated by quantum calculations using the multi-configuration time-dependent Hartree (MCTDH) method and by classical simulations with the trajectory surface hopping (TSH) approach. Six electronic states of A’ symmetry and two states of A” symmetry are involved in the process. Couplings in the excitation region and two conical intersections in the vicinity of the Franck-Condon zone control the non-adiabatic nuclear dynamics. A diabatic representation including all the states and the couplings is determined. Diabatic and adiabatic populations calculated for initial excitation to pure diabatic and adiabatic states lead to a clear understanding of the mechanisms governing the non-adiabatic photodissociation process. The classical and quantum photodissociation cross-sections for absorption in two adiabatic states of the A’ symmetry are calculated. A remarkable agreement between quantum and classical results is obtained regarding the populations and the absorption cross-sections.

  3. Adiabatic tracking for photo- and magneto-association of Bose-Einstein condensates with Kerr nonlinearities

    NASA Astrophysics Data System (ADS)

    Gevorgyan, Mariam; Guérin, Stéphane; Leroy, Claude; Ishkhanyan, Artur; Jauslin, Hans-Rudolf

    2016-11-01

    We develop the method of adiabatic tracking for photo- and magneto-association of Bose-Einstein atomic condensates with models that include Kerr type nonlinearities. We show that the inclusion of these terms can produce qualitatively important modifications in the adiabatic dynamics, like the appearance of bifurcations, in which the trajectory that is being tracked loses its stability. As a consequence the adiabatic theorem does not apply and the adiabatic transfer can be strongly degraded. This degradation can be compensated by using fields that are strong enough compared with the values of the Kerr terms. The main result is that, despite these potentially detrimental features, there is always a choice of the detuning that leads to an efficient adiabatic tracking, even for relatively weak fields.

  4. New Dynamical Scaling Universality for Quantum Networks Across Adiabatic Quantum Phase Transitions

    NASA Astrophysics Data System (ADS)

    Acevedo, O. L.; Quiroga, L.; Rodríguez, F. J.; Johnson, N. F.

    2014-01-01

    We reveal universal dynamical scaling behavior across adiabatic quantum phase transitions in networks ranging from traditional spatial systems (Ising model) to fully connected ones (Dicke and Lipkin-Meshkov-Glick models). Our findings, which lie beyond traditional critical exponent analysis and adiabatic perturbation approximations, are applicable even where excitations have not yet stabilized and, hence, provide a time-resolved understanding of quantum phase transitions encompassing a wide range of adiabatic regimes. We show explicitly that even though two systems may traditionally belong to the same universality class, they can have very different adiabatic evolutions. This implies that more stringent conditions need to be imposed than at present, both for quantum simulations where one system is used to simulate the other and for adiabatic quantum computing schemes.

  5. New Dynamical Scaling Universality for Quantum Networks Across Adiabatic Quantum Phase Transitions

    NASA Astrophysics Data System (ADS)

    Acevedo, Oscar L.; Rodriguez, Ferney J.; Quiroga, Luis; Johnson, Neil F.; Rey, Ana M.

    2014-05-01

    We reveal universal dynamical scaling behavior across adiabatic quantum phase transitions in networks ranging from traditional spatial systems (Ising model) to fully connected ones (Dicke and Lipkin-Meshkov-Glick models). Our findings, which lie beyond traditional critical exponent analysis and adiabatic perturbation approximations, are applicable even where excitations have not yet stabilized and, hence, provide a time-resolved understanding of quantum phase transitions encompassing a wide range of adiabatic regimes. We show explicitly that even though two systems may traditionally belong to the same universality class, they can have very different adiabatic evolutions. This implies that more stringent conditions need to be imposed than at present, both for quantum simulations where one system is used to simulate the other and for adiabatic quantum computing schemes.

  6. Effects of preheat and mix on the fuel adiabat of an imploding capsule

    NASA Astrophysics Data System (ADS)

    Cheng, B.; Kwan, T. J. T.; Wang, Y. M.; Yi, S. A.; Batha, S. H.; Wysocki, F. J.

    2016-12-01

    We demonstrate the effect of preheat, hydrodynamic mix and vorticity on the adiabat of the deuterium-tritium (DT) fuel in fusion capsule experiments. We show that the adiabat of the DT fuel increases resulting from hydrodynamic mixing due to the phenomenon of entropy of mixture. An upper limit of mix, Mclean/MDT ≥ 0.98, is found necessary to keep the DT fuel on a low adiabat. We demonstrate in this study that the use of a high adiabat for the DT fuel in theoretical analysis and with the aid of 1D code simulations could explain some aspects of 3D effects and mix in capsule implosion. Furthermore, we can infer from our physics model and the observed neutron images the adiabat of the DT fuel in the capsule and the amount of mix produced on the hot spot.

  7. Stimulated Raman adiabatic passage in a three-level superconducting circuit

    PubMed Central

    Kumar, K. S.; Vepsäläinen, A.; Danilin, S.; Paraoanu, G. S.

    2016-01-01

    The adiabatic manipulation of quantum states is a powerful technique that opened up new directions in quantum engineering—enabling tests of fundamental concepts such as geometrical phases and topological transitions, and holding the promise of alternative models of quantum computation. Here we benchmark the stimulated Raman adiabatic passage for circuit quantum electrodynamics by employing the first three levels of a transmon qubit. In this ladder configuration, we demonstrate a population transfer efficiency >80% between the ground state and the second excited state using two adiabatic Gaussian-shaped control microwave pulses. By doing quantum tomography at successive moments during the Raman pulses, we investigate the transfer of the population in time domain. Furthermore, we show that this protocol can be reversed by applying a third adiabatic pulse, we study a hybrid nondiabatic–adiabatic sequence, and we present experimental results for a quasi-degenerate intermediate level. PMID:26902454

  8. Is the addition of an assisted driving Hamiltonian always useful for adiabatic evolution?

    NASA Astrophysics Data System (ADS)

    Sun, Jie; Lu, Songfeng; Li, Li

    2017-04-01

    It has been known that when an assisted driving item is added to the main system Hamiltonian, the efficiency of the resultant adiabatic evolution can be significantly improved. In some special cases, it can be seen that only through adding an assisted driving Hamiltonian can the resulting adiabatic evolution be made not to fail. Thus the additional driving Hamiltonian plays an important role in adiabatic computing. In this paper, we show that if the driving Hamiltonian is chosen inappropriately, the adiabatic computation may still fail. More importantly, we find that the adiabatic computation can only succeed if the assisted driving Hamiltonian has a relatively fixed form. This may help us understand why in the related literature all of the driving Hamiltonians used share the same form.

  9. Phase relations and adiabats in boiling seafloor geothermal systems

    USGS Publications Warehouse

    Bischoff, J.L.; Pitzer, Kenneth S.

    1985-01-01

    Observations of large salinity variations and vent temperatures in the range of 380-400??C suggest that boiling or two-phase separation may be occurring in some seafloor geothermal systems. Consideration of flow rates and the relatively small differences in density between vapors and liquids at the supercritical pressures at depth in these systems suggests that boiling is occurring under closed-system conditions. Salinity and temperature of boiling vents can be used to estimate the pressure-temperature point in the subsurface at which liquid seawater first reached the two-phase boundary. Data are reviewed to construct phase diagrams of coexisting brines and vapors in the two-phase region at pressures corresponding to those of the seafloor geothermal systems. A method is developed for calculating the enthalpy and entropy of the coexisting mixtures, and results are used to construct adiabats from the seafloor to the P-T two-phase boundary. Results for seafloor vents discharging at 2300 m below sea level indicate that a 385??C vent is composed of a brine (7% NaCl equivalent) in equilibrium with a vapor (0.1% NaCl). Brine constitutes 45% by weight of the mixture, and the fluid first boiled at approximately 1 km below the seafloor at 415??C, 330 bar. A 400??C vent is primarily vapor (88 wt.%, 0.044% NaCl) with a small amount of brine (26% NaCl) and first boiled at 2.9 km below the seafloor at 500??C, 520 bar. These results show that adiabatic decompression in the two-phase region results in dramatic cooling of the fluid mixture when there is a large fraction of vapor. ?? 1985.

  10. Observational tests of non-adiabatic Chaplygin gas

    SciTech Connect

    Carneiro, S.; Pigozzo, C. E-mail: cpigozzo@ufba.br

    2014-10-01

    In a previous paper [1] it was shown that any dark sector model can be mapped into a non-adiabatic fluid formed by two interacting components, one with zero pressure and the other with equation-of-state parameter ω = -1. It was also shown that the latter does not cluster and, hence, the former is identified as the observed clustering matter. This guarantees that the dark matter power spectrum does not suffer from oscillations or instabilities. It applies in particular to the generalised Chaplygin gas, which was shown to be equivalent to interacting models at both background and perturbation levels. In the present paper we test the non-adiabatic Chaplygin gas against the Hubble diagram of type Ia supernovae, the position of the first acoustic peak in the anisotropy spectrum of the cosmic microwave background and the linear power spectrum of large scale structures. We consider two different compilations of SNe Ia, namely the Constitution and SDSS samples, both calibrated with the MLCS2k2 fitter, and for the power spectrum we use the 2dFGRS catalogue. The model parameters to be adjusted are the present Hubble parameter, the present matter density and the Chaplygin gas parameter α. The joint analysis best fit gives α ≈ - 0.5, which corresponds to a constant-rate energy flux from dark energy to dark matter, with the dark energy density decaying linearly with the Hubble parameter. The ΛCDM model, equivalent to α = 0, stands outside the 3σ confidence interval.

  11. The Adiabatic Contraction of Dark Matter Halos in Numerical Simulations

    NASA Astrophysics Data System (ADS)

    Jesseit, R.; Burkert, A.; Naab, T.

    The flatness of rotation curves in the outer parts of galaxies led to the postulation of a dark component to compensate for the missing mass. The origin of this component is still unknown. Bahcall & Soneira first pointed out in 1985 that a unique ratio for disk to halo mass is needed to produce the flat and featureless rotation curves in agreement with observations. They called this the disk-halo conspiracy. To explain this conspiracy Blumenthal et al. proposed that an adiabtically forming baryonic disk can influence the density structure of its surrounding dark halo. They assumed that the time scale of the baryonic infall is very slow such and the change of mass inside the orbit of a dark matter particle is neglegible. They further assumed that the dark matter particles revolve on circular orbits and are dissipationless. In this case their radial action integral is an adiabatic invariant during the contraction. Blumenthal et al. could find the final density profile of the dark matter, if the final distribution of the baryonic matter is known, through an iterative algorithm. We tested the above assumptions using collisionless N-body simulations. We set up a dark matter halo with a Hernquist density profile and analytically added the potential of an exponential disk. Initially the disk had a very large scale length compared to the halo scale length. During the simulation we reduced the sclae length of the disk and followed the evolution of the dark component. We examined different contraction speeds as well as different combinations of disk mass and scale lenght. We find that the theoretical prediction for the adiabatic contraction is

  12. Adiabatic principles in atom-diatom collisional energy transfer

    SciTech Connect

    Hovingh, W.J.

    1993-01-01

    This work describes the application of numerical methods to the solution of the time dependent Schroedinger equation for non-reactive atom-diatom collisions in which only one of the degrees of freedom has been removed. The basic method involves expanding the wave function in a basis set in two of the diatomic coordinates in a body-fixed frame (with respect to the triatomic complex) and defining the coefficients in that expansion as functions on a grid in the collision coordinate. The wave function is then propagated in time using a split operator method. The bulk of this work is devoted to the application of this formalism to the study of internal rotational predissociation in NeHF, in which quasibound states of the triatom predissociate through the transfer of energy from rotation of the diatom into translational energy in the atom-diatom separation coordinate. The author analyzes the computed time dependent wave functions to calculate the lifetimes for several quasibound states; these are in agreement with time independent quantum calculations using the same potential. Moreover, the time dependent behavior of the wave functions themselves sheds light on the dynamics of the predissociation processes. Finally, the partial cross sections of the products in those processes is determined with multiple exit channels. These show strong selectivity in the orbital angular momentum of the outgoing fragments, which the author explains with an adiabatic channel interpretation of the wave function's dynamics. The author also suggests that the same formalism might profitably be used to investigate the quantum dynamics of [open quotes]quasiresonant vibration-rotation transfer[close quotes], in which remarkably strong propensity rules in certain inelastic atom-diatom collision arise from classical adiabatic invariance theory.

  13. Generation of a pair of photons through the three-body dissociation of a multiply excited water molecule around the double ionization potential

    NASA Astrophysics Data System (ADS)

    Odagiri, Takeshi; Nakano, Motoyoshi; Tanabe, Takehiko; Kumagai, Yoshiaki; Suzuki, Isao H.; Kouchi, Noriyuki

    2009-11-01

    The cross sections for the generation of a photon-pair from excited fragments in photoexcitation of H2O have been measured as a function of incident photon energy. The multiply excited states of H2O have been observed even above the adiabatic double ionization potential.

  14. Pair of Craters

    NASA Technical Reports Server (NTRS)

    2005-01-01

    14 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 1.5 meters per pixel (5 ft/pixel) view of a pair of small meteor impact craters in the Arena Colles region of Mars, located north of Isidis Planitia.

    Location near: 22.7oN, 278.5oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Autumn

  15. Creationism as Science: What Every Teacher-Scientist Should Know.

    ERIC Educational Resources Information Center

    Gatzke, Ken W.

    1985-01-01

    Addresses philosophical problems of the evolution/creationism debate (including underlying assumptions of creationism and nature of science), suggesting that creationism cannot be presented as science in science courses because it fails to qualify as a science. Prediction and explanation, absolute creationism, and a fundamental difficulty in…

  16. Quantum Phases of Fermionic Cold Atoms Through Pairing and Dissociation

    NASA Astrophysics Data System (ADS)

    Lopez, Nicolas; Tsai, Shan-Wen; Timmermans, E.; Lin, Chi-Yong

    2011-03-01

    Cold atom experiments have realized molecule creation consisting of paired fermions and dissociation of weakly bound molecules into correlated fermions by tuning of the interactions with external fields [1,2]. We study many-body correlations in such system where molecules are weakly bound and therefore pairs of fermionic atoms convert into and dissociate from the bound molecule state. This exchange mediates a long-range interaction between the fermions. We consider a simple many-body Hamiltonian that includes the destruction of fermionic atom pairs to form single bosonic molecules and vice versa. We employ a functional renormalization-group approach to search for instabilities from the disordered quantum liquid phase that may arise from a boson mediated fermion-fermion interaction. We calculate the renormalized frequency-dependent fermion interactions vertices and renormalized molecular binding energy.

  17. Aquinas and Contemporary Cosmology: Creation and Beginnings

    NASA Astrophysics Data System (ADS)

    Carroll, William E.

    Discussions in the Middle Ages about creation and the temporal beginning of the world involved sophisticated analyses in theology, metaphysics, and natural philosophy. Mediaeval insights on this subject, especially Thomas Aquinas' defense of the intelligibility of an eternal, created universe, can help to clarify reflections about the philosophical and theological implications of contemporary cosmological theories: from the "singularity" of the Big Bang, to "quantum tunneling from nothing," to multiverse scenarios. Thomas' insights help us to see the value of Georges Lemaître's insistence that his cosmological reflections must be kept separate from an analysis of creation. This essay will look at different senses of "beginning" and examine the claim that creation, in its fundamental meaning, tells us nothing about whether there is a temporal beginning to the universe. Multiverse models, like that recently proposed by Stephen Hawking and Leonard Mlodinow, may challenge certain views of a Grand Designer, but not of a Creator.

  18. Type III burst pair

    NASA Astrophysics Data System (ADS)

    Ning, Zongjun; Fu, Qijun; Lu, Quankang

    2000-05-01

    We present a special solar radio burst detected on 5 January 1994 using the multi-channel (50) spectrometer (1.0-2.0 GHz) of the Beijing Astronomical Observatory (BAO). Sadly, the whole event could not be recorded since it had a broader bandwidth than the limit range of the instrument. The important part was obtained, however. The event is composed of a normal drift type III burst on the lower frequency side and a reverse drift type III burst appearing almost simultaneously on the high side. We call the burst type III a burst pair. It is a typical characteristic of two type III bursts that they are morphologically symmetric about some frequency from 1.64 GHz to 1.78 GHz on the dynamic spectra records, which indicates that there are two different electron beams from the same acceleration region travelling simultaneously in opposite directions (upward and downward). A magnetic reconnection mode is a nice interpretation of type III burst pair since the plasma beta β~=0.01 is much less than 1 and the beams have velocity of about 1.07×10^8 cm s^-1 after leaving the reconnection region if we assume that the ambient magnetic field strength is about 100 G.

  19. Type III burst pair.

    NASA Astrophysics Data System (ADS)

    Zongjun, Ning; Fu, Qijun; Quankang, Lu

    2000-05-01

    Presents a special solar radio burst detected on 5 January 1994 using the multi-channel (50) spectrometer (1.0 - 2.0 GHz) of the Beijing Astronomical Observatory. Sadly, the whole event could not be recorded since it had a broader bandwidth than the limit range of the instrument. The important part was obtained, however. The event is composed of a normal drift type III burst on the lower frequency side and a reverse drift type III burst appearing almost simultaneously on the high side. The authors call the burst type III a burst pair. It is a typical characteristic of two type III bursts that they are morphologically symmetric about some frequency from 1.64 GHz to 1.78 GHz on the dynamic spectra records, which indicates that there are two different electron beams from the same acceleration region travelling simultaneously in opposite directions (upward and downward). A magnetic reconnection mode is an interpretation of type III burst pair.

  20. Adiabat shape Laser Pulses for ablation front instability control and high fuel compression

    NASA Astrophysics Data System (ADS)

    Milovich, Jose; Jones, O. S.; Berzak-Hopkins, L.; Clark, D. S.; Baker, K. L.; Casey, D. T.; Macphee, A. G.; Peterson, J. L.; Robey, H. F.; Smalyuk, V. A.; Weber, C. R.

    2014-10-01

    At the end of the NIC campaign a large body of experimental evidence showed that the point-design implosions driven by low-adiabat pulses had a high degree of mix. To reduce instability a high-adiabat (~3 × higher picket drive) design was fielded in the National Ignition Facility (NIF). The experimental results from this campaign have shown considerable improvement in performance (10 × neutron yields) over the point design with little evidence of mix. However, the adiabat of the implosions may be too high to achieve ignition for the available laser energy. To overcome this difficulty, and to take advantage of the high-picket drives, we have developed hybrid laser pulses that combined the virtue of both designs. These pulses can be thought of achieving adiabat shaping, where the ablator is set in a higher adiabat for instability control, while the fuel is maintained at a lower adiabat favoring higher fuel compression. Using these pulses, recent experiments at the NIF have indeed shown reduced growth rates. In this talk we will present the design of high-yield low-growth DT ignition experiments using these adiabat-shaped pulses. Work performed under the auspices of the U.S. D.O.E. by LLNL under contract DE-AC52-07NA27344.

  1. Perturbation to Mei Symmetry and Adiabatic Invariants for Disturbed El-Nabulsi's Fractional Birkhoff System

    NASA Astrophysics Data System (ADS)

    Song, Chuan-Jing; Zhang, Yi

    2015-08-01

    For El-Nabulsi's fractional Birkhoff system, Mei symmetry perturbation, the corresponding Mei-type adiabatic invariants and Noether-type adiabatic invariants are investigated in this paper. Firstly, based on El-Nabulsi-Birkhoff fractional equations, Mei symmetry and the corresponding Mei conserved quantity, Noether conserved quantity deduced indirectly by Mei symmetry are studied. Secondly, Mei-type exact invariants and Noether-type exact invariants are given on the basis of the definition of adiabatic invatiant. Thirdly, Mei symmetry perturbation, Mei-type adiabatic invariants and Noether-type adiabatic invariants for the disturbed El-Nabulsi's fractional Birkhoff system are studied. Finally, two examples, Hojman-Urrutia problem for Mei-type adiabatic invariants and another for the Noether-type adiabatic invariants, are given to illustrate the application of the results. Supported by the National Natural Science Foundation of China under Grant Nos. 10972151 and 11272227, and the Innovation Program for Scientific Research of Nanjing University of Science and Technology

  2. Energy-Efficient and Secure S-Box circuit using Symmetric Pass Gate Adiabatic Logic

    SciTech Connect

    Kumar, Dinesh; Thapliyal, Himanshu; Mohammad, Azhar; Singh, Vijay; Perumalla, Kalyan S

    2016-01-01

    Differential Power Analysis (DPA) attack is considered to be a main threat while designing cryptographic processors. In cryptographic algorithms like DES and AES, S-Box is used to indeterminate the relationship between the keys and the cipher texts. However, S-box is prone to DPA attack due to its high power consumption. In this paper, we are implementing an energy-efficient 8-bit S-Box circuit using our proposed Symmetric Pass Gate Adiabatic Logic (SPGAL). SPGAL is energy-efficient as compared to the existing DPAresistant adiabatic and non-adiabatic logic families. SPGAL is energy-efficient due to reduction of non-adiabatic loss during the evaluate phase of the outputs. Further, the S-Box circuit implemented using SPGAL is resistant to DPA attacks. The results are verified through SPICE simulations in 180nm technology. SPICE simulations show that the SPGAL based S-Box circuit saves upto 92% and 67% of energy as compared to the conventional CMOS and Secured Quasi-Adiabatic Logic (SQAL) based S-Box circuit. From the simulation results, it is evident that the SPGAL based circuits are energy-efficient as compared to the existing DPAresistant adiabatic and non-adiabatic logic families. In nutshell, SPGAL based gates can be used to build secure hardware for lowpower portable electronic devices and Internet-of-Things (IoT) based electronic devices.

  3. Arbitrary amplitude electro-acoustic solitary waves in an adiabatic dusty plasma

    NASA Astrophysics Data System (ADS)

    Tanjia, Fatema; Mamun, A. A.

    2008-12-01

    The properties of different types of electro-acoustic (namely ion-acoustic (IA), dust ion-acoustic (DIA), and dust-acoustic (DA)) solitary waves (SWs) in an adiabatic dusty plasma (containing negatively charged cold dust, adiabatic hot ions and inertia-less adiabatic hot electrons) are investigated by the pseudo-potential approach. The combined effects of the adiabatic electrons and ions, and negatively charged dust on the basic properties (critical Mach number, amplitude and width) of the arbitrary amplitude electro-acoustic SWs are systematically and explicitly examined. It is found that the combined effects of the adiabatic electrons and ions, and negatively charged dust significantly modify the basic properties (critical Mach number, amplitude and width) of the SWs. It is also found that due to the effect of the adiabaticity of electrons, the negative DIA SWs (which are found to exist in a dusty plasma containing isothermal electrons, cold ions and negatively charged static dust) disappear, i.e. due to the effect of adiabatic electrons, one cannot have negative DIA SWs for any possible set of dusty plasma parameters.

  4. Recent developments in trapping and manipulation of atoms with adiabatic potentials

    NASA Astrophysics Data System (ADS)

    Garraway, Barry M.; Perrin, Hélène

    2016-09-01

    A combination of static and oscillating magnetic fields can be used to ‘dress’ atoms with radio-frequency (RF), or microwave, radiation. The spatial variation of these fields can be used to create an enormous variety of traps for ultra-cold atoms and quantum gases. This article reviews the type and character of these adiabatic traps and the applications which include atom interferometry and the study of low-dimensional quantum systems. We introduce the main concepts of magnetic traps leading to adiabatic dressed traps. The concept of adiabaticity is discussed in the context of the Landau-Zener model. The first bubble trap experiment is reviewed together with the method used for loading it. Experiments based on atom chips show the production of double wells and ring traps. Dressed atom traps can be evaporatively cooled with an additional RF field, and a weak RF field can be used to probe the spectroscopy of the adiabatic potentials. Several approaches to ring traps formed from adiabatic potentials are discussed, including those based on atom chips, time-averaged adiabatic potentials and induction methods. Several proposals for adiabatic lattices with dressed atoms are also reviewed.

  5. Electron-positron pairs beaming in the Breit-Wheeler process

    NASA Astrophysics Data System (ADS)

    Ribeyre, X.; d'Humières, E.; Jansen, O.; Jequier, S.; Tikhonchuk, V. T.

    2017-01-01

    The pair creation from the Breit-Wheeler process is one of the basic processes in the universe. Laser induced intense γ-ray sources will allow a direct observation of this process in the laboratory for the first time. In this paper we demonstrate the effect of pair beaming in the collision of two photon beams which may facilitate the experimental observation of the Breit-Wheeler process.

  6. The Postmodern Sin of Intelligent Design Creationism

    NASA Astrophysics Data System (ADS)

    Pennock, Robert T.

    2010-06-01

    That Intelligent Design Creationism rejects the methodological naturalism of modern science in favor of a premodern supernaturalist worldview is well documented and by now well known. An irony that has not been sufficiently appreciated, however, is the way that ID Creationists try to advance their premodern view by adopting (if only tactically) a radical postmodern perspective. This paper will reveal the deep threads of postmodernism that run through the ID Creationist movement’s arguments, as evidenced in the writings and interviews of its key leaders. Seeing their arguments and activities from this perspective highlights the danger to science posed by both ID Creationism and radical postmodernism.

  7. Exact solution of the p+{\\rm{i}}p Hamiltonian revisited: duality relations in the hole-pair picture

    NASA Astrophysics Data System (ADS)

    Links, Jon; Marquette, Ian; Moghaddam, Amir

    2015-09-01

    We study the exact Bethe ansatz solution of the p+{{i}}p Hamiltonian in a form whereby quantum numbers of states refer to hole-pairs, rather than particle-pairs used in previous studies. We find an asymmetry between these approaches. For an attractive system states in the strong pairing regime take the form of a partial condensate involving two distinct hole-pair creation operators. An analogous feature is not observed in the particle-pair picture of an attractive system.

  8. Arbitrary Amplitude DIA and DA Solitary Waves in Adiabatic Dusty Plasmas

    SciTech Connect

    Mamun, A. A.; Jahan, N.; Shukla, P. K.

    2008-10-15

    The dust-ion-acoustic (DIA) as well as the dust-acoustic (DA) solitary waves (SWs) in an adiabatic dusty plasma are investigated by the pseudo-potential approach which is valid for arbitrary amplitude SWs. The role of the adiabaticity of electrons and ions in modifying the basic features (polarity, speed, amplitude and width) of arbitrary amplitude DIA and DA SWs are explicitly examined. It is found that the effects of the adiabaticity of electrons and ions significantly modify the basic features (polarity, speed, amplitude and width) of the DIA and DA SWs. The implications of our results in space and laboratory dusty plasmas are briefly discussed.

  9. Stochasticity, superadiabaticity, and the theory of adiabatic invariants and guiding center motion

    SciTech Connect

    Dubin, D.H.E.; Krommes, J.A.

    1981-07-01

    The theory of adiabatic invariants is discussed within the modern framework of symplectic Hamiltonian dynamics. The distinctions between exact, adiabatic, and superadiabatic invariants are clarified. The intimate connection between adiabatic (as opposed to exact) invariance and resonant interactions between motions on disparate time scales is elucidated. For the important case of charged particle motion in a strong magnetic field, resonances between gyration, bounce motion, and an external sinusoidal perturbation are described explicitly by introducing a time-dependent symplectic formulation of the guiding center motion. Destruction of invariance is discussed for quite general situations of physical interest, including the case of a trapped particle in a tokamak.

  10. Resonant modal interactions and adiabatic invariance for a nonlinear wave equation in a variable domain

    NASA Astrophysics Data System (ADS)

    Kevorkian, J.; Li, H. K.

    1984-08-01

    The technique of isolating and order reducing transformations for computing adiabatic invariants in finite-degree-of-freedom Hamiltonian sytems is extended to the case of the non-Hamiltonian modal representation of a wave equation with weak nonlinearities in a slowly varying domain. The mechanism of resonant interactions for two or more normal modes whereby the associated actions change rapidly in a short period is exhibited. In the Hamiltonian problem there are a number of global adiabatic invariants associated with each resonance. Conditions for which similar adiabatic invariants can be found for the non-Hamiltonian case are derived. The results are then verified by extensive numerical computations.

  11. Digitized adiabatic quantum computing with a superconducting circuit, part II: Experiment

    NASA Astrophysics Data System (ADS)

    Barends, R.; Shabani, A.; Lamata, L.; Kelly, J.; Mezzacapo, A.; Las Heras, U.; Babbush, R.; Fowler, A. G.; Campbell, B.; Chen, Y.; Chen, Z.; Chiaro, B.; Dunsworth, A.; Jeffrey, E.; Lucero, E.; Megrant, A.; Mutus, J.; Neeley, M.; Neill, C.; O'Malley, P.; Quintana, C.; Roushan, P.; Solano, E.; Neven, H.; Martinis, J.

    A major challenge in quantum computing is to solve general problems with limited physical hardware. We implement digitized adiabatic quantum computing, combining the generality of the adiabatic algorithm with the universality of the digital approach, using a superconducting circuit with nine qubits. We probe the adiabatic evolutions, explore the scaling of errors with system size, and quantify the success of the algorithm for random spin problems. We find that the system can approximate the solutions to both frustrated Ising problems and non-stoquastic problem Hamiltonians with a performance that is comparable.

  12. Multiprocessor switch with selective pairing

    DOEpatents

    Gara, Alan; Gschwind, Michael K; Salapura, Valentina

    2014-03-11

    System, method and computer program product for a multiprocessing system to offer selective pairing of processor cores for increased processing reliability. A selective pairing facility is provided that selectively connects, i.e., pairs, multiple microprocessor or processor cores to provide one highly reliable thread (or thread group). Each paired microprocessor or processor cores that provide one highly reliable thread for high-reliability connect with a system components such as a memory "nest" (or memory hierarchy), an optional system controller, and optional interrupt controller, optional I/O or peripheral devices, etc. The memory nest is attached to a selective pairing facility via a switch or a bus

  13. Substantiation of International Nanomaterials Security Group Creation

    NASA Astrophysics Data System (ADS)

    Sosnov, A.; Sadovnikov, S.; Panfilov, S.; Magarshak, Yu.

    Nanotechnology has achieved the status as one of the critical R&D area. Scientists use the unique properties of atomic and molecular assemblages built at the nanometer scale. The ability to manipulate the physical, chemical, and biological properties of molecules and particles affords to design agents with set up properties. But the technology allows creating not only useful agents. Possible accidental or deliberate creation of new nanoparticles (NPs) with dangerous properties is highly probable minor product of progress in the new area. The article briefly describes some pathways in development and implementation of NPs for medicinal and the similar purposes. Some of NPs can effective facilitate and mask transport of various agents in various environments. Possible creation of new dangerous NPs (e.g. conjugates based on combination of extensively use NPs and chemical, biological and radioactive agents) as well as creation of brand new NPs and nanodevices with unique properties needs creation of international multidiscipline community for security evaluation of nanomaterials and technologies. The community will forecast possible dangerous unexpectedness in the field of nanoscale materials and devices and suggests rational pathways for prevention of the threats.

  14. Reconstructing Professional Learning Community as Collective Creation

    ERIC Educational Resources Information Center

    Allen, David

    2013-01-01

    The article presents a cross-domain inquiry into schoolwide professional learning community. It examines tensions in how professional learning community is conceptualized and how it is enacted in the processes of teacher groups. Drawing on a study of contemporary theatre arts practices, it proposes a model of collective creation that highlights…

  15. Seymour Sarason and the Creation of Settings

    ERIC Educational Resources Information Center

    Cherniss, Cary

    2012-01-01

    One of Seymour Sarason's most original and important works was his book, The Creation of Settings and the Future Societies (Sarason, 1972). In it, he offered numerous insights about what goes wrong when "two or more people come together in new relationships over a sustained period of time in order to achieve certain goals." His hope in writing the…

  16. "Scientific Creationism"--A New Inquisition Brewing?

    ERIC Educational Resources Information Center

    Cloud, Preston

    1977-01-01

    In light of the recent revival of the creationism versus evolution issue, the author briefly summarizes both positions, defends evolution on the basis of fossils and rock ages, and refutes six creationist arguments against evolution. For journal availability, see SO 505 260. (AV)

  17. The Money-Creation Model: Another Pedagogy.

    ERIC Educational Resources Information Center

    Gamble, Ralph C., Jr.

    1991-01-01

    Describes graphical techniques to help explain the multiple creation of deposits that accompany lending in a fractional reserve banking system. Presents a model that emphasizes the banking system, the interaction of total permitted, required, and excess reserves and deposits. Argues that the approach simplifies information to examining a slope…

  18. Dinosaurs on the Ark: The Creation Museum

    ERIC Educational Resources Information Center

    Asma, Stephen T.

    2007-01-01

    In this article, the author describes the Creation Museum, founded by Ken A. Ham and designed as a rebuttal to the evolutionary view taken by other natural history museums. He discusses the socially conservative roots of the museum's exhibits, and presents Ham's answers to questions about the museum. The message of the museum is that the Bible is…

  19. Battle Brewing Over Arkansas Creationism Law.

    ERIC Educational Resources Information Center

    Baum, Rudy

    1981-01-01

    Reports recent proceedings regarding a new law enacted in early 1981 in Arkansas which requires schools that teach evolution to teach what the law calls "creation-science." Opposition to the law by the American Civil Liberties Union is discussed. (CS)

  20. The Postmodern Sin of Intelligent Design Creationism

    ERIC Educational Resources Information Center

    Pennock, Robert T.

    2010-01-01

    That Intelligent Design Creationism rejects the methodological naturalism of modern science in favor of a premodern supernaturalist worldview is well documented and by now well known. An irony that has not been sufficiently appreciated, however, is the way that ID Creationists try to advance their premodern view by adopting (if only tactically) a…

  1. Using Informal Education through Music Video Creation

    ERIC Educational Resources Information Center

    Cayari, Christopher

    2014-01-01

    Music video creation provides students a new way to express themselves and become better performers and consumers of media. This article provides a new perspective on Lucy Green's informal music pedagogy by enabling students to create music videos in music classrooms; thus, students are able to create music videos that informally develop…

  2. Photography and the Creation of Meaning.

    ERIC Educational Resources Information Center

    Quan, Roy H.

    1979-01-01

    In this theoretical discussion, still photography is viewed as a tool which can be used in the creation of meaning and as a medium for social inquiry. Three specific functions of photographic inquiry are explored: the anthropological, the normative, and the intuitive. (Author/SJL)

  3. Behind the Evolution-Creation Science Controversy.

    ERIC Educational Resources Information Center

    Parker, Franklin

    1982-01-01

    Historical background to Arkansas Act 590, mandating inclusion of creationism in public school curriculum, is given, including the history of antievolution bills, emergence of textbook watchers, and political issues in the law's passage. Suggestions are given for elementary and secondary teachers to become informed and active regarding…

  4. Salt Pill Design and Fabrication for Adiabatic Demagnetization Refrigerators

    NASA Technical Reports Server (NTRS)

    Shirron, Peter J.; Mccammon, Dan

    2014-01-01

    The performance of an adiabatic demagnetization refrigerator (ADR) is critically dependent on the design and construction of the salt pills that produce cooling. In most cases, the primary goal is to obtain the largest cooling capacity at the low temperature end of the operating range. The realizable cooling capacity depends on a number of factors, including refrigerant mass, and how efficiently it absorbs heat from the various instrument loads. The design and optimization of "salt pills" for ADR systems depend not only on the mechanical, chemical and thermal properties of the refrigerant, but also on the range of heat fluxes that the salt pill must accommodate. Despite the fairly wide variety of refrigerants available, those used at very low temperature tend to be hydrated salts that require a dedicated thermal bus and must be hermetically sealed, while those used at higher temperature - greater than about 0.5 K - tend to be single-­- or poly-­-crystals that have much simpler requirements for thermal and mechanical packaging. This paper presents a summary of strategies and techniques for designing, optimizing and fabricating salt pills for both low-­- and mid-­-temperature applications.

  5. Decoherence in current induced forces: Application to adiabatic quantum motors

    NASA Astrophysics Data System (ADS)

    Fernández-Alcázar, Lucas J.; Bustos-Marún, Raúl A.; Pastawski, Horacio M.

    2015-08-01

    Current induced forces are not only related with the discrete nature of electrons but also with its quantum character. It is natural then to wonder about the effect of decoherence. Here, we develop the theory of current induced forces including dephasing processes and we apply it to study adiabatic quantum motors (AQMs). The theory is based on Büttiker's fictitious probe model, which here is reformulated for this particular case. We prove that it accomplishes the fluctuation-dissipation theorem. We also show that, in spite of decoherence, the total work performed by the current induced forces remains equal to the pumped charge per cycle times the voltage. We find that decoherence affects not only the current induced forces of the system but also its intrinsic friction and noise, modifying in a nontrivial way the efficiency of AQMs. We apply the theory to study an AQM inspired by a classical peristaltic pump where we surprisingly find that decoherence can play a crucial role by triggering its operation. Our results can help to understand how environmentally induced dephasing affects the quantum behavior of nanomechanical devices.

  6. Random Matrix Approach to Quantum Adiabatic Evolution Algorithms

    NASA Technical Reports Server (NTRS)

    Boulatov, Alexei; Smelyanskiy, Vadier N.

    2004-01-01

    We analyze the power of quantum adiabatic evolution algorithms (Q-QA) for solving random NP-hard optimization problems within a theoretical framework based on the random matrix theory (RMT). We present two types of the driven RMT models. In the first model, the driving Hamiltonian is represented by Brownian motion in the matrix space. We use the Brownian motion model to obtain a description of multiple avoided crossing phenomena. We show that the failure mechanism of the QAA is due to the interaction of the ground state with the "cloud" formed by all the excited states, confirming that in the driven RMT models. the Landau-Zener mechanism of dissipation is not important. We show that the QAEA has a finite probability of success in a certain range of parameters. implying the polynomial complexity of the algorithm. The second model corresponds to the standard QAEA with the problem Hamiltonian taken from the Gaussian Unitary RMT ensemble (GUE). We show that the level dynamics in this model can be mapped onto the dynamics in the Brownian motion model. However, the driven RMT model always leads to the exponential complexity of the algorithm due to the presence of the long-range intertemporal correlations of the eigenvalues. Our results indicate that the weakness of effective transitions is the leading effect that can make the Markovian type QAEA successful.

  7. Resource efficient gadgets for compiling adiabatic quantum optimization problems

    NASA Astrophysics Data System (ADS)

    Babbush, Ryan; O'Gorman, Bryan; Aspuru-Guzik, Alán

    2013-11-01

    We develop a resource efficient method by which the ground-state of an arbitrary k-local, optimization Hamiltonian can be encoded as the ground-state of a (k-1)-local optimization Hamiltonian. This result is important because adiabatic quantum algorithms are often most easily formulated using many-body interactions but experimentally available interactions are generally 2-body. In this context, the efficiency of a reduction gadget is measured by the number of ancilla qubits required as well as the amount of control precision needed to implement the resulting Hamiltonian. First, we optimize methods of applying these gadgets to obtain 2-local Hamiltonians using the least possible number of ancilla qubits. Next, we show a novel reduction gadget which minimizes control precision and a heuristic which uses this gadget to compile 3-local problems with a significant reduction in control precision. Finally, we present numerics which indicate a substantial decrease in the resources required to implement randomly generated, 3-body optimization Hamiltonians when compared to other methods in the literature.

  8. Thermodynamics Analysis of Refinery Sludge Gasification in Adiabatic Updraft Gasifier

    PubMed Central

    Ahmed, Reem; Sinnathambi, Chandra M.; Eldmerdash, Usama; Subbarao, Duvvuri

    2014-01-01

    Limited information is available about the thermodynamic evaluation for biomass gasification process using updraft gasifier. Therefore, to minimize errors, the gasification of dry refinery sludge (DRS) is carried out in adiabatic system at atmospheric pressure under ambient air conditions. The objectives of this paper are to investigate the physical and chemical energy and exergy of product gas at different equivalent ratios (ER). It will also be used to determine whether the cold gas, exergy, and energy efficiencies of gases may be maximized by using secondary air injected to gasification zone under various ratios (0, 0.5, 1, and 1.5) at optimum ER of 0.195. From the results obtained, it is indicated that the chemical energy and exergy of producer gas are magnified by 5 and 10 times higher than their corresponding physical values, respectively. The cold gas, energy, and exergy efficiencies of DRS gasification are in the ranges of 22.9–55.5%, 43.7–72.4%, and 42.5–50.4%, respectively. Initially, all 3 efficiencies increase until they reach a maximum at the optimum ER of 0.195; thereafter, they decline with further increase in ER values. The injection of secondary air to gasification zone is also found to increase the cold gas, energy, and exergy efficiencies. A ratio of secondary air to primary air of 0.5 is found to be the optimum ratio for all 3 efficiencies to reach the maximum values. PMID:24672368

  9. Progress in the Development of a Continuous Adiabatic Demagnetization Refrigerator

    NASA Technical Reports Server (NTRS)

    Shirron, Peter; Canavan, Edgar; DiPirro, Michael; Jackson, Michael; King, Todd; Tuttle, James; Krebs, Carolyn A. (Technical Monitor)

    2002-01-01

    We report on recent progress in the development of a continuous adiabatic demagnetization refrigerator (CADR). Continuous operation avoids the constraints of long hold times and short recycle times that lead to the generally large mass of single-shot ADRs, allowing us to achieve an order of magnitude larger cooling power per unit mass. Our current design goal is 10 micro W of cooling at 50 mK using a 6-10 K heat sink. The estimated mass is less than 10 kg, including magnetic shielding of each stage. The relatively high heat rejection capability allows it to operate with a mechanical cryocooler as part of a cryogen-free, low temperature cooling system. This has the advantages of long mission life and reduced complexity and cost. We have assembled a three-stage CADR and have demonstrated continuous cooling using a superfluid helium bath as the heat sink. The temperature stability is 8 micro K rms or better over the entire cycle, and the cooling power is 2.5 micro W at 60 mK rising to 10 micro W at 100 mK.

  10. Adiabatic calorimetric decomposition studies of 50 wt.% hydroxylamine/water.

    PubMed

    Cisneros, L O; Rogers, W J; Mannan, M S

    2001-03-19

    Calorimetric data can provide a basis for determining potential hazards in reactions, storage, and transportation of process chemicals. This work provides calorimetric data for the thermal decomposition behavior in air of 50wt.% hydroxylamine/water (HA), both with and without added stabilizers, which was measured in closed cells with an automatic pressure tracking adiabatic calorimeter (APTAC). Among the data provided are onset temperatures, reaction order, activation energies, pressures of noncondensable products, thermal stability at 100 degrees C, and the effect of HA storage time. Discussed also are the catalytic effects of carbon steel, stainless steel, stainless steel with silica coating, inconel, titanium, and titanium with silica coating on the reaction self-heat rates and onset temperatures. In borosilicate glass cells, HA was relatively stable at temperatures up to 133 degrees C, where the HA decomposition self-heat rate reached 0.05 degrees C/min. The added stabilizers appeared to reduce HA decomposition rates in glass cells and at ambient temperatures. The tested metals and metal surfaces coated with silica acted as catalysts to lower the onset temperatures and increase the self-heat rates.

  11. Shortcuts to Adiabaticity in Transport of a Single Trapped Ion

    NASA Astrophysics Data System (ADS)

    An, Shuoming; Lv, Dingshun; Campo, Adolfo Del; Kim, Kihwan

    2015-05-01

    We report an experimental study on shortcuts to adiabaticity in the transport of a single 171Yb+ ion trapped in a harmonic potential. In these driving schemes, the application of a force induces a nonadiabatic dynamics in which excitations are tailored so as to preserve the ion motional state in the ground state upon completion of the process. We experimentally apply the laser induced force and realize three different protocols: (1) a transitionless driving with a counterdiabatic term out of phase with the displacement force, (2) a classical protocol assisted by counterdiabatic fields in phase with the main force, (3) and an engineered transport protocol based on the Fourier transform of the trap acceleration. We experimentally compare and discuss the robustness of these protocols under given experimental limitations such as trap frequency drifts. This work was supported by the National Basic Research Program of China under Grants No. 2011CBA00300 (No. 2011CBA00301), the National Natural Science Foundation of China 11374178, and the University of Massachusetts Boston (No. P20150000029279).

  12. Nonequilibrium adiabatic molecular dynamics simulations of methane clathrate hydrate decomposition

    NASA Astrophysics Data System (ADS)

    Alavi, Saman; Ripmeester, J. A.

    2010-04-01

    Nonequilibrium, constant energy, constant volume (NVE) molecular dynamics simulations are used to study the decomposition of methane clathrate hydrate in contact with water. Under adiabatic conditions, the rate of methane clathrate decomposition is affected by heat and mass transfer arising from the breakup of the clathrate hydrate framework and release of the methane gas at the solid-liquid interface and diffusion of methane through water. We observe that temperature gradients are established between the clathrate and solution phases as a result of the endothermic clathrate decomposition process and this factor must be considered when modeling the decomposition process. Additionally we observe that clathrate decomposition does not occur gradually with breakup of individual cages, but rather in a concerted fashion with rows of structure I cages parallel to the interface decomposing simultaneously. Due to the concerted breakup of layers of the hydrate, large amounts of methane gas are released near the surface which can form bubbles that will greatly affect the rate of mass transfer near the surface of the clathrate phase. The effects of these phenomena on the rate of methane hydrate decomposition are determined and implications on hydrate dissociation in natural methane hydrate reservoirs are discussed.

  13. Adiabatic Demagnetisation Refrigerators for Future Sub-Millimetre Space Missions

    NASA Astrophysics Data System (ADS)

    Hepburn, I. D.; Davenport, I.; Smith, A.

    1995-10-01

    Space worthy refrigeration capable of providing a 100 mK and below heat load sink for bolometric detectors will be required for the next generation of sub-millimetre space missions. Adiabatic demagnetisation refrigeration (ADR), being a gravity independent laboratory method for obtaining such temperatures, is a favourable technique for utilisation in space. We show that by considering a 3 salt pill refrigerator rather than the classic single salt pill design the space prohibitive laboratory ADR properties of high magnetic field (6 Tesla) and a<2 K environment (provided by a bath of liquid4He) can be alleviated, while maintaining a sufficient low temperature hold time and short recycle time. The additional salt pills, composed of Gadolinium Gallium Garnet (GGG) provide intermediate cooling stages, enabling operation from a 4 K environment provided by a single 4 K mechanical cooler, thereby providing consumable free operation. Such ADRs could operate with fields as low as 1 Tesla allowing the use of high temperature, mechanically cooled superconducting magnets and so effectively remove the risk of quenching. We discuss the possibility of increasing the hold time from 3 hours, for the model presented, to between 40 and 80 hours, plus reducing the number of salt pills to two, through the use of a more efficient Garnet. We believe the technical advances necessitated by the envisaged ADRs are minimal and conclude that such ADRs offer a long orbital life time, consumable free, high efficiency means of milli-Kelvin cooling, requiring relatively little laboratory development.

  14. Adiabatic Heat of Hydration Calorimetric Measurements for Reference Saltstone Waste

    SciTech Connect

    Bollinger, James

    2006-01-12

    The production of nuclear materials for weapons, medical, and space applications from the mid-1950's through the late-1980's at the Savannah River Site (SRS) generated approximately 35 million gallons of liquid high-level radioactive waste, which is currently being processed into vitrified glass for long-term storage. Upstream of the vitrification process, the waste is separated into three components: high activity insoluble sludge, high activity insoluble salt, and very low activity soluble salts. The soluble salt represents 90% of the 35 million gallons of overall waste and is processed at the SRS Saltstone Facility, where it mixed with cement, blast furnace slag, and flyash, creating a grout-like mixture. The resulting grout is pumped into aboveground storage vaults, where it hydrates into concrete monoliths, called saltstone, thus immobilizing the low-level radioactive salt waste. As the saltstone hydrates, it generates heat that slowly diffuses out of the poured material. To ensure acceptable grout properties for disposal and immobilization of the salt waste, the grout temperature must not exceed 95 C during hydration. Adiabatic calorimetric measurements of the heat generated for a representative sample of saltstone were made to determine the time-dependent heat source term. These measurements subsequently were utilized as input to a numerical conjugate heat transfer model to determine the expected peak temperatures for the saltstone vaults.

  15. Adiabatic Compression Sensitivity of Liquid Fuels and Monopropellants

    NASA Technical Reports Server (NTRS)

    Ismail, Ismail M. K.; Hawkins, Tom W.

    2000-01-01

    Liquid rocket propellants can be sensitive to rapid compression. Such liquids may undergo decomposition and their handling may be accompanied with risk. Decomposition produces small gas bubbles in the liquid, which upon rapid compression may cause catastrophic explosions. The rapid compression can result from mechanical shocks applied on the tank containing the liquid or from rapid closure of the valves installed on the lines. It is desirable to determine the conditions that may promote explosive reactions. At Air Force Research Laboratory (AFRL), we constructed an apparatus and established a safe procedure for estimating the sensitivity of propellant materials towards mechanical shocks (Adiabatic Compression Tester). A sample is placed on a stainless steel U-tube, held isothermally at a temperature between 20 and 150 C then exposed to an abrupt mechanical shock of nitrogen gas at a pressure between 6.9 and 20.7 MPa (1000 to 3000 psi). The apparatus is computer interfaced and is driven with LABTECH NOTEBOOK-pro (registered) Software. In this presentation, the design of the apparatus is shown, the operating procedure is outlined, and the safety issues are addressed. The results obtained on different energetic materials are presented.

  16. Stimulated Raman adiabatic passage in physics, chemistry, and beyond

    NASA Astrophysics Data System (ADS)

    Vitanov, Nikolay V.; Rangelov, Andon A.; Shore, Bruce W.; Bergmann, Klaas

    2017-01-01

    The technique of stimulated Raman adiabatic passage (STIRAP), which allows efficient and selective population transfer between quantum states without suffering loss due to spontaneous emission, was introduced in 1990 by Gaubatz et al.. Since then STIRAP has emerged as an enabling methodology with widespread successful applications in many fields of physics, chemistry, and beyond. This article reviews the many applications of STIRAP emphasizing the developments since 2001, the time when the last major review on the topic was written (Vitanov, Fleischhauer et al.). A brief introduction into the theory of STIRAP and the early applications for population transfer within three-level systems is followed by the discussion of several extensions to multilevel systems, including multistate chains and tripod systems. The main emphasis is on the wide range of applications in atomic and molecular physics (including atom optics, cavity quantum electrodynamics, formation of ultracold molecules, etc.), quantum information (including single- and two-qubit gates, entangled-state preparation, etc.), solid-state physics (including processes in doped crystals, nitrogen-vacancy centers, superconducting circuits, semiconductor quantum dots and wells), and even some applications in classical physics (including waveguide optics, polarization optics, frequency conversion, etc.). Promising new prospects for STIRAP are also presented (including processes in optomechanics, precision experiments, detection of parity violation in molecules, spectroscopy of core-nonpenetrating Rydberg states, population transfer with x-ray pulses, etc.).

  17. Effects of dissipation on an adiabatic quantum search algorithm

    NASA Astrophysics Data System (ADS)

    de Vega, Inés; Bañuls, Mari Carmen; Pérez, A.

    2010-12-01

    According to recent studies (Amin et al 2008 Phys. Rev. Lett. 100 060503), the effect of a thermal bath may improve the performance of a quantum adiabatic search algorithm. In this paper, we compare the effects of such a thermal environment on the algorithm performance with those of a structured environment similar to the one encountered in systems coupled to an electromagnetic field that exists within a photonic crystal. Whereas for all the parameter regimes explored here, the algorithm performance is worsened by contact with a thermal environment, the picture appears to be different when one considers a structured environment. In this case we show that by tuning the environment parameters to certain regimes, the algorithm performance can actually be improved with respect to the closed system case. Additionally, the relevance of considering the dissipation rates as complex quantities is discussed in both cases. More specifically, we find that the imaginary part of the rates cannot be neglected with the usual argument that it simply amounts to an energy shift and in fact influences crucially the system dynamics.

  18. Development of a semi-adiabatic isoperibol solution calorimeter

    SciTech Connect

    Venkata Krishnan, R.; Jogeswararao, G.; Parthasarathy, R.; Premalatha, S.; Prabhakar Rao, J.; Gunasekaran, G.; Ananthasivan, K.

    2014-12-15

    A semi-adiabatic isoperibol solution calorimeter has been indigenously developed. The measurement system comprises modules for sensitive temperature measurement probe, signal processing, data collection, and joule calibration. The sensitivity of the temperature measurement module was enhanced by using a sensitive thermistor coupled with a lock-in amplifier based signal processor. A microcontroller coordinates the operation and control of these modules. The latter in turn is controlled through personal computer (PC) based custom made software developed with LabView. An innovative summing amplifier concept was used to cancel out the base resistance of the thermistor. The latter was placed in the dewar. The temperature calibration was carried out with a standard platinum resistance (PT100) sensor coupled with an 8½ digit multimeter. The water equivalent of this calorimeter was determined by using electrical calibration with the joule calibrator. The experimentally measured values of the quantum of heat were validated by measuring heats of dissolution of pure KCl (for endotherm) and tris (hydroxyl methyl) amino-methane (for exotherm). The uncertainity in the measurements was found to be within ±3%.

  19. Development of a semi-adiabatic isoperibol solution calorimeter.

    PubMed

    Venkata Krishnan, R; Jogeswararao, G; Parthasarathy, R; Premalatha, S; Prabhakar Rao, J; Gunasekaran, G; Ananthasivan, K

    2014-12-01

    A semi-adiabatic isoperibol solution calorimeter has been indigenously developed. The measurement system comprises modules for sensitive temperature measurement probe, signal processing, data collection, and joule calibration. The sensitivity of the temperature measurement module was enhanced by using a sensitive thermistor coupled with a lock-in amplifier based signal processor. A microcontroller coordinates the operation and control of these modules. The latter in turn is controlled through personal computer (PC) based custom made software developed with LabView. An innovative summing amplifier concept was used to cancel out the base resistance of the thermistor. The latter was placed in the dewar. The temperature calibration was carried out with a standard platinum resistance (PT100) sensor coupled with an 8½ digit multimeter. The water equivalent of this calorimeter was determined by using electrical calibration with the joule calibrator. The experimentally measured values of the quantum of heat were validated by measuring heats of dissolution of pure KCl (for endotherm) and tris (hydroxyl methyl) amino-methane (for exotherm). The uncertainity in the measurements was found to be within ±3%.

  20. Development of a semi-adiabatic isoperibol solution calorimeter

    NASA Astrophysics Data System (ADS)

    Venkata Krishnan, R.; Jogeswararao, G.; Parthasarathy, R.; Premalatha, S.; Prabhakar Rao, J.; Gunasekaran, G.; Ananthasivan, K.

    2014-12-01

    A semi-adiabatic isoperibol solution calorimeter has been indigenously developed. The measurement system comprises modules for sensitive temperature measurement probe, signal processing, data collection, and joule calibration. The sensitivity of the temperature measurement module was enhanced by using a sensitive thermistor coupled with a lock-in amplifier based signal processor. A microcontroller coordinates the operation and control of these modules. The latter in turn is controlled through personal computer (PC) based custom made software developed with LabView. An innovative summing amplifier concept was used to cancel out the base resistance of the thermistor. The latter was placed in the dewar. The temperature calibration was carried out with a standard platinum resistance (PT100) sensor coupled with an 8½ digit multimeter. The water equivalent of this calorimeter was determined by using electrical calibration with the joule calibrator. The experimentally measured values of the quantum of heat were validated by measuring heats of dissolution of pure KCl (for endotherm) and tris (hydroxyl methyl) amino-methane (for exotherm). The uncertainity in the measurements was found to be within ±3%.

  1. General background conditions for K-bounce and adiabaticity

    NASA Astrophysics Data System (ADS)

    Romano, Antonio Enea

    2017-03-01

    We study the background conditions for a bounce uniquely driven by a single scalar field model with a generalized kinetic term K( X), without any additional matter field. At the background level we impose the existence of two turning points where the derivative of the Hubble parameter H changes sign and of a bounce point where the Hubble parameter vanishes. We find the conditions for K( X) and the potential which ensure the above requirements. We then give the examples of two models constructed according to these conditions. One is based on a quadratic K( X), and the other on a K( X) which is avoiding divergences of the second time derivative of the scalar field, which may otherwise occur. An appropriate choice of the initial conditions can lead to a sequence of consecutive bounces, or oscillations of H. In the region where these models have a constant potential they are adiabatic on any scale and because of this they may not conserve curvature perturbations on super-horizon scales. While at the perturbation level one class of models is free from ghosts and singularities of the classical equations of motion, in general gradient instabilities are present around the bounce time, because the sign of the squared speed of sound is opposite to the sign of the time derivative of H. We discuss how this kind of instabilities could be avoided by modifying the Lagrangian by introducing Galilean terms in order to prevent a negative squared speed of sound around the bounce.

  2. The Adiabatic Fast Passage magnet for Ultracold Neutron spin manipulation

    NASA Astrophysics Data System (ADS)

    Blatnik, Marie; UCNA Collaboration; UCNB Collaboration

    2014-09-01

    The Ultracold Neutron source at the Los Alamos Neutron Science Center is used to investigate the weak interaction of the Standard Model through the decay of the free neutron, such as a precise measurement of the correlations between the decaying neutron's polarization and the emitted electron or neutrino momenta (the A and B correlation coefficients). These angular correlation measurements require precise control of the neutron polarization. The neutrons are polarized by a 7-Tesla magnetic field, and their spins are flipped by a radio-frequency birdcage resonator using the adiabatic fast passage technique in a 1-Tesla field. Precise knowledge of their polarization and spin-flip efficiency requires the achievement of greater than roughly 99% polarization and 99.9% spin-flipper efficiency. This target performance requires precise characterization and control of the static magnetic field profile in the spinflipper, and the resonator must produce large, uniform radio-frequency fields at 29.2 MHz. Studies of the static field profile in our spin-flipper and measurements of the performance of a modified resonator utilizing silver-coated components will be presented along with its impact of our measurements and the system's performance optimization.

  3. On reaching the adiabatic limit in multi-field inflation

    SciTech Connect

    Renaux-Petel, Sébastien; Turzyński, Krzysztof E-mail: krzysztof-jan.turzynski@fuw.edu.pl

    2015-06-01

    We calculate the scalar spectral index n{sub s} and the tensor-to-scalar ratio r in a class of recently proposed two-field no-scale inflationary models in supergravity. We show that, in order to obtain correct predictions, it is crucial to take into account the coupling between the curvature and the isocurvature perturbations induced by the noncanonical form of the kinetic terms. This coupling enhances the curvature perturbation and suppresses the resulting tensor-to-scalar ratio to the per mille level even for values of the slow-roll parameter ε ∼ 0.01. Beyond these particular models, we emphasise that multifield models of inflation are a priori not predictive, unless one supplies a prescription for the post-inflationary era, or an adiabatic limit is reached before the end of inflation. We examine the conditions that enabled us to actually derive predictions in the models under study, by analysing the various contributions to the effective isocurvature mass in general two-field inflationary models. In particular, we point out a universal geometrical contribution that is important at the end of inflation, and which can be directly extracted from the inflationary Lagrangian, independently of a specific trajectory. Eventually, we point out that spectator fields can lead to oscillatory features in the time-dependent power spectra at the end of inflation. We demonstrate how these features can be model semi-analytically as well as the theoretical uncertainties they can entail.

  4. Salt pill design and fabrication for adiabatic demagnetization refrigerators

    NASA Astrophysics Data System (ADS)

    Shirron, Peter J.; McCammon, Dan

    2014-07-01

    The performance of an adiabatic demagnetization refrigerator (ADR) is critically dependent on the design and construction of the salt pills that produce cooling. In most cases, the primary goal is to obtain the largest cooling capacity at the low temperature end of the operating range. The realizable cooling capacity depends on a number of factors, including refrigerant mass, and how efficiently it absorbs heat from the various instrument loads. The design and optimization of “salt pills” for ADR systems depend not only on the mechanical, chemical and thermal properties of the refrigerant, but also on the range of heat fluxes that the salt pill must accommodate. Despite the fairly wide variety of refrigerants available, those used at very low temperature tend to be hydrated salts that require a dedicated thermal bus and must be hermetically sealed, while those used at higher temperature - greater than about 0.5 K - tend to be single- or poly-crystals that have much simpler requirements for thermal and mechanical packaging. This paper presents a summary of strategies and techniques for designing, optimizing and fabricating salt pills for both low- and mid-temperature applications.

  5. Adiabatic demagnetization refrigerator for use in zero gravity

    NASA Technical Reports Server (NTRS)

    Dingus, Michael L.

    1988-01-01

    In this effort, a new design concept for an adiabatic demagnetization refrigerator (ADR) that is capable of operation in zero gravity has been developed. The design uses a vortex precooler to lower the initial temperature of magnetic salt from the initial space superfluid helium dewar of 1.8 K to 1.1 K. This reduces the required maximum magnetic field from 4 Tesla to 2 Tesla. The laboratory prototype vortex precooler reached a minimum temperature of 0.78 K, and had a cooling power of 1 mW at 1.1 K. A study was conducted to determine the dependence of vortex cooler performance on system element configuration. A superfluid filled capillary heat switch was used in the design. The laboratory prototype ADR reached a minimum temperature of 0.107 K, and maintained temperatures below 0.125 K for 90 minutes. Demagnetization was carried out from a maximum field of 2 T. A soft iron shield was developed that reduced the radial central field to 1 gauss at 0.25 meters.

  6. Microwave photon Fock state generation by stimulated Raman adiabatic passage

    PubMed Central

    Premaratne, Shavindra P.; Wellstood, F. C.; Palmer, B. S.

    2017-01-01

    The deterministic generation of non-classical states of light, including squeezed states, Fock states and Bell states, plays an important role in quantum information processing and exploration of the physics of quantum entanglement. Preparation of these non-classical states in resonators is non-trivial due to their inherent harmonicity. Here we use stimulated Raman adiabatic passage to generate microwave photon Fock states in a superconducting circuit quantum electrodynamics system comprised of a fixed-frequency transmon qubit in a three-dimensional microwave cavity at 20 mK. A two-photon process is employed to overcome a first order forbidden transition and the first, second and third Fock states are demonstrated. We also demonstrate how this all-microwave technique can be used to generate an arbitrary superposition of Fock states. Simulations of the system are in excellent agreement with the data and fidelities of 89%, 68% and 43% are inferred for the first three Fock states respectively. PMID:28128205

  7. Thermodynamics analysis of refinery sludge gasification in adiabatic updraft gasifier.

    PubMed

    Ahmed, Reem; Sinnathambi, Chandra M; Eldmerdash, Usama; Subbarao, Duvvuri

    2014-01-01

    Limited information is available about the thermodynamic evaluation for biomass gasification process using updraft gasifier. Therefore, to minimize errors, the gasification of dry refinery sludge (DRS) is carried out in adiabatic system at atmospheric pressure under ambient air conditions. The objectives of this paper are to investigate the physical and chemical energy and exergy of product gas at different equivalent ratios (ER). It will also be used to determine whether the cold gas, exergy, and energy efficiencies of gases may be maximized by using secondary air injected to gasification zone under various ratios (0, 0.5, 1, and 1.5) at optimum ER of 0.195. From the results obtained, it is indicated that the chemical energy and exergy of producer gas are magnified by 5 and 10 times higher than their corresponding physical values, respectively. The cold gas, energy, and exergy efficiencies of DRS gasification are in the ranges of 22.9-55.5%, 43.7-72.4%, and 42.5-50.4%, respectively. Initially, all 3 efficiencies increase until they reach a maximum at the optimum ER of 0.195; thereafter, they decline with further increase in ER values. The injection of secondary air to gasification zone is also found to increase the cold gas, energy, and exergy efficiencies. A ratio of secondary air to primary air of 0.5 is found to be the optimum ratio for all 3 efficiencies to reach the maximum values.

  8. Non-locality, adiabaticity, thermodynamics and electron energy probability functions

    NASA Astrophysics Data System (ADS)

    Boswell, Roderick; Zhang, Yunchao; Charles, Christine; Takahashi, Kazunori

    2016-09-01

    Thermodynamic properties are revisited for electrons that are governed by nonlocal electron energy probability functions in a plasma of low collisionality. Measurements in a laboratory helicon double layer experiment have shown that the effective electron temperature and density show a polytropic correlation with an index of γe = 1 . 17 +/- 0 . 02 along the divergent magnetic field, implying a nearly isothermal plasma (γe = 1) with heat being brought into the system. However, the evolution of electrons along the divergent magnetic field is essentially an adiabatic process, which should have a γe = 5 / 3 . The reason for this apparent contradiction is that the nearly collisionless plasma is very far from local thermodynamic equilibrium and the electrons behave nonlocally. The corresponding effective electron enthalpy has a conservation relation with the potential energy, which verifies that there is no heat transferred into the system during the electron evolution. The electrons are shown in nonlocal momentum equilibrium under the electric field and the gradient of the effective electron pressure. The convective momentum of ions, which can be assumed as a cold species, is determined by the effective electron pressure and the effective electron enthalpy is shown to be the source for ion acceleration. For these nearly collisionless plasmas, the use of traditional thermodynamic concepts can lead to very erroneous conclusions regarding the thermal conductivity.

  9. Adiabatic contraction revisited: Implications for primordial black holes

    NASA Astrophysics Data System (ADS)

    Capela, Fabio; Pshirkov, Maxim; Tinyakov, Peter

    2014-10-01

    We simulate the adiabatic contraction of a dark matter (DM) distribution during the process of the star formation, paying particular attention to the phase space distribution of the DM particles after the contraction. Assuming the initial uniform density and Maxwellian distribution of DM velocities, we find that the number n(r) of DM particles within the radius r scales like n(r)∝r1.5, leading to the DM density profile ρ∝r-1.5, in agreement with the Liouville theorem and previous numerical studies. At the same time, the number of DM particles ν(r) with periastra smaller than r is parametrically larger, ν(r)∝r, implying that many particles contributing at any given moment into the density ρ(r) at small r have very elongated orbits and spend most of their time at distances larger than r. This has implications for the capture of DM by stars in the process of their formation. As a concrete example we consider the case of primordial black holes (PBHs). We show that accounting for very eccentric orbits boosts the amount of captured PBH by a factor of up to 2×103 depending on the PBH mass, improving correspondingly the previously derived constraints on the PBH abundance.

  10. A counterexample and a modification to the adiabatic approximation theorem in quantum mechanics

    NASA Technical Reports Server (NTRS)

    Gingold, H.

    1991-01-01

    A counterexample to the adiabatic approximation theorem is given when degeneracies are present. A formulation of an alternative version is proposed. A complete asymptotic decomposition for n dimensional self-adjoint Hamiltonian systems is restated and used.

  11. Experimental realization of stimulated Raman shortcut-to-adiabatic passage with cold atoms

    PubMed Central

    Du, Yan-Xiong; Liang, Zhen-Tao; Li, Yi-Chao; Yue, Xian-Xian; Lv, Qing-Xian; Huang, Wei; Chen, Xi; Yan, Hui; Zhu, Shi-Liang

    2016-01-01

    Accurate control of a quantum system is a fundamental requirement in many areas of modern science ranging from quantum information processing to high-precision measurements. A significantly important goal in quantum control is preparing a desired state as fast as possible, with sufficiently high fidelity allowed by available resources and experimental constraints. Stimulated Raman adiabatic passage (STIRAP) is a robust way to realize high-fidelity state transfer but it requires a sufficiently long operation time to satisfy the adiabatic criteria. Here we theoretically propose and then experimentally demonstrate a shortcut-to-adiabatic protocol to speed-up the STIRAP. By modifying the shapes of the Raman pulses, we experimentally realize a fast and high-fidelity stimulated Raman shortcut-to-adiabatic passage that is robust against control parameter variations. The all-optical, robust and fast protocol demonstrated here provides an efficient and practical way to control quantum systems. PMID:27511807

  12. Start-up of the reversed-field pinch in an adiabatic manner

    NASA Astrophysics Data System (ADS)

    Caramana, E. J.

    1981-03-01

    Purely adiabatic formation of a reversed-field pinch is examined as a possible means of access to diffuse, stable reversed-field equilibria. Ideal MHD equations describing adiabatic reversed-field pinch formation are solved to obtain the electric fields and plasma density at the wall characteristic of the initial state and the states through which the system must pass adiabatically. It is shown that if the states through which the plasma evolves adiabatically to a final Bessel-function model state decay resistively, the magnetic energy lost is small. The effects of resistive MHD activity analogous to that observed in tokamaks on reversed-field pinch start-up are also considered.

  13. Experimental realization of stimulated Raman shortcut-to-adiabatic passage with cold atoms

    NASA Astrophysics Data System (ADS)

    Du, Yan-Xiong; Liang, Zhen-Tao; Li, Yi-Chao; Yue, Xian-Xian; Lv, Qing-Xian; Huang, Wei; Chen, Xi; Yan, Hui; Zhu, Shi-Liang

    2016-08-01

    Accurate control of a quantum system is a fundamental requirement in many areas of modern science ranging from quantum information processing to high-precision measurements. A significantly important goal in quantum control is preparing a desired state as fast as possible, with sufficiently high fidelity allowed by available resources and experimental constraints. Stimulated Raman adiabatic passage (STIRAP) is a robust way to realize high-fidelity state transfer but it requires a sufficiently long operation time to satisfy the adiabatic criteria. Here we theoretically propose and then experimentally demonstrate a shortcut-to-adiabatic protocol to speed-up the STIRAP. By modifying the shapes of the Raman pulses, we experimentally realize a fast and high-fidelity stimulated Raman shortcut-to-adiabatic passage that is robust against control parameter variations. The all-optical, robust and fast protocol demonstrated here provides an efficient and practical way to control quantum systems.

  14. Deep proton tunneling in the electronically adiabatic and non-adiabatic limits: comparison of the quantum and classical treatment of donor-acceptor motion in a protein environment.

    PubMed

    Benabbas, Abdelkrim; Salna, Bridget; Sage, J Timothy; Champion, Paul M

    2015-03-21

    Analytical models describing the temperature dependence of the deep tunneling rate, useful for proton, hydrogen, or hydride transfer in proteins, are developed and compared. Electronically adiabatic and non-adiabatic expressions are presented where the donor-acceptor (D-A) motion is treated either as a quantized vibration or as a classical "gating" distribution. We stress the importance of fitting experimental data on an absolute scale in the electronically adiabatic limit, which normally applies to these reactions, and find that vibrationally enhanced deep tunneling takes place on sub-ns timescales at room temperature for typical H-bonding distances. As noted previously, a small room temperature kinetic isotope effect (KIE) does not eliminate deep tunneling as a major transport channel. The quantum approach focuses on the vibrational sub-space composed of the D-A and hydrogen atom motions, where hydrogen bonding and protein restoring forces quantize the D-A vibration. A Duschinsky rotation is mandated between the normal modes of the reactant and product states and the rotation angle depends on the tunneling particle mass. This tunnel-mass dependent rotation contributes substantially to the KIE and its temperature dependence. The effect of the Duschinsky rotation is solved exactly to find the rate in the electronically non-adiabatic limit and compared to the Born-Oppenheimer (B-O) approximation approach. The B-O approximation is employed to find the rate in the electronically adiabatic limit, where we explore both harmonic and quartic double-well potentials for the hydrogen atom bound states. Both the electronically adiabatic and non-adiabatic rates are found to diverge at high temperature unless the proton coupling includes the often neglected quadratic term in the D-A displacement from equilibrium. A new expression is presented for the electronically adiabatic tunnel rate in the classical limit for D-A motion that should be useful to experimentalists working near

  15. Deep proton tunneling in the electronically adiabatic and non-adiabatic limits: Comparison of the quantum and classical treatment of donor-acceptor motion in a protein environment

    SciTech Connect

    Benabbas, Abdelkrim; Salna, Bridget; Sage, J. Timothy; Champion, Paul M.

    2015-03-21

    Analytical models describing the temperature dependence of the deep tunneling rate, useful for proton, hydrogen, or hydride transfer in proteins, are developed and compared. Electronically adiabatic and non-adiabatic expressions are presented where the donor-acceptor (D-A) motion is treated either as a quantized vibration or as a classical “gating” distribution. We stress the importance of fitting experimental data on an absolute scale in the electronically adiabatic limit, which normally applies to these reactions, and find that vibrationally enhanced deep tunneling takes place on sub-ns timescales at room temperature for typical H-bonding distances. As noted previously, a small room temperature kinetic isotope effect (KIE) does not eliminate deep tunneling as a major transport channel. The quantum approach focuses on the vibrational sub-space composed of the D-A and hydrogen atom motions, where hydrogen bonding and protein restoring forces quantize the D-A vibration. A Duschinsky rotation is mandated between the normal modes of the reactant and product states and the rotation angle depends on the tunneling particle mass. This tunnel-mass dependent rotation contributes substantially to the KIE and its temperature dependence. The effect of the Duschinsky rotation is solved exactly to find the rate in the electronically non-adiabatic limit and compared to the Born-Oppenheimer (B-O) approximation approach. The B-O approximation is employed to find the rate in the electronically adiabatic limit, where we explore both harmonic and quartic double-well potentials for the hydrogen atom bound states. Both the electronically adiabatic and non-adiabatic rates are found to diverge at high temperature unless the proton coupling includes the often neglected quadratic term in the D-A displacement from equilibrium. A new expression is presented for the electronically adiabatic tunnel rate in the classical limit for D-A motion that should be useful to experimentalists working

  16. Stereo Pair, Pasadena, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This stereoscopic image pair is a perspective view that shows the western part of the city of Pasadena, California, looking north toward the San Gabriel Mountains. Portions of the cities of Altadena and La Canada Flintridge are also shown. The cluster of large buildings left of center, at the base of the mountains, is the Jet Propulsion Laboratory. This image shows the power of combining data from different sources to create planning tools to study problems that affect large urban areas. In addition to the well-known earthquake hazards, Southern California is affected by a natural cycle of fire and mudflows. Data shown in this image can be used to predict both how wildfires spread over the terrain and how mudflows are channeled down the canyons.

    The image was created from three datasets: the Shuttle Radar Topography Mission (SRTM) supplied the elevation, U. S. Geological Survey digital aerial photography provided the image detail, and the Landsat Thematic Mapper provided the color. The United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota, provided the Landsat data and the aerial photography. The image can be viewed in 3-D by viewing the left image with the right eye and the right image with the left eye (cross-eyed viewing), or by downloading and printing the image pair, and viewing them with a stereoscope.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration

  17. High Rayleigh number heat transfer in a horizontal cylinder with adiabatic wall

    NASA Technical Reports Server (NTRS)

    Schiroky, G. H.; Rosenberger, F.

    1984-01-01

    The present investigation is concerned with an experimentally guided approach to the estimation of Nusselt numbers (Nu) at high Rayleigh numbers (Ra) for a cylinder with an adiabatic side wall. The Rayleigh number dependence of the Nusselt number for a horizontal cylinder with an adiabatic wall is presented in a graph. The obtained data are compared with results reported by Shih (1981). Shih has extended a three-term expansion for velocity and temperature distributions reported by Bejan and Tien (1978).

  18. Pygmy stars: first pair.

    PubMed

    Zwicky, F

    1966-07-01

    The binary LP 101-15/16 having the proper motion of 1.62 seconds of arc per year has been studied with the prime-focus spectrograph of the 200-inch (508 cm) telescope. Indications are that LP 101-15/16 is the first pair of pygmy stars ever discovered. One of its components, LP 101-16, is probably a blue pygmy star which is at least four magnitudes fainter than the ordinary white dwarfs. Also, two of the Balmer lines in absorption appear to be displaced toward the red by amounts which indicate the existence of an Einstein gravitational red shift corresponding to about 1000 km sec-1. On the other hand LP 101-15 is red and shows an entirely new type of spectrum, which suggests that it may be a first representative of a type of red pygmy star which is 2.5 magnitudes fainter than the M-type dwarf stars of the main sequence.

  19. Extended Bose-Hubbard model with pair hopping induced by a quadratically coupled optomechanical system

    NASA Astrophysics Data System (ADS)

    Huang, Yue-Xin; Zhou, Xiang-Fa; Guo, Guang-Can; Zhang, Yong-Sheng

    2016-10-01

    We present a scheme to realize the (extended) Bose-Hubbard model in an N -coupled optomechanical system. By treating the cavities as intermediary and eliminating them adiabatically with the condition of large detuning or fast decay, we can obtain the effective Hamiltonian for the N oscillators, with the regular terms in the Bose-Hubbard model, i.e., the pair tunnelings and the density-density interactions. Then we verify and provide the condition for our approximation with numerical results. Due to the existence of the pair tunnelings and the density-density interactions, we can investigate the density wave and supersolid phases in our model. Moreover, we also discuss the competition between the regular tunneling and the pair tunneling.

  20. Creation of a Data Base on Energetic Materials

    DTIC Science & Technology

    1987-08-10

    of Detonation (Detonation Energy) Detonation Products (Explosion Decomposition Formula Products) Decomposition Products Combustion Products Ratio of...impact Adiabatic Flame Temperature sensitivity test) Auto-Ignition Temperature Decomposition Temperature Sympathetic Detonation C-H-N-O Analysis Heat