Observers' measurements in premetric electrodynamics: Time and radar length

NASA Astrophysics Data System (ADS)

Gürlebeck, Norman; Pfeifer, Christian

2018-04-01

The description of an observer's measurement in general relativity and the standard model of particle physics is closely related to the spacetime metric. In order to understand and interpret measurements, which test the metric structure of the spacetime, like the classical Michelson-Morley, Ives-Stilwell, Kennedy-Thorndike experiments or frequency comparison experiments in general, it is necessary to describe them in theories, which go beyond the Lorentzian metric structure. However, this requires a description of an observer's measurement without relying on a metric. We provide such a description of an observer's measurement of the fundamental quantities time and length derived from a premetric perturbation of Maxwell's electrodynamics and a discussion on how these measurements influence classical relativistic observables like time dilation and length contraction. Most importantly, we find that the modification of electrodynamics influences the measurements at two instances: the propagation of light is altered as well as the observer's proper time normalization. When interpreting the results of a specific experiment, both effects cannot be disentangled, in general, and have to be taken into account.

In Appreciation Julian Schwinger: From Nuclear Physics and Quantum Electrodynamics to Source Theory and Beyond

NASA Astrophysics Data System (ADS)

Milton, Kimball A.

2007-01-01

Julian Schwinger’s influence on twentieth-century science is profound and pervasive. He is most famous for his renormalization theory of quantum electrodynamics, for which he shared the Nobel Prize in Physics for 1965 with Richard Feynman and Sin-itiro Tomonaga. This triumph undoubtedly was his most heroic work, but his legacy lives on chiefly through subtle and elegant work in classical electrodynamics, quantum variational principles, proper-time methods, quantum anomalies, dynamical mass generation, partial symmetry, and much more. Starting as just a boy, he rapidly became one of the preeminent nuclear physicists in the world in the late 1930s, led the theoretical development of radar technology at the Massachusetts Institute of Technology during World War II, and soon after the war conquered quantum electrodynamics, becoming the leading quantum-field theorist for two decades, before taking a more iconoclastic route during the last quarter century of his life.

Resonant electrodynamic heating of stellar coronal loops: An LRC circuit analogue

NASA Technical Reports Server (NTRS)

Ionson, J. A.

1980-01-01

The electrodynamic coupling of stellar coronal loops to underlying beta velocity fields. A rigorous analysis revealed that the physics can be represented by a simple yet equivalent LRC circuit analogue. This analogue points to the existence of global structure oscillations which resonantly excite internal field line oscillations at a spatial resonance within the coronal loop. Although the width of this spatial resonance, as well as the induced currents and coronal velocity field, explicitly depend upon viscosity and resistivity, the resonant form of the generalized electrodynamic heating function is virtually independent of irreversibilities. This is a classic feature of high quality resonators that are externally driven by a broad band source of spectral power. Applications to solar coronal loops result in remarkable agreement with observations.

Geometric Algebra for Physicists

NASA Astrophysics Data System (ADS)

Doran, Chris; Lasenby, Anthony

2007-11-01

Preface; Notation; 1. Introduction; 2. Geometric algebra in two and three dimensions; 3. Classical mechanics; 4. Foundations of geometric algebra; 5. Relativity and spacetime; 6. Geometric calculus; 7. Classical electrodynamics; 8. Quantum theory and spinors; 9. Multiparticle states and quantum entanglement; 10. Geometry; 11. Further topics in calculus and group theory; 12. Lagrangian and Hamiltonian techniques; 13. Symmetry and gauge theory; 14. Gravitation; Bibliography; Index.

Quantum-enabled temporal and spectral mode conversion of microwave signals

PubMed Central

Andrews, R. W.; Reed, A. P.; Cicak, K.; Teufel, J. D.; Lehnert, K. W.

2015-01-01

Electromagnetic waves are ideal candidates for transmitting information in a quantum network as they can be routed rapidly and efficiently between locations using optical fibres or microwave cables. Yet linking quantum-enabled devices with cables has proved difficult because most cavity or circuit quantum electrodynamics systems used in quantum information processing can only absorb and emit signals with a specific frequency and temporal envelope. Here we show that the temporal and spectral content of microwave-frequency electromagnetic signals can be arbitrarily manipulated with a flexible aluminium drumhead embedded in a microwave circuit. The aluminium drumhead simultaneously forms a mechanical oscillator and a tunable capacitor. This device offers a way to build quantum microwave networks using separate and otherwise mismatched components. Furthermore, it will enable the preparation of non-classical states of motion by capturing non-classical microwave signals prepared by the most coherent circuit quantum electrodynamics systems. PMID:26617386

Electromagnetic fields with vanishing quantum corrections

NASA Astrophysics Data System (ADS)

Ortaggio, Marcello; Pravda, Vojtěch

2018-04-01

We show that a large class of null electromagnetic fields are immune to any modifications of Maxwell's equations in the form of arbitrary powers and derivatives of the field strength. These are thus exact solutions to virtually any generalized classical electrodynamics containing both non-linear terms and higher derivatives, including, e.g., non-linear electrodynamics as well as QED- and string-motivated effective theories. This result holds not only in a flat or (anti-)de Sitter background, but also in a larger subset of Kundt spacetimes, which allow for the presence of aligned gravitational waves and pure radiation.

Spin Pumping in Electrodynamically Coupled Magnon-Photon Systems.

PubMed

Bai, Lihui; Harder, M; Chen, Y P; Fan, X; Xiao, J Q; Hu, C-M

2015-06-05

We use electrical detection, in combination with microwave transmission, to investigate both resonant and nonresonant magnon-photon coupling at room temperature. Spin pumping in a dynamically coupled magnon-photon system is found to be distinctly different from previous experiments. Characteristic coupling features such as modes anticrossing, linewidth evolution, peculiar line shape, and resonance broadening are systematically measured and consistently analyzed by a theoretical model set on the foundation of classical electrodynamic coupling. Our experimental and theoretical approach paves the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling.

Electrodynamics and Spacetime Geometry: Foundations

NASA Astrophysics Data System (ADS)

Cabral, Francisco; Lobo, Francisco S. N.

2017-02-01

We explore the intimate connection between spacetime geometry and electrodynamics. This link is already implicit in the constitutive relations between the field strengths and excitations, which are an essential part of the axiomatic structure of electromagnetism, clearly formulated via integration theory and differential forms. We review the foundations of classical electromagnetism based on charge and magnetic flux conservation, the Lorentz force and the constitutive relations. These relations introduce the conformal part of the metric and allow the study of electrodynamics for specific spacetime geometries. At the foundational level, we discuss the possibility of generalizing the vacuum constitutive relations, by relaxing the fixed conditions of homogeneity and isotropy, and by assuming that the symmetry properties of the electro-vacuum follow the spacetime isometries. The implications of this extension are briefly discussed in the context of the intimate connection between electromagnetism and the geometry (and causal structure) of spacetime.

Optimal Orbit Maneuvers with Electrodynamic Tethers

DTIC Science & Technology

2006-06-01

orbital elements , which completely describe a unique orbit ; equinoctial elements are not employed but left for future iterations of the formulation...periods in the maneuver. Follow on work, uch as the transformation of this state vector from classical orbital elements to the quinoctial set of...

Quantum dynamical simulations of local field enhancement in metal nanoparticles.

PubMed

Negre, Christian F A; Perassi, Eduardo M; Coronado, Eduardo A; Sánchez, Cristián G

2013-03-27

Field enhancements (Γ) around small Ag nanoparticles (NPs) are calculated using a quantum dynamical simulation formalism and the results are compared with electrodynamic simulations using the discrete dipole approximation (DDA) in order to address the important issue of the intrinsic atomistic structure of NPs. Quite remarkably, in both quantum and classical approaches the highest values of Γ are located in the same regions around single NPs. However, by introducing a complete atomistic description of the metallic NPs in optical simulations, a different pattern of the Γ distribution is obtained. Knowing the correct pattern of the Γ distribution around NPs is crucial for understanding the spectroscopic features of molecules inside hot spots. The enhancement produced by surface plasmon coupling is studied by using both approaches in NP dimers for different inter-particle distances. The results show that the trend of the variation of Γ versus inter-particle distance is different for classical and quantum simulations. This difference is explained in terms of a charge transfer mechanism that cannot be obtained with classical electrodynamics. Finally, time dependent distribution of the enhancement factor is simulated by introducing a time dependent field perturbation into the Hamiltonian, allowing an assessment of the localized surface plasmon resonance quantum dynamics.

An elementary argument for the magnetic field outside a solenoid

NASA Astrophysics Data System (ADS)

Pathak, Aritro

2017-01-01

The evaluation of the magnetic field inside and outside a uniform current density infinite solenoid of uniform cross-section is an elementary problem in classical electrodynamics that all undergraduate Physics students study. Symmetry properties of the cylinder and the judicious use of Ampere’s circuital law leads to correct results; however it does not explain why the field is non zero for a finite length solenoid, and why it vanishes as the solenoid becomes infinitely long. An argument is provided in Farley and Price (2001 Am. J. Phys. 69 751), explaining how the magnetic field behaves outside the solenoid and not too far from it, as a function of the length of the solenoid. A calculation is also outlined for obtaining the field just outside the circular cross section solenoid, in the classic text Classical Electrodynamics by Jackson, 3rd edn (John Wiley and Sons, Inc.), problems 5.3-5.5. The purpose of this paper is to provide an elementary argument for why the field becomes negligible as the length of the solenoid is increased. A quantitative analysis is provided for the field outside the solenoid, at radial distances large compared to the linear dimension of the solenoid cross section.

SIM(1)-VSR Maxwell-Chern-Simons electrodynamics

NASA Astrophysics Data System (ADS)

Bufalo, R.

2016-06-01

In this paper we propose a very special relativity (VSR)-inspired generalization of the Maxwell-Chern-Simons (MCS) electrodynamics. This proposal is based upon the construction of a proper study of the SIM (1)-VSR gauge-symmetry. It is shown that the VSR nonlocal effects present a significant and healthy departure from the usual MCS theory. The classical dynamics is analysed in full detail, by studying the solution for the electric field and static energy for this configuration. Afterwards, the interaction energy between opposite charges is derived and we show that the VSR effects play an important part in obtaining a (novel) finite expression for the static potential.

Constraints on the extremely high-energy cosmic ray accelerators from classical electrodynamics

NASA Astrophysics Data System (ADS)

Aharonian, F. A.; Belyanin, A. A.; Derishev, E. V.; Kocharovsky, V. V.; Kocharovsky, Vl. V.

2002-07-01

We formulate the general requirements, set by classical electrodynamics, on the sources of extremely high-energy cosmic rays (EHECRs). It is shown that the parameters of EHECR accelerators are strongly limited not only by the particle confinement in large-scale magnetic fields or by the difference in electric potentials (generalized Hillas criterion) but also by the synchrotron radiation, the electro-bremsstrahlung, or the curvature radiation of accelerated particles. Optimization of these requirements in terms of an accelerator's size and magnetic field strength results in the ultimate lower limit to the overall source energy budget, which scales as the fifth power of attainable particle energy. Hard γ rays accompanying generation of EHECRs can be used to probe potential acceleration sites. We apply the results to several populations of astrophysical objects-potential EHECR sources-and discuss their ability to accelerate protons to 1020 eV and beyond. The possibility of gain from ultrarelativistic bulk flows is addressed, with active galactic nuclei and gamma-ray bursts being the examples.

Constraints on the extremely high-energy cosmic rays accelerators from classical electrodynamics

NASA Astrophysics Data System (ADS)

Belyanin, A.; Aharonian, F.; Derishev, E.; Kocharovsky, V.; Kocharovsky, V.

We formulate the general requirements, set by classical electrodynamics, to the sources of extremely high-energy cosmic rays (EHECRs). It is shown that the parameters of EHECR accelerators are strongly limited not only by the particle confinement in large-scale magnetic field or by the difference in electric potentials (generalized Hillas criterion), but also by the synchrotron radiation, the electro-bremsstrahlung, or the curvature radiation of accelerated particles. Optimization of these requirements in terms of accelerator's size and magnetic field strength results in the ultimate lower limit to the overall source energy budget, which scales as the fifth power of attainable particle energy. Hard gamma-rays accompanying generation of EHECRs can be used to probe potential acceleration sites. We apply the results to several populations of astrophysical objects - potential EHECR sources - and discuss their ability to accelerate protons to 1020 eV and beyond. A possibility to gain from ultrarelativistic bulk flows is addressed, with Active Galactic Nuclei and Gamma-Ray Bursts being the examples.

Modeling light-induced charge transfer dynamics across a metal-molecule-metal junction: Bridging classical electrodynamics and quantum dynamics

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

Hu, Zixuan; Ratner, Mark A.; Seideman, Tamar, E-mail: t-seideman@northwestern.edu

2014-12-14

We develop a numerical approach for simulating light-induced charge transport dynamics across a metal-molecule-metal conductance junction. The finite-difference time-domain method is used to simulate the plasmonic response of the metal structures. The Huygens subgridding technique, as adapted to Lorentz media, is used to bridge the vastly disparate length scales of the plasmonic metal electrodes and the molecular system, maintaining accuracy. The charge and current densities calculated with classical electrodynamics are transformed to an electronic wavefunction, which is then propagated through the molecular linker via the Heisenberg equations of motion. We focus mainly on development of the theory and exemplify ourmore » approach by a numerical illustration of a simple system consisting of two silver cylinders bridged by a three-site molecular linker. The electronic subsystem exhibits fascinating light driven dynamics, wherein the charge density oscillates at the driving optical frequency, exhibiting also the natural system timescales, and a resonance phenomenon leads to strong conductance enhancement.« less

A proposed measurement of optical orbital and spin angular momentum and its implications for photon angular momentum

NASA Astrophysics Data System (ADS)

Leader, Elliot

2018-04-01

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

Energy density and energy flow of plasmonic waves in bilayer graphene

NASA Astrophysics Data System (ADS)

Moradi, Afshin

2017-07-01

The propagation of plasmonic waves in bilayer graphene is studied based on the classical electrodynamics. The interactions between conduction electrons confined to move on the surface of each layer are taken into account via the two-dimensional linearized hydrodynamic model. The energy theorem of electrodynamics is cast in a form which yields expressions for energy density and energy flow of p-polarized surface plasmon polariton waves in bilayer graphene. Numerical results show that the presence of two layers causes the appearance of two branches in the dispersion relation that introduce alterations in the physical behavior of the energy, power flow and the energy transport velocity, in comparison with the results of monolayer graphene.

Derivation of the cut-off length from the quantum quadratic enhancement of a mass in vacuum energy constant Lambda

NASA Astrophysics Data System (ADS)

Fukushima, Kimichika; Sato, Hikaru

2018-04-01

Ultraviolet self-interaction energies in field theory sometimes contain meaningful physical quantities. The self-energies in such as classical electrodynamics are usually subtracted from the rest mass. For the consistent treatment of energies as sources of curvature in the Einstein field equations, this study includes these subtracted self-energies into vacuum energy expressed by the constant Lambda (used in such as Lambda-CDM). In this study, the self-energies in electrodynamics and macroscopic classical Einstein field equations are examined, using the formalisms with the ultraviolet cut-off scheme. One of the cut-off formalisms is the field theory in terms of the step-function-type basis functions, developed by the present authors. The other is a continuum theory of a fundamental particle with the same cut-off length. Based on the effectiveness of the continuum theory with the cut-off length shown in the examination, the dominant self-energy is the quadratic term of the Higgs field at a quantum level (classical self-energies are reduced to logarithmic forms by quantum corrections). The cut-off length is then determined to reproduce today's tiny value of Lambda for vacuum energy. Additionally, a field with nonperiodic vanishing boundary conditions is treated, showing that the field has no zero-point energy.

Does Bohm's Quantum Force Have a Classical Origin?

NASA Astrophysics Data System (ADS)

Lush, David C.

2016-08-01

In the de Broglie-Bohm formulation of quantum mechanics, the electron is stationary in the ground state of hydrogenic atoms, because the quantum force exactly cancels the Coulomb attraction of the electron to the nucleus. In this paper it is shown that classical electrodynamics similarly predicts the Coulomb force can be effectively canceled by part of the magnetic force that occurs between two similar particles each consisting of a point charge moving with circulatory motion at the speed of light. Supposition of such motion is the basis of the Zitterbewegung interpretation of quantum mechanics. The magnetic force between two luminally-circulating charges for separation large compared to their circulatory motions contains a radial inverse square law part with magnitude equal to the Coulomb force, sinusoidally modulated by the phase difference between the circulatory motions. When the particles have equal mass and their circulatory motions are aligned but out of phase, part of the magnetic force is equal but opposite the Coulomb force. This raises a possibility that the quantum force of Bohmian mechanics may be attributable to the magnetic force of classical electrodynamics. It is further shown that relative motion between the particles leads to modulation of the magnetic force with spatial period equal to the de Broglie wavelength.

Does Light from Steady Sources Bear Any Observable Imprint of the Dispersive Intergalactic Medium?

NASA Astrophysics Data System (ADS)

Lieu, Richard; Duan, Lingze

2018-02-01

There has recently been some interest in the prospect of detecting ionized intergalactic baryons by examining the properties of incoherent light from background cosmological sources, namely quasars. Although the paper by Lieu et al. proposed a way forward, it was refuted by the later theoretical work of Hirata & McQuinn and the observational study of Hales et al. In this paper we investigate in detail the manner in which incoherent radiation passes through a dispersive medium both from the frameworks of classical and quantum electrodynamics, leading us to conclude that the premise of Lieu et al. would only work if the pulses involved are genuinely classical ones containing many photons per pulse; unfortunately, each photon must not be treated as a pulse that is susceptible to dispersive broadening. We are nevertheless able to change the tone of the paper at this juncture by pointing out that because current technology allows one to measure the phase of individual modes of radio waves from a distant source, the most reliable way of obtaining irrefutable evidence of dispersion, namely via the detection of its unique signature of a quadratic spectral phase, may well be already accessible. We demonstrate how this technique is only applied to measure the column density of the ionized intergalactic medium.

Distributions in Spherical Coordinates with Applications to Classical Electrodynamics

ERIC Educational Resources Information Center

Gsponer, Andre

2007-01-01

A general and rigorous method to deal with singularities at the origin of a polar coordinate system is presented. Its power derives from a clear distinction between the radial distance and the radial coordinate variable, which makes that all delta functions and their derivatives are automatically generated, and ensures that the Gauss theorem is…

Global solutions to the electrodynamic two-body problem on a straight line

NASA Astrophysics Data System (ADS)

Bauer, G.; Deckert, D.-A.; Dürr, D.; Hinrichs, G.

2017-06-01

The classical electrodynamic two-body problem has been a long standing open problem in mathematics. For motion constrained to the straight line, the interaction is similar to that of the two-body problem of classical gravitation. The additional complication is the presence of unbounded state-dependent delays in the Coulomb forces due to the finiteness of the speed of light. This circumstance renders the notion of local solutions meaningless, and therefore, straightforward ODE techniques cannot be applied. Here, we study the time-symmetric case, i.e., the Fokker-Schwarzschild-Tetrode (FST) equations, comprising both advanced and retarded delays. We extend the technique developed in Deckert and Hinrichs (J Differ Equ 260:6900-6929, 2016), where existence of FST solutions was proven on the half line, to ensure global existence—a result that had been obtained by Bauer (Ein Existenzsatz für die Wheeler-Feynman-Elektrodynamik, Herbert Utz Verlag, München, 1997). Due to the novel technique, the presented proof is shorter and more transparent but also relies on the idea to employ asymptotic data to characterize solutions.

Is the Lorentz signature of the metric of spacetime electromagnetic in origin?

NASA Astrophysics Data System (ADS)

Itin, Yakov; Hehl, Friedrich W.

2004-07-01

We formulate a premetric version of classical electrodynamics in terms of the excitation H=( H, D) and the field strength F=( E, B). A local, linear, and symmetric spacetime relation between H and F is assumed. It yields, if electric/magnetic reciprocity is postulated, a Lorentzian metric of spacetime thereby excluding Euclidean signature (which is, nevertheless, discussed in some detail). Moreover, we determine the Dufay law (repulsion of like charges and attraction of opposite ones), the Lenz rule (the relative sign in Faraday's law), and the sign of the electromagnetic energy. In this way, we get a systematic understanding of the sign rules and the sign conventions in electrodynamics. The question in the title of the paper is answered affirmatively.

Pair production in classical Stueckelberg-Horwitz-Piron electrodynamics

NASA Astrophysics Data System (ADS)

Land, Martin

2015-05-01

We calculate pair production from bremsstrahlung as a classical effect in Stueckelberg-Horwitz electrodynamics. In this framework, worldlines are traced out dynamically through the evolution of events xμ(τ) parameterized by a chronological time τ that is independent of the spacetime coordinates. These events, defined in an unconstrained 8D phase space, interact through five τ-dependent gauge fields induced by the event evolution. The resulting theory differs in its underlying mechanics from conventional electromagnetism, but coincides with Maxwell theory in an equilibrium limit. In particular, the total mass-energy-momentum of particles and fields is conserved, but the mass-shell constraint is lifted from individual interacting events, so that the Feynman-Stueckelberg interpretation of pair creation/annihilation is implemented in classical mechanics. We consider a three-stage interaction which when parameterized by the laboratory clock x0 appears as (1) particle-1 scatters on a heavy nucleus to produce bremsstrahlung, (2) the radiation field produces a particle/antiparticle pair, (3) the antiparticle is annihilated with particle-2 in the presence of a second heavy nucleus. When parameterized in chronological time τ, the underlying process develops as (1) particle-2 scatters on the second nucleus and begins evolving backward in time with negative energy, (2) particle-1 scatters on the first nucleus and releases bremsstrahlung, (3) particle-2 absorbs radiation which returns it to forward time evolution with positive energy.

Theorem: A Static Magnetic N-pole Becomes an Oscillating Electric N-pole in a Cosmic Axion Field

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

Hill, Christopher T.

We show for the classical Maxwell equations, including the axion electromagnetic anomaly source term, that a cosmic axion field induces an oscillating electric N-moment for any static magnetic N-moment. This is a straightforward result, accessible to anyone who has taken a first year graduate course in electrodynamics.

Local U(2,2) symmetry in relativistic quantum mechanics

NASA Astrophysics Data System (ADS)

Finster, Felix

1998-12-01

Local gauge freedom in relativistic quantum mechanics is derived from a measurement principle for space and time. For the Dirac equation, one obtains local U(2,2) gauge transformations acting on the spinor index of the wave functions. This local U(2,2) symmetry allows a unified description of electrodynamics and general relativity as a classical gauge theory.

Born-Infeld magnetars: larger than classical toroidal magnetic fields and implications for gravitational-wave astronomy

NASA Astrophysics Data System (ADS)

Pereira, Jonas P.; Coelho, Jaziel G.; de Lima, Rafael C. R.

2018-05-01

Magnetars are neutron stars presenting bursts and outbursts of X- and soft-gamma rays that can be understood with the presence of very large magnetic fields. In this setting, nonlinear electrodynamics should be taken into account for a more accurate description of such compact systems. We study that in the context of ideal magnetohydrodynamics and make a realization of our analysis to the case of the well known Born-Infeld (BI) electromagnetism in order to come up with some of its astrophysical consequences. We focus here on toroidal magnetic fields as motivated by already known magnetars with low dipolar magnetic fields and their expected relevance in highly magnetized stars. We show that BI electrodynamics leads to larger toroidal magnetic fields when compared to Maxwell's electrodynamics. Hence, one should expect higher production of gravitational waves (GWs) and even more energetic giant flares from nonlinear stars. Given current constraints on BI's scale field, giant flare energetics and magnetic fields in magnetars, we also find that the maximum magnitude of magnetar ellipticities should be 10^{-6}-10^{-5}. Besides, BI electrodynamics may lead to a maximum increase of order 10-20% of the GW energy radiated from a magnetar when compared to Maxwell's, while much larger percentages may arise for other physically motivated scenarios. Thus, nonlinear theories of the electromagnetism might also be probed in the near future with the improvement of GW detectors.

The radiation impedance of an electrodynamic tether with end connectors

NASA Technical Reports Server (NTRS)

Hastings, Daniel E.; Wang, J.

1987-01-01

Electrodynamic tethers are wires deployed across the earth's geomagnetic field through which a current is flowing. The radiation impedance of a tether with end connectors carrying an ac current is computed from classical antenna theory. This simulates the use of a tether on a space structure. It is shown that the current flow pattern at the tether connector is critical to determining the overall radiation impedance. If the tether makes direct electrical contact with the ionosphere then radiation impedances of the order of several thousand Ohms can be expected. If the only electrical contact is through the end connectors then the impedance is only a few Ohms for a dc current rising to several tens of Ohms for an ac current with frequencies in the whistler range.

Middle atmospheric electrodynamics

NASA Technical Reports Server (NTRS)

Kelley, M. C.

1983-01-01

A review is presented of the advances made during the last few years with respect to the study of the electrodynamics in the earth's middle atmosphere. In a report of the experimental work conducted, attention is given to large middle atmospheric electric fields, the downward coupling of high altitude processes into the middle atmosphere, and upward coupling of tropospheric processes into the middle atmosphere. It is pointed out that new developments in tethered balloons and superpressure balloons should greatly increase the measurement duration of earth-ionospheric potential measurements and of stratospheric electric field measurements in the next few years. Theoretical work considered provides an excellent starting point for study of upward coupling of transient and dc electric fields. Hays and Roble (1979) were the first to construct a model which included orographic features as well as the classical thunderstorm generator.

CORRIGENDUM: Editorial note

NASA Astrophysics Data System (ADS)

Rae, A. I. M.

2002-07-01

The first sentence of this comment should read as follows: It has been drawn to our attention that a comment published in our January issue [1] contains the statement that `the functions {1, sin2 α, cos 2α}...are clearly linearly independent...'. References [1]Figueroa-Navarro C 2002 A comment on Gluskin's note on J D Jackson's Classical Electrodynamics Eur. J. Phys. 23 L1-3

Kohn-Sham approach to quantum electrodynamical density-functional theory: Exact time-dependent effective potentials in real space.

PubMed

Flick, Johannes; Ruggenthaler, Michael; Appel, Heiko; Rubio, Angel

2015-12-15

The density-functional approach to quantum electrodynamics extends traditional density-functional theory and opens the possibility to describe electron-photon interactions in terms of effective Kohn-Sham potentials. In this work, we numerically construct the exact electron-photon Kohn-Sham potentials for a prototype system that consists of a trapped electron coupled to a quantized electromagnetic mode in an optical high-Q cavity. Although the effective current that acts on the photons is known explicitly, the exact effective potential that describes the forces exerted by the photons on the electrons is obtained from a fixed-point inversion scheme. This procedure allows us to uncover important beyond-mean-field features of the effective potential that mark the breakdown of classical light-matter interactions. We observe peak and step structures in the effective potentials, which can be attributed solely to the quantum nature of light; i.e., they are real-space signatures of the photons. Our findings show how the ubiquitous dipole interaction with a classical electromagnetic field has to be modified in real space to take the quantum nature of the electromagnetic field fully into account.

Polarizabilities and van der Waals C{sub 6} coefficients of fullerenes from an atomistic electrodynamics model: Anomalous scaling with number of carbon atoms

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

Saidi, Wissam A., E-mail: alsaidi@pitt.edu; Norman, Patrick

2016-07-14

The van der Waals C{sub 6} coefficients of fullerenes are shown to exhibit an anomalous dependence on the number of carbon atoms N such that C{sub 6} ∝ N{sup 2.2} as predicted using state-of-the-art quantum mechanical calculations based on fullerenes with small sizes, and N{sup 2.75} as predicted using a classical-metallic spherical-shell approximation of the fullerenes. We use an atomistic electrodynamics model where each carbon atom is described by a polarizable object to extend the quantum mechanical calculations to larger fullerenes. The parameters of this model are optimized to describe accurately the static and complex polarizabilities of the fullerenes bymore » fitting against accurate ab initio calculations. This model shows that C{sub 6} ∝ N{sup 2.8}, which is supportive of the classical-metallic spherical-shell approximation. Additionally, we show that the anomalous dependence of the polarizability on N is attributed to the electric charge term, while the dipole–dipole term scales almost linearly with the number of carbon atoms.« less

One-loop quantum gravity repulsion in the early Universe.

PubMed

Broda, Bogusław

2011-03-11

Perturbative quantum gravity formalism is applied to compute the lowest order corrections to the classical spatially flat cosmological Friedmann-Lemaître-Robertson-Walker solution (for the radiation). The presented approach is analogous to the approach applied to compute quantum corrections to the Coulomb potential in electrodynamics, or rather to the approach applied to compute quantum corrections to the Schwarzschild solution in gravity. In the framework of the standard perturbative quantum gravity, it is shown that the corrections to the classical deceleration, coming from the one-loop graviton vacuum polarization (self-energy), have (UV cutoff free) opposite to the classical repulsive properties which are not negligible in the very early Universe. The repulsive "quantum forces" resemble those known from loop quantum cosmology.

Speeds of light in Stueckelberg-Horwitz-Piron electrodynamics

NASA Astrophysics Data System (ADS)

Land, Martin

2017-05-01

Stueckelberg-Horwitz-Piron (SHP) electrodynamics formalizes the distinction between coordinate time (measured by laboratory clocks) and chronology (temporal ordering) by defining 4D spacetime events x μ as functions of an external evolution parameter τ. As τ grows monotonically, the spacetime evolution of classical events x μ (τ) trace out particle worldlines dynamically and induce the five U(1) gauge potentials through which events interact. In analogy with the constant c that associates a unit of length x 0 with intervals of time t in standard relativity, we introduce a constant c 5 associated with the external time τ. Whereas the nonrelativistic limit of special relativity can be found by taking c → ∞, we show that 5D SHP goes over to an equilibrium state of Maxwell theory in the limit c 5 → 0. Thus, the dimensionless ratio c 5/c parameterizes the deviation of SHP from standard electrodynamics, in particular the coupling of events. Put another way, Maxwell theory can be understood as currents and fields relaxing to an equilibrium independent of chronological time as c 5 τ slows to zero. We find that taking 0 < c 5/c < 1 enables the resolution of several longstanding difficulties in SHP theory.

Parametric resonance in quantum electrodynamics vacuum birefringence

NASA Astrophysics Data System (ADS)

Arza, Ariel; Elias, Ricardo Gabriel

2018-05-01

Vacuum magnetic birefringence is one of the most interesting nonlinear phenomena in quantum electrodynamics because it is a pure photon-photon result of the theory and it directly signalizes the violation of the classical superposition principle of electromagnetic fields in the full quantum theory. We perform analytical and numerical calculations when an electromagnetic wave interacts with an oscillating external magnetic field. We find that in an ideal cavity, when the external field frequency is around the electromagnetic wave frequency, the normal and parallel components of the wave suffer parametric resonance at different rates, producing a vacuum birefringence effect growing in time. We also study the case where there is no cavity and the oscillating magnetic field is spatially localized in a region of length L . In both cases we find also a rotation of the elliptical axis.

Classical BV Theories on Manifolds with Boundary

NASA Astrophysics Data System (ADS)

Cattaneo, Alberto S.; Mnev, Pavel; Reshetikhin, Nicolai

2014-12-01

In this paper we extend the classical BV framework to gauge theories on spacetime manifolds with boundary. In particular, we connect the BV construction in the bulk with the BFV construction on the boundary and we develop its extension to strata of higher codimension in the case of manifolds with corners. We present several examples including electrodynamics, Yang-Mills theory and topological field theories coming from the AKSZ construction, in particular, the Chern-Simons theory, the BF theory, and the Poisson sigma model. This paper is the first step towards developing the perturbative quantization of such theories on manifolds with boundary in a way consistent with gluing.

Quasinormal modes of scale dependent black holes in (1 +2 )-dimensional Einstein-power-Maxwell theory

NASA Astrophysics Data System (ADS)

Rincón, Ángel; Panotopoulos, Grigoris

2018-01-01

We study for the first time the stability against scalar perturbations, and we compute the spectrum of quasinormal modes of three-dimensional charged black holes in Einstein-power-Maxwell nonlinear electrodynamics assuming running couplings. Adopting the sixth order Wentzel-Kramers-Brillouin (WKB) approximation we investigate how the running of the couplings change the spectrum of the classical theory. Our results show that all modes corresponding to nonvanishing angular momentum are unstable both in the classical theory and with the running of the couplings, while the fundamental mode can be stable or unstable depending on the running parameter and the electric charge.

Preparation of two-qubit steady entanglement through driving a single qubit.

PubMed

Shen, Li-Tuo; Chen, Rong-Xin; Yang, Zhen-Biao; Wu, Huai-Zhi; Zheng, Shi-Biao

2014-10-15

Inspired by a recent paper [J. Phys. B 47, 055502 (2014)], we propose a simplified scheme to generate and stabilize a Bell state of two qubits coupled to a resonator. In the scheme only one qubit is needed to be driven by external classical fields, and the entanglement dynamics is independent of the phases of these fields and insensitive to their amplitude fluctuations. This is a distinct advantage as compared with the previous ones that require each qubit to be addressed by well-controlled classical fields. Numerical simulation shows that the steady singlet state with high fidelity can be obtained with currently available techniques in circuit quantum electrodynamics.

Trouble with the Lorentz law of force: incompatibility with special relativity and momentum conservation.

PubMed

Mansuripur, Masud

2012-05-11

The Lorentz law of force is the fifth pillar of classical electrodynamics, the other four being Maxwell's macroscopic equations. The Lorentz law is the universal expression of the force exerted by electromagnetic fields on a volume containing a distribution of electrical charges and currents. If electric and magnetic dipoles also happen to be present in a material medium, they are traditionally treated by expressing the corresponding polarization and magnetization distributions in terms of bound-charge and bound-current densities, which are subsequently added to free-charge and free-current densities, respectively. In this way, Maxwell's macroscopic equations are reduced to his microscopic equations, and the Lorentz law is expected to provide a precise expression of the electromagnetic force density on material bodies at all points in space and time. This Letter presents incontrovertible theoretical evidence of the incompatibility of the Lorentz law with the fundamental tenets of special relativity. We argue that the Lorentz law must be abandoned in favor of a more general expression of the electromagnetic force density, such as the one discovered by Einstein and Laub in 1908. Not only is the Einstein-Laub formula consistent with special relativity, it also solves the long-standing problem of "hidden momentum" in classical electrodynamics.

Derivation of the Lorentz force law, the magnetic field concept and the Faraday Lenz and magnetic Gauss laws using an invariant formulation of the Lorentz transformation

NASA Astrophysics Data System (ADS)

Field, J. H.

2006-06-01

It is demonstrated how the right-hand sides of the Lorentz transformation equations may be written, in a Lorentz-invariant manner, as 4-vector scalar products. This implies the existence of invariant length intervals analogous to invariant proper time intervals. An important distinction between the physical meanings of the space time and energy momentum 4-vectors is pointed out. The formalism is shown to provide a short derivation of the Lorentz force law of classical electrodynamics, and the conventional definition of the magnetic field, in terms of spatial derivatives of the 4-vector potential, as well as the Faraday Lenz law and the Gauss law for magnetic fields. The connection between the Gauss law for the electric field and the electrodynamic Ampère law, due to the 4-vector character of the electromagnetic potential, is also pointed out.

Black hole solution in the framework of arctan-electrodynamics

NASA Astrophysics Data System (ADS)

Kruglov, S. I.

An arctan-electrodynamics coupled with the gravitational field is investigated. We obtain the regular black hole solution that at r →∞ gives corrections to the Reissner-Nordström solution. The corrections to Coulomb’s law at r →∞ are found. We evaluate the mass of the black hole that is a function of the dimensional parameter β introduced in the model. The magnetically charged black hole was investigated and we have obtained the magnetic mass of the black hole and the metric function at r →∞. The regular black hole solution is obtained at r → 0 with the de Sitter core. We show that there is no singularity of the Ricci scalar for electrically and magnetically charged black holes. Restrictions on the electric and magnetic fields are found that follow from the requirement of the absence of superluminal sound speed and the requirement of a classical stability.

On the self-force in Bopp-Podolsky electrodynamics

NASA Astrophysics Data System (ADS)

Gratus, Jonathan; Perlick, Volker; Tucker, Robin W.

2015-10-01

In the classical vacuum Maxwell-Lorentz theory the self-force of a charged point particle is infinite. This makes classical mass renormalization necessary and, in the special relativistic domain, leads to the Abraham-Lorentz-Dirac equation of motion possessing unphysical run-away and pre-acceleration solutions. In this paper we investigate whether the higher-order modification of classical vacuum electrodynamics suggested by Bopp, Landé, Thomas and Podolsky in the 1940s, can provide a solution to this problem. Since the theory is linear, Green-function techniques enable one to write the field of a charged point particle on Minkowski spacetime as an integral over the particle’s history. By introducing the notion of timelike worldlines that are ‘bounded away from the backward light-cone’ we are able to prescribe criteria for the convergence of such integrals. We also exhibit a timelike worldline yielding singular fields on a lightlike hyperplane in spacetime. In this case the field is mildly singular at the event where the particle crosses the hyperplane. Even in the case when the Bopp-Podolsky field is bounded, it exhibits a directional discontinuity as one approaches the point particle. We describe a procedure for assigning a value to the field on the particle worldline which enables one to define a finite Lorentz self-force. This is explicitly derived leading to an integro-differential equation for the motion of the particle in an external electromagnetic field. We conclude that any worldline solutions to this equation belonging to the categories discussed in the paper have continuous four-velocities.

Classical and non-classical effective medium theories: New perspectives

NASA Astrophysics Data System (ADS)

Tsukerman, Igor

2017-05-01

Future research in electrodynamics of periodic electromagnetic composites (metamaterials) can be expected to produce sophisticated homogenization theories valid for any composition and size of the lattice cell. The paper outlines a promising path in that direction, leading to non-asymptotic and nonlocal homogenization models, and highlights aspects of homogenization that are often overlooked: the finite size of the sample and the role of interface boundaries. Classical theories (e.g. Clausius-Mossotti, Maxwell Garnett), while originally derived from a very different set of ideas, fit well into the proposed framework. Nonlocal effects can be included in the model, making an order-of-magnitude accuracy improvements possible. One future challenge is to determine what effective parameters can or cannot be obtained for a given set of constituents of a metamaterial lattice cell, thereby delineating the possible from the impossible in metamaterial design.

Electrodynamic Tether Operations beyond the Ionosphere in the Low-Density Magnetosphere

NASA Technical Reports Server (NTRS)

Stone, Nobie H.

2007-01-01

In the classical concept for the operation of electrodynamic tethers in space, a voltage is generated across the tether, either by the tether's orbital motion through the earth's planetary magnetic field or by a power supply; electrons are then collected from the ionospheric plasma at the positive pole; actively emitted back into space at the negative pole; and the circuit is closed by currents driven through the ambient conducting ionosphere. This concept has been proven to work in space by the Tethered Satellite System TSS-1 and TSS-1R Space Shuttle missions; and the Plasma Motor-Generator (PMG) tether flight experiment. However, it limits electrodynamic tether operations to the F-region of the ionosphere where the plasma density is sufficient to conduct the required currents--in other words, between altitudes of approximately 200 to 1000 km in sunlight. In the earth's shadow, the ionospheric density drops precipitously and tether operations, using the above approach, are not effective--even within this altitude range. There are numerous missions that require in-space propulsion in the Earth's shadow and/or outside of the above altitude range. This paper will, therefore, present the fundamentals of a concept that would allow electrodynamic tethers to operate almost anywhere within the magnetosphere, the region of space containing the earth's planetary magnetic field. In other words, because operations would be virtually independent of any ambient plasma, the range of electrodynamic operations would be extended into the earth's shadow and out to synchronous orbit--forty times the present operational range. The key to this concept is the active generation of plasma at each pole of the tether so that current generation ,does not depend on the conductivity of the ambient ionosphere. Arguments will be presented, based on ,existing flight data, which shed light on the behavior of charge emissions in space and show the plausibility of the concept.

Electromagnetic scattering and emission by a fixed multi-particle object in local thermal equilibrium: General formalism.

PubMed

Mishchenko, Michael I

2017-10-01

The majority of previous studies of the interaction of individual particles and multi-particle groups with electromagnetic field have focused on either elastic scattering in the presence of an external field or self-emission of electromagnetic radiation. In this paper we apply semi-classical fluctuational electrodynamics to address the ubiquitous scenario wherein a fixed particle or a fixed multi-particle group is exposed to an external quasi-polychromatic electromagnetic field as well as thermally emits its own electromagnetic radiation. We summarize the main relevant axioms of fluctuational electrodynamics, formulate in maximally rigorous mathematical terms the general scattering-emission problem for a fixed object, and derive such fundamental corollaries as the scattering-emission volume integral equation, the Lippmann-Schwinger equation for the dyadic transition operator, the multi-particle scattering-emission equations, and the far-field limit. We show that in the framework of fluctuational electrodynamics, the computation of the self-emitted component of the total field is completely separated from that of the elastically scattered field. The same is true of the computation of the emitted and elastically scattered components of quadratic/bilinear forms in the total electromagnetic field. These results pave the way to the practical computation of relevant optical observables.

Evaluation of parameters for particles acceleration by the zero-point field of quantum electrodynamics

NASA Technical Reports Server (NTRS)

Rueda, A.

1985-01-01

That particles may be accelerated by vacuum effects in quantum field theory has been repeatedly proposed in the last few years. A natural upshot of this is a mechanism for cosmic rays (CR) primaries acceleration. A mechanism for acceleration by the zero-point field (ZPE) when the ZPE is taken in a realistic sense (in opposition to a virtual field) was considered. Originally the idea was developed within a semiclassical context. The classical Einstein-Hopf model (EHM) was used to show that free isolated electromagnrtically interacting particles performed a random walk in phase space and more importantly in momentum space when submitted to the perennial action of the so called classical electromagnrtic ZPE.

United States Air Force Summer Faculty Research Program. 1985 Technical Report. Volume 3.

DTIC Science & Technology

1985-12-01

Canadian Journal of Microbiology 30:63-67. Jones, W.D. and J. Greenberg. Modification of methods used in bacteriophage typing of Mycobacterium tuberculosis ...Sands Missile Range, New Mexico . 7. Nicolaides, J.D., "Free Flight Missile Dynamics," Lecture Notes, Depurtnent of Aero-Space Engineering, University of...Univ. of New Mexico , Albuquerque, New Mexico , August 1967, pp. 123-138. 2. Jackson, J.D., Classical Electrodynamics, New York, New York, John Wiley

Evanescent radiation, quantum mechanics and the Casimir effect

NASA Technical Reports Server (NTRS)

Schatten, Kenneth H.

1989-01-01

An attempt to bridge the gap between classical and quantum mechanics and to explain the Casimir effect is presented. The general nature of chaotic motion is discussed from two points of view: the first uses catastrophe theory and strange attractors to describe the deterministic view of this motion; the underlying framework for chaos in these classical dynamic systems is their extreme sensitivity to initial conditions. The second interpretation refers to randomness associated with probabilistic dynamics, as for Brownian motion. The present approach to understanding evanescent radiation and its relation to the Casimir effect corresponds to the first interpretation, whereas stochastic electrodynamics corresponds to the second viewpoint. The nonlinear behavior of the electromagnetic field is also studied. This well-understood behavior is utilized to examine the motions of two orbiting charges and shows a closeness between the classical behavior and the quantum uncertainty principle. The evanescent radiation is used to help explain the Casimir effect.

Exploring Ultrahigh-Intensity Laser-Plasma Interaction Physics with QED Particle-in-Cell Simulations

NASA Astrophysics Data System (ADS)

Luedtke, S. V.; Yin, L.; Labun, L. A.; Albright, B. J.; Stark, D. J.; Bird, R. F.; Nystrom, W. D.; Hegelich, B. M.

2017-10-01

Next generation high-intensity lasers are reaching intensity regimes where new physics-quantum electrodynamics (QED) corrections to otherwise classical plasma dynamics-becomes important. Modeling laser-plasma interactions in these extreme settings presents a challenge to traditional particle-in-cell (PIC) codes, which either do not have radiation reaction or include only classical radiation reaction. We discuss a semi-classical approach to adding quantum radiation reaction and photon production to the PIC code VPIC. We explore these intensity regimes with VPIC, compare with results from the PIC code PSC, and report on ongoing work to expand the capability of VPIC in these regimes. This work was supported by the U.S. DOE, Los Alamos National Laboratory Science program, LDRD program, NNSA (DE-NA0002008), and AFOSR (FA9550-14-1-0045). HPC resources provided by TACC, XSEDE, and LANL Institutional Computing.

Exact solutions to the Mo-Papas and Landau-Lifshitz equations

NASA Astrophysics Data System (ADS)

Rivera, R.; Villarroel, D.

2002-10-01

Two exact solutions of the Mo-Papas and Landau-Lifshitz equations for a point charge in classical electrodynamics are presented here. Both equations admit as an exact solution the motion of a charge rotating with constant speed in a circular orbit. These equations also admit as an exact solution the motion of two identical charges rotating with constant speed at the opposite ends of a diameter. These exact solutions allow one to obtain, starting from the equation of motion, a definite formula for the rate of radiation. In both cases the rate of radiation can also be obtained, with independence of the equation of motion, from the well known fields of a point charge, that is, from the Maxwell equations. The rate of radiation obtained from the Mo-Papas equation in the one-charge case coincides with the rate of radiation that comes from the Maxwell equations; but in the two-charge case the results do not coincide. On the other hand, the rate of radiation obtained from the Landau-Lifshitz equation differs from the one that follows from the Maxwell equations in both the one-charge and two-charge cases. This last result does not support a recent statement by Rohrlich in favor of considering the Landau-Lifshitz equation as the correct and exact equation of motion for a point charge in classical electrodynamics.

Geometrical aspects in optical wave-packet dynamics.

PubMed

Onoda, Masaru; Murakami, Shuichi; Nagaosa, Naoto

2006-12-01

We construct a semiclassical theory for propagation of an optical wave packet in a nonconducting medium with a periodic structure of dielectric permittivity and magnetic permeability, i.e., a nonconducting photonic crystal. We employ a quantum-mechanical formalism in order to clarify its link to those of electronic systems. It involves the geometrical phase, i.e., Berry's phase, in a natural way, and describes an interplay between orbital motion and internal rotation. Based on the above theory, we discuss the geometrical aspects of the optical Hall effect. We also consider a reduction of the theory to a system without periodic structure and apply it to the transverse shift of an optical beam at an interface reflection or refraction. For a generic incident beam with an arbitrary polarization, an identical result for the transverse shift of each reflected or transmitted beam is given by the following different approaches: (i) analytic evaluation of wave-packet dynamics, (ii) total angular momentum (TAM) conservation for individual photons, and (iii) numerical simulation of wave-packet dynamics. It is consistent with a result by classical electrodynamics. This means that the TAM conservation for individual photons is already taken into account in wave optics, i.e., classical electrodynamics. Finally, we show an application of our theory to a two-dimensional photonic crystal, and propose an optimal design for the enhancement of the optical Hall effect in photonic crystals.

Self field electromagnetism and quantum phenomena

NASA Astrophysics Data System (ADS)

Schatten, Kenneth H.

1994-07-01

Quantum Electrodynamics (QED) has been extremely successful inits predictive capability for atomic phenomena. Thus the greatest hope for any alternative view is solely to mimic the predictive capability of quantum mechanics (QM), and perhaps its usefulness will lie in gaining a better understanding of microscopic phenomena. Many ?paradoxes? and problematic situations emerge in QED. To combat the QED problems, the field of Stochastics Electrodynamics (SE) emerged, wherein a random ?zero point radiation? is assumed to fill all of space in an attmept to explain quantum phenomena, without some of the paradoxical concerns. SE, however, has greater failings. One is that the electromagnetic field energy must be infinit eto work. We have examined a deterministic side branch of SE, ?self field? electrodynamics, which may overcome the probelms of SE. Self field electrodynamics (SFE) utilizes the chaotic nature of electromagnetic emissions, as charges lose energy near atomic dimensions, to try to understand and mimic quantum phenomena. These fields and charges can ?interact with themselves? in a non-linear fashion, and may thereby explain many quantum phenomena from a semi-classical viewpoint. Referred to as self fields, they have gone by other names in the literature: ?evanesccent radiation?, ?virtual photons?, and ?vacuum fluctuations?. Using self fields, we discuss the uncertainty principles, the Casimir effects, and the black-body radiation spectrum, diffraction and interference effects, Schrodinger's equation, Planck's constant, and the nature of the electron and how they might be understood in the present framework. No new theory could ever replace QED. The self field view (if correct) would, at best, only serve to provide some understanding of the processes by which strange quantum phenomena occur at the atomic level. We discuss possible areas where experiments might be employed to test SFE, and areas where future work may lie.

Laser opacity in underdense preplasma of solid targets due to quantum electrodynamics effects

NASA Astrophysics Data System (ADS)

Wang, W.-M.; Gibbon, P.; Sheng, Z.-M.; Li, Y.-T.; Zhang, J.

2017-07-01

We investigate how next-generation laser pulses at 10 -200 PW interact with a solid target in the presence of a relativistically underdense preplasma produced by amplified spontaneous emission (ASE). Laser hole boring and relativistic transparency are strongly restrained due to the generation of electron-positron pairs and γ -ray photons via quantum electrodynamics (QED) processes. A pair plasma with a density above the initial preplasma density is formed, counteracting the electron-free channel produced by hole boring. This pair-dominated plasma can block laser transport and trigger an avalanchelike QED cascade, efficiently transferring the laser energy to the photons. This renders a 1 -μ m scale-length, underdense preplasma completely opaque to laser pulses at this power level. The QED-induced opacity therefore sets much higher contrast requirements for such a pulse in solid-target experiments than expected by classical plasma physics. Our simulations show, for example, that proton acceleration from the rear of a solid with a preplasma would be strongly impaired.

John Wheeler, 1933 - 1959: Particles and Weapons

NASA Astrophysics Data System (ADS)

Ford, Kenneth

2009-05-01

During the early part of his career, John Archibald Wheeler made an astonishing number of contributions to nuclear and particle physics, as well as to classical electrodynamics, often in collaboration with another physicist. He was also a major contributor to the Manhattan Project (in Chicago and Hanford rather than Los Alamos), and, following World War II, became an influential scientific cold warrior. His early achievements in physics include the calculated scattering of light by light (with Gregory Breit), the prediction of nuclear rotational states (with Edward Teller), the theory of fission (with Niels Bohr), action-at-a-distance electrodynamics (with Richard Feynman), the theory of positronium, the universal weak interaction (with Jayme Tiomno), and the proposed use of the muon as a nuclear probe particle. He gained modest fame as the person who identified xenon 135 as a reactor poison. His Project Matterhorn contributed significantly to the design of the H bomb, and his Project 137, which he had hoped would flower into a major defense lab, served as the precursor to the Jason group.

Absorbing Boundary Conditions in Quantum Relativistic Mechanics for Spinless Particles Subject to a Classical Electromagnetic Field

NASA Astrophysics Data System (ADS)

Sater, Julien

The theory of Artificial Boundary Conditions described by Antoine et al. [2,4-6] for the Schrodinger equation is applied to the Klein-Gordon (KG) in two-dimensions (2-D) for spinless particles subject to electromagnetic fields. We begin by providing definitions for a basic understanding of the theory of operators, differential geometry and wave front sets needed to discuss the factorization theorem thanks to Nirenberg and Hormander [14, 16]. The laser-free Klein-Gordon equation in 1-D is then discussed, followed by the case including electrodynamics potentials, concluding with the KG equation in 2-D space with electrodynamics potentials. We then consider numerical simulations of the laser-particle KG equation, which includes a brief analysis of a finite difference scheme. The conclusion integrates a discussion of the numerical results, the successful completion of the objective set forth, a declaration of the unanswered encountered questions and a suggestion of subjects for further research.

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

Guzatov, D. V., E-mail: dm-guzatov@mail.ru

Analytic expressions for the radiative and nonradiative decay rates for an electric quadrupole source (atom, molecule) in the vicinity of a spherical particle (dielectric, metal) have been derived and analyzed within the classical electrodynamics. It has been shown that the highest increase in the decay rates appears in the quasi-static case, when the wavelength of the transition in question is much larger than the characteristic size of the system formed by the particle and the quadrupole. Asymptotic expressions for the decay rates have been derived for this case.

A theoretical investigation of single-molecule fluorescence detection on thin metallic layers.

PubMed

Enderlein, J

2000-04-01

In the present paper, the excitation and detection of single-molecule fluorescence over thin metallic films is studied theoretically within the framework of classical electrodynamics. The model takes into account the specific conditions of surface plasmon-assisted optical excitation, fluorescence quenching by the metal film, and detection geometry. Extensive numerical results are presented for gold, silver, and aluminum films, showing the detectable fluorescence intensities and their dependence on film thickness and the fluorescent molecule's position under optimal excitation conditions.

Few-electron Qubits in Silicon Quantum Electronic Devices

DTIC Science & Technology

2014-09-01

Jackson. Classical electrodynamics. Wiley, 1999. [60] C. Fasth, A. Fuhrer, L. Samuelson, Vitaly N . Golovach, and Daniel Loss. Phys. Rev. Lett., 98...quantum dots. Among these systems, Si is very promising since it can be isotopically purified to eliminate -1 n ...-tno:>tinn J...,~~~+;..,., f1.,JrJ...1.2]. Taking t he AlGaAs/ GaAs system as an example, the most crucial part of t he heterostructure is t he interface between t he n -type AlGaAs and

Analogy between electromagnetic potentials and wave-like dynamic variables with connections to quantum theory

NASA Astrophysics Data System (ADS)

Yang, Chen

2018-05-01

The transitions from classical theories to quantum theories have attracted many interests. This paper demonstrates the analogy between the electromagnetic potentials and wave-like dynamic variables with their connections to quantum theory for audiences at advanced undergraduate level and above. In the first part, the counterpart relations in the classical electrodynamics (e.g. gauge transform and Lorenz condition) and classical mechanics (e.g. Legendre transform and free particle condition) are presented. These relations lead to similar governing equations of the field variables and dynamic variables. The Lorenz gauge, scalar potential and vector potential manifest a one-to-one similarity to the action, Hamiltonian and momentum, respectively. In the second part, the connections between the classical pictures of electromagnetic field and particle to quantum picture are presented. By characterising the states of electromagnetic field and particle via their (corresponding) variables, their evolution pictures manifest the same algebraic structure (isomorphic). Subsequently, pictures of the electromagnetic field and particle are compared to the quantum picture and their interconnections are given. A brief summary of the obtained results are presented at the end of the paper.

From Waves to Particle Tracks and Quantum Probabilities

NASA Astrophysics Data System (ADS)

Falkenburg, Brigitte

Here, the measurement methods for identifying massive charged particles are investigated. They have been used from early cosmic ray studies up to the present day. Laws such as the classical Lorentz force and Einstein's relativistic kinematics were established before the rise of quantum mechanics. Later, it became crucial to measure the energy loss of charged particles in matter. In 1930, Bethe developed a semi-classical model based on the quantum mechanics of scattering. In the early 1930s, he and others calculated the passage of charged particles through matter including pair creation and bremsstrahlung. Due to missing trust in quantum electrodynamics, however, only semi-empirical methods were employed in order to estimate the mass and charge from the features of particle tracks. In 1932, Anderson inserted a lead plate into the cloud chamber in order to determine the flight direction and charge of the `positive electron'. In the 1940s, nuclear emulsions helped to resolve puzzles about particle identification and quantum electrodynamics. Later, the measurement theory was extended in a cumulative process by adding conservation laws for dynamic properties, probabilistic quantum formulas for resonances, scattering cross sections, etc. The measurement method was taken over from cosmic ray studies to the era of particle accelerators, and finally taken back from there to astroparticle physics. The measurement methods remained the same, but in the transition from particle to astroparticle physics the focus of interest shifted. Indeed, the experimental methods of both fields explore the grounds of `new physics' in complementary ways.

Inflation and acceleration of the universe by nonlinear magnetic monopole fields

NASA Astrophysics Data System (ADS)

Övgün, A.

2017-02-01

Despite impressive phenomenological success, cosmological models are incomplete without an understanding of what happened at the big bang singularity. Maxwell electrodynamics, considered as a source of the classical Einstein field equations, leads to the singular isotropic Friedmann solutions. In the context of Friedmann-Robertson-Walker (FRW) spacetime, we show that singular behavior does not occur for a class of nonlinear generalizations of the electromagnetic theory for strong fields. A new mathematical model is proposed for which the analytical nonsingular extension of FRW solutions is obtained by using the nonlinear magnetic monopole fields.

Dark matter and weak signals of quantum spacetime

NASA Astrophysics Data System (ADS)

Doplicher, Sergio; Fredenhagen, Klaus; Morsella, Gerardo; Pinamonti, Nicola

2017-03-01

In physically motivated models of quantum spacetime, a U (1 ) gauge theory turns into a U (∞ ) gauge theory; hence, free classical electrodynamics is no longer free and neutral fields may have electromagnetic interactions. We discuss the last point for scalar fields, as a way to possibly describe dark matter; we have in mind the gravitational collapse of binary systems or future applications to self-gravitating Bose-Einstein condensates as possible sources of evidence of quantum gravitational phenomena. The effects considered so far, however, seem too faint to be detectable at present.

Relativistic impulse dynamics.

PubMed

Swanson, Stanley M

2011-08-01

Classical electrodynamics has some annoying rough edges. The self-energy of charges is infinite without a cutoff. The calculation of relativistic trajectories is difficult because of retardation and an average radiation reaction term. By reconceptuallizing electrodynamics in terms of exchanges of impulses rather than describing it by forces and potentials, we eliminate these problems. A fully relativistic theory using photonlike null impulses is developed. Numerical calculations for a two-body, one-impulse-in-transit model are discussed. A simple relationship between center-of-mass scattering angle and angular momentum was found. It reproduces the Rutherford cross section at low velocities and agrees with the leading term of relativistic distinguishable-particle quantum cross sections (Møller, Mott) when the distance of closest approach is larger than the Compton wavelength of the particle. Magnetism emerges as a consequence of viewing retarded and advanced interactions from the vantage point of an instantaneous radius vector. Radiation reaction becomes the local conservation of energy-momentum between the radiating particle and the emitted impulse. A net action is defined that could be used in developing quantum dynamics without potentials. A reinterpretation of Newton's laws extends them to relativistic motion.

Multiscale Electrodynamics/Time-Dependent Density Functional Theory Modeling of Coupled Plasmon/Molecule Excitations

NASA Astrophysics Data System (ADS)

Lopata, Kenneth; Smith, Holden

The coupled dynamics of molecular chromophores and plasmons at surface of metal nanostructures are important for a range of processes such as molecular sensing, light harvesting, and near-field photochemistry. Modeling these dynamics from first principles, however, is challenging, as the large system sizes precludes a purely quantum mechanical treatment. In this talk I will present an approach based on propagating the plasmonic currents and fields using electrodynamics (finite-difference time-domain) with each chromophore described using an isolated quantum sub-region embedded in the overall classical background. This approach can be readily parallelized over these quantum regions, which enables large multiscale simulations of tens or hundreds of dyes, each of which is described individually by real-time time-dependent density functional theory. Application to gold nanoparticles coated with malachite green and rhodamine 6G monolayers shows good agreement with experimentally measured coupling spectra, including the polariton peaks, as well as the plasmon and molecular depletions. This research was supported by the Louisiana Board of Regents Research Competitiveness Subprogram under Contract Number LEQSF(2014-17)-RD-A-0.

X-ray phase-contrast imaging: the quantum perspective

NASA Astrophysics Data System (ADS)

Slowik, J. M.; Santra, R.

2013-08-01

Time-resolved phase-contrast imaging using ultrafast x-ray sources is an emerging method to investigate ultrafast dynamical processes in matter. Schemes to generate attosecond x-ray pulses have been proposed, bringing electronic timescales into reach and emphasizing the demand for a quantum description. In this paper, we present a method to describe propagation-based x-ray phase-contrast imaging in nonrelativistic quantum electrodynamics. We explain why the standard scattering treatment via Fermi’s golden rule cannot be applied. Instead, the quantum electrodynamical treatment of phase-contrast imaging must be based on a different approach. It turns out that it is essential to select a suitable observable. Here, we choose the quantum-mechanical Poynting operator. We determine the expectation value of our observable and demonstrate that the leading order term describes phase-contrast imaging. It recovers the classical expression of phase-contrast imaging. Thus, it makes the instantaneous electron density of non-stationary electronic states accessible to time-resolved imaging. Interestingly, inelastic (Compton) scattering does automatically not contribute in leading order, explaining the success of the semiclassical description.

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

Zadora, A. S., E-mail: as.zadora@physics.msu.ru

The objective of the present study is to consider in more detail the exotic color-charge-glow effect discovered recently and to analyze its possible physical manifestations associated with the treatment of ensembles of color-charged particles at a classical level. The ways in which this effect may appear in arbitrary systems consisting of pointlike massive particles and admitting the partition into elementary configurations like color charges and color dipoles are studied. The possible influence of this effect on particle dynamics (in particular, on gluon distributions) is also examined. Particle collisions at a given impact parameters are considered for a natural regularization ofmore » emerging expressions. It is shown that, in the case of reasonable impact-parameter values, collisions may proceed in the electrodynamic mode, in which case the charge-glow contribution to field strengths is suppressed in relation to what we have in the electrodynamic picture. From an analysis of the color-echo situation, it follows that the above conclusion remains valid for more complicated particle configurations as well, since hard gluon fields may arise only owing to a direct collision rather than owing to any echo-like effects.« less

Experimental Quantum Randomness Processing Using Superconducting Qubits

NASA Astrophysics Data System (ADS)

Yuan, Xiao; Liu, Ke; Xu, Yuan; Wang, Weiting; Ma, Yuwei; Zhang, Fang; Yan, Zhaopeng; Vijay, R.; Sun, Luyan; Ma, Xiongfeng

2016-07-01

Coherently manipulating multipartite quantum correlations leads to remarkable advantages in quantum information processing. A fundamental question is whether such quantum advantages persist only by exploiting multipartite correlations, such as entanglement. Recently, Dale, Jennings, and Rudolph negated the question by showing that a randomness processing, quantum Bernoulli factory, using quantum coherence, is strictly more powerful than the one with classical mechanics. In this Letter, focusing on the same scenario, we propose a theoretical protocol that is classically impossible but can be implemented solely using quantum coherence without entanglement. We demonstrate the protocol by exploiting the high-fidelity quantum state preparation and measurement with a superconducting qubit in the circuit quantum electrodynamics architecture and a nearly quantum-limited parametric amplifier. Our experiment shows the advantage of using quantum coherence of a single qubit for information processing even when multipartite correlation is not present.

Plasmonic eigenmodes in individual and bow-tie graphene nanotriangles

NASA Astrophysics Data System (ADS)

Wang, Weihua; Christensen, Thomas; Jauho, Antti-Pekka; Thygesen, Kristian S.; Wubs, Martijn; Mortensen, N. Asger

2015-04-01

In classical electrodynamics, nanostructured graphene is commonly modeled by the computationally demanding problem of a three-dimensional conducting film of atomic-scale thickness. Here, we propose an efficient alternative two-dimensional electrostatic approach where all calculation procedures are restricted to the graphene sheet. Furthermore, to explore possible quantum effects, we perform tight-binding calculations, adopting a random-phase approximation. We investigate multiple plasmon modes in 20 nm equilateral triangles of graphene, treating the optical response classically as well as quantum mechanically. Compared to the classical plasmonic spectrum which is ``blind'' to the edge termination, we find that the quantum plasmon frequencies exhibit blueshifts in the case of armchair edge termination of the underlying atomic lattice, while redshifts are found for zigzag edges. Furthermore, we find spectral features in the zigzag case which are associated with electronic edge states not present for armchair termination. Merging pairs of triangles into dimers, plasmon hybridization leads to energy splitting that appears strongest in classical calculations while splitting is lower for armchair edges and even more reduced for zigzag edges. Our various results illustrate a surprising phenomenon: Even 20 nm large graphene structures clearly exhibit quantum plasmonic features due to atomic-scale details in the edge termination.

Relating renormalizability of D-dimensional higher-order electromagnetic and gravitational models to the classical potential at the origin

NASA Astrophysics Data System (ADS)

Accioly, Antonio; Correia, Gilson; de Brito, Gustavo P.; de Almeida, José; Herdy, Wallace

2017-03-01

Simple prescriptions for computing the D-dimensional classical potential related to electromagnetic and gravitational models, based on the functional generator, are built out. These recipes are employed afterward as a support for probing the premise that renormalizable higher-order systems have a finite classical potential at the origin. It is also shown that the opposite of the conjecture above is not true. In other words, if a higher-order model is renormalizable, it is necessarily endowed with a finite classical potential at the origin, but the reverse of this statement is untrue. The systems used to check the conjecture were D-dimensional fourth-order Lee-Wick electrodynamics, and the D-dimensional fourth- and sixth-order gravity models. A special attention is devoted to New Massive Gravity (NMG) since it was the analysis of this model that inspired our surmise. In particular, we made use of our premise to resolve trivially the issue of the renormalizability of NMG, which was initially considered to be renormalizable, but it was shown some years later to be non-renormalizable. We remark that our analysis is restricted to local models in which the propagator has simple and real poles.

On the Lienard-Wiechert potentials

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

Whitney, C.K.

1988-09-01

Very recently, questions have started to surface concerning the well-known Lienard-Wiechert potentials describing relativistically moving point sources in classical electrodynamics. The existence of questions prompts a review of the original derivations by Lienard and Wiechert. These were done at the turn of the present century, and so predate the development of relevant modern techniques from special relativity theory and generalized function theory. Only purely geometric reasoning was used. That reasoning is reviewed here, and a previously unrecognized flaw is noted. When this flaw is remedied, the potentials are slightly altered and become consistent with other new results reported elsewhere.

Dark energy simulacrum in nonlinear electrodynamics

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

Labun, Lance; Rafelski, Johann

2010-03-15

Quasiconstant external fields in nonlinear electromagnetism generate a global contribution proportional to g{sup {mu}{nu}}in the energy-momentum tensor, thus a simulacrum of dark energy. To provide a thorough understanding of the origin and strength of its effects, we undertake a complete theoretical and numerical study of the energy-momentum tensor T{sup {mu}{nu}}for nonlinear electromagnetism. The Euler-Heisenberg nonlinearity due to quantum fluctuations of spinor and scalar matter fields is considered and contrasted with the properties of classical nonlinear Born-Infeld electromagnetism. We address modifications of charged particle kinematics by strong background fields.

Nature of the electromagnetic force between classical magnetic dipoles

NASA Astrophysics Data System (ADS)

Mansuripur, Masud

2017-09-01

The Lorentz force law of classical electrodynamics states that the force 𝑭𝑭 exerted by the magnetic induction 𝑩𝑩 on a particle of charge 𝑞𝑞 moving with velocity 𝑽𝑽 is given by 𝑭𝑭 = 𝑞𝑞𝑽𝑽 × 𝑩𝑩. Since this force is orthogonal to the direction of motion, the magnetic field is said to be incapable of performing mechanical work. Yet there is no denying that a permanent magnet can readily perform mechanical work by pushing/pulling on another permanent magnet or by attracting pieces of magnetizable material such as scrap iron or iron filings. We explain this apparent contradiction by examining the magnetic Lorentz force acting on an Amperian current loop, which is the model for a magnetic dipole. We then extend the discussion by analyzing the Einstein-Laub model of magnetic dipoles in the presence of external magnetic fields.

Optical properties of medium size noble and transition metal nanoparticles

NASA Astrophysics Data System (ADS)

Idrobo, Juan C.; Pantelides, Sokrates T.

2009-03-01

Using first-principles methods within time dependent density functional theory and the local density approximation (TDLDA) the absorption spectra of medium size (˜20-80 atoms) silver, gold and copper nanoparticles have been calculated. The nanoparticles are fcc fragments with different aspect ratios. We find that in the case of Ag nanoparticles is well reproduced by classical electrodynamics theory based in Mie's formalism, using the dielectric function of bulk Ag and taking into account the nanoparticle shape. For the case of Cu and Au, there is a similarity in the overall features of the quantum mechanical and classical spectra, but no detailed agreement. We will discuss the role that the d-electrons among all the different elements and the surface states play in controlling the optical properties of the nanoparticles. This work was supported by GOALI NSF grant (DMR-0513048), DOE, the Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, and Alcoa Inc.

Lorentz-invariant three-vectors and alternative formulation of relativistic dynamics

NASA Astrophysics Data System (ADS)

RÈ©bilas, Krzysztof

2010-03-01

Besides the well-known scalar invariants, there also exist vectorial invariants in special relativity. It is shown that the three-vector (dp⃗/dt)∥+γv(dp⃗/dt)⊥ is invariant under the Lorentz transformation. The subscripts ∥ and ⊥ denote the respective components with respect to the direction of the velocity of the body v⃗, and p⃗ is the relativistic momentum. We show that this vector is equal to a force F⃗R, which satisfies the classical Newtonian law F⃗R=ma⃗R in the instantaneous inertial rest frame of an accelerating body. Therefore, the relation F⃗R=(dp⃗/dt)∥+γv(dp⃗/dt)⊥, based on the Lorentz-invariant vectors, may be used as an invariant (not merely a covariant) relativistic equation of motion in any inertial system of reference. An alternative approach to classical electrodynamics based on the invariant three-vectors is proposed.

Superradiant Quantum Heat Engine.

PubMed

Hardal, Ali Ü C; Müstecaplıoğlu, Özgür E

2015-08-11

Quantum physics revolutionized classical disciplines of mechanics, statistical physics, and electrodynamics. One branch of scientific knowledge however seems untouched: thermodynamics. Major motivation behind thermodynamics is to develop efficient heat engines. Technology has a trend to miniaturize engines, reaching to quantum regimes. Development of quantum heat engines (QHEs) requires emerging field of quantum thermodynamics. Studies of QHEs debate whether quantum coherence can be used as a resource. We explore an alternative where it can function as an effective catalyst. We propose a QHE which consists of a photon gas inside an optical cavity as the working fluid and quantum coherent atomic clusters as the fuel. Utilizing the superradiance, where a cluster can radiate quadratically faster than a single atom, we show that the work output becomes proportional to the square of the number of the atoms. In addition to practical value of cranking up QHE, our result is a fundamental difference of a quantum fuel from its classical counterpart.

Anomalous electrical conductivity of nanoscale colloidal suspensions.

PubMed

Chakraborty, Suman; Padhy, Sourav

2008-10-28

The electrical conductivity of colloidal suspensions containing nanoscale conducting particles is nontrivially related to the particle volume fraction and the electrical double layer thickness. Classical electrochemical models, however, tend to grossly overpredict the pertinent effective electrical conductivity values, as compared to those obtained under experimental conditions. We attempt to address this discrepancy by appealing to the complex interconnection between the aggregation kinetics of the nanoscale particles and the electrodynamics within the double layer. In particular, we model the consequent alterations in the effective electrophoretic mobility values of the suspension by addressing the fundamentals of agglomeration-deagglomeration mechanisms through the pertinent variations in the effective particulate dimensions, solid fractions, as well as the equivalent suspension viscosity. The consequent alterations in the electrical conductivity values provide a substantially improved prediction of the corresponding experimental findings and explain the apparent anomalous behavior predicted by the classical theoretical postulates.

Mixed quantum-classical electrodynamics: Understanding spontaneous decay and zero-point energy

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

Li, Tao E.; Nitzan, Abraham; Sukharev, Maxim

The dynamics of an electronic two-level system coupled to an electromagnetic field are simulated explicitly for one- and three-dimensional systems through semiclassical propagation of the Maxwell-Liouville equations. Here, we consider three flavors of mixed quantum-classical dynamics: (i) the classical path approximation (CPA), (ii) Ehrenfest dynamics, and (iii) symmetrical quasiclassical (SQC) dynamics. Our findings are as follows: (i) The CPA fails to recover a consistent description of spontaneous emission, (ii) a consistent “spontaneous” emission can be obtained from Ehrenfest dynamics, provided that one starts in an electronic superposition state, and (iii) spontaneous emission is always obtained using SQC dynamics. Using themore » SQC and Ehrenfest frameworks, we further calculate the dynamics following an incoming pulse, but here we find very different responses: SQC and Ehrenfest dynamics deviate sometimes strongly in the calculated rate of decay of the transient excited state. Nevertheless, our work confirms the earlier observations by Miller [J. Chem. Phys. 69, 2188 (1978)] that Ehrenfest dynamics can effectively describe some aspects of spontaneous emission and highlights interesting possibilities for studying light-matter interactions with semiclassical mechanics.« less

Mixed quantum-classical electrodynamics: Understanding spontaneous decay and zero-point energy

NASA Astrophysics Data System (ADS)

Li, Tao E.; Nitzan, Abraham; Sukharev, Maxim; Martinez, Todd; Chen, Hsing-Ta; Subotnik, Joseph E.

2018-03-01

The dynamics of an electronic two-level system coupled to an electromagnetic field are simulated explicitly for one- and three-dimensional systems through semiclassical propagation of the Maxwell-Liouville equations. We consider three flavors of mixed quantum-classical dynamics: (i) the classical path approximation (CPA), (ii) Ehrenfest dynamics, and (iii) symmetrical quasiclassical (SQC) dynamics. Our findings are as follows: (i) The CPA fails to recover a consistent description of spontaneous emission, (ii) a consistent "spontaneous" emission can be obtained from Ehrenfest dynamics, provided that one starts in an electronic superposition state, and (iii) spontaneous emission is always obtained using SQC dynamics. Using the SQC and Ehrenfest frameworks, we further calculate the dynamics following an incoming pulse, but here we find very different responses: SQC and Ehrenfest dynamics deviate sometimes strongly in the calculated rate of decay of the transient excited state. Nevertheless, our work confirms the earlier observations by Miller [J. Chem. Phys. 69, 2188 (1978), 10.1063/1.436793] that Ehrenfest dynamics can effectively describe some aspects of spontaneous emission and highlights interesting possibilities for studying light-matter interactions with semiclassical mechanics.

Mixed quantum-classical electrodynamics: Understanding spontaneous decay and zero-point energy

DOE PAGES

Li, Tao E.; Nitzan, Abraham; Sukharev, Maxim; ...

2018-03-12

The dynamics of an electronic two-level system coupled to an electromagnetic field are simulated explicitly for one- and three-dimensional systems through semiclassical propagation of the Maxwell-Liouville equations. Here, we consider three flavors of mixed quantum-classical dynamics: (i) the classical path approximation (CPA), (ii) Ehrenfest dynamics, and (iii) symmetrical quasiclassical (SQC) dynamics. Our findings are as follows: (i) The CPA fails to recover a consistent description of spontaneous emission, (ii) a consistent “spontaneous” emission can be obtained from Ehrenfest dynamics, provided that one starts in an electronic superposition state, and (iii) spontaneous emission is always obtained using SQC dynamics. Using themore » SQC and Ehrenfest frameworks, we further calculate the dynamics following an incoming pulse, but here we find very different responses: SQC and Ehrenfest dynamics deviate sometimes strongly in the calculated rate of decay of the transient excited state. Nevertheless, our work confirms the earlier observations by Miller [J. Chem. Phys. 69, 2188 (1978)] that Ehrenfest dynamics can effectively describe some aspects of spontaneous emission and highlights interesting possibilities for studying light-matter interactions with semiclassical mechanics.« less

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.).

Prequantum classical statistical field theory: background field as a source of everything?

NASA Astrophysics Data System (ADS)

Khrennikov, Andrei

2011-07-01

Prequantum classical statistical field theory (PCSFT) is a new attempt to consider quantum mechanics (QM) as an emergent phenomenon, cf. with De Broglie's "double solution" approach, Bohmian mechanics, stochastic electrodynamics (SED), Nelson's stochastic QM and its generalization by Davidson, 't Hooft's models and their development by Elze. PCSFT is a comeback to a purely wave viewpoint on QM, cf. with early Schrodinger. There is no quantum particles at all, only waves. In particular, photons are simply wave-pulses of the classical electromagnetic field, cf. SED. Moreover, even massive particles are special "prequantum fields": the electron field, the neutron field, and so on. PCSFT claims that (sooner or later) people will be able to measure components of these fields: components of the "photonic field" (the classical electromagnetic field of low intensity), electronic field, neutronic field, and so on. At the moment we are able to produce quantum correlations as correlations of classical Gaussian random fields. In this paper we are interested in mathematical and physical reasons of usage of Gaussian fields. We consider prequantum signals (corresponding to quantum systems) as composed of a huge number of wave-pulses (on very fine prequantum time scale). We speculate that the prequantum background field (the field of "vacuum fluctuations") might play the role of a source of such pulses, i.e., the source of everything.

An eigenvalue approach to quantum plasmonics based on a self-consistent hydrodynamics method

NASA Astrophysics Data System (ADS)

Ding, Kun; Chan, C. T.

2018-02-01

Plasmonics has attracted much attention not only because it has useful properties such as strong field enhancement, but also because it reveals the quantum nature of matter. To handle quantum plasmonics effects, ab initio packages or empirical Feibelman d-parameters have been used to explore the quantum correction of plasmonic resonances. However, most of these methods are formulated within the quasi-static framework. The self-consistent hydrodynamics model offers a reliable approach to study quantum plasmonics because it can incorporate the quantum effect of the electron gas into classical electrodynamics in a consistent manner. Instead of the standard scattering method, we formulate the self-consistent hydrodynamics method as an eigenvalue problem to study quantum plasmonics with electrons and photons treated on the same footing. We find that the eigenvalue approach must involve a global operator, which originates from the energy functional of the electron gas. This manifests the intrinsic nonlocality of the response of quantum plasmonic resonances. Our model gives the analytical forms of quantum corrections to plasmonic modes, incorporating quantum electron spill-out effects and electrodynamical retardation. We apply our method to study the quantum surface plasmon polariton for a single flat interface.

Renormalizable Electrodynamics of Scalar and Vector Mesons. Part II

DOE R&D Accomplishments Database

Salam, Abdus; Delbourgo, Robert

1964-01-01

The "gauge" technique" for solving theories introduced in an earlier paper is applied to scalar and vector electrodynamics. It is shown that for scalar electrodynamics, there is no {lambda}φ*2φ2 infinity in the theory, while with conventional subtractions vector electrodynamics is completely finite. The essential ideas of the gauge technique are explained in section 3, and a preliminary set of rules for finite computation in vector electrodynamics is set out in Eqs. (7.28) - (7.34).

BOOK REVIEW: Mathematica for Theoretical Physics: Electrodynamics, Quantum Mechanics, General Relativity and Fractals

NASA Astrophysics Data System (ADS)

Heusler, Stefan

2006-12-01

The main focus of the second, enlarged edition of the book Mathematica for Theoretical Physics is on computational examples using the computer program Mathematica in various areas in physics. It is a notebook rather than a textbook. Indeed, the book is just a printout of the Mathematica notebooks included on the CD. The second edition is divided into two volumes, the first covering classical mechanics and nonlinear dynamics, the second dealing with examples in electrodynamics, quantum mechanics, general relativity and fractal geometry. The second volume is not suited for newcomers because basic and simple physical ideas which lead to complex formulas are not explained in detail. Instead, the computer technology makes it possible to write down and manipulate formulas of practically any length. For researchers with experience in computing, the book contains a lot of interesting and non-trivial examples. Most of the examples discussed are standard textbook problems, but the power of Mathematica opens the path to more sophisticated solutions. For example, the exact solution for the perihelion shift of Mercury within general relativity is worked out in detail using elliptic functions. The virial equation of state for molecules' interaction with Lennard-Jones-like potentials is discussed, including both classical and quantum corrections to the second virial coefficient. Interestingly, closed solutions become available using sophisticated computing methods within Mathematica. In my opinion, the textbook should not show formulas in detail which cover three or more pages—these technical data should just be contained on the CD. Instead, the textbook should focus on more detailed explanation of the physical concepts behind the technicalities. The discussion of the virial equation would benefit much from replacing 15 pages of Mathematica output with 15 pages of further explanation and motivation. In this combination, the power of computing merged with physical intuition would be of benefit even for newcomers. In summary, this book shows in a convincing manner how classical problems in physics can be attacked with modern computing technology. The second volume is interesting for experienced users of Mathematica. For students, the textbook can be very useful in combination with a seminar.

Quantum-classical transition of photon-Carnot engine induced by quantum decoherence

NASA Astrophysics Data System (ADS)

Quan, H. T.; Zhang, P.; Sun, C. P.

2006-03-01

We study the physical implementation of the photon-Carnot engine (PCE) based on the cavity quantum electrodynamics system [M. O. Scully, M. Suhail Zubairy, G. S. Agarwal, and H. Walther, Science 299, 862 (2003)]. Here we analyze two decoherence mechanisms for the more practical systems of PCE, the dissipation of photon field, and the pure dephasing of the input atoms. As a result we find that (i) the PCE can work well to some extent even in the existence of the cavity loss (photon dissipation) and (ii) the short-time atomic dephasing, which can destroy the PCE, is a fatal problem to be overcome.

Classical field configurations and infrared slavery

NASA Astrophysics Data System (ADS)

Swanson, Mark S.

1987-09-01

The problem of determining the energy of two spinor particles interacting through massless-particle exchange is analyzed using the path-integral method. A form for the long-range interaction energy is obtained by analyzing an abridged vertex derived from the parent theory. This abridged vertex describes the radiation of zero-momentum particles by pointlike sources. A path-integral formalism for calculating the energy of the radiation field associated with this abridged vertex is developed and applications are made to determine the energy necessary for adiabatic separation of two sources in quantum electrodynamics and for an SU(2) Yang-Mills theory. The latter theory is shown to be consistent with confinement via infrared slavery.

G. E. M. Jauncey and the Compton Effect

NASA Astrophysics Data System (ADS)

Jenkin, John

In late 1922 Arthur Holly Compton (1892-1962) discovered that an X-ray quantum of radiation undergoes a discrete change in wavelength when it experiences a billiard-ball collision with a single atomic electron, a phenomenon that became known as the Compton effect and for which he shared the Nobel Prize in Physics for 1927. But for more than five years before he made his discovery, Compton had analyzed X-ray scattering in terms of classical electrodynamics. I suggest that his colleague at Washington University in St. Louis, G. E. M. Jauncey (1888-1947), helped materially to persuade him to embrace the quantum interpretation of his X-ray scattering experiments.

Hybrid plasmonic systems: from optical transparencies to strong coupling and entanglement

NASA Astrophysics Data System (ADS)

Gray, Stephen K.

2018-02-01

Classical electrodynamics and quantum mechanical models of quantum dots and molecules interacting with plasmonic systems are discussed. Calculations show that just one quantum dot interacting with a plasmonic system can lead to interesting optical effects, including optical transparencies and more general Fano resonance features that can be tailored with ultrafast laser pulses. Such effects can occur in the limit of moderate coupling between quantum dot and plasmonic system. The approach to the strong coupling regime is also discussed. In cases with two or more quantum dots within a plasmonic system, the possibility of quantum entanglement mediated through the dissipative plasmonic structure arises.

Regular black holes from semi-classical down to Planckian size

NASA Astrophysics Data System (ADS)

Spallucci, Euro; Smailagic, Anais

In this paper, we review various models of curvature singularity free black holes (BHs). In the first part of the review, we describe semi-classical solutions of the Einstein equations which, however, contains a “quantum” input through the matter source. We start by reviewing the early model by Bardeen where the metric is regularized by-hand through a short-distance cutoff, which is justified in terms of nonlinear electro-dynamical effects. This toy-model is useful to point-out the common features shared by all regular semi-classical black holes. Then, we solve Einstein equations with a Gaussian source encoding the quantum spread of an elementary particle. We identify, the a priori arbitrary, Gaussian width with the Compton wavelength of the quantum particle. This Compton-Gauss model leads to the estimate of a terminal density that a gravitationally collapsed object can achieve. We identify this density to be the Planck density, and reformulate the Gaussian model assuming this as its peak density. All these models, are physically reliable as long as the BH mass is big enough with respect to the Planck mass. In the truly Planckian regime, the semi-classical approximation breaks down. In this case, a fully quantum BH description is needed. In the last part of this paper, we propose a nongeometrical quantum model of Planckian BHs implementing the Holographic Principle and realizing the “classicalization” scenario recently introduced by Dvali and collaborators. The classical relation between the mass and radius of the BH emerges only in the classical limit, far away from the Planck scale.

Hamiltonian structure of classical N-body systems of finite-size particles subject to EM interactions

NASA Astrophysics Data System (ADS)

Cremaschini, C.; Tessarotto, M.

2012-01-01

An open issue in classical relativistic mechanics is the consistent treatment of the dynamics of classical N-body systems of mutually interacting particles. This refers, in particular, to charged particles subject to EM interactions, including both binary interactions and self-interactions ( EM-interacting N- body systems). The correct solution to the question represents an overriding prerequisite for the consistency between classical and quantum mechanics. In this paper it is shown that such a description can be consistently obtained in the context of classical electrodynamics, for the case of a N-body system of classical finite-size charged particles. A variational formulation of the problem is presented, based on the N -body hybrid synchronous Hamilton variational principle. Covariant Lagrangian and Hamiltonian equations of motion for the dynamics of the interacting N-body system are derived, which are proved to be delay-type ODEs. Then, a representation in both standard Lagrangian and Hamiltonian forms is proved to hold, the latter expressed by means of classical Poisson Brackets. The theory developed retains both the covariance with respect to the Lorentz group and the exact Hamiltonian structure of the problem, which is shown to be intrinsically non-local. Different applications of the theory are investigated. The first one concerns the development of a suitable Hamiltonian approximation of the exact equations that retains finite delay-time effects characteristic of the binary interactions and self-EM-interactions. Second, basic consequences concerning the validity of Dirac generator formalism are pointed out, with particular reference to the instant-form representation of Poincaré generators. Finally, a discussion is presented both on the validity and possible extension of the Dirac generator formalism as well as the failure of the so-called Currie "no-interaction" theorem for the non-local Hamiltonian system considered here.

Tunneling decay of false vortices

NASA Astrophysics Data System (ADS)

Lee, Bum-Hoon; Lee, Wonwoo; MacKenzie, Richard; Paranjape, M. B.; Yajnik, U. A.; Yeom, Dong-han

2013-10-01

We consider the decay of vortices trapped in the false vacuum of a theory of scalar electrodynamics in 2+1 dimensions. The potential is inspired by models with intermediate symmetry breaking to a metastable vacuum that completely breaks a U(1) symmetry, while in the true vacuum, the symmetry is unbroken. The false vacuum is unstable through the formation of true vacuum bubbles; however, the rate of decay can be extremely long. On the other hand, the false vacuum can contain metastable vortex solutions. These vortices contain the true vacuum inside in addition to a unit of magnetic flux and the appropriate topologically nontrivial false vacuum outside. We numerically establish the existence of vortex solutions which are classically stable; however, they can decay via tunneling. In general terms, they tunnel to a configuration which is a large, thin-walled vortex configuration that is now classically unstable to the expansion of its radius. We compute an estimate for the tunneling amplitude in the semiclassical approximation. We believe our analysis would be relevant to superconducting thin films or superfluids.

Quantum optical effective-medium theory and transformation quantum optics for metamaterials

NASA Astrophysics Data System (ADS)

Wubs, Martijn; Amooghorban, Ehsan; Zhang, Jingjing; Mortensen, N. Asger

2016-09-01

While typically designed to manipulate classical light, metamaterials have many potential applications for quantum optics as well. We argue why a quantum optical effective-medium theory is needed. We present such a theory for layered metamaterials that is valid for light propagation in all spatial directions, thereby generalizing earlier work for one-dimensional propagation. In contrast to classical effective-medium theory there is an additional effective parameter that describes quantum noise. Our results for metamaterials are based on a rather general Lagrangian theory for the quantum electrodynamics of media with both loss and gain. In the second part of this paper, we present a new application of transformation optics whereby local spontaneous-emission rates of quantum emitters can be designed. This follows from an analysis how electromagnetic Green functions trans- form under coordinate transformations. Spontaneous-emission rates can be either enhanced or suppressed using invisibility cloaks or gradient index lenses. Furthermore, the anisotropic material profile of the cloak enables the directional control of spontaneous emission.

Understanding the Magnetosphere: The Counter-intuitive Simplicity of Cosmic Electrodynamics

NASA Astrophysics Data System (ADS)

Vasyliūnas, V. M.

2008-12-01

Planetary magnetospheres exhibit an amazing variety of phenomena, unlimited in complexity if followed into endlessly fine detail. The challenge of theory is to understand this variety and complexity, ultimately by seeing how the observed effects follow from the basic equations of physics (a point emphasized by Eugene Parker). The basic equations themselves are remarkably simple, only their consequences being exceedingly complex (a point emphasized by Fred Hoyle). In this lecture I trace the development of electrodynamics as an essential ingredient of magnetospheric physics, through the three stages it has undergone to date. Stage I is the initial application of MHD concepts and constraints (sometimes phrased in equivalent single-particle terms). Stage II is the classical formulation of self-consistent coupling between magnetosphere and ionosphere. Stage III is the more recent recognition that properly elucidating time sequence and cause-effect relations requires Maxwell's equations combined with the unique constraints of large-scale plasma. Problems and controversies underlie the transition from each stage to the following. For each stage, there are specific observed aspects of the magnetosphere that can be understood at its level; also, each stage implies a specific way to formulate unresolved questions (particularly important in this age of extensive multi-point observations and ever-more-detailed numerical simulations).

Ultrastrong light fields (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 29 October 2014)

NASA Astrophysics Data System (ADS)

2015-01-01

On 29 October 2014, the scientific session "Super strong light fields" of the Physical Sciences Division (PSD), Russian Academy of Sciences (RAS), was held at the conference hall of the Lebedev Physical Institute, RAS.The agenda of the session announced on the website http://www.gpad.ac.ru of the PSD RAS contains the reports: (1) Bychenkov V Yu (Lebedev Physical Institute, RAS, Moscow) "Laser acceleration of ions: New results and prospects for applications"; (2) Kostyukov I Yu (Institute of Applied Physics, RAS, Nizhnii Novgorod) "Plasma methods for electron acceleration: the state of the art and outlook"; (3) Zheltikov A M (Lomonosov Moscow State University, Moscow) "Nonlinear optics of mid-IR ultrashort pulses"; (4) Narozhnyi N B, Fedotov A M (Moscow Engineering Physics Institute, Nuclear Research University, Moscow) "Quantum electrodynamics cascades in intense laser fields."Papers written on the basis of oral presentations 1-4 are published below. • Laser acceleration of ions: recent results and prospects for applications, V Yu Bychenkov, A V Brantov, E A Govras, V F Kovalev Physics-Uspekhi, 2015, Volume 58, Number 1, Pages 71-81 • Plasma-based methods for electron acceleration: current status and prospects, I Yu Kostyukov, A M Pukhov Physics-Uspekhi, 2015, Volume 58, Number 1, Pages 81-88 • Subterawatt femtosecond pulses in the mid-infrared range: new spatiotemporal dynamics of high-power electromagnetic fields, A V Mitrofanov, D A Sidorov-Biryukov, A A Voronin, A Pugžlys, G Andriukaitis, E A Stepanov, S Ališauskas, T Flöri, A B Fedotov, V Ya Panchenko, A Baltuška, A M Zheltikov Physics-Uspekhi, 2015, Volume 58, Number 1, Pages 89-94 • Quantum-electrodynamic cascades in intense laser fields, N B Narozhny, A M Fedotov Physics-Uspekhi, 2015, Volume 58, Number 1, Pages 95-102

Middle atmosphere electrodynamics: Report of the workshop on the Role of the Electrodynamics of the Middle Atmosphere on Solar Terrestrial Coupling

NASA Technical Reports Server (NTRS)

Maynard, N. C. (Editor)

1979-01-01

Significant deficiencies exist in the present understanding of the basic physical processes taking place within the middle atmosphere (the region between the tropopause and the mesopause), and in the knowledge of the variability of many of the primary parameters that regulate Middle Atmosphere Electrodynamics (MAE). Knowledge of the electrical properties, i.e., electric fields, plasma characteristics, conductivity and currents, and the physical processes that govern them is of fundamental importance to the physics of the region. Middle atmosphere electrodynamics may play a critical role in the electrodynamical aspects of solar-terrestrial relations. As a first step, the Workshop on the Role of the Electrodynamics of the Middle Atmosphere on Solar-Terrestrial Coupling was held to review the present status and define recommendations for future MAE research.

Double-Slit Interference Pattern for a Macroscopic Quantum System

NASA Astrophysics Data System (ADS)

Naeij, Hamid Reza; Shafiee, Afshin

2016-12-01

In this study, we solve analytically the Schrödinger equation for a macroscopic quantum oscillator as a central system coupled to two environmental micro-oscillating particles. Then, the double-slit interference patterns are investigated in two limiting cases, considering the limits of uncertainty in the position probability distribution. Moreover, we analyze the interference patterns based on a recent proposal called stochastic electrodynamics with spin. Our results show that when the quantum character of the macro-system is decreased, the diffraction pattern becomes more similar to a classical one. We also show that, depending on the size of the slits, the predictions of quantum approach could be apparently different with those of the aforementioned stochastic description.

Gamma Rays at Very High Energies

NASA Astrophysics Data System (ADS)

Aharonian, Felix

This chapter presents the elaborated lecture notes on Gamma Rays at Very High Energies given by Felix Aharonian at the 40th Saas-Fee Advanced Course on "Astrophysics at Very High Energies". Any coherent description and interpretation of phenomena related to gammarays requires deep knowledge of many disciplines of physics like nuclear and particle physics, quantum and classical electrodynamics, special and general relativity, plasma physics, magnetohydrodynamics, etc. After giving an introduction to gamma-ray astronomy the author discusses the astrophysical potential of ground-based detectors, radiation mechanisms, supernova remnants and origin of the galactic cosmic rays, TeV emission of young supernova remnants, gamma-emission from the Galactic center, pulsars, pulsar winds, pulsar wind nebulae, and gamma-ray loud binaries.

The first dozen years of the history of ITEP Theoretical Physics Laboratory

NASA Astrophysics Data System (ADS)

Ioffe, B. L.

2013-01-01

The theoretical investigations at ITEP in the years 1945 - 1958 are reviewed. There are exposed the most important theoretical results, obtained in the following branches of physics: (1) the theory of nuclear reactors on thermal neutrons; (2) the hydrogen bomb project ("Tube" in USSR and "Classical Super" in USA); (3) radiation theory; (4) low temperature physics; (5) quantum electrodynamics and quantum field theories; (6) parity violation in weak interactions, the theory of β-decay and other weak processes; (7) strong interaction and nuclear physics. To the review are added the English translations of a few papers, originally published in Russian, but unknown (or almost unknown) to Western readers.

Notes on Born-Infeld-type electrodynamics

NASA Astrophysics Data System (ADS)

Kruglov, S. I.

2017-11-01

We propose a new model of nonlinear electrodynamics (NLED) with three parameters. Born-Infeld (BI) electrodynamics and exponential electrodynamics are particular cases of this model. The phenomenon of vacuum birefringence in the external magnetic field is studied. We show that there is no singularity of the electric field at the origin of point-like charged particles. The corrections to Coulomb’s law at r →∞ are obtained. We calculate the total electrostatic energy of charges, for different parameters of the model, which is finite.

Remarks on Heisenberg-Euler-type electrodynamics

NASA Astrophysics Data System (ADS)

Kruglov, S. I.

2017-05-01

We consider Heisenberg-Euler-type model of nonlinear electrodynamics with two parameters. Heisenberg-Euler electrodynamics is a particular case of this model. Corrections to Coulomb’s law at r →∞ are obtained and energy conditions are studied. The total electrostatic energy of charged particles is finite. The charged black hole solution in the framework of nonlinear electrodynamics is investigated. We find the asymptotic of the metric and mass functions at r →∞. Corrections to the Reissner-Nordström solution are obtained.

The PROPEL Electrodynamic Tether Demonstration Mission

NASA Technical Reports Server (NTRS)

Bilen, Sven G.; Johnson, C. Les; Wiegmann, Bruce M.; Alexander, Leslie; Gilchrist, Brian E.; Hoyt, Robert P.; Elder, Craig H.; Fuhrhop, Keith P.; Scadera, Michael

2012-01-01

The PROPEL ("Propulsion using Electrodynamics") mission will demonstrate the operation of an electrodynamic tether propulsion system in low Earth orbit and advance its technology readiness level for multiple applications. The PROPEL mission has two primary objectives: first, to demonstrate the capability of electrodynamic tether technology to provide robust and safe, near-propellantless propulsion for orbit-raising, de-orbit, plane change, and station keeping, as well as to perform orbital power harvesting and formation flight; and, second, to fully characterize and validate the performance of an integrated electrodynamic tether propulsion system, qualifying it for infusion into future multiple satellite platforms and missions with minimal modification. This paper provides an overview of the PROPEL system and design reference missions; mission goals and required measurements; and ongoing PROPEL mission design efforts.

Introduction to Electrodynamics

NASA Astrophysics Data System (ADS)

Griffiths, David J.

2017-06-01

1. Vector analysis; 2. Electrostatics; 3. Potentials; 4. Electric fields in matter; 5. Magnetostatics; 6. Magnetic fields in matter; 7. Electrodynamics; 8. Conservation laws; 9. Electromagnetic waves; 10. Potentials and fields; 11. Radiation; 12. Electrodynamics and relativity; Appendix A. Vector calculus in curvilinear coordinates; Appendix B. The Helmholtz theorem; Appendix C. Units; Index.

Conceptual Assessment Tool for Advanced Undergraduate Electrodynamics

ERIC Educational Resources Information Center

Baily, Charles; Ryan, Qing X.; Astolfi, Cecilia; Pollock, Steven J.

2017-01-01

As part of ongoing investigations into student learning in advanced undergraduate courses, we have developed a conceptual assessment tool for upper-division electrodynamics (E&M II): the Colorado UppeR-division ElectrodyNamics Test (CURrENT). This is a free response, postinstruction diagnostic with 6 multipart questions, an optional 3-question…

Classical electromagnetic radiation of the Dirac electron

NASA Technical Reports Server (NTRS)

Lanyi, G.

1973-01-01

A wave-function-dependent four-vector potential is added to the Dirac equation in order to achieve conservation of energy and momentum for a Dirac electron and its emitted electromagnetic field. The resultant equation contains solutions which describe transitions between different energy states of the electron. As a consequence it is possible to follow the space-time evolution of such a process. This evolution is shown in the case of the spontaneous emission of an electromagnetic field by an electron bound in a hydrogen-like atom. The intensity of the radiation and the spectral distribution are calculated for transitions between two eigenstates. The theory gives a self-consistent deterministic description of some simple radiation processes without using quantum electrodynamics or the correspondence principle.

Non-linear non-local molecular electrodynamics with nano-optical fields.

PubMed

Chernyak, Vladimir Y; Saurabh, Prasoon; Mukamel, Shaul

2015-10-28

The interaction of optical fields sculpted on the nano-scale with matter may not be described by the dipole approximation since the fields may vary appreciably across the molecular length scale. Rather than incrementally adding higher multipoles, it is advantageous and more physically transparent to describe the optical process using non-local response functions that intrinsically include all multipoles. We present a semi-classical approach for calculating non-local response functions based on the minimal coupling Hamiltonian. The first, second, and third order response functions are expressed in terms of correlation functions of the charge and the current densities. This approach is based on the gauge invariant current rather than the polarization, and on the vector potential rather than the electric and magnetic fields.

Variational tricomplex of a local gauge system, Lagrange structure and weak Poisson bracket

NASA Astrophysics Data System (ADS)

Sharapov, A. A.

2015-09-01

We introduce the concept of a variational tricomplex, which is applicable both to variational and nonvariational gauge systems. Assigning this tricomplex with an appropriate symplectic structure and a Cauchy foliation, we establish a general correspondence between the Lagrangian and Hamiltonian pictures of one and the same (not necessarily variational) dynamics. In practical terms, this correspondence allows one to construct the generating functional of a weak Poisson structure starting from that of a Lagrange structure. As a byproduct, a covariant procedure is proposed for deriving the classical BRST charge of the BFV formalism by a given BV master action. The general approach is illustrated by the examples of Maxwell’s electrodynamics and chiral bosons in two dimensions.

Long-distance Lienard-Wiechert potentials and qq-bar spin dependence

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

Childers, R.W.

1987-12-15

The long-range spin dependence of the qq interaction is considered in a model in which the confining potential is required to be the static limit of retarded scalar and vector potentials analogous to the Lienard-Wiechert potentials of classical electrodynamics. A generalization of Darwin's method is used to obtain the corresponding Hamiltonian. The long-distance spin-dependent interaction is found to be determined completely by only two potentials: namely, the static scalar and vector potentials. This is to be compared with the four potentials required in Eichten and Feinberg's general formulation. Two different solutions are allowed by Gromes's theorem. In one, the scalarmore » potential can be linear; in the other, it must be logarithmic.« less

Hotspot-mediated non-dissipative and ultrafast plasmon passage

NASA Astrophysics Data System (ADS)

Roller, Eva-Maria; Besteiro, Lucas V.; Pupp, Claudia; Khorashad, Larousse Khosravi; Govorov, Alexander O.; Liedl, Tim

2017-08-01

Plasmonic nanoparticles hold great promise as photon handling elements and as channels for coherent transfer of energy and information in future all-optical computing devices. Coherent energy oscillations between two spatially separated plasmonic entities via a virtual middle state exemplify electron-based population transfer, but their realization requires precise nanoscale positioning of heterogeneous particles. Here, we show the assembly and optical analysis of a triple-particle system consisting of two gold nanoparticles with an inter-spaced silver island. We observe strong plasmonic coupling between the spatially separated gold particles, mediated by the connecting silver particle, with almost no dissipation of energy. As the excitation energy of the silver island exceeds that of the gold particles, only quasi-occupation of the silver transfer channel is possible. We describe this effect both with exact classical electrodynamic modelling and qualitative quantum-mechanical calculations. We identify the formation of strong hotspots between all particles as the main mechanism for the lossless coupling and thus coherent ultrafast energy transfer between the remote partners. Our findings could prove useful for quantum gate operations, as well as for classical charge and information transfer processes.

Modelling of auroral electrodynamical processes: Magnetosphere to mesosphere

NASA Technical Reports Server (NTRS)

Chiu, Y. T.; Gorney, D. J.; Kishi, A. M.; Newman, A. L.; Schulz, M.; Walterscheid, R. L.; CORNWALL; Prasad, S. S.

1982-01-01

Research conducted on auroral electrodynamic coupling between the magnetosphere and ionosphere-atmosphere in support of the development of a global scale kinetic plasma theory is reviewed. Topics covered include electric potential structure in the evening sector; morning and dayside auroras; auroral plasma formation; electrodynamic coupling with the thermosphere; and auroral electron interaction with the atmosphere.

The propagator of stochastic electrodynamics

NASA Astrophysics Data System (ADS)

Cavalleri, G.

1981-01-01

The "elementary propagator" for the position of a free charged particle subject to the zero-point electromagnetic field with Lorentz-invariant spectral density ~ω3 is obtained. The nonstationary process for the position is solved by the stationary process for the acceleration. The dispersion of the position elementary propagator is compared with that of quantum electrodynamics. Finally, the evolution of the probability density is obtained starting from an initial distribution confined in a small volume and with a Gaussian distribution in the velocities. The resulting probability density for the position turns out to be equal, to within radiative corrections, to ψψ* where ψ is the Kennard wave packet. If the radiative corrections are retained, the present result is new since the corresponding expression in quantum electrodynamics has not yet been found. Besides preceding quantum electrodynamics for this problem, no renormalization is required in stochastic electrodynamics.

Bekenstein inequalities and nonlinear electrodynamics

NASA Astrophysics Data System (ADS)

Peñafiel, M. L.; Falciano, F. T.

2017-12-01

Bekenstein and Mayo proposed a generalized bound for the entropy, which implies some inequalities between the charge, energy, angular momentum, and size of the macroscopic system. Dain has shown that Maxwell's electrodynamics satisfies all three inequalities. We investigate the validity of these relations in the context of nonlinear electrodynamics and show that Born-Infeld electrodynamics satisfies all of them. However, contrary to the linear theory, there is no rigidity statement in Born-Infeld. We study the physical meaning and the relationship between these inequalities, and in particular, we analyze the connection between the energy-angular momentum inequality and causality.

Research Technology

NASA Image and Video Library

2004-04-15

This is an artist's concept of an orbiting space vehicle in the Jovian system using an electrodynamic tether propellantless propulsion system. Electrodynamic tethers offer the potential to greatly extend and enhance future scientific missions to Jupiter and the Jovian system. Like Earth, Jupiter posses a strong magnetic field and a significant magnetosphere. This may make it feasible to operate electrodynamic tethers for propulsion and power generation.

Implementation Options for the PROPEL Electrodynamic Tether Demonstration Mission

NASA Technical Reports Server (NTRS)

Bilen, Sven G.; Johnson, Les; Gilchrist, Brian E.; Hoyt, Robert P.; Elder, Craig H.; Fuhrhop, Keith P.; Scadera, Michael P.; Stone, Nobie H.

2014-01-01

The PROPEL flight mission concept will demonstrate the safe use of an electrodynamic tether for generating thrust. PROPEL is being designed to be a versatile electrodynamic-tether system for multiple end users and to be flexible with respect to platform. As such, several implementation options are being explored, including a comprehensive mission design for PROPEL with a mission duration of six months; a space demonstration mission concept design with configuration of a pair of tethered satellites, one of which is the Japanese H-II Transfer Vehicle; and an ESPA-based system. We report here on these possible implementation options for PROPEL. electrodynamic tether; PROPEL demonstration mission; propellantless propulsion

Electrodynamic Bare Tether Systems as a Thruster for the Momentum-Exchange/Electrodynamic Reboost(MXER)Project

NASA Technical Reports Server (NTRS)

Khazanov, G. V.; Krivorutsky, E. N.; Gallagher, D. L.

2006-01-01

The concept of electrodynamic tether propulsion has a number of attractive features and has been widely discussed for different applications. Different system designs have been proposed and compared during the last 10 years. In spite of this, the choice of proper design for any particular mission is a unique problem. Such characteristics of tether performance as system acceleration, efficiency, etc., should be calculated and compared on the basis of the known capability of a tether to collect electrical current. We discuss the choice of parameters for circular and tape tethers with regard to the Momentum-Exchange/Electrodynamic Reboost (MXER) tether project.

Structure of Aristotelian electrodynamics

NASA Astrophysics Data System (ADS)

Jacobson, Ted

2015-07-01

Aristotelian electrodynamics (AE) describes the regime of a plasma with a very strong electric field that is not shorted out, with the charge current determined completely by pair production and the balance of the Lorentz 4-force against the curvature radiation reaction. Here it is shown how the principal null directions and associated eigenvalues of the field tensor govern AE, and how force-free electrodynamics arises smoothly from AE when the eigenvalues (and therefore the electric field in some frame) vanish. A criterion for validity of AE and force-free electrodynamics is proposed in terms of a pair of "field curvature scalars" formed from the first derivative of the principal null directions.

Electrodynamic Arrays Having Nanomaterial Electrodes

NASA Technical Reports Server (NTRS)

Trigwell, Steven (Inventor); Biris, Alexandru S. (Inventor); Calle, Carlos I. (Inventor)

2013-01-01

An electrodynamic array of conductive nanomaterial electrodes and a method of making such an electrodynamic array. In one embodiment, a liquid solution containing nanomaterials is deposited as an array of conductive electrodes on a substrate, including rigid or flexible substrates such as fabrics, and opaque or transparent substrates. The nanomaterial electrodes may also be grown in situ. The nanomaterials may include carbon nanomaterials, other organic or inorganic nanomaterials or mixtures.

An Experiment on the Limits of Quantum Electro-dynamics

DOE R&D Accomplishments Database

Barber, W. C.; Richter, B.; Panofsky, W. K. H.; O'Neill, G. K.; Gittelman, B.

1959-06-01

The limitations of previously performed or suggested electrodynamic cutoff experiments are reviewed, and an electron-electron scattering experiment to be performed with storage rings to investigate further the limits of the validity of quantum electrodynamics is described. The foreseen experimental problems are discussed, and the results of the associated calculations are given. The parameters and status of the equipment are summarized. (D.C.W.)

Reduced Order Podolsky Model

NASA Astrophysics Data System (ADS)

Thibes, Ronaldo

2017-02-01

We perform the canonical and path integral quantizations of a lower-order derivatives model describing Podolsky's generalized electrodynamics. The physical content of the model shows an auxiliary massive vector field coupled to the usual electromagnetic field. The equivalence with Podolsky's original model is studied at classical and quantum levels. Concerning the dynamical time evolution, we obtain a theory with two first-class and two second-class constraints in phase space. We calculate explicitly the corresponding Dirac brackets involving both vector fields. We use the Senjanovic procedure to implement the second-class constraints and the Batalin-Fradkin-Vilkovisky path integral quantization scheme to deal with the symmetries generated by the first-class constraints. The physical interpretation of the results turns out to be simpler due to the reduced derivatives order permeating the equations of motion, Dirac brackets and effective action.

Free electron laser and fundamental physics

NASA Astrophysics Data System (ADS)

Dattoli, Giuseppe; Nguyen, Federico

2018-03-01

This review paper is devoted to the understanding of free-electron lasers (FEL) as devices for fundamental physics (FP) studies. After clarifying what FP stands for, we select some aspects of the FEL physics which can be viewed as fundamental. Furthermore, we discuss the perspective uses of the FEL in FP experiments. Regarding the FP aspects of the FEL, we analyze the quantum electrodynamics (QED) nature of the underlying laser mechanism. We look for the truly quantum signature in a process whose phenomenology is dominated by classical effects. As to the use of FEL as a tool for FP experiments we discuss the realization of a device dedicated to the study of non-linear effects in QED such as photon-photon scattering and shining-through-the-wall experiments planned to search for dark matter candidates like axions.

A case study of the cusp electrodynamics by the Aureol-3 satellite - Evidence for FTE signatures?

NASA Technical Reports Server (NTRS)

Bosqued, Jean M.; Berthelier, Annick; Berthelier, Jean J.; Escoubet, Christophe P.

1991-01-01

Particle and field data from a pass of the Aureol-3 satellite through the polar cusp, several minutes after the southward turning of the IMF, are analyzed in detail. Superposed on the classical cusp, characterized by the typical ion and electron precipitations, several very narrow arcs are detected where large fluxes of electrons and ions, accelerated to 2-4 keV, precipitate simultaneously. These localized arcs correspond to the upward current sheets of a succession in latitude of narrow, alternatively upward and downward field-aligned current sheets. The data suggest that the satellite has crossed the ionospheric footprints of 2 adjacent flux transfer events separated by 100-150 km in latitude. Electric spikes and electromagnetic turbulence are typically associated with the region of downward currents.

Electron microscopy of electromagnetic waveforms.

PubMed

Ryabov, A; Baum, P

2016-07-22

Rapidly changing electromagnetic fields are the basis of almost any photonic or electronic device operation. We report how electron microscopy can measure collective carrier motion and fields with subcycle and subwavelength resolution. A collimated beam of femtosecond electron pulses passes through a metamaterial resonator that is previously excited with a single-cycle electromagnetic pulse. If the probing electrons are shorter in duration than half a field cycle, then time-frozen Lorentz forces distort the images quasi-classically and with subcycle time resolution. A pump-probe sequence reveals in a movie the sample's oscillating electromagnetic field vectors with time, phase, amplitude, and polarization information. This waveform electron microscopy can be used to visualize electrodynamic phenomena in devices as small and fast as available. Copyright © 2016, American Association for the Advancement of Science.

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

Sanchez-Monroy, J.A., E-mail: antosan@gmail.com; Quimbay, C.J., E-mail: cjquimbayh@unal.edu.co; Centro Internacional de Fisica, Bogota D.C.

In the context of a semiclassical approach where vectorial gauge fields can be considered as classical fields, we obtain exact static solutions of the SU(N) Yang-Mills equations in an (n+1)-dimensional curved space-time, for the cases n=1,2,3. As an application of the results obtained for the case n=3, we consider the solutions for the anti-de Sitter and Schwarzschild metrics. We show that these solutions have a confining behavior and can be considered as a first step in the study of the corrections of the spectra of quarkonia in a curved background. Since the solutions that we find in this work aremore » valid also for the group U(1), the case n=2 is a description of the (2+1) electrodynamics in the presence of a point charge. For this case, the solution has a confining behavior and can be considered as an application of the planar electrodynamics in a curved space-time. Finally we find that the solution for the case n=1 is invariant under a parity transformation and has the form of a linear confining solution. - Highlights: Black-Right-Pointing-Pointer We study exact static confining solutions of the SU(N) Yang-Mills equations in an (n+1)-dimensional curved space-time. Black-Right-Pointing-Pointer The solutions found are a first step in the study of the corrections on the spectra of quarkonia in a curved background. Black-Right-Pointing-Pointer A expression for the confinement potential in low dimensionality is found.« less

Hybrid Circuit Quantum Electrodynamics: Coupling a Single Silicon Spin Qubit to a Photon

DTIC Science & Technology

2015-01-01

HYBRID CIRCUIT QUANTUM ELECTRODYNAMICS: COUPLING A SINGLE SILICON SPIN QUBIT TO A PHOTON PRINCETON UNIVERSITY JANUARY 2015 FINAL...SILICON SPIN QUBIT TO A PHOTON 5a. CONTRACT NUMBER FA8750-12-2-0296 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Jason R. Petta...architectures. 15. SUBJECT TERMS Quantum Computing, Quantum Hybrid Circuits, Quantum Electrodynamics, Coupling a Single Silicon Spin Qubit to a Photon

Non-existence of rest-frame spin-eigenstate spinors in their own electrodynamics

NASA Astrophysics Data System (ADS)

Fabbri, Luca; da Rocha, Roldão

2018-05-01

We assume a physical situation where gravity with torsion is neglected for an electrodynamically self-interacting spinor that will be taken in its rest-frame and spin-eigenstate: we demonstrate that under this circumstance no solution exists for the system of field equations. Despite such a situation might look artificial nevertheless it represents the instance that is commonly taken as the basis for all computations of quantum electrodynamics.

[Application of classic formulae in treatment of hypertension].

PubMed

Xiong, Xing-Jiang; Wang, Jie

2013-06-01

Classic formulae have a wide prospect in the treatment of hypertension with such advantages as symposium relief, improvement of body constitution and uncontrollable blood pressure factors. The paper systematically reviews the application of classic formula in pre-hypertension, different stages of hypertension, special type of hypertension, secondary hypertension, and uncontrollable blood pressure factors. It is believed that classic formulae are effective under the premise of their in-depth understanding of objective indications, modern pathogenesis and evolvement regularity.

Nanostructures Exploit Hybrid-Polariton Resonances

NASA Technical Reports Server (NTRS)

Anderson, Mark

2008-01-01

Nanostructured devices that exploit the hybrid-polariton resonances arising from coupling among photons, phonons, and plasmons are subjects of research directed toward the development of infrared-spectroscopic sensors for measuring extremely small quantities of molecules of interest. The spectroscopic techniques in question are surface enhanced Raman scattering (SERS) and surface enhanced infrared absorption (SEIRA). An important intermediate goal of this research is to increase the sensitivity achievable by these techniques. The basic idea of the approach being followed in this research is to engineer nanostructured devices and thereby engineer their hybrid-polariton resonances to concentrate infrared radiation incident upon their surfaces in such a manner as to increase the absorption of the radiation for SEIRA and measure the frequency shifts of surface vibrational modes. The underlying hybrid-polariton-resonance concept is best described by reference to experimental devices that have been built and tested to demonstrate the concept. The nanostructure of each such device includes a matrix of silicon carbide particles of approximately 1 micron in diameter that are supported on a potassium bromide (KBr) or poly(tetrafluoroethylene) [PTFE] window. These grains are sputter-coated with gold grains of 40-nm size (see figure). From the perspective of classical electrodynamics, in this nanostructure, that includes a particulate or otherwise rough surface, the electric-field portion of an incident electromagnetic field becomes concentrated on the particles when optical resonance conditions are met. Going beyond the perspective of classical electrodynamics, it can be seen that when the resonance frequencies of surface phonons and surface plasmons overlap, the coupling of the resonances gives rise to an enhanced radiation-absorption or -scattering mechanism. The sizes, shapes, and aggregation of the particles determine the frequencies of the resonances. Hence, the task of designing a nanostructure to exhibit the desired radiation-absorption properties translates, in large part, to selecting particle sizes and shapes to obtain the desired enhanced coupling of energy from photons to plasmons and phonons. To broaden the spectral region(s) of enhanced absorption, one would select a distribution of particle sizes and shapes.

Multiscale Modeling of Plasmon-Exciton Dynamics of Malachite Green Monolayers on Gold Nanoparticles

NASA Astrophysics Data System (ADS)

Smith, Holden; Karam, Tony; Haber, Louis; Lopata, Kenneth

A multi-scale hybrid quantum/classical approach using classical electrodynamics and a collection of discrete two level quantum system is used to investigate the coupling dynamics of malachite green monolayers adsorbed to the surface of a spherical gold nanoparticle (NP). This method utilizes finite difference time domain (FDTD) to describe the plasmonic response of the NP and a two-level quantum description for the molecule via the Maxwell/Liouville equation. The molecular parameters are parameterized using CASPT2 for the energies and transition dipole moments, with the dephasing lifetime fit to experiment. This approach is suited to simulating thousands of molecules on the surface of a plasmonic NP. There is good agreement with experimental extinction measurements, predicting the plasmon and molecule depletions. Additionally, this model captures the polariton peaks overlapped with a Fano-type resonance profile observed in the experimental extinction measurements. This technique shows promise for modeling plasmon/molecule interactions in chemical sensing and light harvesting in multi-chromophore systems. This material is based upon work supported by the National Science Foundation under the NSF EPSCoR Cooperative Agreement No. EPS-1003897 and the Louisiana Board of Regents Research Competitiveness Subprogram under Contract Number LEQSF(2014-17)-RD-A-0.

Multiscale Modeling of Plasmon-Exciton Dynamics of Malachite Green Monolayers on Gold Nanoparticles

NASA Astrophysics Data System (ADS)

Smith, Holden; Karam, Tony; Haber, Louis; Lopata, Kenneth

A multi-scale hybrid quantum/classical approach using classical electrodynamics and a collection of discrete two-level quantum system is used to investigate the coupling dynamics of malachite green monolayers adsorbed to the surface of a spherical gold nanoparticle (NP). This method utilizes finite difference time domain (FDTD) to describe the plasmonic response of the NP and a two-level quantum description for the molecule via the Maxwell/Liouville equation. The molecular parameters are parameterized using CASPT2 for the energies and transition dipole moments, with the dephasing lifetime fit to experiment. This approach is suited to simulating thousands of molecules on the surface of a plasmonic NP. There is good agreement with experimental extinction measurements, predicting the plasmon and molecule depletions. Additionally, this model captures the polariton peaks overlapped with a Fano-type resonance profile observed in the experimental extinction measurements. This technique shows promise for modeling plasmon/molecule interactions in chemical sensing and light harvesting in multi-chromophore systems. This material is based upon work supported by the National Science Foundation under the NSF EPSCoR Cooperative Agreement No. EPS-1003897 and by the Louisiana Board of Regents Research Competitiveness Subprogram under Contract Number LEQSF(2014-17)-RD-A-0.

Competing Spin Liquids and Hidden Spin-Nematic Order in Spin Ice with Frustrated Transverse Exchange

NASA Astrophysics Data System (ADS)

Taillefumier, Mathieu; Benton, Owen; Yan, Han; Jaubert, L. D. C.; Shannon, Nic

2017-10-01

Frustration in magnetic interactions can give rise to disordered ground states with subtle and beautiful properties. The spin ices Ho2 Ti2 O7 and Dy2 Ti2 O7 exemplify this phenomenon, displaying a classical spin-liquid state, with fractionalized magnetic-monopole excitations. Recently, there has been great interest in closely related "quantum spin-ice" materials, following the realization that anisotropic exchange interactions could convert spin ice into a massively entangled, quantum spin liquid, where magnetic monopoles become the charges of an emergent quantum electrodynamics. Here we show that even the simplest model of a quantum spin ice, the XXZ model on the pyrochlore lattice, can realize a still-richer scenario. Using a combination of classical Monte Carlo simulation, semiclassical molecular-dynamics simulation, and analytic field theory, we explore the properties of this model for frustrated transverse exchange. We find not one, but three competing forms of spin liquid, as well as a phase with hidden, spin-nematic order. We explore the experimental signatures of each of these different states, making explicit predictions for inelastic neutron scattering. These results show an intriguing similarity to experiments on a range of pyrochlore oxides.

Hot spot-mediated non-dissipative and ultrafast plasmon passage.

PubMed

Roller, Eva-Maria; Besteiro, Lucas V; Pupp, Claudia; Khorashad, Larousse Khosravi; Govorov, Alexander O; Liedl, Tim

2017-08-01

Plasmonic nanoparticles hold great promise as photon handling elements and as channels for coherent transfer of energy and information in future all-optical computing devices.1-5 Coherent energy oscillations between two spatially separated plasmonic entities via a virtual middle state exemplify electron-based population transfer, but their realization requires precise nanoscale positioning of heterogeneous particles.6-10 Here, we show the assembly and optical analysis of a triple particle system consisting of two gold nanoparticles with an inter-spaced silver island. We observe strong plasmonic coupling between the spatially separated gold particles mediated by the connecting silver particle with almost no dissipation of energy. As the excitation energy of the silver island exceeds that of the gold particles, only quasi-occupation of the silver transfer channel is possible. We describe this effect both with exact classical electrodynamic modeling and qualitative quantum-mechanical calculations. We identify the formation of strong hot spots between all particles as the main mechanism for the loss-less coupling and thus coherent ultra-fast energy transfer between the remote partners. Our findings could prove useful for quantum gate operations, but also for classical charge and information transfer processes.

Microscopic Electron Dynamics in Metal Nanoparticles for Photovoltaic Systems.

PubMed

Kluczyk, Katarzyna; Jacak, Lucjan; Jacak, Witold; David, Christin

2018-06-25

Nanoparticles—regularly patterned or randomly dispersed—are a key ingredient for emerging technologies in photonics. Of particular interest are scattering and field enhancement effects of metal nanoparticles for energy harvesting and converting systems. An often neglected aspect in the modeling of nanoparticles are light interaction effects at the ultimate nanoscale beyond classical electrodynamics. Those arise from microscopic electron dynamics in confined systems, the accelerated motion in the plasmon oscillation and the quantum nature of the free electron gas in metals, such as Coulomb repulsion and electron diffusion. We give a detailed account on free electron phenomena in metal nanoparticles and discuss analytic expressions stemming from microscopic (Random Phase Approximation—RPA) and semi-classical (hydrodynamic) theories. These can be incorporated into standard computational schemes to produce more reliable results on the optical properties of metal nanoparticles. We combine these solutions into a single framework and study systematically their joint impact on isolated Au, Ag, and Al nanoparticles as well as dimer structures. The spectral position of the plasmon resonance and its broadening as well as local field enhancement show an intriguing dependence on the particle size due to the relevance of additional damping channels.

High-Performance Ion Mobility Spectrometry Using Hourglass Electrodynamic Funnel And Internal Ion Funnel

DOEpatents

Smith, Richard D.; Tang, Keqi; Shvartsburg, Alexandre A.

2004-11-16

A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.

An Overview of Electrodynamic Tether Performance in the Jovian System

NASA Technical Reports Server (NTRS)

Gallagher, Dennis; Johnson, Les; Bagenal, Fran; Moore, James

1998-01-01

The Jovian magnetosphere with its strong magnetic field and rapid planetary rotation present new opportunities and challenges for the use of electrodynamic tethers. An overview of the basic plasma physics properties of an electrodynamic tether moving through the Jovian magnetosphere is examined. Tether use for both propulsion and power generation are considered. Close to the planet, tether propulsive forces are found to be as high as 50 Newtons and power levels as high as 1 million Watts.

Propulsion and Levitation with a Large Electrodynamic Wheel

NASA Astrophysics Data System (ADS)

Gaul, Nathan; Lane, Hannah

We constructed an electrodynamic wheel using a motorized bicycle wheel with a radius of 12 inches and 36 one-inch cube magnets attached to the rim of the wheel. The radial magnetic field on the outside of the wheel was maximized by arranging the magnets into a series of Halbach arrays which amplify the field on one side of the array and reduce it on the other side. Rotating the wheel produces a rapidly oscillating magnetic field. When a conductive metal ``track'' is placed in this area of strong magnetic flux, eddy currents are produced in the track. These eddy currents create magnetic fields that interact with the magnetic fields from the electrodynamic wheel. The interaction of the magnetic fields produces lift and drag forces on the track which were measured with force gauges. Measurements were taken at a variety of wheel speeds, and the results were compared to the theoretical prediction that there should be a linear relationship between the lift and drag forces with increasing wheel speed. Partial levitation was achieved with the current electrodynamic wheel. In the future, the wheel will be upgraded to include 72 magnets rather than 36 magnets. This will double the frequency at which the magnetic field oscillates, increasing the magnetic flux. Electrodynamic wheels have applications to the transportation industry, since multiple electrodynamic wheels could be used on a vehicle to produce a lift and propulsion force over a conductive track.

Start-up and control method and apparatus for resonant free piston Stirling engine

DOEpatents

Walsh, Michael M.

1984-01-01

A resonant free-piston Stirling engine having a new and improved start-up and control method and system. A displacer linear electrodynamic machine is provided having an armature secured to and movable with the displacer and having a stator supported by the Stirling engine housing in juxtaposition to the armature. A control excitation circuit is provided for electrically exciting the displacer linear electrodynamic machine with electrical excitation signals having substantially the same frequency as the desired frequency of operation of the Stirling engine. The excitation control circuit is designed so that it selectively and controllably causes the displacer electrodynamic machine to function either as a generator load to extract power from the displacer or the control circuit selectively can be operated to cause the displacer electrodynamic machine to operate as an electric drive motor to apply additional input power to the displacer in addition to the thermodynamic power feedback to the displacer whereby the displacer linear electrodynamic machine also is used in the electric drive motor mode as a means for initially starting the resonant free-piston Stirling engine.

Microscopic description of exciton polaritons in direct two-band semiconductors

NASA Astrophysics Data System (ADS)

Nguyen, Van Trong; Mahler, Günter

1999-07-01

Based on a quantum electrodynamical formulation, a microscopic description of exciton polaritons in a two-band semiconductor is presented. We show that the interband exchange Coulomb interaction, responsible for the coupling of the exciton with the longitudinal part of the induced field, should be treated on equal footing together with the coupling to the transverse part of the induced field (the photon field). The constitutive relation is established to connect the current density with the total electric field of polaritons. The classical Maxwell equations are derived from the quantum representation of photons to get a closed system of equations. The temporal evolution for an initial excited exciton state is studied in detail and an anisotropic polariton vacuum Rabi splitting is shown to occur. A number of up-to-now unresolved discrepancies in the literature are clarified.

The Fourth Law of Motion in Classical Mechanics and Electrodynamics

NASA Astrophysics Data System (ADS)

Pinheiro, Mario J.

2010-01-01

Newton's second law has limited scope of application when transient phenomena are at stake. We endeavor here to consider a modification of Newton's second law in order to take into account sudden change (surge) of angular momentum or linear momentum. It is shown that space react back according to a kind of induction law that is related to inertia, but also appears to give evidence of a "fluidic" nature of space itself. The back-reaction is quantified by the time rate of the angular momentum flux threading a surface, mass dependent, and bearing similarity to the quantum mechanics phase shift, present in the Aharonov-Bohm and Aharonov-Casher effects, thus giving evidence of the property of vacuum polarization, a phenomena which is relative to local space. It is formulated a kind of (qualitative) Lenz law that gives an explanation to precession.

Reexamination of Induction Heating of Primitive Bodies in Protoplanetary Disks

NASA Astrophysics Data System (ADS)

Menzel, Raymond L.; Roberge, Wayne G.

2013-10-01

We reexamine the unipolar induction mechanism for heating asteroids originally proposed in a classic series of papers by Sonett and collaborators. As originally conceived, induction heating is caused by the "motional electric field" that appears in the frame of an asteroid immersed in a fully ionized, magnetized solar wind and drives currents through its interior. However, we point out that classical induction heating contains a subtle conceptual error, in consequence of which the electric field inside the asteroid was calculated incorrectly. The problem is that the motional electric field used by Sonett et al. is the electric field in the freely streaming plasma far from the asteroid; in fact, the motional field vanishes at the asteroid surface for realistic assumptions about the plasma density. In this paper we revisit and improve the induction heating scenario by (1) correcting the conceptual error by self-consistently calculating the electric field in and around the boundary layer at the asteroid-plasma interface; (2) considering weakly ionized plasmas consistent with current ideas about protoplanetary disks; and (3) considering more realistic scenarios that do not require a fully ionized, powerful T Tauri wind in the disk midplane. We present exemplary solutions for two highly idealized flows that show that the interior electric field can either vanish or be comparable to the fields predicted by classical induction depending on the flow geometry. We term the heating driven by these flows "electrodynamic heating," calculate its upper limits, and compare them to heating produced by short-lived radionuclides.

Introduction of a Classical Level in Quantum Theory

NASA Astrophysics Data System (ADS)

Prosperi, G. M.

2016-11-01

In an old paper of our group in Milano a formalism was introduced for the continuous monitoring of a system during a certain interval of time in the framework of a somewhat generalized approach to quantum mechanics (QM). The outcome was a distribution of probability on the space of all the possible continuous histories of a set of quantities to be considered as a kind of coarse grained approximation to some ordinary quantum observables commuting or not. In fact the main aim was the introduction of a classical level in the context of QM, treating formally a set of basic quantities, to be considered as beables in the sense of Bell, as continuously taken under observation. However the effect of such assumption was a permanent modification of the Liouville-von Neumann equation for the statistical operator by the introduction of a dissipative term which is in conflict with basic conservation rules in all reasonable models we had considered. Difficulties were even encountered for a relativistic extension of the formalism. In this paper I propose a modified version of the original formalism which seems to overcome both difficulties. First I study the simple models of an harmonic oscillator and a free scalar field in which a coarse grain position and a coarse grained field respectively are treated as beables. Then I consider the more realistic case of spinor electrodynamics in which only certain coarse grained electric and magnetic fields are introduced as classical variables and no matter related quantities.

Pathfinder

NASA Image and Video Library

2004-04-15

This picture is an artist's concept of an orbiting vehicle using the Electrodynamic Tethers Propulsion System. Relatively short electrodynamic tethers can use solar power to push against a planetary magnetic field to achieve propulsion without the expenditure of propellant.

Teaching Classic Probability Problems With Modern Digital Tools

ERIC Educational Resources Information Center

Abramovich, Sergei; Nikitin, Yakov Yu.

2017-01-01

This article is written to share teaching ideas about using commonly available computer applications--a spreadsheet, "The Geometer's Sketchpad", and "Wolfram Alpha"--to explore three classic and historically significant problems from the probability theory. These ideas stem from the authors' work with prospective economists,…

Conserved charges for black holes in Einstein-Gauss-Bonnet gravity coupled to nonlinear electrodynamics in AdS space

NASA Astrophysics Data System (ADS)

Mišković, Olivera; Olea, Rodrigo

2011-01-01

Motivated by possible applications within the framework of anti-de Sitter gravity/conformal field theory correspondence, charged black holes with AdS asymptotics, which are solutions to Einstein-Gauss-Bonnet gravity in D dimensions, and whose electric field is described by nonlinear electrodynamics are studied. For a topological static black hole ansatz, the field equations are exactly solved in terms of the electromagnetic stress tensor for an arbitrary nonlinear electrodynamic Lagrangian in any dimension D and for arbitrary positive values of Gauss-Bonnet coupling. In particular, this procedure reproduces the black hole metric in Born-Infeld and conformally invariant electrodynamics previously found in the literature. Altogether, it extends to D>4 the four-dimensional solution obtained by Soleng in logarithmic electrodynamics, which comes from vacuum polarization effects. Falloff conditions for the electromagnetic field that ensure the finiteness of the electric charge are also discussed. The black hole mass and vacuum energy as conserved quantities associated to an asymptotic timelike Killing vector are computed using a background-independent regularization of the gravitational action based on the addition of counterterms which are a given polynomial in the intrinsic and extrinsic curvatures.

Conserved charges for black holes in Einstein-Gauss-Bonnet gravity coupled to nonlinear electrodynamics in AdS space

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

Miskovic, Olivera; Olea, Rodrigo; Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso

2011-01-15

Motivated by possible applications within the framework of anti-de Sitter gravity/conformal field theory correspondence, charged black holes with AdS asymptotics, which are solutions to Einstein-Gauss-Bonnet gravity in D dimensions, and whose electric field is described by nonlinear electrodynamics are studied. For a topological static black hole ansatz, the field equations are exactly solved in terms of the electromagnetic stress tensor for an arbitrary nonlinear electrodynamic Lagrangian in any dimension D and for arbitrary positive values of Gauss-Bonnet coupling. In particular, this procedure reproduces the black hole metric in Born-Infeld and conformally invariant electrodynamics previously found in the literature. Altogether, itmore » extends to D>4 the four-dimensional solution obtained by Soleng in logarithmic electrodynamics, which comes from vacuum polarization effects. Falloff conditions for the electromagnetic field that ensure the finiteness of the electric charge are also discussed. The black hole mass and vacuum energy as conserved quantities associated to an asymptotic timelike Killing vector are computed using a background-independent regularization of the gravitational action based on the addition of counterterms which are a given polynomial in the intrinsic and extrinsic curvatures.« less

Timelike Momenta In Quantum Electrodynamics

DOE R&D Accomplishments Database

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

1965-12-01

In this note we discuss the possibility of studying the quantum electrodynamics of timelike photon propagators in muon or electron pair production by incident high energy muon or electron beams from presently available proton or electron accelerators.

Electrodynamics panel presentation

NASA Technical Reports Server (NTRS)

Mccoy, J.

1986-01-01

The Plasma Motor Generator (PMG) concept is explained in detail. The PMG tether systems being used to calculate the estimated performance data is described. The voltage drops and current contact geometries involved in the operation of an electrodynamic tether are displayed illustrating the comparative behavior of hollow cathodes, electron guns, and passive collectors for current coupling into the ionosphere. The basic PMG design involving the massive tether cable with little or no satellite mass at the far end(s) are also described. The Jupiter mission and its use of electrodynamic tethers are given. The need for demonstration experiments is stressed.

Towards a Unified Field Theory for Classical Electrodynamics

NASA Astrophysics Data System (ADS)

Benci, Vieri; Fortunato, Donato

2004-09-01

In this paper we introduce a model which describes the relation of matter and the electromagnetic field from a unitarian standpoint in the spirit of ideas of Born and Infeld. In this model, based on a semilinear perturbation of Maxwell equations, the particles are finite-energy solitary waves due to the presence of the nonlinearity. In this respect the matter and the electromagnetic field have the same nature. Finite energy means that particles have finite mass and this makes electrodynamics consistent with the special relativity. We analyze the invariants of the motion of the semilinear Maxwell equations (SME) and their static solutions. In the magnetostatic case (i.e., when the electric field E = 0 and the magnetic field H does not depend on time) SME are reduced to the semilinear equation where ∇× denotes the curloperator, f‧ is the gradient of a strictly convex smooth function f:R3→R and A:R3→R3 is the gauge potential related to the magnetic field H (H = ∇× A). Due to the presence of the curl operator, (1) is a strongly degenerate elliptic equation. Moreover, physical considerations impel f to be flat at zero (f‧‧(0)=0) and this fact leads us to study the problem in a functional setting related to the Orlicz space Lp+Lq. The existence of a nontrivial finite- energy solution of (1) is proved under suitable growth conditions on f. The proof is carried out by using a suitable variational framework related to the Hodge splitting of the vector field A.

High Performance Ion Mobility Spectrometry Using Hourglass Electrodynamic Funnel And Internal Ion Funnel

DOEpatents

Smith, Richard D.; Tang, Keqi; Shvartsburg, Alexandre A.

2005-11-22

A method and apparatus enabling increased sensitivity in ion mobility spectrometry/mass spectrometry instruments which substantially reduces or eliminates the loss of ions in ion mobility spectrometer drift tubes utilizing a device for transmitting ions from an ion source which allows the transmission of ions without significant delay to an hourglass electrodynamic ion funnel at the entrance to the drift tube and/or an internal ion funnel at the exit of the drift tube. An hourglass electrodynamic funnel is formed of at least an entry element, a center element, and an exit element, wherein the aperture of the center element is smaller than the aperture of the entry element and the aperture of the exit elements. Ions generated in a relatively high pressure region by an ion source at the exterior of the hourglass electrodynamic funnel are transmitted to a relatively low pressure region at the entrance of the hourglass funnel through a conductance limiting orifice. Alternating and direct electrical potentials are applied to the elements of the hourglass electrodynamic funnel thereby drawing ions into and through the hourglass electrodynamic funnel thereby introducing relatively large quantities of ions into the drift tube while maintaining the gas pressure and composition at the interior of the drift tube as distinct from those at the entrance of the electrodynamic funnel and allowing a positive gas pressure to be maintained within the drift tube, if desired. An internal ion funnel is provided within the drift tube and is positioned at the exit of said drift tube. The advantage of the internal ion funnel is that ions that are dispersed away from the exit aperture within the drift tube, such as those that are typically lost in conventional drift tubes to any subsequent analysis or measurement, are instead directed through the exit of the drift tube, vastly increasing the amount of ions exiting the drift tube.

Understanding the Longitudinal Variability of Equatorial Electrodynamics using integrated Ground- and Space-based Observations

NASA Astrophysics Data System (ADS)

Yizengaw, E.; Moldwin, M.; Zesta, E.

2015-12-01

The currently funded African Meridian B-Field Education and Research (AMBER) magnetometer array comprises more than thirteen magnetometers stationed globally in the vicinity of geomagnetic equator. One of the main objectives of AMBER network is to understand the longitudinal variability of equatorial electrodynamics as function of local time, magnetic activity, and season. While providing complete meridian observation in the region and filling the largest land-based gap in global magnetometer coverage, the AMBER array addresses two fundamental areas of space physics: first, the processes governing electrodynamics of the equatorial ionosphere as a function of latitude (or L-shell), local time, longitude, magnetic activity, and season, and second, ULF pulsation strength at low/mid-latitude regions and its connection with equatorial electrojet and density fluctuation. The global AMBER network can also be used to augment observations from space-based instruments, such us the triplet SWARM mission and the upcoming ICON missions. Thus, in coordination with space-based and other ground-based observations, the AMBER magnetometer network provides a great opportunity to understand the electrodynamics that governs equatorial ionosphere motions. In this paper we present the longitudinal variability of the equatorial electrodynamics using the combination of instruments onboard SWARM and C/NOFS satellites and ground-based AMBER network. Both ground- and pace-based observations show stronger dayside and evening sector equatorial electrodynamics in the American and Asian sectors compared to the African sector. On the other hand, the African sector is home to stronger and year-round ionospheric bubbles/irregularities compared to the American and Asian sectors. This raises the question if the evening sector equatorial electrodynamics (vertical drift), which is believed to be the main cause for the enhancement of Rayleigh-Taylor (RT) instability growth rate, is stronger in the American sector and weaker in the African sector - why are the occurrence and amplitude of equatorial irregularities stronger in the African sector?

Lorentz-violating electrodynamics and the cosmic microwave background.

PubMed

Kostelecký, V Alan; Mewes, Matthew

2007-07-06

Possible Lorentz-violating effects in the cosmic microwave background are studied. We provide a systematic classification of renormalizable and nonrenormalizable operators for Lorentz violation in electrodynamics and use polarimetric observations to search for the associated violations.

Electrodynamic pressure modulation of protein stability in cosolvents.

PubMed

Damodaran, Srinivasan

2013-11-19

Cosolvents affect structural stability of proteins in aqueous solutions. A clear understanding of the mechanism by which cosolvents impact protein stability is critical to understanding protein folding in a biological milieu. In this study, we investigated the Lifshitz-van der Waals dispersion interaction of seven different solutes with nine globular proteins and report that in an aqueous medium the structure-stabilizing solutes exert a positive electrodynamic pressure, whereas the structure-destabilizing solutes exert a negative electrodynamic pressure on the proteins. The net increase in the thermal denaturation temperature (ΔTd) of a protein in 1 M solution of various solutes was linearly related to the electrodynamic pressure (PvdW) between the solutes and the protein. The slope of the PvdW versus ΔTd plots was protein-dependent. However, we find a positive linear relationship (r(2) = 0.79) between the slope (i.e., d(ΔTd)/dPvdW) and the adiabatic compressibility (βs) of the proteins. Together, these results clearly indicate that the Lifshitz's dispersion forces are inextricably involved in solute-induced stabilization/destabilization of globular proteins. The positive and/or negative electrodynamic pressure generated by the solute-protein interaction across the water medium seems to be the fundamental mechanism by which solutes affect protein stability. This is at variance with the existing preferential hydration concept. The implication of these results is significant in the sense that, in addition to the hydrophobic effect that drives protein folding, the electrodynamic forces between the proteins and solutes in the biological milieu also might play a role in the folding process as well as in the stability of the folded state.

Feedback between neutral winds and auroral arc electrodynamics

NASA Technical Reports Server (NTRS)

Lyons, L. R.; Walterscheid, R. L.

1986-01-01

The feedback between neutral atmospheric winds and the electrodynamics of a stable, discrete auroral arc is analyzed. The ionospheric current continuity equation and the equation for neutral gas acceleration by ion drag are solved simultaneously, as a function of time. The results show that, in general, the electric field in the ionosphere adjusts to neutral wind acceleration so as to keep auroral field-aligned currents and electron acceleration approximately independent of time. It is thus concluded that the neutral winds that develop as a result of the electrodynamical forcing associated with an arc do not significantly affect the intensity of the arc.

Flying relativistic mirrors for nonlinear QED studies.

NASA Astrophysics Data System (ADS)

Bulanov, Stepan; Schroeder, Carl; Esarey, Eric; Leemans, Wim

2017-10-01

Recent progress in laser technology has led to a dramatic increase of laser power and intensity. As a result, the laser-matter interaction will happen in the radiation dominated regimes. In a strong electromagnetic field, electrons can be accelerated to such high velocities that the radiation reaction starts to play an important role. The radiation effects change drastically the laser-plasma interaction leading to fast energy losses. Moreover, previously unexplored regimes of the interaction will be entered into, in which quantum electrodynamics (QED) can occur. Depending on the laser intensity and wavelength, either classical or quantum mode of radiation reaction prevail. In order to study different regimes of interaction as well as the transition from one into another the utilization of flying relativistic mirrors, which can generate electromagnetic pulses with varying frequency and intensity, is proposed. The scheme is demonstrated for multiphoton Compton scattering. Work supported by U.S. DOE under Contract No. DE-AC02-05CH11231.

Why Don't They Understand Us?

NASA Astrophysics Data System (ADS)

Kvasz, Ladislav

The aim of the article is to provide teachers some ideas about the development of physical knowledge and to make them more receptive to the differences between their and the students thinking. I want to show, that these differences lie not only in the richness of experience, but also in the structure of this experience. I try to point to some of these differences lying in the content, form and meaningfulness. The article is based on an adapted version of Piaget's model of the growth of physical knowledge. The model represents the changes of semantic understanding, formal language and logical structure of a theory during its historical development. I illustrate the model on the development of classical mechanics, but similar changes can be found also in the history of electrodynamics or quantum mechanics. The central idea of the paper is to use this model of the historical development of physical knowledge in analysis of the cognitive processes in physics education.

Homogeneous quantum electrodynamic turbulence

NASA Technical Reports Server (NTRS)

Shebalin, John V.

1992-01-01

The electromagnetic field equations and Dirac equations for oppositely charged wave functions are numerically time-integrated using a spatial Fourier method. The numerical approach used, a spectral transform technique, is based on a continuum representation of physical space. The coupled classical field equations contain a dimensionless parameter which sets the strength of the nonlinear interaction (as the parameter increases, interaction volume decreases). For a parameter value of unity, highly nonlinear behavior in the time-evolution of an individual wave function, analogous to ideal fluid turbulence, is observed. In the truncated Fourier representation which is numerically implemented here, the quantum turbulence is homogeneous but anisotropic and manifests itself in the nonlinear evolution of equilibrium modal spatial spectra for the probability density of each particle and also for the electromagnetic energy density. The results show that nonlinearly interacting fermionic wave functions quickly approach a multi-mode, dynamic equilibrium state, and that this state can be determined by numerical means.

Passion at a Distance

NASA Astrophysics Data System (ADS)

Howard, Don

In 1984, Abner Shimony invented the expression, "passion at a distance," to characterize the distinctive relationship of two entangled quantum mechanical systems [1]. It is neither the local causality of pushes, pulls, and central forces familiar from classical mechanics and electrodynamics, nor the non-local causality of instantaneous or just superluminal action at a distance that would spell trouble for relativity theory. This mode of connection of entangled systems has them feeling one another's presence and properties enough to ensure the strong correlations revealed in the Bell experiments, correlations that undergird everything from superfluidity and superconductivity to quantum computing and quantum teleportation, but not in a way that permits direct control of one by manipulation of the other. Intended to echo Aristotle's distinguishing of "potentiality" from "actuality" as different senses of "being," Shimony's "passion at a distance" is all about tendency and propensity, not the concreteness whose misplacement in realm of the physical was lamented by Alfred North Whitehead.

A multiscale quantum mechanics/electromagnetics method for device simulations.

PubMed

Yam, ChiYung; Meng, Lingyi; Zhang, Yu; Chen, GuanHua

2015-04-07

Multiscale modeling has become a popular tool for research applying to different areas including materials science, microelectronics, biology, chemistry, etc. In this tutorial review, we describe a newly developed multiscale computational method, incorporating quantum mechanics into electronic device modeling with the electromagnetic environment included through classical electrodynamics. In the quantum mechanics/electromagnetics (QM/EM) method, the regions of the system where active electron scattering processes take place are treated quantum mechanically, while the surroundings are described by Maxwell's equations and a semiclassical drift-diffusion model. The QM model and the EM model are solved, respectively, in different regions of the system in a self-consistent manner. Potential distributions and current densities at the interface between QM and EM regions are employed as the boundary conditions for the quantum mechanical and electromagnetic simulations, respectively. The method is illustrated in the simulation of several realistic systems. In the case of junctionless field-effect transistors, transfer characteristics are obtained and a good agreement between experiments and simulations is achieved. Optical properties of a tandem photovoltaic cell are studied and the simulations demonstrate that multiple QM regions are coupled through the classical EM model. Finally, the study of a carbon nanotube-based molecular device shows the accuracy and efficiency of the QM/EM method.

Experimental Results of Schlicher's Thrusting Antenna

NASA Technical Reports Server (NTRS)

Fralick, Gustave C.; Niedra, Janis M.

2001-01-01

Experiments were conducted to test the claims by Rex L. Schlicher, et al., (Patent 5,142,86 1) that a certain antenna geometry produces thrust greatly exceeding radiation reaction, when driven by repetitive, fast rise, and relatively slower decay current pulses. In order to test this hypothesis, the antenna was suspended by strings as a 3 in pendulum. Current pulses were fed to the antenna along the suspension path by a very flexible coaxial line constructed from loudspeaker cable and copper braid sheath. When driving the antenna via this cabling, our pulser was capable of sustaining 1200 A pulses at a rate of 30 per second up to a minute. In this way, bursts of pulses could be delivered in synch with the pendulum period in order to build up any motion. However, when using a laser beam passing through a lens attached to the antenna to amplify linear displacement by a factor of at least 25, no correlated motion of the beam spot could be detected on a distant wall. We conclude, in agreement with the momentum theorem of classical electromagnetic theory, that any thrust produced is far below practically useful levels. Hence, within classical electrodynamics, there is little hope of detecting any low level motion that cannot be explained by interactions with surrounding structural steel and the Earth's magnetic field.

Testing Born-Infeld electrodynamics in waveguides.

PubMed

Ferraro, Rafael

2007-12-07

Waveguides can be employed to test nonlinear effects in electrodynamics. We solve Born-Infeld equations for TE waves in a rectangular waveguide. We show that the energy velocity acquires a dependence on the amplitude, and harmonic components appear as a consequence of the nonlinear behavior.

Experimental simulation of monogamy relation between contextuality and nonlocality in classical light.

PubMed

Li, Tao; Zhang, Xiong; Zeng, Qiang; Wang, Bo; Zhang, Xiangdong

2018-04-30

The Clauser-Horne-Shimony-Holt (CHSH) inequality and the Klyachko-Can-Binicioglu-Shumovski (KCBS) inequality present a tradeoff on the no-disturbance (ND) principle. Recently, the fundamental monogamy relation between contextuality and nonlocality in quantum theory has been demonstrated experimentally. Here we show that such a relation and tradeoff can also be simulated in classical optical systems. Using polarization, path and orbital angular momentum of the classical optical beam, in classical optical experiment we have observed the stringent monogamy relation between the two inequalities by implementing the projection measurement. Our results show the application prospect of the concepts developed recently in quantum information science to classical optical system and optical information processing.

REEXAMINATION OF INDUCTION HEATING OF PRIMITIVE BODIES IN PROTOPLANETARY DISKS

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

Menzel, Raymond L.; Roberge, Wayne G., E-mail: menzer@rpi.edu, E-mail: roberw@rpi.edu

2013-10-20

We reexamine the unipolar induction mechanism for heating asteroids originally proposed in a classic series of papers by Sonett and collaborators. As originally conceived, induction heating is caused by the 'motional electric field' that appears in the frame of an asteroid immersed in a fully ionized, magnetized solar wind and drives currents through its interior. However, we point out that classical induction heating contains a subtle conceptual error, in consequence of which the electric field inside the asteroid was calculated incorrectly. The problem is that the motional electric field used by Sonett et al. is the electric field in themore » freely streaming plasma far from the asteroid; in fact, the motional field vanishes at the asteroid surface for realistic assumptions about the plasma density. In this paper we revisit and improve the induction heating scenario by (1) correcting the conceptual error by self-consistently calculating the electric field in and around the boundary layer at the asteroid-plasma interface; (2) considering weakly ionized plasmas consistent with current ideas about protoplanetary disks; and (3) considering more realistic scenarios that do not require a fully ionized, powerful T Tauri wind in the disk midplane. We present exemplary solutions for two highly idealized flows that show that the interior electric field can either vanish or be comparable to the fields predicted by classical induction depending on the flow geometry. We term the heating driven by these flows 'electrodynamic heating', calculate its upper limits, and compare them to heating produced by short-lived radionuclides.« less

A letter of intent for an experiment to study strong electromagnetic fields at RHIC via multiple electromagnetic processes

NASA Technical Reports Server (NTRS)

Fatyga, M.; Norbury, John W.

1992-01-01

An experimental program at the Relativistic Heavy Ion Collider (RHIC) which is designed to study nonperturbative aspects of electrodynamics is outlined. Additional possibilities for new studies of electrodynamics via multiple electromagnetic processes are also described.

Vacuum nonlinear electrodynamic polarization effects in hard emission of pulsars and magnetars

NASA Astrophysics Data System (ADS)

Denisov, V. I.; Sokolov, V. A.; Svertilov, S. I.

2017-09-01

The nonlinear electrodynamics influence of pulsar magnetic field on the electromagnetic pulse polarization is discussed from the point of observation interpretation. The calculations of pulsar magnetic field impact on the electromagnetic pulse polarization are made in such a way to make it easier to interpret these effects in space experiments. The law of hard emission pulse propagation in the pulsar magnetic field according to the vacuum (nonlinear electrodynamics is obtained. It has been shown, that due to the birefringence in the vacuum the front part of any hard emission pulse coming from a pulsar should be linearly polarized and the rest of pulse can have arbitrary polarization. The observational possibilities of vacuum birefringence are discussed. In this paper we give the estimations of detector parameters such as effective area, exposure time and necessity of polarization measurements with high accuracy. The combination of large area and extremely long exposure time gives the good opportunity to search the fine polarization effects like vacuum nonlinear electrodynamics birefringence.

Multiphysics elastodynamic finite element analysis of space debris deorbit stability and efficiency by electrodynamic tethers

NASA Astrophysics Data System (ADS)

Li, Gangqiang; Zhu, Zheng H.; Ruel, Stephane; Meguid, S. A.

2017-08-01

This paper developed a new multiphysics finite element method for the elastodynamic analysis of space debris deorbit by a bare flexible electrodynamic tether. Orbital motion limited theory and dynamics of flexible electrodynamic tethers are discretized by the finite element method, where the motional electric field is variant along the tether and coupled with tether deflection and motion. Accordingly, the electrical current and potential bias profiles of tether are solved together with the tether dynamics by the nodal position finite element method. The newly proposed multiphysics finite element method is applied to analyze the deorbit dynamics of space debris by electrodynamic tethers with a two-stage energy control strategy to ensure an efficient and stable deorbit process. Numerical simulations are conducted to study the coupled effect between the motional electric field and the tether dynamics. The results reveal that the coupling effect has a significant influence on the tether stability and the deorbit performance. It cannot be ignored when the libration and deflection of the tether are significant.

Vacuum nonlinear electrodynamic polarization effects in hard emission of pulsars and magnetars

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

Denisov, V.I.; Sokolov, V.A.; Svertilov, S.I., E-mail: vid.msu@yandex.ru, E-mail: sokolov.sev@inbox.ru, E-mail: sis@coronas.ru

The nonlinear electrodynamics influence of pulsar magnetic field on the electromagnetic pulse polarization is discussed from the point of observation interpretation. The calculations of pulsar magnetic field impact on the electromagnetic pulse polarization are made in such a way to make it easier to interpret these effects in space experiments. The law of hard emission pulse propagation in the pulsar magnetic field according to the vacuum (nonlinear electrodynamics is obtained. It has been shown, that due to the birefringence in the vacuum the front part of any hard emission pulse coming from a pulsar should be linearly polarized and themore » rest of pulse can have arbitrary polarization. The observational possibilities of vacuum birefringence are discussed. In this paper we give the estimations of detector parameters such as effective area, exposure time and necessity of polarization measurements with high accuracy. The combination of large area and extremely long exposure time gives the good opportunity to search the fine polarization effects like vacuum nonlinear electrodynamics birefringence.« less

TESSX: A Mission for Space Exploration with Tethers

NASA Technical Reports Server (NTRS)

Cosmo, Mario L.; Lorenzini, Enrico C.; Gramer, Daniel J.; Hoffman, John H.; Mazzoleni, Andre P.

2005-01-01

Tethers offer significant potential for substantially increasing payload mass fraction, increasing spacecraft lifetime, enhancing long-term space travel, and enabling the understanding and development of gravity-dependent technologies required for Moon and Mars exploration. The development of the Tether Electrodynamic Spin-up and Survivability Experiment (TESSX) will support applications relevant to NASA's new exploration initiative, including: artificial gravity generation, formation flying, electrodynamic propulsion, momentum exchange, and multi-amp current collection and emission. Under the broad term TESSX, we are currently evaluating several different tether system configurations and operational modes. The initial results of this work are presented, including hardware development, orbital dynamics simulations, and electrodynamics design and analysis.

Space station operations enhancement using tethers

NASA Astrophysics Data System (ADS)

Bekey, I.

1984-10-01

Space tethers represent a tool of unusual versatility for applications to operations involving space stations. The present investigation is concerned with a number of applications which exploit the dynamic, static, and electrodynamic properties of tethers. One of the simplest applications of a tethered system on the Space Station might be that of a remote docking port, allowing the Shuttle to dock with no contamination or disturbance effects. Attention is also given to tethered platforms, a tethered microgravity facility, a tethered space station propellant facility, electrodynamic tether principles, a tether power generator, a tether thrust generator (motor), and an electrodynamic tether for drag makeup and energy storage.

A comment on the paper by R.I. Khrapko 'On the possibility of an experiment on 'nonlocality' of electrodynamics'

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

Venediktov, V Yu

2015-04-30

This methodological note is dedicated to the analysis of the imaginary experiment proposed in the paper by R.I. Khrapko 'On the possibility of an experiment on 'nonlocality' of electrodynamics' [Quantum Electronics, 42, 1133 (2012)]. (discussion)

Students' Difficulties with Vector Calculus in Electrodynamics

ERIC Educational Resources Information Center

Bollen, Laurens; van Kampen, Paul; De Cock, Mieke

2015-01-01

Understanding Maxwell's equations in differential form is of great importance when studying the electrodynamic phenomena discussed in advanced electromagnetism courses. It is therefore necessary that students master the use of vector calculus in physical situations. In this light we investigated the difficulties second year students at KU Leuven…

Electrostatics in Stueckelberg-Horwitz electrodynamics

NASA Astrophysics Data System (ADS)

Land, Martin

2013-04-01

In this paper, we study fundamental aspects of electrostatics as a special case in Stueckelberg-Horwitz electromagnetic theory. In this theory, spacetime events xμ(τ) evolve in an unconstrained 8-dimensional phase space, interacting through five τ-dependent gauge fields induced by the current densities associated with their evolutions. The chronological time τ was introduced as an independent evolution parameter in order to free the laboratory clock x0 to evolve alternately 'forward' and 'backward' in time according to the sign of the energy, thus providing a classical implementation of the Feynman-Stueckelberg interpretation of pair creation/annihilation. The resulting theory differs in its underlying mechanics from conventional electromagnetism, but coincides with Maxwell theory in an equilibrium limit. After a brief review of Stueckelberg-Horwitz electrodynamics, we obtain the field produced by an event in uniform motion and verify that it satisfies the field equations. We study this field in the rest frame of the event, where it depends explicitly on coordinate time x0 and the parameter τ, as well as spatial distance R. Calculating with this generalized Coulomb field, we demonstrate how Gauss's theorem and Stoke's theorem apply in 4D spacetime, and obtain the fields associated with a charged line and a charged sheet. Finally, we use the field of the charged sheet to study a static event in the vicinity of a potential barrier. In all of these cases, we observe a small transfer of mass from the field to the particle. It is seen that for an event in the field of an oppositely charged sheet of sufficient density, the event can reverse time direction, providing a specific model for pair phenomena.

Relationship of the Cognitive Functions of Prospective Science Teachers and Their Knowledge, Knowledge Levels, Success and Success Levels

ERIC Educational Resources Information Center

Ismail, Yilmaz

2017-01-01

This study reveals the transformation of prospective science teachers into knowledgeable individuals through classical, combination, and information theories. It distinguishes between knowledge and success, and between knowledge levels and success levels calculated each through three theories. The relation between the knowledge of prospective…

Developing a Questionnaire to Assess the Probability Content Knowledge of Prospective Primary School Teachers

ERIC Educational Resources Information Center

Gómez-Torres, Emilse; Batanero, Carmen; Díaz, Carmen; Contreras, José Miguel

2016-01-01

In this paper we describe the development of a questionnaire designed to assess the probability content knowledge of prospective primary school teachers. Three components of mathematical knowledge for teaching and three different meanings of probability (classical, frequentist and subjective) are considered. The questionnaire content is based on…

Lamb Shift in Nonrelativistic Quantum Electrodynamics.

ERIC Educational Resources Information Center

Grotch, Howard

1981-01-01

The bound electron self-energy or Lamb shift is calculated in nonrelativistic quantum electrodynamics. Retardation is retained and also an interaction previously dropped in other nonrelativistic approaches is kept. Results are finite without introducing a cutoff and lead to a Lamb shift in hydrogen of 1030.9 MHz. (Author/JN)

Electrodynamics in One Dimension: Radiation and Reflection

ERIC Educational Resources Information Center

Asti, G.; Coisson, R.

2011-01-01

Problems involving polarized plane waves and currents on sheets perpendicular to the wavevector involve only one component of the fields, so it is possible to discuss electrodynamics in one dimension. Taking for simplicity linearly polarized sinusoidal waves, we can derive the field emitted by currents (analogous to dipole radiation in three…

Conceptual assessment tool for advanced undergraduate electrodynamics

NASA Astrophysics Data System (ADS)

Baily, Charles; Ryan, Qing X.; Astolfi, Cecilia; Pollock, Steven J.

2017-12-01

As part of ongoing investigations into student learning in advanced undergraduate courses, we have developed a conceptual assessment tool for upper-division electrodynamics (E&M II): the Colorado UppeR-division ElectrodyNamics Test (CURrENT). This is a free response, postinstruction diagnostic with 6 multipart questions, an optional 3-question preinstruction test, and accompanying grading rubrics. The instrument's development was guided by faculty-consensus learning goals and research into common student difficulties. It can be used to gauge the effectiveness of transformed pedagogy, and to gain insights into student thinking in the covered topic areas. We present baseline data representing 500 students across 9 institutions, along with validity, reliability, and discrimination measures of the instrument and scoring rubric.

Middle Atmosphere Electrodynamics During a Thunderstorm

NASA Technical Reports Server (NTRS)

Croskey, Charles L.

1996-01-01

Rocket-based instrumentation investigations of middle atmospheric electrodynamics during thunderstorms were conducted in coordination with balloon-measurements at Wallops Island, Virginia. Middle atmosphere electrodynamics and energy coupling are of particular importance to associated electrical processes at lower and higher altitudes. Objectives of this research effort included: (1) investigation of thunderstorm effects on middle atmosphere electrical structure, including spatial and temporal dependence; (2) characterization of electric field transients and the associated energy deposited at various altitudes; (3) evaluation of the vertical Maxwell current density over a thunderstorm to study the coupling of energy to higher altitudes; and (4) investigation of the coupling of energy to the ionosphere and the current supplied to the 'global circuit.'

Students' difficulties with vector calculus in electrodynamics

NASA Astrophysics Data System (ADS)

Bollen, Laurens; van Kampen, Paul; De Cock, Mieke

2015-12-01

Understanding Maxwell's equations in differential form is of great importance when studying the electrodynamic phenomena discussed in advanced electromagnetism courses. It is therefore necessary that students master the use of vector calculus in physical situations. In this light we investigated the difficulties second year students at KU Leuven encounter with the divergence and curl of a vector field in mathematical and physical contexts. We have found that they are quite skilled at doing calculations, but struggle with interpreting graphical representations of vector fields and applying vector calculus to physical situations. We have found strong indications that traditional instruction is not sufficient for our students to fully understand the meaning and power of Maxwell's equations in electrodynamics.

Discrete-time quantum walk with nitrogen-vacancy centers in diamond coupled to a superconducting flux qubit

NASA Astrophysics Data System (ADS)

Hardal, Ali Ü. C.; Xue, Peng; Shikano, Yutaka; Müstecaplıoğlu, Özgür E.; Sanders, Barry C.

2013-08-01

We propose a quantum-electrodynamics scheme for implementing the discrete-time, coined quantum walk with the walker corresponding to the phase degree of freedom for a quasimagnon field realized in an ensemble of nitrogen-vacancy centers in diamond. The coin is realized as a superconducting flux qubit. Our scheme improves on an existing proposal for implementing quantum walks in cavity quantum electrodynamics by removing the cumbersome requirement of varying drive-pulse durations according to mean quasiparticle number. Our improvement is relevant to all indirect-coin-flip cavity quantum-electrodynamics realizations of quantum walks. Our numerical analysis shows that this scheme can realize a discrete quantum walk under realistic conditions.

Electrodynamic Tether Propulsion and Power Generation at Jupiter

NASA Technical Reports Server (NTRS)

Gallagher, D. L.; Johnson, L.; Moore, J.; Bagenal, F.

1998-01-01

The results of a study performed to evaluate the feasibility and merits of using an electrodynamic tether for propulsion and power generation for a spacecraft in the Jovian system are presented. The environment of the Jovian system has properties which are particularly favorable for utilization of an electrodynamic tether. Specifically, the planet has a strong magnetic field and the mass of the planet dictates high orbital velocities which, when combined with the planet's rapid rotation rate, can produce very large relative velocities between the magnetic field and the spacecraft. In a circular orbit close to the planet, tether propulsive forces are found to be as high as 50 N and power levels as high as 1 MW.

Fractal electrodynamics via non-integer dimensional space approach

NASA Astrophysics Data System (ADS)

Tarasov, Vasily E.

2015-09-01

Using the recently suggested vector calculus for non-integer dimensional space, we consider electrodynamics problems in isotropic case. This calculus allows us to describe fractal media in the framework of continuum models with non-integer dimensional space. We consider electric and magnetic fields of fractal media with charges and currents in the framework of continuum models with non-integer dimensional spaces. An application of the fractal Gauss's law, the fractal Ampere's circuital law, the fractal Poisson equation for electric potential, and equation for fractal stream of charges are suggested. Lorentz invariance and speed of light in fractal electrodynamics are discussed. An expression for effective refractive index of non-integer dimensional space is suggested.

Quantum Electrodynamics: Theory

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

Lincoln, Don

The Standard Model of particle physics is composed of several theories that are added together. The most precise component theory is the theory of quantum electrodynamics or QED. In this video, Fermilab’s Dr. Don Lincoln explains how theoretical QED calculations can be done. This video links to other videos, giving the viewer a deep understanding of the process.

BIonic system: Extraction of Lovelock gravity from a Born-Infeld-type theory

NASA Astrophysics Data System (ADS)

Naimi, Yaghoob; Sepehri, Alireza; Ghaffary, Tooraj; Ghaforyan, Hossein; Ebrahimzadeh, Majid

It was shown that both Lovelock gravity and Born-Infeld (BI) electrodynamics can be obtained from low effective limit of string theory. Motivated by the mentioned unique origin of the gauge-gravity theories, we are going to find a close relation between them. In this research, we start from the Lagrangian of a BI-type nonlinear electrodynamics with an exponential form to extract the action of Lovelock gravity. We investigate the origin of Lovelock gravity in a system of branes which are connected with each other by different wormholes through a BIonic system. These wormholes are produced as due to the nonlinear electrodynamics which are emerged on the interacting branes. By approaching branes, wormholes dissolve into branes and Lovelock gravity is generated. Also, throats of some wormholes become smaller than their horizons and they transit to black holes. Generalizing calculations to M-theory, it is found that by compacting Mp-branes, Lovelock gravity changes to nonlinear electrodynamics and thus both of them have the same origin. This result is consistent with the prediction of BIonic model in string theory.

Metaphorical Perceptions of Prospective Music Teachers towards "Traditional Turkish Classical Music Course" Concept

ERIC Educational Resources Information Center

Eldemir, Abdurrahim Can

2016-01-01

The purpose of this study is to determine the perceptions of prospective music teachers towards Traditional Turkish Art Music course by means of metaphors. Phenomenological design, one of qualitative study methods, was used in the study. The study group of our research consists of juniors and seniors studying in the Music Education Division,…

On spacetime structure and electrodynamics

NASA Astrophysics Data System (ADS)

Ni, Wei-Tou

2016-10-01

Electrodynamics is the most tested fundamental physical theory. Relativity arose from the completion of Maxwell-Lorentz electrodynamics. Introducing the metric gij as gravitational potential in 1913, versed in general (coordinate-)covariant formalism in 1914 and shortly after the completion of general relativity, Einstein put the Maxwell equations in general covariant form with only the constitutive relation between the excitation and the field dependent on and connected by the metric in 1916. Further clarification and developments by Weyl in 1918, Murnaghan in 1921, Kottler in 1922 and Cartan in 1923 together with the corresponding developments in electrodynamics of continuous media by Bateman in 1910, Tamm in 1924, Laue in 1952 and Post in 1962 established the premetric formalism of electrodynamics. Since almost all phenomena electrodynamics deal with have energy scales much lower than the Higgs mass energy and intermediate boson energy, electrodynamics of continuous media should be applicable and the constitutive relation of spacetime/vacuum should be local and linear. What is the key characteristic of the spacetime/vacuum? It is the Weak Equivalence Principle I (WEP I) for photons/wave packets of light which states that the spacetime trajectory of light in a gravitational field depends only on its initial position and direction of propagation, and does not depend on its frequency (energy) and polarization, i.e. nonbirefringence of light propagation in spacetime/vacuum. With this principle it is proved by the author in 1981 in the weak field limit, and by Lammerzahl and Hehl in 2004 together with Favaro and Bergamin in 2011 without assuming the weak-field condition that the constitutive tensor must be of the core metric form with only two additional degrees of freedom — the pseudoscalar (Abelian axion or EM axion) degree of freedom and the scalar (dilaton) degree of freedom (i.e. metric with axion and dilaton). In this paper, we review this connection and the ultrahigh precision empirical tests of nonbirefringence together with present status of tests of cosmic Abelian axion and dilaton. If the stronger version of WEP is assumed, i.e. WEP II for photons (wave packets of light) which states in addition to WEP I also that the polarization state of the light would not change (e.g. no polarization rotation for linear polarized light) and no amplification/attenuation of light, then no Abelian (EM) axion and no dilaton, and we have a pure metric theory.

Brilliant GeV gamma-ray flash from inverse Compton scattering in the QED regime

NASA Astrophysics Data System (ADS)

Gong, Z.; Hu, R. H.; Lu, H. Y.; Yu, J. Q.; Wang, D. H.; Fu, E. G.; Chen, C. E.; He, X. T.; Yan, X. Q.

2018-04-01

An all-optical scheme is proposed for studying laser plasma based incoherent photon emission from inverse Compton scattering in the quantum electrodynamic regime. A theoretical model is presented to explain the coupling effects among radiation reaction trapping, the self-generated magnetic field and the spiral attractor in phase space, which guarantees the transfer of energy and angular momentum from electromagnetic fields to particles. Taking advantage of a prospective ˜ 1023 W cm-2 laser facility, 3D particle-in-cell simulations show a gamma-ray flash with unprecedented multi-petawatt power and brightness of 1.7 × 1023 photons s-1 mm-2 mrad-2/0.1% bandwidth (at 1 GeV). These results bode well for new research directions in particle physics and laboratory astrophysics exploring laser plasma interactions.

Simulations of relativistic quantum plasmas using real-time lattice scalar QED

NASA Astrophysics Data System (ADS)

Shi, Yuan; Xiao, Jianyuan; Qin, Hong; Fisch, Nathaniel J.

2018-05-01

Real-time lattice quantum electrodynamics (QED) provides a unique tool for simulating plasmas in the strong-field regime, where collective plasma scales are not well separated from relativistic-quantum scales. As a toy model, we study scalar QED, which describes self-consistent interactions between charged bosons and electromagnetic fields. To solve this model on a computer, we first discretize the scalar-QED action on a lattice, in a way that respects geometric structures of exterior calculus and U(1)-gauge symmetry. The lattice scalar QED can then be solved, in the classical-statistics regime, by advancing an ensemble of statistically equivalent initial conditions in time, using classical field equations obtained by extremizing the discrete action. To demonstrate the capability of our numerical scheme, we apply it to two example problems. The first example is the propagation of linear waves, where we recover analytic wave dispersion relations using numerical spectrum. The second example is an intense laser interacting with a one-dimensional plasma slab, where we demonstrate natural transition from wakefield acceleration to pair production when the wave amplitude exceeds the Schwinger threshold. Our real-time lattice scheme is fully explicit and respects local conservation laws, making it reliable for long-time dynamics. The algorithm is readily parallelized using domain decomposition, and the ensemble may be computed using quantum parallelism in the future.

Force, torque, linear momentum, and angular momentum in classical electr odynamics

NASA Astrophysics Data System (ADS)

Mansuripur, Masud

2017-10-01

The classical theory of electrodynamics is built upon Maxwell's equations and the concepts of electromagnetic (EM) field, force, energy, and momentum, which are intimately tied together by Poynting's theorem and by the Lorentz force law. Whereas Maxwell's equations relate the fields to their material sources, Poynting's theorem governs the flow of EM energy and its exchange between fields and material media, while the Lorentz law regulates the back-and-forth transfer of momentum between the media and the fields. An alternative force law, first proposed by Einstein and Laub, exists that is consistent with Maxwell's equations and complies with the conservation laws as well as with the requirements of special relativity. While the Lorentz law requires the introduction of hidden energy and hidden momentum in situations where an electric field acts on a magnetized medium, the Einstein-Laub (E-L) formulation of EM force and torque does not invoke hidden entities under such circumstances. Moreover, total force/torque exerted by EM fields on any given object turns out to be independent of whether the density of force/torque is evaluated using the law of Lorentz or that of Einstein and Laub. Hidden entities aside, the two formulations differ only in their predicted force and torque distributions inside matter. Such differences in distribution are occasionally measurable, and could serve as a guide in deciding which formulation, if either, corresponds to physical reality.

Prospects for Finite-Difference Time-Domain (FDTD) Computational Electrodynamics

NASA Astrophysics Data System (ADS)

Taflove, Allen

2002-08-01

FDTD is the most powerful numerical solution of Maxwell's equations for structures having internal details. Relative to moment-method and finite-element techniques, FDTD can accurately model such problems with 100-times more field unknowns and with nonlinear and/or time-variable parameters. Hundreds of FDTD theory and applications papers are published each year. Currently, there are at least 18 commercial FDTD software packages for solving problems in: defense (especially vulnerability to electromagnetic pulse and high-power microwaves); design of antennas and microwave devices/circuits; electromagnetic compatibility; bioelectromagnetics (especially assessment of cellphone-generated RF absorption in human tissues); signal integrity in computer interconnects; and design of micro-photonic devices (especially photonic bandgap waveguides, microcavities; and lasers). This paper explores emerging prospects for FDTD computational electromagnetics brought about by continuing advances in computer capabilities and FDTD algorithms. We conclude that advances already in place point toward the usage by 2015 of ultralarge-scale (up to 1E11 field unknowns) FDTD electromagnetic wave models covering the frequency range from about 0.1 Hz to 1E17 Hz. We expect that this will yield significant benefits for our society in areas as diverse as computing, telecommunications, defense, and public health and safety.

Guidebook for analysis of tether applications

NASA Technical Reports Server (NTRS)

Carroll, J. A.

1985-01-01

This guidebook is intended as a tool to facilitate initial analyses of proposed tether applications in space. Topics disscussed include: orbit and orbit transfer equations; orbital perturbations; aerodynamic drag; thermal balance; micrometeoroids; gravity gradient effects; tether control strategies; momentum transfer; orbit transfer by tethered release/rendezvous; impact hazards for tethers; electrodynamic tether principles; and electrodynamic libration control issues.

MURI Center for Multidimensional Surface-Enhanced Sensing and Spectroscopy

DTIC Science & Technology

2007-06-30

and detection using SERS; new understanding of the electromagnetic enhancement properties of nanohole arrays; new first principles theoretical Page 2...support for the experimental program: 1. Studies of the electrodynamics of molecules adsorbed on anisotropic nanoparticles and nanoholes to determine...nanoparticles. George C. Schatz Electrodynamics of metal nanoparticles, small clusters of nanoparticles and nanoholes . We have performed extensive

Application of Science Aesthetics in the Teaching of Electrodynamics

ERIC Educational Resources Information Center

Li, Haiyan

2010-01-01

As the important part of the theoretical physics, the electrodynamics is a theoretical basic course of the physics and relative subjects. To adapt the demands for cultivating the target of highly-quality talents in the 21st century, the aesthetic principle can be used in the teaching to stimulate students' learning desire and cultivate students'…

Electrodynamics, Differential Forms and the Method of Images

ERIC Educational Resources Information Center

Low, Robert J.

2011-01-01

This paper gives a brief description of how Maxwell's equations are expressed in the language of differential forms and use this to provide an elegant demonstration of how the method of images (well known in electrostatics) also works for electrodynamics in the presence of an infinite plane conducting boundary. The paper should be accessible to an…

Electrodynamics; Problems and solutions

NASA Astrophysics Data System (ADS)

Ilie, Carolina C.; Schrecengost, Zachariah S.

2018-05-01

This book of problems and solutions is a natural continuation of Ilie and Schrecengost's first book Electromagnetism: Problems and Solutions. Aimed towards students who would like to work independently on more electrodynamics problems in order to deepen their understanding and problem-solving skills, this book discusses main concepts and techniques related to Maxwell's equations, conservation laws, electromagnetic waves, potentials and fields, and radiation.

Quantum Electrodynamics: Theory

ScienceCinema

Lincoln, Don

2018-01-16

The Standard Model of particle physics is composed of several theories that are added together. The most precise component theory is the theory of quantum electrodynamics or QED. In this video, Fermilab’s Dr. Don Lincoln explains how theoretical QED calculations can be done. This video links to other videos, giving the viewer a deep understanding of the process.

Atomic electron energies including relativistic effects and quantum electrodynamic corrections

NASA Technical Reports Server (NTRS)

Aoyagi, M.; Chen, M. H.; Crasemann, B.; Huang, K. N.; Mark, H.

1977-01-01

Atomic electron energies have been calculated relativistically. Hartree-Fock-Slater wave functions served as zeroth-order eigenfunctions to compute the expectation of the total Hamiltonian. A first order correction to the local approximation was thus included. Quantum-electrodynamic corrections were made. For all orbitals in all atoms with 2 less than or equal to Z less than or equal to 106, the following quantities are listed: total energies, electron kinetic energies, electron-nucleus potential energies, electron-electron potential energies consisting of electrostatic and Breit interaction (magnetic and retardation) terms, and vacuum polarization energies. These results will serve for detailed comparison of calculations based on other approaches. The magnitude of quantum electrodynamic corrections is exhibited quantitatively for each state.

Charge instabilities due to local charge conjugation symmetry in /2+1 dimensions

NASA Astrophysics Data System (ADS)

Bais, F. A.; Striet, J.

2003-08-01

Alice electrodynamics (AED) is a theory of electrodynamics in which charge conjugation is a local gauge symmetry. In this paper we investigate a charge instability in alice electrodynamics in 2+1 dimensions due to this local charge conjugation. The instability manifests itself through the creation of a pair of alice fluxes. The final state is one in which the charge is completely delocalized, i.e., it is carried as cheshire charge by the flux pair that gets infinitely separated. We determine the decay rate in terms of the parameters of the model. The relation of this phenomenon with other salient features of 2-dimensional compact QED, such as linear confinement due to instantons/monopoles, is discussed.

Electrodynamical forbiddance of a strong quadrupole interaction in surface enhanced optical processes. Experimental confirmation of the existence in fullerene C{sub 60}

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

Polubotko, A. M., E-mail: alex.marina@mail.ioffe.ru; Chelibanov, V. P., E-mail: Chelibanov@gmail.com

2017-02-15

It is demonstrated that in the SERS and SEIRA spectra of the fullerene C{sub 60}, the lines, which are forbidden in usual Raman and IR spectra and allowed in SERS and SEIRA, are absent. In addition the enhancement SERS coefficient in a single molecule detection regime is ~10{sup 8} instead of the value 10{sup 14}–10{sup 15}, characteristic for this phenomenon. These results are explained by the existence of so-called electrodynamical forbiddance of a strong quadrupole light-molecule interaction, which arises because of belonging of C{sup 60} to the icosahedral symmetry group and due to the electrodynamical law divE = 0.

Stabilization of a programmed rotation mode for a satellite with electrodynamic attitude control system

NASA Astrophysics Data System (ADS)

Aleksandrov, A. Yu.; Aleksandrova, E. B.; Tikhonov, A. A.

2018-07-01

The paper deals with a dynamically symmetric satellite in a circular near-Earth orbit. The satellite is equipped with an electrodynamic attitude control system based on Lorentz and magnetic torque properties. The programmed satellite attitude motion is such that the satellite slowly rotates around the axis of its dynamical symmetry. Unlike previous publications, we consider more complex and practically more important case where the axis is fixed in the orbital frame in an inclined position with respect to the local vertical axis. The satellite stabilization in the programmed attitude motion is studied. The gravitational disturbing torque acting on the satellite attitude dynamics is taken into account since it is the largest disturbing torque. The novelty of the proposed approach is based on the usage of electrodynamic attitude control system. With the aid of original construction of a Lyapunov function, new conditions under which electrodynamic control solves the problem are obtained. Sufficient conditions for asymptotic stability of the programmed motion are found in terms of inequalities for the values of control parameters. The results of a numerical simulation are presented to demonstrate the effectiveness of the proposed approach.

Global ionospheric dynamics and electrodynamics during geomagnetic storms (Invited)

NASA Astrophysics Data System (ADS)

Mannucci, A. J.; Tsurutani, B.; Verkhoglyadova, O. P.; Komjathy, A.; Butala, M. D.

2013-12-01

Globally distributed total electron content (TEC) data has become an important tool for exploring the consequences of storm-time electrodynamics. Magnetosphere-ionosphere coupling during the main phase is responsible for the largest ionospheric effects observed during geomagnetic storms, mediated by global scale electrodynamics. Recent research using case studies reveals a complex picture of M-I coupling and its relationship to interplanetary drivers such as the solar wind electric field. Periods of direct coupling exist where the solar wind electric field is strongly correlated with prompt penetration electric fields, observed as enhanced vertical plasma drifts or an enhanced electrojet in the daytime equatorial ionosphere. Periods of decoupling between low latitude electric fields and the solar wind electric field are also observed, but the factors distinguishing these two types of response have not been clearly identified. Recent studies during superstorms suggest a role for the transverse (y-component) of the interplanetary magnetic field, which affects magnetospheric current systems and therefore may affect M-I coupling, with significant ionospheric consequences. Observations of the global ionospheric response to a range of geomagnetic storm intensities are presented. Scientific understanding of the different factors that affect electrodynamic aspects of M-I coupling are discussed.

Radiation and matter: Electrodynamics postulates and Lorenz gauge

NASA Astrophysics Data System (ADS)

Bobrov, V. B.; Trigger, S. A.; van Heijst, G. J.; Schram, P. P.

2016-11-01

In general terms, we have considered matter as the system of charged particles and quantized electromagnetic field. For consistent description of the thermodynamic properties of matter, especially in an extreme state, the problem of quantization of the longitudinal and scalar potentials should be solved. In this connection, we pay attention that the traditional postulates of electrodynamics, which claim that only electric and magnetic fields are observable, is resolved by denial of the statement about validity of the Maxwell equations for microscopic fields. The Maxwell equations, as the generalization of experimental data, are valid only for averaged values. We show that microscopic electrodynamics may be based on postulation of the d'Alembert equations for four-vector of the electromagnetic field potential. The Lorenz gauge is valid for the averages potentials (and provides the implementation of the Maxwell equations for averages). The suggested concept overcomes difficulties under the electromagnetic field quantization procedure being in accordance with the results of quantum electrodynamics. As a result, longitudinal and scalar photons become real rather than virtual and may be observed in principle. The longitudinal and scalar photons provide not only the Coulomb interaction of charged particles, but also allow the electrical Aharonov-Bohm effect.

Effects of heavy-ion irradiation on the microwave surface impedance of (Ba1-x K x )Fe2As2 single crystals

NASA Astrophysics Data System (ADS)

Ghigo, G.; Torsello, D.; Gerbaldo, R.; Gozzelino, L.; Laviano, F.; Tamegai, T.

2018-07-01

The electrodynamic response of Ba1-x K x Fe2As2 single crystals at the microwave frequencies has been investigated by means of a coplanar resonator technique, at different values of non-magnetic disorder introduced into the samples by heavy-ion irradiation. The surface impedance Z s = R s + iX s conforms to the classical skin effect above the critical temperature. Below T c, R s monotonically decreases while X s shows a peak, which evolves as a function of the irradiation fluence. The disorder-dependent Z s (T) curves are analyzed within a two-fluid model, suitably modified to account for a finite quasiparticle fraction at T = 0. The analysis gives, for the unirradiated crystal, quasiparticle relaxation times τ that are in good agreement with previous literature. Smaller τ values are deduced for the disordered crystals, both in the normal and in the superconducting states. The limits of application of the model are discussed.

The energy of a prolate spheroidal shell in a uniform magnetic field

NASA Astrophysics Data System (ADS)

Koksharov, Yu. A.

2017-04-01

The problem of the energy of a spheroidal magnetic shell, solved by methods of classical electrodynamics, arises, in particular, upon the study of thin-wall biocompatible microcapsules in connection with a pressing issue of targeted drug delivery. The drug inside a microcapsule should be released from the shell at a required instant of time by destroying the capsule's shell. The placement inside a shell of magnetic nanoparticles sensitive to an external magnetic field theoretically makes it possible to solve both problems: to transport a capsule to the required place and to destroy its shell. In particular, the shell can be destroyed under the action of internal stress when the shape of a capsule is changed. In this paper, the analysis of the model of a magnetic microcapsule in the form of a prolate spheroidal shell is performed and formulas for the magnetostatic and magnetic free energy when the magnetic field is directed along the major axis of the spheroid are derived.

Principle of Magnetodynamics for Composite Magnetic Pole

NASA Astrophysics Data System (ADS)

Animalu, Alexander

2014-03-01

It is shown in this paper that geometry provides the key to the new magnetodynamics principle of operation of the machine (invented by Dr. Ezekiel Izuogu) which has an unexpected feature of driving a motor with static magnetic field. Essentially, because an array of like magnetic poles of the machine is arranged in a half circular array of a cylindrical geometry, the array creates a non-pointlike magnet pole that may be represented by a ``magnetic current loop'' at the position of the pivot of the movable arm. As a result, in three-dimensional space, it is possible to characterize the symmetry of the stator magnetic field B and the magnetic current loop J as a cube-hexagon system by a 6-vector (J,B) (with J.B ≠0) comprising a 4x4 antisymmetric tensor analogous to the conventional electric and magnetic 6-vector (E,B) (with E.B ≠0) comprising the 4x4 antisymmetric tensor of classical electrodynamics The implications are discussed. Supported by International Centre for Basic Research, Abuja, Nigeria.

Electromagnetic Probes: A Chronometer of Heavy Ion Collision

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

Sinha, Bikash

I have known Predhiman for quite some time and I consider his friendship a great privilege. He along with some of his colleagues made the almost unique transition time to time from Quantum Electrodynamics of his (almost classical) electromagnetic plasma to Quantum Chromodynamics of quarks and gluons. Some of the papers are unique in the sense they surface up to the centre stage of the field of quarks and gluons giving us a new insight; the particular paper of Bannur and Kaw discussing the stability of quark gluon plasma is a particularly interesting one.I wish Predhiman the very best onmore » this occasion and sincerely hope for a long vital and fruitful life that lies ahead.Interestingly enough this transition from QED (electromagnetic plasma) to QCD plasma (Quark Gluon Plasma) was motivated by consuming a very special kind of Indian soft nuts on Sunday afternoons, the consumers consisted of two persons, P. K. Kaw and Jitendra Parikh - some nuts!« less

Quantized Electromagnetic-Field Propagation in General Non-Local and Non-Stationary Dispersive and Absorbing Media

NASA Astrophysics Data System (ADS)

Jacobs, Verne

Dynamical descriptions for the propagation of quantized electromagnetic fields, in the presence of environmental interactions, are systematically and self-consistently developed in the complimentary Schrödinger and Heisenberg pictures. An open-systems (non-equilibrium) quantum-electrodynamics description is thereby provided for electromagnetic-field propagation in general non-local and non-stationary dispersive and absorbing optical media, including a fundamental microscopic treatment of decoherence and relaxation processes due to environmental collisional and electromagnetic interactions. Particular interest is centered on entangled states and other non-classical states of electromagnetic fields, which may be created by non-linear electromagnetic interactions and detected by the measurement of various electromagnetic-field correlation functions. Accordingly, we present dynamical descriptions based on general forms of electromagnetic-field correlation functions involving both the electric-field and the magnetic-field components of the electromagnetic field, which are treated on an equal footing. Work supported by the Office of Naval Research through the Basic Research Program at The Naval Research Laboratory.

Passion at a Distance

NASA Astrophysics Data System (ADS)

Howard, Don

In 1984, Abner Shimony invented the expression, “passion at a distance,” to characterize the distinctive relationship of two entangled quantum mechanical systems [1]. It is neither the local causality of pushes, pulls, and central forces familiar from classical mechanics and electrodynamics, nor the non-local causality of instantaneous or just superluminal action at a distance that would spell trouble for relativity theory. This mode of connection of entangled systems has them feeling one another's presence and properties enough to ensure the strong correlations revealed in the Bell experiments, correlations that undergird everything from superfluidity and superconductivity to quantum computing and quantum teleportation, but not in a way that permits direct control of one by manipulation of the other. Intended to echo Aristotle's distinguishing of “potentiality” from “actuality” as different senses of “being,” Shimony's “passion at a distance” is all about tendency and propensity, not the concreteness whose misplacement in realm of the physical was lamented by Alfred North Whitehead.

FDTD chiral brain tissue model for specific absorption rate determination under radiation from mobile phones at 900 and 1800 MHz

NASA Astrophysics Data System (ADS)

Zamorano, M.; Torres-Silva, H.

2006-04-01

A new electrodynamics model formed by chiral bioplasma, which represents the human head inner structure and makes it possible to analyse its behaviour when it is irradiated by a microwave electromagnetic field from cellular phones, is presented. The finite-difference time-domain (FDTD) numeric technique is used, which allows simulation of the electromagnetic fields, deduced with Maxwell's equations, and allows us to simulate the specific absorption rate (SAR). The results show the SAR behaviour as a function of the input power and the chirality factor. In considering the chiral brain tissue in the proposed human head model, the two more important conclusions of our work are the following: (a) the absorption of the electromagnetic fields from cellular phones is stronger, so the SAR coefficient is higher than that using the classical model, when values of the chiral factor are of order of 1; (b) 'inverse skin effect' shows up at 1800 MHz, with respect to a 900 MHz source.

A magnetic gradient induced force in NMR restricted diffusion experiments

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

Ghadirian, Bahman; Stait-Gardner, Tim; Castillo, Reynaldo

2014-03-28

We predict that the phase cancellation of a precessing magnetisation field carried by a diffusing species in a bounded geometry under certain nuclear magnetic resonance pulsed magnetic field gradient sequences results in a small force over typically micrometre length scales. Our calculations reveal that the total magnetisation energy in a pore under the influence of a pulsed gradient will be distance-dependent thus resulting in a force acting on the boundary. It is shown that this effect of the magnetisation of diffusing particles will appear as either an attractive or repulsive force depending on the geometry of the pore and magneticmore » properties of the material. A detailed analysis is performed for the case of a pulsed gradient spin-echo experiment on parallel planes. It is shown that the force decays exponentially in terms of the spin-spin relaxation. The proof is based on classical electrodynamics. An application of this effect to soft matter is suggested.« less

ALPhA Laboratory Immersion in Plasma Physics

NASA Astrophysics Data System (ADS)

Dominguez, A.; Zwicker, A.; Williams, J. D.

2016-10-01

According to the FESAC, as recently as 2014 there were a total of just 14 universities offering strong curricula in MFE sciences. Similarly, it was reported that 8 and 19 universities offer strong HEDPL and Discovery Plasma programs respectively. At the undergraduate level, there is also a lack of plasma physics in the curricula. This, regardless of its rich insights into the core subfields of physics, i.e., classical mechanics, electrodynamics, statistical mechanics and quantum phenomena. The coauthors have been leading a plasma physics workshop for the last 3 years directed at undergraduate physics professors and lecturers. The workshop is centered around a versatile and relatively inexpensive (< 10 k) plasma discharge experiment which lets students explore Panchen's Law, spectroscopy and Langmuir probes. The workshop is part of the Advanced Laboratory Physics Association (ALPhA) Laboratory Immersions, and its objective is for the participants to become familiar with the experiments and incorporate them into their home institution's curricula as junior labs, senior labs or independent student projects.

Electrodynamic Context of Magnetopause Dynamics Observed by Magnetospheric Multiscale

NASA Technical Reports Server (NTRS)

Anderson, Brian J.; Russell, Christopher T.; Strangeway, Robert J.; Plaschke, Ferdinand; Magnes, Werner; Fischer, David; Korth, Haje; Merkin, Viacheslav G.; Barnes, Robin J.; Waters, Colin L.;

Formation and dynamics of a plasma in superstrong laser fields including radiative and quantum electrodynamics effects

NASA Astrophysics Data System (ADS)

Artemenko, I. I.; Golovanov, A. A.; Kostyukov, I. Yu.; Kukushkina, T. M.; Lebedev, V. S.; Nerush, E. N.; Samsonov, A. S.; Serebryakov, D. A.

2016-12-01

Studies of phenomena accompanying the interaction of superstrong electromagnetic fields with matter, in particular, the generation of an electron-positron plasma, acceleration of electrons and ions, and the generation of hard electromagnetic radiation are briefly reviewed. The possibility of using thin films to initiate quantum electrodynamics cascades in the field of converging laser pulses is analyzed. A model is developed to describe the formation of a plasma cavity behind a laser pulse in the transversely inhomogeneous plasma and the generation of betatron radiation by electrons accelerated in this cavity. Features of the generation of gamma radiation, as well as the effect of quantum electrodynamics effects on the acceleration of ions, at the interaction of intense laser pulses with solid targets are studied.

The application of the electrodynamic separator in minerals beneficiation

NASA Astrophysics Data System (ADS)

Skowron, M.; Syrek, P.; Surowiak, A.

2017-05-01

The aim of presented paper is elaboration of methodology of upgrading natural minerals in example of chalcocite and bornite sample. The results were obtained by means of laboratory drum separator. This device operates in accordance to properties of materials, which in this case was electrical conductivity. The study contains the analysis of the forces occurring inside of electrodynamic separator chamber, that act on the particles of various electrical properties. Both, the potential and electric field strength distributions were calculated, with set of separators setpoints. Theoretical analysis influenced on separator parameters, and hence impacted the empirical results too. Next, the authors conducted empirical research on chalcocite and bornite beneficiation by means of electrodynamic separation. The results of this process were shown graphically in form of upgrading curves of chalcocite considering elementary copper and lead.

Magnetically charged regular black hole in a model of nonlinear electrodynamics

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

Ma, Meng-Sen, E-mail: mengsenma@gmail.com

2015-11-15

We obtain a magnetically charged regular black hole in general relativity. The source to the Einstein field equations is nonlinear electrodynamic field in a physically reasonable model of nonlinear electrodynamics (NED). “Physically” here means the NED model is constructed on the basis of three conditions: the Maxwell asymptotic in the weak electromagnetic field limit; the presence of vacuum birefringence phenomenon; and satisfying the weak energy condition (WEC). In addition, we analyze the thermodynamic properties of the regular black hole in two ways. According to the usual black hole thermodynamics, we calculate the heat capacity at constant charge, from which wemore » know the smaller black hole is more stable. We also employ the horizon thermodynamics to discuss the thermodynamic quantities, especially the heat capacity at constant pressure.« less

Computational electrodynamics in material media with constraint-preservation, multidimensional Riemann solvers and sub-cell resolution - Part I, second-order FVTD schemes

NASA Astrophysics Data System (ADS)

Balsara, Dinshaw S.; Taflove, Allen; Garain, Sudip; Montecinos, Gino

2017-11-01

While classic finite-difference time-domain (FDTD) solutions of Maxwell's equations have served the computational electrodynamics (CED) community very well, formulations based on Godunov methodology have begun to show advantages. We argue that the formulations presented so far are such that FDTD schemes and Godunov-based schemes each have their own unique advantages. However, there is currently not a single formulation that systematically integrates the strengths of both these major strains of development. While an early glimpse of such a formulation was offered in Balsara et al. [16], that paper focused on electrodynamics in plasma. Here, we present a synthesis that integrates the strengths of both FDTD and Godunov-based schemes into a robust single formulation for CED in material media. Three advances make this synthesis possible. First, from the FDTD method, we retain (but somewhat modify) a spatial staggering strategy for the primal variables. This provides a beneficial constraint preservation for the electric displacement and magnetic induction vector fields via reconstruction methods that were initially developed in some of the first author's papers for numerical magnetohydrodynamics (MHD). Second, from the Godunov method, we retain the idea of upwinding, except that this idea, too, has to be significantly modified to use the multi-dimensionally upwinded Riemann solvers developed by the first author. Third, we draw upon recent advances in arbitrary derivatives in space and time (ADER) time-stepping by the first author and his colleagues. We use the ADER predictor step to endow our method with sub-cell resolving capabilities so that the method can be stiffly stable and resolve significant sub-cell variation in the material properties within a zone. Overall, in this paper, we report a new scheme for numerically solving Maxwell's equations in material media, with special attention paid to a second-order-accurate formulation. Several numerical examples are presented to show that the proposed technique works. Because of its sub-cell resolving ability, the new method retains second-order accuracy even when material permeability and permittivity vary by an order-of-magnitude over just one or two zones. Furthermore, because the new method is also unconditionally stable in the presence of stiff source terms (i.e., in problems involving giant conductivity variations), it can handle several orders-of-magnitude variation in material conductivity over just one or two zones without any reduction of the time-step. Consequently, the CFL depends only on the propagation speed of light in the medium being studied.

A Toy Model of Quantum Electrodynamics in (1 + 1) Dimensions

ERIC Educational Resources Information Center

Boozer, A. D.

2008-01-01

We present a toy model of quantum electrodynamics (QED) in (1 + 1) dimensions. The QED model is much simpler than QED in (3 + 1) dimensions but exhibits many of the same physical phenomena, and serves as a pedagogical introduction to both QED and quantum field theory in general. We show how the QED model can be derived by quantizing a toy model of…

Topological solitons in 8-spinor mie electrodynamics

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

Rybakov, Yu. P., E-mail: soliton4@mail.ru

2013-10-15

We investigate the effective 8-spinor field model suggested earlier as the generalization of nonlinear Mie electrodynamics. We first study in pure spinorial model the existence of topological solitons endowed with the nontrivial Hopf invariant Q{sub H}, which can be interpreted as the lepton number. Electromagnetic field being included as the perturbation, we estimate the energy and the spin of the localized charged configuration.

Stable structures of microparticles in the electrodynamic trap created by the corona discharge

NASA Astrophysics Data System (ADS)

Vladimirov, V. I.; Deputatova, L. V.; Filinov, V. S.; Lapitsky, D. S.; Pecherkin, V. Ya; Syrovatka, R. A.; Vasilyak, L. M.; Petrov, O. F.

2018-01-01

For the first time the stable structures of microparticles in a dynamic linear trap with corona electrodes have been obtained. The possibility for capturing and confining of microparticles in a linear electrodynamic trap with corona electrodes at atmospheric pressure has been studied experimentally. The corona discharge on the electrodes of the trap was generated by an alternating electric field.

Laterality Defects Other Than Situs Inversus Totalis in Primary Ciliary Dyskinesia

PubMed Central

Davis, Stephanie D.; Ferkol, Thomas; Dell, Sharon D.; Rosenfeld, Margaret; Olivier, Kenneth N.; Sagel, Scott D.; Milla, Carlos; Zariwala, Maimoona A.; Wolf, Whitney; Carson, Johnny L.; Hazucha, Milan J.; Burns, Kimberlie; Robinson, Blair; Knowles, Michael R.; Leigh, Margaret W.

2014-01-01

BACKGROUND: Motile cilia dysfunction causes primary ciliary dyskinesia (PCD), situs inversus totalis (SI), and a spectrum of laterality defects, yet the prevalence of laterality defects other than SI in PCD has not been prospectively studied. METHODS: In this prospective study, participants with suspected PCD were referred to our multisite consortium. We measured nasal nitric oxide (nNO) level, examined cilia with electron microscopy, and analyzed PCD-causing gene mutations. Situs was classified as (1) situs solitus (SS), (2) SI, or (3) situs ambiguus (SA), including heterotaxy. Participants with hallmark electron microscopic defects, biallelic gene mutations, or both were considered to have classic PCD. RESULTS: Of 767 participants (median age, 8.1 years, range, 0.1-58 years), classic PCD was defined in 305, including 143 (46.9%), 125 (41.0%), and 37 (12.1%) with SS, SI, and SA, respectively. A spectrum of laterality defects was identified with classic PCD, including 2.6% and 2.3% with SA plus complex or simple cardiac defects, respectively; 4.6% with SA but no cardiac defect; and 2.6% with an isolated possible laterality defect. Participants with SA and classic PCD had a higher prevalence of PCD-associated respiratory symptoms vs SA control participants (year-round wet cough, P < .001; year-round nasal congestion, P = .015; neonatal respiratory distress, P = .009; digital clubbing, P = .021) and lower nNO levels (median, 12 nL/min vs 252 nL/min; P < .001). CONCLUSIONS: At least 12.1% of patients with classic PCD have SA and laterality defects ranging from classic heterotaxy to subtle laterality defects. Specific clinical features of PCD and low nNO levels help to identify PCD in patients with laterality defects. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT00323167; URL: www.clinicaltrials.gov PMID:24577564

Non-US electrodynamic launchers research and development

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

Parker, J.V.; Batteh, J.H.; Greig, J.R.

Electrodynamic launcher research and development work of scientists outside the United States is analyzed and assessed by six internationally recognized US experts in the field of electromagnetic and electrothermal launchers. The assessment covers five broad technology areas: (1) Experimental railguns; (2) Railgun theory and design; (3) Induction launchers; (4) Electrothermal guns; (5) Energy storage and power supplies. The overall conclusion is that non-US work on electrodynamic launchers is maturing rapidly after a relatively late start in many countries. No foreign program challenges the US efforts in scope, but it is evident that the United States may be surpassed in somemore » technologies within the next few years. Until recently, published Russian work focused on hypervelocity for research purposes. Within the last two years, large facilities have been described where military-oriented development has been underway since the mid-1980s. Financial support for these large facilities appears to have collapsed, leaving no effective effort to develop practical launchers for military or civilian applications. Electrodynamic launcher research in Europe is making rapid progress by focusing on a single application, tactical launchers for the military. Four major laboratories, in Britain, France, Germany, and the Netherlands, are working on this problem. Though narrower in scope than the US effort, the European work enjoys a continuity of support that has accelerated its progress. The next decade will see the deployment of electrodynamic launcher technology, probably in the form of an electrothermal-chemical upgrade for an existing gun system. The time scale for deployment of electromagnetic launchers is entirely dependent on the level of research-and-development effort. If resources remain limited, the advantage will lie with cooperative efforts that have reasonably stable funding such as the present French-German program.« less

Five degrees of freedom linear state-space representation of electrodynamic thrust bearings

NASA Astrophysics Data System (ADS)

Van Verdeghem, J.; Kluyskens, V.; Dehez, B.

2017-09-01

Electrodynamic bearings can provide stable and contactless levitation of rotors while operating at room temperatures. Depending solely on passive phenomena, specific models have to be developed to study the forces they exert and the resulting rotordynamics. In recent years, models allowing us to describe the axial dynamics of a large range of electrodynamic thrust bearings have been derived. However, these bearings being devised to be integrated into fully magnetic suspensions, the existing models still suffer from restrictions. Indeed, assuming the spin speed as varying slowly, a rigid rotor is characterised by five independent degrees of freedom whereas early models only considered the axial degree. This paper presents a model free of the previous limitations. It consists in a linear state-space representation describing the rotor's complete dynamics by considering the impact of the rotor axial, radial and angular displacements as well as the gyroscopic effects. This set of ten equations depends on twenty parameters whose identification can be easily performed through static finite element simulations or quasi-static experimental measurements. The model stresses the intrinsic decoupling between the axial dynamics and the other degrees of freedom as well as the existence of electrodynamic angular torques restoring the rotor to its nominal position. Finally, a stability analysis performed on the model highlights the presence of two conical whirling modes related to the angular dynamics, namely the nutation and precession motions. The former, whose intrinsic stability depends on the ratio between polar and transverse moments of inertia, can be easily stabilised through external damping whereas the latter, which is stable up to an instability threshold linked to the angular electrodynamic cross-coupling stiffness, is less impacted by that damping.

EMC Test Report Electrodynamic Dust Shield

NASA Technical Reports Server (NTRS)

Carmody, Lynne M.; Boyette, Carl B.

2014-01-01

This report documents the Electromagnetic Interference E M I evaluation performed on the Electrodynamic Dust Shield (EDS) which is part of the MISSE-X System under the Electrostatics and Surface Physics Laboratory at Kennedy Space Center. Measurements are performed to document the emissions environment associated with the EDS units. The purpose of this report is to collect all information needed to reproduce the testing performed on the Electrodynamic Dust Shield units, document data gathered during testing, and present the results. This document presents information unique to the measurements performed on the Bioculture Express Rack payload; using test methods prepared to meet SSP 30238 requirements. It includes the information necessary to satisfy the needs of the customer per work order number 1037104. The information presented herein should only be used to meet the requirements for which it was prepared.

Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator

NASA Astrophysics Data System (ADS)

Wu, Liang; Salehi, M.; Koirala, N.; Moon, J.; Oh, S.; Armitage, N. P.

2016-12-01

Topological insulators have been proposed to be best characterized as bulk magnetoelectric materials that show response functions quantized in terms of fundamental physical constants. Here, we lower the chemical potential of three-dimensional (3D) Bi2Se3 films to ~30 meV above the Dirac point and probe their low-energy electrodynamic response in the presence of magnetic fields with high-precision time-domain terahertz polarimetry. For fields higher than 5 tesla, we observed quantized Faraday and Kerr rotations, whereas the dc transport is still semiclassical. A nontrivial Berry’s phase offset to these values gives evidence for axion electrodynamics and the topological magnetoelectric effect. The time structure used in these measurements allows a direct measure of the fine-structure constant based on a topological invariant of a solid-state system.

Problems of Technical Electrodynamics (Selected Articles),

DTIC Science & Technology

1984-04-11

copy available. ii DC 83143001 PAGE 1 PROBLEMS OF TECHNICAL ELECTRODYNAMICS. DOC - 83143001 PAGE 2 In the collector /collection are connected the...composite/ compound reliable in mechanical sense forgings of rotors with a weight of 250 t and it is more and rotor binding bands. These K forgings must be...go - calculated coefficient, which considers the character of temperature field. With a linear change in temperature .=1, with parabolic =3

Correlating the Structure, Optical Spectra, and Electrodynamics of Single Silver Nanocubes

DTIC Science & Technology

2009-01-27

Correlating the Structure, Optical Spectra, and Electrodynamics of Single Silver Nanocubes Jeffrey M. McMahon,†,‡ Yingmin Wang,§ Leif J. Sherry...response and detailed structural information for a single nanoparticle, using a silver (Ag) nanocube as the example. By carefully incorporating the HRTEM...this work is to describe the relationship between the optical response, morphology, and dielectric environment of a single silver (Ag) cubic

Pathfinder

NASA Image and Video Library

2001-07-01

This photograph shows two Marshall Space Flight Center (MSFC) engineers, Mark Vaccaro (left) and Ken Welzyn, testing electrodynamic tethers in the MSFC Tether Winding and Spark Testing Facility. For 4 years, MSFC and industry partners have been developing the Propulsive Small Expendable Deployer System experiment, called ProSEDS. ProSEDS will test electrodynamic tether propulsion technology. Electrodynamic tethers are long, thin wires that collect electrical current when passing through a magnetic field. The tether works as a thruster as a magnetic field exerts a force on a current-carrying wire. Since electrodynamic tethers require no propellant, they could substantially reduce the weight of the spacecraft and provide a cost-effective method of reboosting spacecraft. The initial flight of ProSEDS is scheduled to fly aboard an Air Force Delta II rocket in the summer of 2002. In orbit, ProSEDS will deploy from a Delta II second stage. It will be a 3.1-mile (5 kilometer) long, ultrathin base-wire tether cornected with a 6.2-mile (10 kilometer) long non-conducting tether. This photograph shows Less Johnson, a scientist at MSFC, inspecting the nonconducting part of a tether as it exits a deployer similar to the one to be used in the ProSEDS experiment. The ProSEDS experiment is managed by the Space Transportation Directorate at MSFC.

Shock wave polarizations and optical metrics in the Born and the Born–Infeld electrodynamics

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

Minz, Christoph, E-mail: christoph.minz@alumni.tu-berlin.de; Borzeszkowski, Horst-Heino von, E-mail: borzeszk@mailbox.tu-berlin.de; Chrobok, Thoralf, E-mail: tchrobok@mailbox.tu-berlin.de

We analyze the behavior of shock waves in nonlinear theories of electrodynamics. For this, by use of generalized Hadamard step functions of increasing order, the electromagnetic potential is developed in a series expansion near the shock wave front. This brings about a corresponding expansion of the respective electromagnetic field equations which allows for deriving relations that determine the jump coefficients in the expansion series of the potential. We compute the components of a suitable gauge-normalized version of the jump coefficients given for a prescribed tetrad compatible with the shock front foliation. The solution of the first-order jump relations shows that,more » in contrast to linear Maxwell’s electrodynamics, in general the propagation of shock waves in nonlinear theories is governed by optical metrics and polarization conditions describing the propagation of two differently polarized waves (leading to a possible appearance of birefringence). In detail, shock waves are analyzed in the Born and Born–Infeld theories verifying that the Born–Infeld model exhibits no birefringence and the Born model does. The obtained results are compared to those ones found in literature. New results for the polarization of the two different waves are derived for Born-type electrodynamics.« less

Electrodynamic Dust Shield for Surface Exploration Activities on the Moon and Mars

NASA Technical Reports Server (NTRS)

Calle, C. I.; Immer, C. D.; Clements, J. S.; Chen, A.; Buhler, C. R.; Lundeen, P.; Mantovani, J. G.; Starnes, J. W.; Michalenko, M.; Mazumder, M. K.

2006-01-01

The Apollo missions to the moon showed that lunar dust can hamper astronaut surface activities due to its ability to cling to most surfaces. NASA's Mars exploration landers and rovers have also shown that the problem is equally hard if not harder on Mars. In this paper, we report on our efforts to develop and electrodynamic dust shield to prevent the accumulation of dust on surfaces and to remove dust already adhering to those surfaces. The parent technology for the electrodynamic dust shield, developed in the 1970s, has been shown to lift and transport charged and uncharged particles using electrostatic and dielectrophoretic forces. This technology has never been applied for space applications on Mars or the moon due to electrostatic breakdown concerns. In this paper, we show that an appropriate design can prevent the electrostatic breakdown at the low Martian atmospheric pressures. We are also able to show that uncharged dust can be lifted and removed from surfaces under simulated Martian environmental conditions. This technology has many potential benefits for removing dust from visors, viewports and many other surfaces as well as from solar arrays. We have also been able to develop a version of the electrodynamic dust shield working under. hard vacuum conditions. This version should work well on the moon.

Complex temperature dependence of coupling and dissipation of cavity magnon polaritons from millikelvin to room temperature

NASA Astrophysics Data System (ADS)

Boventer, Isabella; Pfirrmann, Marco; Krause, Julius; Schön, Yannick; Kläui, Mathias; Weides, Martin

2018-05-01

Hybridized magnonic-photonic systems are key components for future information processing technologies such as storage, manipulation, or conversion of data both in the classical (mostly at room temperature) and quantum (cryogenic) regime. In this work, we investigate a yttrium-iron-garnet sphere coupled strongly to a microwave cavity over the full temperature range from 290 K to 30 mK . The cavity-magnon polaritons are studied from the classical to the quantum regimes where the thermal energy is less than one resonant microwave quanta, i.e., at temperatures below 1 K . We compare the temperature dependence of the coupling strength geff(T ) , describing the strength of coherent energy exchange between spin ensemble and cavity photon, to the temperature behavior of the saturation magnetization evolution Ms(T ) and find strong deviations at low temperatures. The temperature dependence of magnonic disspation is governed at intermediate temperatures by rare-earth impurity scattering leading to a strong peak at 40 K . The linewidth κm decreases to 1.2 MHz at 30 mK , making this system suitable as a building block for quantum electrodynamics experiments. We achieve an electromagnonic cooperativity in excess of 20 over the entire temperature range, with values beyond 100 in the millikelvin regime as well as at room temperature. With our measurements, spectroscopy on strongly coupled magnon-photon systems is demonstrated as versatile tool for spin material studies over large temperature ranges. Key parameters are provided in a single measurement, thus simplifying investigations significantly.

Surprising structures hiding in Penrose’s future null infinity

NASA Astrophysics Data System (ADS)

Newman, Ezra T.

2017-07-01

Since the late1950s, almost all discussions of asymptotically flat (Einstein-Maxwell) space-times have taken place in the context of Penrose’s null infinity, I+. In addition, almost all calculations have used the Bondi coordinate and tetrad systems. Beginning with a known asymptotically flat solution to the Einstein-Maxwell equations, we show first, that there are other natural coordinate systems, near I+, (analogous to light-cones in flat-space) that are based on (asymptotically) shear-free null geodesic congruences (analogous to the flat-space case). Using these new coordinates and their associated tetrad, we define the complex dipole moment, (the mass dipole plus i times angular momentum), from the l  =  1 harmonic coefficient of a component of the asymptotic Weyl tensor. Second, from this definition, from the Bianchi identities and from the Bondi-Sachs mass and linear momentum, we show that there exists a large number of results—identifications and dynamics—identical to those of classical mechanics and electrodynamics. They include, among many others, {P}=M{v}+..., {L}= {r} × {P} , spin, Newton’s second law with the rocket force term (\\dotM v) and radiation reaction, angular momentum conservation and others. All these relations take place in the rather mysterious H-space rather than in space-time. This leads to the enigma: ‘why do these well known relations of classical mechanics take place in H-space?’ and ‘What is the physical meaning of H-space?’

Scalar quantum electrodynamics via Duffin-Kemmer-Petiau gauge theory in the Heisenberg picture: Vacuum polarization

NASA Astrophysics Data System (ADS)

Beltran, J.; Maia, N. T.; Pimentel, B. M.

2018-04-01

Scalar Quantum Electrodynamics is investigated in the Heisenberg picture via the Duffin-Kemmer-Petiau gauge theory. On this framework, a perturbative method is used to compute the vacuum polarization tensor and its corresponding induced current for the case of a charged scalar field in the presence of an external electromagnetic field. Charge renormalization is brought into discussion for the interpretation of the results for the vacuum polarization.

Comparison of the DeWitt metric in general relativity with the fourth-rank constitutive tensors in electrodynamics and in elasticity theory

NASA Astrophysics Data System (ADS)

Hehl, Friedrich W.; Kiefer, Claus

2018-01-01

We perform a short comparison between the local and linear constitutive tensor χ ^{λ ν σ κ } in four-dimensional electrodynamics, the elasticity tensor c^{ijkl} in three-dimensional elasticity theory, and the DeWitt metric G^{abcd} in general relativity, with {a,b,\\ldots =1,2,3}. We find that the DeWitt metric has only six independent components.

Gravitational induction

NASA Astrophysics Data System (ADS)

Bini, Donato; Cherubini, Christian; Chicone, Carmen; Mashhoon, Bahram

2008-11-01

We study the linear post-Newtonian approximation to general relativity known as gravitoelectromagnetism (GEM); in particular, we examine the similarities and differences between GEM and electrodynamics. Notwithstanding some significant differences between them, we find that a special nonstationary metric in GEM can be employed to show explicitly that it is possible to introduce gravitational induction within GEM in close analogy with Faraday's law of induction and Lenz's law in electrodynamics. Some of the physical implications of gravitational induction are briefly discussed.

Electromagnetic perturbations of black holes in general relativity coupled to nonlinear electrodynamics

NASA Astrophysics Data System (ADS)

Toshmatov, Bobir; Stuchlík, Zdeněk; Schee, Jan; Ahmedov, Bobomurat

2018-04-01

The electromagnetic (EM) perturbations of the black hole solutions in general relativity coupled to nonlinear electrodynamics (NED) are studied for both electrically and magnetically charged black holes, assuming that the EM perturbations do not alter the spacetime geometry. It is shown that the effective potentials of the electrically and magnetically charged black holes related to test perturbative NED EM fields are related to the effective metric governing the photon motion, contrary to the effective potential of the linear electrodynamic (Maxwell) field that is related to the spacetime metric. Consequently, corresponding quasinormal (QN) frequencies differ as well. As a special case, we study new family of the NED black hole solutions which tend in the weak field limit to the Maxwell field, giving the Reissner-Nordström (RN) black hole solution. We compare the NED Maxwellian black hole QN spectra with the RN black hole QN spectra.

Teleparallel theories of gravity as analogue of nonlinear electrodynamics

NASA Astrophysics Data System (ADS)

Hohmann, Manuel; Järv, Laur; Krššák, Martin; Pfeifer, Christian

2018-05-01

The teleparallel formulation of gravity theories reveals close structural analogies to electrodynamics, which are more hidden in their usual formulation in terms of the curvature of spacetime. We show how every locally Lorentz invariant teleparallel theory of gravity with second-order field equations can be understood as built from a gravitational field strength and excitation tensor which are related to each other by a constitutive relation, analogous to the premetric construction of theories of electrodynamics. We demonstrate how the previously studied models of f (T ) and f (Tax,Tten,Tvec) gravity as well as teleparallel dark energy can be formulated in this language. The advantage of this approach to gravity is that the field equations for different models all take the same compact form and general results can be obtained. An important new such result we find is a constraint which relates the field equations of the tetrad and the spin connection.

Thermodynamic instability of topological black holes in Gauss-Bonnet gravity with a generalized electrodynamics

NASA Astrophysics Data System (ADS)

Hendi, S. H.; Panahiyan, S.

2014-12-01

Motivated by the string corrections on the gravity and electrodynamics sides, we consider a quadratic Maxwell invariant term as a correction of the Maxwell Lagrangian to obtain exact solutions of higher dimensional topological black holes in Gauss-Bonnet gravity. We first investigate the asymptotically flat solutions and obtain conserved and thermodynamic quantities which satisfy the first law of thermodynamics. We also analyze thermodynamic stability of the solutions by calculating the heat capacity and the Hessian matrix. Then, we focus on horizon-flat solutions with an anti-de Sitter (AdS) asymptote and produce a rotating spacetime with a suitable transformation. In addition, we calculate the conserved and thermodynamic quantities for asymptotically AdS black branes which satisfy the first law of thermodynamics. Finally, we perform thermodynamic instability criterion to investigate the effects of nonlinear electrodynamics in canonical and grand canonical ensembles.

Terahertz-infrared electrodynamics of single-wall carbon nanotube films

NASA Astrophysics Data System (ADS)

Zhukova, E. S.; Grebenko, A. K.; Bubis, A. V.; Prokhorov, A. S.; Belyanchikov, M. A.; Tsapenko, A. P.; Gilshteyn, E. P.; Kopylova, D. S.; Gladush, Yu G.; Anisimov, A. S.; Anzin, V. B.; Nasibulin, A. G.; Gorshunov, B. P.

2017-11-01

Broad-band (4-20 000 cm-1) spectra of real and imaginary conductance of a set of high-quality pristine and AuCl3-doped single-walled carbon nanotube (SWCNT) films with different transparency are systematically measured. It is shown that while the high-energy (≥1 eV) response is determined by well-known interband transitions, the lower-energy electrodynamic properties of the films are fully dominated by unbound charge carriers. Their main spectral effect is seen as the free-carrier Drude-type contribution. Partial localization of these carriers leads to a weak plasmon resonance around 100 cm-1. At the lowest frequencies, below 10 cm-1, a gap-like feature is detected whose origin is associated with the energy barrier experienced by the carriers at the intersections between SWCNTs. It is assumed that these three mechanisms are universal and determine the low-frequency terahertz-infrared electrodynamics of SWCNT wafer-scale films.

Numerical and Analytical Model of an Electrodynamic Dust Shield for Solar Panels on Mars

NASA Technical Reports Server (NTRS)

Calle, C. I.; Linell, B.; Chen, A.; Meyer, J.; Clements, S.; Mazumder, M. K.

2006-01-01

Masuda and collaborators at the University of Tokyo developed a method to confine and transport particles called the electric curtain in which a series of parallel electrodes connected to an AC source generates a traveling wave that acts as a contactless conveyor. The curtain electrodes can be excited by a single-phase or a multi-phase AC voltage. A multi-phase curtain produces a non-uniform traveling wave that provides controlled transport of those particles [1-6]. Multi-phase electric curtains from two to six phases have been developed and studied by several research groups [7-9]. We have developed an Electrodynamic Dust Shield prototype using threephase AC voltage electrodes to remove dust from surfaces. The purpose of the modeling work presented here is to research and to better understand the physics governing the electrodynamic shield, as well as to advance and to support the experimental dust shield research.

Scheme for implementing perfect quantum teleportation with four-qubit entangled states in cavity quantum electrodynamics

NASA Astrophysics Data System (ADS)

Tang, Jing-Wu; Zhao, Guan-Xiang; He, Xiong-Hui

2011-05-01

Recently, Peng et al. [2010 Eur. Phys. J. D 58 403] proposed to teleport an arbitrary two-qubit state with a family of four-qubit entangled states, which simultaneously include the tensor product of two Bell states, linear cluster state and Dicke-class state. This paper proposes to implement their scheme in cavity quantum electrodynamics and then presents a new family of four-qubit entangled state |Ω4>1234. It simultaneously includes all the well-known four-qubit entangled states which can be used to teleport an arbitrary two-qubit state. The distinct advantage of the scheme is that it only needs a single setup to prepare the whole family of four-qubit entangled states, which will be very convenient for experimental realization. After discussing the experimental condition in detail, we show the scheme may be feasible based on present technology in cavity quantum electrodynamics.

Hybrid test on building structures using electrodynamic fatigue test machine

NASA Astrophysics Data System (ADS)

Xu, Zhao-Dong; Wang, Kai-Yang; Guo, Ying-Qing; Wu, Min-Dong; Xu, Meng

2017-01-01

Hybrid simulation is an advanced structural dynamic experimental method that combines experimental physical models with analytical numerical models. It has increasingly been recognised as a powerful methodology to evaluate structural nonlinear components and systems under realistic operating conditions. One of the barriers for this advanced testing is the lack of flexible software for hybrid simulation using heterogeneous experimental equipment. In this study, an electrodynamic fatigue test machine is made and a MATLAB program is developed for hybrid simulation. Compared with the servo-hydraulic system, electrodynamic fatigue test machine has the advantages of small volume, easy operation and fast response. A hybrid simulation is conducted to verify the flexibility and capability of the whole system whose experimental substructure is one spring brace and numerical substructure is a two-storey steel frame structure. Experimental and numerical results show the feasibility and applicability of the whole system.

Electrodynamic tether system study: Extended study

NASA Technical Reports Server (NTRS)

1988-01-01

This document is the final report of a study performed by Ball Space Systems Division (BSSD) for the NASA Johnson Space Center under an extension to contract NAS9-17666. The tasks for the extended study were as follows: (1) Define an interface between the Electrodynamic Tether System (ETS) and the Space Station (SS); (2) Identify growth paths for the 100 kW ETS defined in the original study to a 200 kW level of performance; (3) Quantify orbit perturbations caused by cyclic day/night operations of a Plasma Motor/Generator (PMG) on the SS and explore methods of minimizing these effects; (4) Define the analyses, precursor technology, ground tests, and precursor demonstrations leading up to a demonstration mission for an electrodynamic tether system that would be capable of producing maneuvering thrust levels of 25 newtons; and (5) Propose a development schedule for the demonstration mission and preliminary cost estimates.

JOURNAL SCOPE GUIDELINES: Paper classification scheme

NASA Astrophysics Data System (ADS)

2005-06-01

This scheme is used to clarify the journal's scope and enable authors and readers to more easily locate the appropriate section for their work. For each of the sections listed in the scope statement we suggest some more detailed subject areas which help define that subject area. These lists are by no means exhaustive and are intended only as a guide to the type of papers we envisage appearing in each section. We acknowledge that no classification scheme can be perfect and that there are some papers which might be placed in more than one section. We are happy to provide further advice on paper classification to authors upon request (please email jphysa@iop.org). 1. Statistical physics numerical and computational methods statistical mechanics, phase transitions and critical phenomena quantum condensed matter theory Bose-Einstein condensation strongly correlated electron systems exactly solvable models in statistical mechanics lattice models, random walks and combinatorics field-theoretical models in statistical mechanics disordered systems, spin glasses and neural networks nonequilibrium systems network theory 2. Chaotic and complex systems nonlinear dynamics and classical chaos fractals and multifractals quantum chaos classical and quantum transport cellular automata granular systems and self-organization pattern formation biophysical models 3. Mathematical physics combinatorics algebraic structures and number theory matrix theory classical and quantum groups, symmetry and representation theory Lie algebras, special functions and orthogonal polynomials ordinary and partial differential equations difference and functional equations integrable systems soliton theory functional analysis and operator theory inverse problems geometry, differential geometry and topology numerical approximation and analysis geometric integration computational methods 4. Quantum mechanics and quantum information theory coherent states eigenvalue problems supersymmetric quantum mechanics scattering theory relativistic quantum mechanics semiclassical approximations foundations of quantum mechanics and measurement theory entanglement and quantum nonlocality geometric phases and quantum tomography quantum tunnelling decoherence and open systems quantum cryptography, communication and computation theoretical quantum optics 5. Classical and quantum field theory quantum field theory gauge and conformal field theory quantum electrodynamics and quantum chromodynamics Casimir effect integrable field theory random matrix theory applications in field theory string theory and its developments classical field theory and electromagnetism metamaterials 6. Fluid and plasma theory turbulence fundamental plasma physics kinetic theory magnetohydrodynamics and multifluid descriptions strongly coupled plasmas one-component plasmas non-neutral plasmas astrophysical and dusty plasmas

From quantum to classical interactions between a free electron and a surface

NASA Astrophysics Data System (ADS)

Beierle, Peter James

Quantum theory is often cited as being one of the most empirically validated theories in terms of its predictive power and precision. These attributes have led to numerous scientific discoveries and technological advancements. However, the precise relationship between quantum and classical physics remains obscure. The prevailing description is known as decoherence theory, where classical physics emerges from a more general quantum theory through environmental interaction. Sometimes referred to as the decoherence program, it does not solve the quantum measurement problem. We believe experiments performed between the microscopic and macroscopic world may help finish the program. The following considers a free electron that interacts with a surface (the environment), providing a controlled decoherence mechanism. There are non-decohering interactions to be examined and quantified before the weaker decohering effects are filtered out. In the first experiment, an electron beam passes over a surface that's illuminated by low-power laser light. This induces a surface charge redistribution causing the electron deflection. This phenomenon's parameters are investigated. This system can be well understood in terms of classical electrodynamics, and the technological applications of this electron beam switch are considered. Such phenomena may mask decoherence effects. A second experiment tests decoherence theory by introducing a nanofabricated diffraction grating before the surface. The electron undergoes diffraction through the grating, but as the electron passes over the surface it's predicted by various physical models that the electron will lose its wave interference property. Image charge based models, which predict a larger loss of contrast than what is observed, are falsified (despite experiencing an image charge force). A theoretical study demonstrates how a loss of contrast may not be due to the irreversible process decoherence, but dephasing (a reversible process due to randomization of the wavefunction's phase). To resolve this ambiguity, a correlation function on an ensemble of diffraction patterns is analyzed after an electron undergoes either process in a path integral calculation. The diffraction pattern is successfully recovered for dephasing, but not for decoherence, thus verifying it as a potential tool in experimental studies to determine the nature of the observed process.

Usefulness of classical homeopathy for the prophylaxis of recurrent urinary tract infections in individuals with chronic neurogenic lower urinary tract dysfunction.

PubMed

Pannek, Jürgen; Pannek-Rademacher, Susanne; Jus, Mohinder S; Wöllner, Jens; Krebs, Jörg

2018-02-27

Context/Objective to investigate the usefulness of classical homeopathy for the prevention of recurrent urinary tract infections (UTI) in patients with spinal cord injury (SCI). Design prospective study. Setting rehabilitation center in Switzerland. Participants patients with chronic SCI and ≥3 UTI/year. Interventions Participants were treated either with a standardized prophylaxis alone or in combination with homeopathy. Outcome measures The number of UTI, general and specific quality of life (QoL), and satisfaction with homeopathic treatment were assessed prospectively for one year. Results Ten patients were in the control group; 25 patients received adjunctive homeopathic treatment. The median number of self-reported UTI in the homeopathy group decreased significantly, whereas it remained unchanged in the control group. The domain incontinence impact of the KHQ improved significantly (P = 0.035), whereas the general QoL did not change. The satisfaction with homeopathic care was high. Conclusions Adjunctive homeopathic treatment lead to a significant decrease of UTI in SCI patients. Therefore, classical homeopathy could be considered in SCI patients with recurrent UTI. Trial registration ClinicalTrials.gov. (NCT01477502).

Scientific Studies of the High-Latitude Ionosphere with the Ionosphere Dynamics and ElectroDynamics - Data Assimilation (IDED-DA) Model

DTIC Science & Technology

2014-09-23

conduct simulations with a high-latitude data assimilation model. The specific objectives are to study magnetosphere-ionosphere ( M -I) coupling processes...based on three physics-based models, including a magnetosphere-ionosphere ( M -I) electrodynamics model, an ionosphere model, and a magnetic...inversion code. The ionosphere model is a high-resolution version of the Ionosphere Forecast Model ( IFM ), which is a 3-D, multi-ion model of the ionosphere

Electrodynamics on extrasolar giant planets

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

Koskinen, T. T.; Yelle, R. V.; Lavvas, P.

2014-11-20

Strong ionization on close-in extrasolar giant planets (EGPs) suggests that their atmospheres may be affected by ion drag and resistive heating arising from wind-driven electrodynamics. Recent models of ion drag on these planets, however, are based on thermal ionization only and do not include the upper atmosphere above the 1 mbar level. These models are also based on simplified equations of resistive magnetohydrodynamics that are not always valid in extrasolar planet atmospheres. We show that photoionization dominates over thermal ionization over much of the dayside atmosphere above the 100 mbar level, creating an upper ionosphere dominated by ionization of Hmore » and He and a lower ionosphere dominated by ionization of metals such as Na, K, and Mg. The resulting dayside electron densities on close-in exoplanets are higher than those encountered in any planetary ionosphere of the solar system, and the conductivities are comparable to the chromosphere of the Sun. Based on these results and assumed magnetic fields, we constrain the conductivity regimes on close-in EGPs and use a generalized Ohm's law to study the basic effects of electrodynamics in their atmospheres. We find that ion drag is important above the 10 mbar level where it can also significantly alter the energy balance through resistive heating. Due to frequent collisions of the electrons and ions with the neutral atmosphere, however, ion drag is largely negligible in the lower atmosphere below the 10 mbar level for a reasonable range of planetary magnetic moments. We find that the atmospheric conductivity decreases by several orders of magnitude in the night side of tidally locked planets, leading to a potentially interesting large-scale dichotomy in electrodynamics between the day and night sides. A combined approach that relies on UV observations of the upper atmosphere, phase curve and Doppler measurements of global dynamics, and visual transit observations to probe the alkali metals can potentially be used to constrain electrodynamics in the future.« less

Electrodynamic Tethers and E-Sails as Active Experiment Testbeds and Technologies in Space

NASA Astrophysics Data System (ADS)

Gilchrist, B. E.; Wiegmann, B.; Johnson, L.; Bilen, S. G.; Habash Krause, L.; Miars, G.; Leon, O.

2017-12-01

The use of small-to-large flexible structures in space such as tethers continues to be studied for scientific and technology applications. Here we will consider tether electrodynamic and electrostatic interactions with magneto-plasmas in ionospheres, magnetospheres, and interplanetary space. These systems are enabling fundamental studies of basic plasma physics phenomena, allowing direct studies of the space environment, and generating technological applications beneficial for science missions. Electrodynamic tethers can drive current through the tether based on the Lorenz force adding or extracting energy from its orbit allowing for the study of charged bodies or plasma plumes moving through meso-sonic magnetoplasmas [1]. Technologically, this also generates propulsive forces requiring no propellant and little or no consumables in any planetary system with a magnetic field and ionosphere, e.g., Jupiter [2]. Further, so called electric sails (E-sails) are being studied to provide thrust through momentum exchange with the hypersonic solar wind. The E-sail uses multiple, very long (10s of km) charged, mostly bare rotating conducting tethers to deflect solar wind protons. It is estimated that a spacecraft could achieve a velocity over 100 km/s with time [3,4]. 1. Banks, P.M., "Review of electrodynamic tethers for space plasma science," J. Spacecraft and Rockets, vol. 26, no. 4, pp. 234-239, 1989. 2. Talley, C., J. Moore, D. Gallagher, and L. Johnson, "Propulsion and power from a rotating electrodynamic tether at Jupiter," 38th AIAA Aerospace Sciences Meeting and Exhibit, January 2000. 3. Janhunen, P., "The electric sail—A new propulsion method which may enable fast missions to the outer solar system," J. British Interpl. Soc., vol. 61, no. 8, pp. 322-325, 2008. 4. Wiegman, B., T. Scheider, A. Heaton, J. Vaughn, N. Stone, and K. Wright, "The Heliopause Electrostatic Rapid Transit System (HERTS)—Design, trades, and analyses performed in a two-year NASA investigation of electric sail propulsion systems," 53rd AIAA/SAE/ASEE Joint Propulsion Conf., 10-12 July 2017, Atlanta, GA.

Simulations of radiation pressure experiments narrow down the energy and momentum of light in matter

NASA Astrophysics Data System (ADS)

Bethune-Waddell, Max; Chau, Kenneth J.

2015-12-01

Consensus on a single electrodynamic theory has yet to be reached. Discord was seeded over a century ago when Abraham and Minkowski proposed different forms of electromagnetic momentum density and has since expanded in scope with the gradual introduction of other forms of momentum and force densities. Although degenerate sets of electrodynamic postulates can be fashioned to comply with global energy and momentum conservation, hope remains to isolate a single theory based on detailed comparison between force density predictions and radiation pressure experiments. This comparison is two-fold challenging because there are just a handful of quantitative radiation pressure measurements over the past century and the solutions developed from different postulates, which consist of approximate expressions and inferential deductions, are scattered throughout the literature. For these reasons, it is appropriate to conduct a consolidated and comprehensive re-analysis of past experiments under the assumption that the momentum and energy of light in matter are degenerate. We create a combined electrodynamic/fluid dynamic simulation testbed that uses five historically significant sets of electrodynamic postulates, including those by Abraham and Minkowski, to model radiation pressure under diverse configurations with minimal assumptions. This leads to new interpretations of landmark investigations of light momentum, including the Balazs thought experiment, the Jones-Richards and Jones-Leslie measurements of radiation pressure on submerged mirrors, observations of laser-deformed fluid surfaces, and experiments on optical trapping and tractor beaming of dielectric particles. We discuss the merits and demerits of each set of postulates when compared to available experimental evidence and fundamental conservation laws. Of the five sets of postulates, the Abraham and Einstein-Laub postulates provide the greatest consistency with observations and the most physically plausible descriptions of electrodynamic interactions. Force density predictions made by these two postulates are unique under many conditions and their experimental isolation is potentially within reach.

Psychosocial work factors and sleep problems: findings from the French national SIP survey.

PubMed

Chazelle, Emilie; Chastang, Jean-François; Niedhammer, Isabelle

2016-04-01

This study aimed at exploring the cross-sectional and prospective associations between psychosocial work factors and sleep problems. The study population consisted of a national representative sample of the French working population (SIP survey). The sample sizes were 7506 and 3555 for the cross-sectional and prospective analyses. Sleep problems were defined by either sleep disturbances or insufficient sleep duration at least several times a week. Psychosocial work factors included classical (job strain model factors) and emergent factors (recognition, insecurity, role/ethical conflict, emotional demands, work-life imbalance, etc.). Occupational factors related to working time/hours and physical work environment were also included as well as covariates related to factors outside work. Statistical analyses were performed using weighted Poisson regression analysis. In the cross-sectional analyses, psychological demands, low social support, low recognition, emotional demands, perception of danger, work-life imbalance and night work were found to be associated with sleep problems. In the prospective analyses, psychological demands and night work were predictive of sleep problems. Using a less conservative method, more factors were found to be associated with sleep problems. Dose-response associations were observed, showing that the more frequent the exposure to these factors, the higher the risk of sleep problems. No effect of repeated exposure was found on sleep problems. Classical and emergent psychosocial work factors were associated with sleep problems. More prospective studies and prevention policies may be needed.

Metal Ion Modeling Using Classical Mechanics

PubMed Central

2017-01-01

Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems. PMID:28045509

QED (quantum-electrodynamical) theory of excess spontaneous emission noise

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

Milonni, P.W.

1990-01-01

The results of a quantum-electrodynamical theory of excess spontaneous emission noise in lossy resonators will be presented. The Petermann K factor'' does not enter into the spontaneous emission rate of a single atom in the cavity. The QED theory allows different interpretations of the K factor, and we use this fact to justify semiclassical analyses and to provide in one example a simple derivation of K in terms of the amplification of the quantum vacuum field entering the resonator through its mirrors. 17 refs.

Soliton configurations in generalized Mie electrodynamics

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

Rybakov, Yu. P., E-mail: soliton4@mail.ru

2011-07-15

The generalization of the Mie electrodynamics within the scope of the effective 8-spinor field model is suggested, with the Lagrangian including Higgs-like potential and higher degrees of the invariant A{sub Micro-Sign }A{sup Micro-Sign }. Using special Brioschi 8-spinor identity, we show that the model includes the Skyrme and the Faddeev models as particular cases. We investigate the large-distance asymptotic of static solutions and estimate the electromagnetic contribution to the energy of the localized charged configuration.

High voltage characteristics of the electrodynamic tether and the generation of power and propulsion

NASA Technical Reports Server (NTRS)

Williamson, P. R.

1986-01-01

The Tethered Satellite System (TSS) will deploy and retrieve a satellite from the Space Shuttle orbiter with a tether of up to 100 km in length attached between the satellite and the orbiter. The characteristics of the TSS which are related to high voltages, electrical currents, energy storage, power, and the generation of plasma waves are described. A number of specific features of the tether system of importance in assessing the operational characteristics of the electrodynamic TSS are identified.

The resolved layer of a collisionless, high beta, supercritical, quasi-perpendicular shock wave. II - Dissipative fluid electrodynamics

NASA Technical Reports Server (NTRS)

Scudder, J. D.; Aggson, T. L.; Mangeney, A.; Lacombe, C.; Harvey, C. C.

1986-01-01

Using the results of Scudder et al. (1986) on the bow shock wave observed by ISEE satellites, a quantitative description is presented of the electrodynamics of ion and electron fluids, and phase-standing wave interaction which manifests itself as a supercritical MHD shock. The cross-shock electrical profile was determined in both the normal incidence frame and in the deHoffman-Teller frame by two different methods, and the results were compared with dc electric field measurements.

Desert Research and Technology Studies Exposure of Lotus Coated Electrodynamic Shield Samples

NASA Technical Reports Server (NTRS)

Rodriquez, Marcello; Peters, Wanda C.; Straka, Sharon A.; Jones, Craig B.

2011-01-01

The Lotus dust mitigation coating and the electrodynamic shield (EDS) are two new technologies currently being developed by NASA as countermeasures for addressing dust accumulation for long-duration human space exploration. These combined technologies were chosen by the Habitation Demonstration Unit (HDU) program for desert dust exposure at the Desert Research and Technologies Studies (D-RaTS) test site in Arizona. Characterization of these samples was performed prior to, during and post D-RaTS exposure.

International Space Station Electrodynamic Tether Reboost Study

NASA Technical Reports Server (NTRS)

Johnson, L.; Herrmann, M.

1998-01-01

The International Space Station (ISS) will require periodic reboost due to atmospheric aerodynamic drag. This is nominally achieved through the use of thruster firings by the attached Progress M spacecraft. Many Progress flights to the ISS are required annually. Electrodynamic tethers provide an attractive alternative in that they can provide periodic reboost or continuous drag cancellation using no consumables, propellant, nor conventional propulsion elements. The system could also serve as an emergency backup reboost system used only in the event resupply and reboost are delayed for some reason.

(2 + 1)-dimensional dynamical black holes in Einstein-nonlinear Maxwell theory

NASA Astrophysics Data System (ADS)

Gurtug, O.; Mazharimousavi, S. Habib; Halilsoy, M.

2018-02-01

Radiative extensions of BTZ metric in 2 + 1 dimensions are found which are sourced by nonlinear Maxwell fields and a null current. This may be considered as generalization of the problem formulated long go by Vaidya and Bonnor. The mass and charge are functions of retarded/advanced null coordinate apt for decay/inflation. The new solutions are constructed through a Theorem that works remarkably well for any nonlinear electrodynamic model. Hawking temperature is analyzed for the case of the Born-Infeld electrodynamics.

Neural network analysis of electrodynamic activity of yeast cells around 1 kHz

NASA Astrophysics Data System (ADS)

Janca, R.

2011-12-01

This paper deals with data analysis of electrodynamic activity of two mutants of yeast cells, cell cycle of which is synchronized and non-synchronized, respectively. We used data already published by Jelinek et al. and treat them with data mining method based on the multilayer neural network. Intersection of data mining and statistical distribution of the noise shows significant difference between synchronized and non-synchronized yeasts not only in total power, but also discrete frequencies.

Radiation-reaction force on a small charged body to second order

NASA Astrophysics Data System (ADS)

Moxon, Jordan; Flanagan, Éanna

2018-05-01

In classical electrodynamics, an accelerating charged body emits radiation and experiences a corresponding radiation-reaction force, or self-force. We extend to higher order in the total charge a previous rigorous derivation of the electromagnetic self-force in flat spacetime by Gralla, Harte, and Wald. The method introduced by Gralla, Harte, and Wald computes the self-force from the Maxwell field equations and conservation of stress-energy in a limit where the charge, size, and mass of the body go to zero, and it does not require regularization of a singular self-field. For our higher-order computation, an adjustment of the definition of the mass of the body is necessary to avoid including self-energy from the electromagnetic field sourced by the body in the distant past. We derive the evolution equations for the mass, spin, and center-of-mass position of the body through second order. We derive, for the first time, the second-order acceleration dependence of the evolution of the spin (self-torque), as well as a mixing between the extended body effects and the acceleration-dependent effects on the overall body motion.

The Deflection Plate Analyzer: A Technique for Space Plasma Measurements Under Highly Disturbed Conditions

NASA Technical Reports Server (NTRS)

Wright, Kenneth H., Jr.; Dutton, Ken; Martinez, Nelson; Smith, Dennis; Stone, Nobie H.

2004-01-01

A technique has been developed to measure the characteristics of space plasmas under highly disturbed conditions; e.g., non-Maxwellian plasmas with strong drifting populations and plasmas contaminated by spacecraft outgassing. The present method is an extension of the capabilities of the Differential Ion Flux Probe (DIFP) to include a mass measurement that does not include either high voltage or contamination sensitive devices such as channeltron electron multipliers or microchannel plates. This reduces the complexity and expense of instrument fabrication, testing, and integration of flight hardware as compared to classical mass analyzers. The new instrument design is called the Deflection Plate Analyzer (DPA) and can deconvolve multiple ion streams and analyze each stream for ion flux intensity (density), velocity (including direction of motion), mass, and temperature (or energy distribution). The basic functionality of the DPA is discussed. The performance characteristics of a flight instrument as built for an electrodynamic tether mission, the Propulsive Small Expendable Deployer System (ProSEDS), and the instrument s role in measuring key experimental conditions are also discussed.

Quantum description of a field in macroscopic electrodynamics and photon properties in transparent media

NASA Astrophysics Data System (ADS)

Toptygin, I. N.

2017-12-01

Applying a quantum mechanical treatment to a high-frequency macroscopic electromagnetic field and radiative phenomena in a medium, we construct quantum operators for energy-momentum tensor components in dispersive media and find their eigenvalues, which are different in the Minkowski and Abraham representations. It is shown that the photon momentum in a medium resulting from the quantization of the vector potential differs from that defined from Abraham’s symmetric energy-momentum-tensor but is equal to the momentum defined from the Minkowski tensor. A similar result is obtained by calculating the intrinsic angular momentum (spin) of an electro-magnetic field in the medium. Only the Minkowski tensor leads to the experimentally confirmed spin values that are multiples of ħ, providing the grounds for choosing the Minkowski representation as the proper form for the momentum density of a transverse electromagnetic field in a transparent medium, in both classical and quantum descriptions of the field. The Abraham representation is unsuitable for this purpose and leads to contradictions. The conclusion drawn does not apply to quasistatic and static fields.

Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

NASA Astrophysics Data System (ADS)

Aaboud, M.; Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Abidi, S. H.; Abouzeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adachi, S.; Adamczyk, L.; Adelman, J.; Adersberger, M.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agheorghiesei, C.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akatsuka, S.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Ali, B.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Alshehri, A. A.; Alstaty, M.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antel, C.; Antonelli, M.; Antonov, A.; Antrim, D. J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Araujo Ferraz, V.; Arce, A. T. H.; Ardell, R. E.; Arduh, F. A.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Armitage, L. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Artz, S.; Asai, S.; Asbah, N.; Ashkenazi, A.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baas, A. E.; Baca, M. J.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Baines, J. T.; Bajic, M.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. 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H.; Smiesko, J.; Smirnov, N.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, J. W.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snyder, I. M.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Sokhrannyi, G.; Solans Sanchez, C. A.; Solar, M.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Son, H.; Song, H. Y.; Sopczak, A.; Sorin, V.; Sosa, D.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spangenberg, M.; Spanò, F.; Sperlich, D.; Spettel, F.; Spieker, T. M.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; St. Denis, R. D.; Stabile, A.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, G. H.; Stark, J.; Stark, S. H.; Staroba, P.; Starovoitov, P.; Stärz, S.; Staszewski, R.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Suchek, S.; Sugaya, Y.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Suruliz, K.; Suster, C. J. E.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swiatlowski, M.; Swift, S. P.; Sydorenko, A.; Sykora, I.; Sykora, T.; Ta, D.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tanaka, J.; Tanaka, M.; Tanaka, R.; Tanaka, S.; Tanioka, R.; Tannenwald, B. B.; Tapia Araya, S.; Tapprogge, S.; Tarem, S.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, A. C.; Taylor, G. N.; Taylor, P. T. E.; Taylor, W.; Teixeira-Dias, P.; Temple, D.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, P. D.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tipton, P.; Tisserant, S.; Todome, K.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, B.; Tornambe, P.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Treado, C. J.; Trefzger, T.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Trofymov, A.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tsang, K. W.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsui, K. M.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tu, Y.; Tudorache, A.; Tudorache, V.; Tulbure, T. T.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turgeman, D.; Turk Cakir, I.; Turra, R.; Tuts, P. M.; Ucchielli, G.; Ueda, I.; Ughetto, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usui, J.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valdes Santurio, E.; Valencic, N.; Valentinetti, S.; Valero, A.; Valéry, L.; Valkar, S.; Vallier, A.; Valls Ferrer, J. A.; van den Wollenberg, W.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vankov, P.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varni, C.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vasquez, J. G.; Vasquez, G. A.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veeraraghavan, V.; Veloce, L. M.; Veloso, F.; Veneziano, S.; Ventura, A.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vetterli, M. C.; Viaux Maira, N.; Viazlo, O.; Vichou, I.; Vickey, T.; Vickey Boeriu, O. E.; Viehhauser, G. H. A.; Viel, S.; Vigani, L.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vishwakarma, A.; Vittori, C.; Vivarelli, I.; Vlachos, S.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wallangen, V.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, Q.; Wang, R.; Wang, S. M.; Wang, T.; Wang, W.; Wang, W.; Wang, Z.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Watkins, P. M.; Watson, A. T.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, A. F.; Webb, S.; Weber, M. S.; Weber, S. W.; Weber, S. A.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M. D.; Werner, P.; Wessels, M.; Whalen, K.; Whallon, N. L.; Wharton, A. M.; White, A.; White, M. J.; White, R.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilk, F.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winston, O. J.; Winter, B. T.; Wittgen, M.; Wobisch, M.; Wolf, T. M. H.; Wolff, R.; Wolter, M. W.; Wolters, H.; Worm, S. D.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xi, Z.; Xia, L.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yigitbasi, E.; Yildirim, E.; Yorita, K.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yusuff, I.; Zabinski, B.; Zacharis, G.; Zaidan, R.; Zaitsev, A. M.; Zakharchuk, N.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, L.; Zhang, M.; Zhang, R.; Zhang, R.; Zhang, X.; Zhang, Y.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, M.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; Zou, R.; Zur Nedden, M.; Zwalinski, L.

2017-09-01

Light-by-light scattering (γγ --> γγ) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 μb-1 of lead-lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 +/- 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pb + Pb (γγ) --> Pb(*) + Pb(*)γγ, for photon transverse energy ET > 3 GeV, photon absolute pseudorapidity |η| < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 +/- 24 (stat.) +/- 17 (syst.) nb, which is in agreement with the standard model predictions.

Theories of Matter, Space and Time, Volume 2; Quantum theories

NASA Astrophysics Data System (ADS)

Evans, N.; King, S. F.

2018-06-01

This book and its prequel Theories of Matter Space and Time: Classical Theories grew out of courses that we have both taught as part of the undergraduate degree program in Physics at Southampton University, UK. Our goal was to guide the full MPhys undergraduate cohort through some of the trickier areas of theoretical physics that we expect our undergraduates to master. Here we teach the student to understand first quantized relativistic quantum theories. We first quickly review the basics of quantum mechanics which should be familiar to the reader from a prior course. Then we will link the Schrödinger equation to the principle of least action introducing Feynman's path integral methods. Next, we present the relativistic wave equations of Klein, Gordon and Dirac. Finally, we convert Maxwell's equations of electromagnetism to a wave equation for photons and make contact with quantum electrodynamics (QED) at a first quantized level. Between the two volumes we hope to move a student's understanding from their prior courses to a place where they are ready, beyond, to embark on graduate level courses on quantum field theory.

The Deflection Plate Analyzer: A Technique for Space Plasma Measurements Under Highly Disturbed Conditions

NASA Technical Reports Server (NTRS)

Wright, Kenneth H., Jr.; Dutton, Ken; Martinez, Nelson; Smith, Dennis; Stone, Nobie H.

2003-01-01

A technique has been developed to measure the characteristics of space plasmas under highly disturbed conditions; e.g., non-Maxwellian plasmas with strong drifting populations and plasmas contaminated by spacecraft outgassing. The present method is an extension of the capabilities of the Differential Ion Flux Probe (DIFP) to include a mass measurement that does not include either high voltage or contamination sensitive devices such as channeltron electron multipliers or microchannel plates. This reduces the complexity and expense of instrument fabrication, testing, and integration of flight hardware as compared to classical mass analyzers. The new instrument design is called the Deflection Plate Analyzer (DPA) and can deconvolve multiple ion streams and analyze each stream for ion flux intensity (density), velocity (including direction of motion), mass, and temperature (or energy distribution). The basic functionality of the DPA is discussed. The performance characteristics of a flight instrument as built for an electrodynamic tether mission, the Propulsive Small Expendable Deployer System (ProSEDS), and the instrument s role in measuring key experimental conditions are also discussed.

QED Based Calculation of the Fine Structure Constant

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

Lestone, John Paul

2016-10-13

Quantum electrodynamics is complex and its associated mathematics can appear overwhelming for those not trained in this field. Here, semi-classical approaches are used to obtain a more intuitive feel for what causes electrostatics, and the anomalous magnetic moment of the electron. These intuitive arguments lead to a possible answer to the question of the nature of charge. Virtual photons, with a reduced wavelength of λ, are assumed to interact with isolated electrons with a cross section of πλ 2. This interaction is assumed to generate time-reversed virtual photons that are capable of seeking out and interacting with other electrons. Thismore » exchange of virtual photons between particles is assumed to generate and define the strength of electromagnetism. With the inclusion of near-field effects the model presented here gives a fine structure constant of ~1/137 and an anomalous magnetic moment of the electron of ~0.00116. These calculations support the possibility that near-field corrections are the key to understanding the numerical value of the dimensionless fine structure constant.« less

Super-Planckian far-field radiative heat transfer

NASA Astrophysics Data System (ADS)

Fernández-Hurtado, V.; Fernández-Domínguez, A. I.; Feist, J.; García-Vidal, F. J.; Cuevas, J. C.

2018-01-01

We present here a theoretical analysis that demonstrates that the far-field radiative heat transfer between objects with dimensions smaller than the thermal wavelength can overcome the Planckian limit by orders of magnitude. To guide the search for super-Planckian far-field radiative heat transfer, we make use of the theory of fluctuational electrodynamics and derive a relation between the far-field radiative heat transfer and the directional absorption efficiency of the objects involved. Guided by this relation, and making use of state-of-the-art numerical simulations, we show that the far-field radiative heat transfer between highly anisotropic objects can largely overcome the black-body limit when some of their dimensions are smaller than the thermal wavelength. In particular, we illustrate this phenomenon in the case of suspended pads made of polar dielectrics like SiN or SiO2. These structures are widely used to measure the thermal transport through nanowires and low-dimensional systems and can be employed to test our predictions. Our work illustrates the dramatic failure of the classical theory to predict the far-field radiative heat transfer between micro- and nanodevices.

Micro- to macroscale perspectives on space plasmas

NASA Technical Reports Server (NTRS)

Eastman, Timothy E.

1993-01-01

The Earth's magnetosphere is the most accessible of natural collisionless plasma environments; an astrophysical plasma 'laboratory'. Magnetospheric physics has been in an exploration phase since its origin 35 years ago but new coordinated, multipoint observations, theory, modeling, and simulations are moving this highly interdisciplinary field of plasma science into a new phase of synthesis and understanding. Plasma systems are ones in which binary collisions are relatively negligible and collective behavior beyond the microscale emerges. Most readily accessible natural plasma systems are collisional and nearest-neighbor classical interactions compete with longer-range plasma effects. Except for stars, most space plasmas are collisionless, however, and the effects of electrodynamic coupling dominate. Basic physical processes in such collisionless plasmas occur at micro-, meso-, and macroscales that are not merely reducible to each other in certain crucial ways as illustrated for the global coupling of the Earth's magnetosphere and for the nonlinear dynamics of charged particle motion in the magnetotail. Such global coupling and coherence makes the geospace environment, the domain of solar-terrestrial science, the most highly coupled of all physical geospheres.

Particle merging algorithm for PIC codes

NASA Astrophysics Data System (ADS)

Vranic, M.; Grismayer, T.; Martins, J. L.; Fonseca, R. A.; Silva, L. O.

2015-06-01

Particle-in-cell merging algorithms aim to resample dynamically the six-dimensional phase space occupied by particles without distorting substantially the physical description of the system. Whereas various approaches have been proposed in previous works, none of them seemed to be able to conserve fully charge, momentum, energy and their associated distributions. We describe here an alternative algorithm based on the coalescence of N massive or massless particles, considered to be close enough in phase space, into two new macro-particles. The local conservation of charge, momentum and energy are ensured by the resolution of a system of scalar equations. Various simulation comparisons have been carried out with and without the merging algorithm, from classical plasma physics problems to extreme scenarios where quantum electrodynamics is taken into account, showing in addition to the conservation of local quantities, the good reproducibility of the particle distributions. In case where the number of particles ought to increase exponentially in the simulation box, the dynamical merging permits a considerable speedup, and significant memory savings that otherwise would make the simulations impossible to perform.

Spectrum and Angular Distribution of γ-rays from Radiative Damping in Extremely Relativistic Laser-Plasma Interaction

NASA Astrophysics Data System (ADS)

Pandit, Rishi; Sentoku, Yasuhiko

2013-10-01

Effects of the radiative damping in the interaction of extremely intense laser (> 1022 W/cm2) with dense plasma is studied via a relativistic collisional particle-in-cell simulation, PICLS. When the laser intensity is getting close to 1024 W/cm2, the effect of quantum electrodynamics (QED) appears. We had calculated γ-rays from the radiative damping processes based on the classical model [1], but had taken into account the QED effect [2] in the spectrum calculation. In ultra-intense laser-plasma interaction, electrons are accelerated by the strong laser fields and emit γ-ray photons mainly via two processes, namely, Bremsstrahlung and radiative damping. Such relativistic γ-ray has wide range of frequencies and the angular distribution depends on the hot electron source. Comparing the details of γ-rays from the Bremsstrahlung and the radiative damping in simulations, we will discuss the laser parameters and the target conditions (geometry and material) to distinguish the photons from each process and also the QED effect in the γ-rays spectrum at the extremely relativistic intensity. Supported by US DOE DE-SC0008827.

Genetic markers enhance coronary risk prediction in men: the MORGAM prospective cohorts.

PubMed

Hughes, Maria F; Saarela, Olli; Stritzke, Jan; Kee, Frank; Silander, Kaisa; Klopp, Norman; Kontto, Jukka; Karvanen, Juha; Willenborg, Christina; Salomaa, Veikko; Virtamo, Jarmo; Amouyel, Phillippe; Arveiler, Dominique; Ferrières, Jean; Wiklund, Per-Gunner; Baumert, Jens; Thorand, Barbara; Diemert, Patrick; Trégouët, David-Alexandre; Hengstenberg, Christian; Peters, Annette; Evans, Alun; Koenig, Wolfgang; Erdmann, Jeanette; Samani, Nilesh J; Kuulasmaa, Kari; Schunkert, Heribert

2012-01-01

More accurate coronary heart disease (CHD) prediction, specifically in middle-aged men, is needed to reduce the burden of disease more effectively. We hypothesised that a multilocus genetic risk score could refine CHD prediction beyond classic risk scores and obtain more precise risk estimates using a prospective cohort design. Using data from nine prospective European cohorts, including 26,221 men, we selected in a case-cohort setting 4,818 healthy men at baseline, and used Cox proportional hazards models to examine associations between CHD and risk scores based on genetic variants representing 13 genomic regions. Over follow-up (range: 5-18 years), 1,736 incident CHD events occurred. Genetic risk scores were validated in men with at least 10 years of follow-up (632 cases, 1361 non-cases). Genetic risk score 1 (GRS1) combined 11 SNPs and two haplotypes, with effect estimates from previous genome-wide association studies. GRS2 combined 11 SNPs plus 4 SNPs from the haplotypes with coefficients estimated from these prospective cohorts using 10-fold cross-validation. Scores were added to a model adjusted for classic risk factors comprising the Framingham risk score and 10-year risks were derived. Both scores improved net reclassification (NRI) over the Framingham score (7.5%, p = 0.017 for GRS1, 6.5%, p = 0.044 for GRS2) but GRS2 also improved discrimination (c-index improvement 1.11%, p = 0.048). Subgroup analysis on men aged 50-59 (436 cases, 603 non-cases) improved net reclassification for GRS1 (13.8%) and GRS2 (12.5%). Net reclassification improvement remained significant for both scores when family history of CHD was added to the baseline model for this male subgroup improving prediction of early onset CHD events. Genetic risk scores add precision to risk estimates for CHD and improve prediction beyond classic risk factors, particularly for middle aged men.

An innovative multi-gap clutch based on magneto-rheological fluids and electrodynamic effects: magnetic design and experimental characterization

NASA Astrophysics Data System (ADS)

Rizzo, R.

2017-01-01

In this paper an innovative multi-gap magnetorheological clutch is described. It is inspired by a device previously developed by the author’s research group and contains a novel solution based on electrodynamic effects, capable to considerably improve the transmissible torque during the engagement phase. Since this (transient) phase is characterized by a non-zero angular speed between the two clutch shafts, the rotation of a permanent magnets system, used to excite the fluid, induces eddy currents on some conductive material strategically positioned in the device. As a consequence, an electromagnetic torque is produced which is added to the torque transmitted by the magnetorheological fluid only. Once the clutch is completely engaged and the relative speed between the two shafts is zero, the electrodynamic effects vanish and the device operates like a conventional magnetorheological clutch. The system is investigated and designed by means a 3D FEM model and the performance of the device is experimentally validated on a prototype.

Topologically massive magnetic monopoles

NASA Astrophysics Data System (ADS)

Aliev, A. N.; Nutku, Y.; Saygili, K.

2000-10-01

We show that in the Maxwell-Chern-Simons theory of topologically massive electrodynamics the Dirac string of a monopole becomes a cone in anti-de Sitter space with the opening angle of the cone determined by the topological mass, which in turn is related to the square root of the cosmological constant. This proves to be an example of a physical system, a priori completely unrelated to gravity, which nevertheless requires curved spacetime for its very existence. We extend this result to topologically massive gravity coupled to topologically massive electrodynamics within the framework of the theory of Deser, Jackiw and Templeton. The two-component spinor formalism, which is a Newman-Penrose type approach for three dimensions, is extended to include both the electrodynamical and gravitational topologically massive field equations. Using this formalism exact solutions of the coupled Deser-Jackiw-Templeton and Maxwell-Chern-Simons field equations for a topologically massive monopole are presented. These are homogeneous spaces with conical deficit. Pure Einstein gravity coupled to the Maxwell-Chern-Simons field does not admit such a monopole solution.

SL(2,R) duality-symmetric action for electromagnetic theory with electric and magnetic sources

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

Lee, Choonkyu, E-mail: cklee@phya.snu.ac.kr; School of Physics, Korea Institute for Advanced Study, Seoul 130-722; Min, Hyunsoo, E-mail: hsmin@dirac.uos.ac.kr

2013-12-15

For the SL(2,R) duality-invariant generalization of Maxwell electrodynamics in the presence of both electric and magnetic sources, we formulate a local, manifestly duality-symmetric, Zwanziger-type action by introducing a pair of four-potentials A{sup μ} and B{sup μ} in a judicious way. On the two potentials A{sup μ} and B{sup μ} the SL(2,R) duality transformation acts in a simple linear manner. In quantum theory including charged source fields, this action can be recast as a SL(2,Z)-invariant action. Also given is a Zwanziger-type action for SL(2,R) duality-invariant Born–Infeld electrodynamics which can be important for D-brane dynamics in string theory. -- Highlights: •We formulatemore » a local, manifestly duality-symmetric, Zwanziger-type action. •Maxwell electrodynamics is generalized to include dilaton and axion fields. •SL(2,R) symmetry is manifest. •We formulate a local, manifestly duality-symmetric, nonlinear Born–Infeld action with SL(2,R) symmetry.« less

Experimental detection of long-distance interactions between biomolecules through their diffusion behavior: numerical study.

PubMed

Nardecchia, Ilaria; Spinelli, Lionel; Preto, Jordane; Gori, Matteo; Floriani, Elena; Jaeger, Sebastien; Ferrier, Pierre; Pettini, Marco

2014-08-01

The dynamical properties and diffusive behavior of a collection of mutually interacting particles are numerically investigated for two types of long-range interparticle interactions: Coulomb-electrostatic and dipole-electrodynamic. It is shown that when the particles are uniformly distributed throughout the accessible space, the self-diffusion coefficient is always lowered by the considered interparticle interactions, irrespective of their attractive or repulsive character. This fact is also confirmed by a simple model to compute the correction to the Brownian diffusion coefficient due to the interactions among the particles. These interactions are also responsible for the onset of dynamical chaos and an associated chaotic diffusion which still follows an Einstein-Fick-like law for the mean-square displacement as a function of time. Transitional phenomena are observed for Coulomb-electrostatic (repulsive) and dipole-electrodynamic (attractive) interactions considered both separately and in competition. The outcomes reported in this paper clearly indicate a feasible experimental method to probe the activation of resonant electrodynamic interactions among biomolecules.

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

Sule, Nishant; Yifat, Yuval; Gray, Stephen K.

We examine the formation and concomitant rotation of electrodynamically bound dimers (EBD) of 150nm diameter Ag nanoparticles trapped in circularly polarized focused Gaussian beams. The rotation frequency of an EBD increases linearly with the incident beam power, reaching high mean values of ~ 4kHz for a relatively low incident power of 14mW. Using a coupled-dipole/effective polarizability model, we reveal that retardation of the scattered fields and electrodynamic interactions can lead to a “negative torque” causing rotation of the EBD in the direction opposite to that of the circular polarization. This intriguing opposite-handed rotation due to negative torque is clearly demonstratedmore » using electrodynamics-Langevin dynamics simulations by changing particle separations and thus varying the retardation effects. Finally, negative torque is also demonstrated in experiments from statistical analysis of the EBD trajectories. These results demonstrate novel rotational dynamics of nanoparticles in optical matter using circular polarization and open a new avenue to control orientational dynamics through coupling to interparticle separation.« less

Randomized trial of electrodynamic microneedle combined with 5% minoxidil topical solution for the treatment of Chinese male Androgenetic alopecia.

PubMed

Bao, Linlin; Gong, Lin; Guo, Menger; Liu, Taoming; Shi, Anyu; Zong, Haifeng; Xu, Xuegang; Chen, Hongduo; Gao, Xinghua; Li, Yuanhong

2017-10-13

In treating androgenetic alopecia, 5% minoxidil is a commonly used topical drug. By using electrodynamic microneedle at the same time may increase absorption of minoxidil and further stimulate hair growth. A 24-week, randomized, evaluator blinded, comparative study was performed to evaluate the efficacy of treating Chinese male androgenetic alopecia using microneedle combined with 5% minoxidil topical solution. Randomized subjects received topical 5% minoxidil (group 1, n = 20), local electrodynamic microneedle treatments (group 2, n = 20), or local electrodynamic microneedle treatments plus topical 5% minoxidil (group 3, n = 20). A total of 12 microneedle treatments were performed every 2 weeks with 2ml 5% minoxidil delivery in group 3 during each microneedle treatment. Patient receiving topical 5% minoxidil applied 1 ml of the solution twice daily over the course of the study. A total of 60 Chinese male subjects with Norwood-Hamilton type III-VI androgenetic alopecia were treated. The mean improvement in total hair density from baseline to 24 weeks was 18.8/cm 2 in group 1, 23.4/cm 2 in group 2, and 38.3/cm 2 in group 3. The hair growth in the 3 groups was significantly different (P = 0.002), but there were no significant differences in toxicity found between the 3 groups. Treatment with microneedle plus topical 5% minoxidil was associated with the best hair growth.

Current Closure in the Auroral Ionosphere: Results from the Auroral Current and Electrodynamics Structure Rocket Mission

NASA Technical Reports Server (NTRS)

Kaeppler, S. R.; Kletzing, C. A.; Bounds, S. R.; Gjerloev, J. W.; Anderson, B. J.; Korth, H.; LaBelle, J. W.; Dombrowski, M. P.; Lessard, M.; Pfaff, R. F.;

Current Closure in the Auroral Ionosphere: Results from the Auroral Current and Electrodynamics Structure Rocket Mission

NASA Technical Reports Server (NTRS)

Kaeppler, S. R.; Kletzing, C. A.; Bounds, S. R.; Gjerloev, J. W.; Anderson, B. J.; Korth, H.; LaBelle, J. W.; Dombrowski, M. P.; Lessard, M.; Pfaff, R. F.;

GAIA modeling of electrodynamics in the lower ionosphere during a severe solar flare event

NASA Astrophysics Data System (ADS)

Matsumura, M.; Shiokawa, K.; Shinagawa, H.; Jin, H.; Fujiwara, H.; Miyoshi, Y.; Otsuka, Y.

2016-12-01

Recent studies indicated that the ionospheric F-region disturbances due to solar flare irradiance are controlled not only by photoionization but also by electrodynamical changes of the ionosphere [Liu et al., 2007; Qian et al., 2012]. The electric field changes during solar flare events occur mainly in the E-region due to the X-ray flux enhancement, and in the equatorial counter electrojet regions the eastward electric field turns into westward below 107-km altitude [Manju and Viswanathan, 2005]. The TIME-GCM model has been used to investigate the flare-related electrodynamics of the ionosphere [Qian et al., 2012]. However, the model did not consider the flare effects at altitudes below 97 km due to the ionospheric lower boundary of the model. On the other hand, the GAIA model [Jin et al., 2011] can simulate electron density variations and electrodynamics around and below 100 km because the model does not have the limitation of the lower boundary. We have improved the GAIA model to incorporate the Flare Irradiance Spectral Model (FISM) [Chamberlin et al., 2007; 2008] to understand the global response of the whole ionosphere including E and D regions to the solar flares. We have performed a simulation for the X17 flare event of October 28, 2003, and have showed that soft X-ray considerably enhances conductivity even at an altitude of 80 km. We will report its effect on the ionospheric electric field and the equatorial electrojet currents.

Optimal antibunching in passive photonic devices based on coupled nonlinear resonators

NASA Astrophysics Data System (ADS)

Ferretti, S.; Savona, V.; Gerace, D.

2013-02-01

We propose the use of weakly nonlinear passive materials for prospective applications in integrated quantum photonics. It is shown that strong enhancement of native optical nonlinearities by electromagnetic field confinement in photonic crystal resonators can lead to single-photon generation only exploiting the quantum interference of two coupled modes and the effect of photon blockade under resonant coherent driving. For realistic system parameters in state of the art microcavities, the efficiency of such a single-photon source is theoretically characterized by means of the second-order correlation function at zero-time delay as the main figure of merit, where major sources of loss and decoherence are taken into account within a standard master equation treatment. These results could stimulate the realization of integrated quantum photonic devices based on non-resonant material media, fully integrable with current semiconductor technology and matching the relevant telecom band operational wavelengths, as an alternative to single-photon nonlinear devices based on cavity quantum electrodynamics with artificial atoms or single atomic-like emitters.

Alternative paradigm for the cosmic objects formation: New prospects

NASA Astrophysics Data System (ADS)

Harutyunian, Haik A.

2017-12-01

We consider here briefly the cosmogonic concept suggested by Viktor Ambartsumian in the last century for explaining the formation of cosmic objects. He grounded his concept using the observational facts available in 40s-60s of the last century. The analysis of observational data allowed him to conclude that cosmic objects formation takes place up to nowadays. The second and more "heretical" conclusion he arrived at persuades that the origination and further evolution of cosmic objects goes on in course of gradual decay of proto-stellar matter at all hierarchical levels. We argue that this approach appeared first time in Ambartsumian's papers devoted to the problems of quantum electrodynamics. Later on his concept on objects formation due to decay of protostellar dense matter was rejected because the known laws of physics do not allow existence of huge masses consisted of superdense matter. We bring to the readers' attention, that the discovery of dark energy changes the situation drastically and opens new rooms for the ideas forgotten by the scientific community.

Nuclear recoil effect on g-factor of heavy ions: prospects for tests of quantum electrodynamics in a new region

NASA Astrophysics Data System (ADS)

Malyshev, A. V.; Shabaev, V. M.; Glazov, D. A.; Tupitsyn, I. I.

2017-12-01

The nuclear recoil effect on the g-factor of H- and Li-like heavy ions is evaluated to all orders in αZ. The calculations include an approximate treatment of the nuclear size and the electron-electron interaction corrections to the recoil effect. As the result, the second largest contribution to the theoretical uncertainty of the g-factor values of 208Pb79+ and 238U89+ is strongly reduced. Special attention is paid to tests of the QED recoil effect on the g-factor in experiments with heavy ions. It is found that, while the QED recoil effect on the g-factor value is masked by the uncertainties of the nuclear size and nuclear polarization contributions, it can be probed on a few-percent level in the specific difference of the g-factors of H- and Li-like heavy ions. This provides a unique opportunity to test QED in a new region-strong-coupling regime beyond the Furry picture.

Nuclear Recoil Effect on the g-Factor of Heavy Ions: Prospects for Tests of Quantum Electrodynamics in a New Region

NASA Astrophysics Data System (ADS)

Malyshev, A. V.; Shabaev, V. M.; Glazov, D. A.; Tupitsyn, I. I.

2017-12-01

The nuclear recoil effect on the g-factor of H- and Li-like heavy ions is evaluated to all orders in αZ. The calculations include an approximate treatment of the nuclear size and the electron-electron interaction corrections to the recoil effect. As the result, the second largest contribution to the theoretical uncertainty of the g-factor values of 208Pb79+ and 238U89+ is strongly reduced. Special attention is paid to tests of the QED recoil effect on the g-factor in experiments with heavy ions. It is found that, while the QED recoil effect on the gfactor value is masked by the uncertainties of the nuclear size and nuclear polarization contributions, it can be probed on a few-percent level in the specific difference of the g-factors of H- and Li-like heavy ions. This provides a unique opportunity to test QED in a new region of the strong-coupling regime beyond the Furry picture.

Spin–cavity interactions between a quantum dot molecule and a photonic crystal cavity

PubMed Central

Vora, Patrick M.; Bracker, Allan S.; Carter, Samuel G.; Sweeney, Timothy M.; Kim, Mijin; Kim, Chul Soo; Yang, Lily; Brereton, Peter G.; Economou, Sophia E.; Gammon, Daniel

2015-01-01

The integration of InAs/GaAs quantum dots into nanophotonic cavities has led to impressive demonstrations of cavity quantum electrodynamics. However, these demonstrations are primarily based on two-level excitonic systems. Efforts to couple long-lived quantum dot electron spin states with a cavity are only now succeeding. Here we report a two-spin–cavity system, achieved by embedding an InAs quantum dot molecule within a photonic crystal cavity. With this system we obtain a spin singlet–triplet Λ-system where the ground-state spin splitting exceeds the cavity linewidth by an order of magnitude. This allows us to observe cavity-stimulated Raman emission that is highly spin-selective. Moreover, we demonstrate the first cases of cavity-enhanced optical nonlinearities in a solid-state Λ-system. This provides an all-optical, local method to control the spin exchange splitting. Incorporation of a highly engineerable quantum dot molecule into the photonic crystal architecture advances prospects for a quantum network. PMID:26184654

Electric and magnetic dipoles in the Lorentz and Einstein-Laub formulations of classical electrodynamics

NASA Astrophysics Data System (ADS)

Mansuripur, Masud

2015-01-01

The classical theory of electrodynamics cannot explain the existence and structure of electric and magnetic dipoles, yet it incorporates such dipoles into its fundamental equations, simply by postulating their existence and properties, just as it postulates the existence and properties of electric charges and currents. Maxwell's macroscopic equations are mathematically exact and self-consistent differential equations that relate the electromagnetic (EM) field to its sources, namely, electric charge-density 𝜌𝜌free, electric current-density 𝑱𝑱free, polarization 𝑷𝑷, and magnetization 𝑴𝑴. At the level of Maxwell's macroscopic equations, there is no need for models of electric and magnetic dipoles. For example, whether a magnetic dipole is an Amperian current-loop or a Gilbertian pair of north and south magnetic monopoles has no effect on the solution of Maxwell's equations. Electromagnetic fields carry energy as well as linear and angular momenta, which they can exchange with material media—the seat of the sources of the EM field—thereby exerting force and torque on these media. In the Lorentz formulation of classical electrodynamics, the electric and magnetic fields, 𝑬𝑬 and 𝑩𝑩, exert forces and torques on electric charge and current distributions. An electric dipole is then modeled as a pair of electric charges on a stick (or spring), and a magnetic dipole is modeled as an Amperian current loop, so that the Lorentz force law can be applied to the corresponding (bound) charges and (bound) currents of these dipoles. In contrast, the Einstein-Laub formulation circumvents the need for specific models of the dipoles by simply providing a recipe for calculating the force- and torque-densities exerted by the 𝑬𝑬 and 𝑯𝑯 fields on charge, current, polarization and magnetization. The two formulations, while similar in many respects, have significant differences. For example, in the Lorentz approach, the Poynting vector is 𝑺𝑺𝐿𝐿 = 𝜇𝜇0 -1𝑬𝑬 × 𝑩𝑩, and the linear and angular momentum densities of the EM field are 𝓹𝓹𝐿𝐿 = 𝜀𝜀0𝑬𝑬 × 𝑩𝑩 and 𝓛𝓛𝐿𝐿 = 𝒓𝒓 × 𝓹𝓹𝐿𝐿, whereas in the Einstein-Laub formulation the corresponding entities are 𝑺𝑺𝐸𝐸𝐸𝐸= 𝑬𝑬 × 𝑯𝑯, 𝓹𝓹𝐸𝐸𝐸𝐸= 𝑬𝑬 × 𝑯𝑯⁄𝑐𝑐2, and 𝓛𝓛𝐸𝐸𝐸𝐸= 𝒓𝒓 × 𝓹𝓹𝐸𝐸𝐸𝐸. (Here 𝜇𝜇0 and 𝜀𝜀0 are the permeability and permittivity of free space, 𝑐𝑐 is the speed of light in vacuum, 𝑩𝑩 = 𝜇𝜇0𝑯𝑯 + 𝑴𝑴, and 𝒓𝒓 is the position vector.) Such differences can be reconciled by recognizing the need for the so-called hidden energy and hidden momentum associated with Amperian current loops of the Lorentz formalism. (Hidden entities of the sort do not arise in the Einstein-Laub treatment of magnetic dipoles.) Other differences arise from over-simplistic assumptions concerning the equivalence between free charges and currents on the one hand, and their bound counterparts on the other. A more nuanced treatment of EM force and torque densities exerted on polarization and magnetization in the Lorentz approach would help bridge the gap that superficially separates the two formulations. Atoms and molecules may collide with each other and, in general, material constituents can exchange energy, momentum, and angular momentum via direct mechanical interactions. In the case of continuous media, elastic and hydrodynamic stresses, phenomenological forces such as those related to exchange coupling in ferromagnets, etc., subject small volumes of materials to external forces and torques. Such matter-matter interactions, although fundamentally EM in nature, are distinct from field-matter interactions in classical physics. Beyond the classical regime, however, the dichotomy that distinguishes the EM field from EM sources gets blurred. An electron's wavefunction may overlap that of an atomic nucleus, thereby initiating a contact interaction between the magnetic dipole moments of the two particles. Or a neutron passing through a ferromagnetic material may give rise to scattering events involving overlaps between the wave-functions of the neutron and magnetic electrons. Such matter-matter interactions exert equal and opposite forces and/or torques on the colliding particles, and their observable effects often shed light on the nature of the particles involved. It is through such observations that the Amperian model of a magnetic dipole has come to gain prominence over the Gilbertian model. In situations involving overlapping particle wave-functions, it is imperative to take account of the particle-particle interaction energy when computing the scattering amplitudes. As far as total force and total torque on a given volume of material are concerned, such particle-particle interactions do not affect the outcome of calculations, since the mutual actions of the two (overlapping) particles cancel each other out. Both Lorentz and Einstein-Laub formalisms thus yield the same total force and total torque on a given volume—provided that hidden entities are properly removed. The Lorentz formalism, with its roots in the Amperian current-loop model, correctly predicts the interaction energy between two overlapping magnetic dipoles 𝒎𝒎1 and 𝒎𝒎2 as being proportional to -𝒎𝒎1 • 𝒎𝒎2. In contrast, the Einstein-Laub formalism, which is ignorant of such particle-particle interactions, needs to account for them separately.

Capabilities of electrodynamic shakers when used for mechanical shock testing

NASA Technical Reports Server (NTRS)

Keegan, W. B.

1973-01-01

The results of a research task to investigate the capabilities of electrodynamic vibrators (shakers) to perform mechanical shock tests are presented. The simulation method employed was that of developing a transient whose shock response spectrum matched the desired shock response spectrum. Areas investigated included the maximum amplitude capabilities of the shaker systems, the ability to control the shape of the resultant shock response spectrum, the response levels induced at frequencies outside the controlled bandwidth, and the nonlinearities in structural response induced by a change in test level.

Electrodynamic Dust Shield for Lunar/ISS Experiment Project

NASA Technical Reports Server (NTRS)

Zeitlin, Nancy; Calle, Carlos; Hogue, Michael; Johansen, Michael; Mackey, Paul

2015-01-01

The Electrostatics and Surface Physics Laboratory at Kennedy Space Center is developing a dust mitigation experiment and testing it on the lunar surface and on the International Space Station (ISS). The Electrodynamic Dust Shield (EDS) clears dust off surfaces and prevents accumulation by using a pattern of electrodes to generate a non-uniform electric field over the surface being protected. The EDS experiment will repel dust off materials such as painted Kapton and glass to demonstrate applications for thermal radiators, camera lenses, solar panels, and other hardware and equipment.

Chemical Remote Sensing ’Proof of Concept’,

DTIC Science & Technology

1981-03-31

A122 579 CHEMICAL REMOTE SENSING ;PROOF OF CONCEPT’(U) UTAH 1/I \\ STATE UNIV LOGAN ELECTRO-DYNAMICS LAB BARTSCHI ET AL. 31 MAR 81 SCIENTIFC-8...STANDARDS -I963-A AFGL-TR-81-021 2 CHEMICAL REMOTE SENSING "Proof of Concept" B.Y. Bartschi F. P. DelGreco M. Ahmadjian Electro-Dynamics Laboratories...Applications of remote sensing 2 2.2 Program Development 4 -O 3.1 Optical Layout 6 3.2 Block Diagram of Sensor System 7 3.3 Sensor Facility 10 3.4

Strong lensing of a regular black hole with an electrodynamics source

NASA Astrophysics Data System (ADS)

Manna, Tuhina; Rahaman, Farook; Molla, Sabiruddin; Bhadra, Jhumpa; Shah, Hasrat Hussain

2018-05-01

In this paper we have investigated the gravitational lensing phenomenon in the strong field regime for a regular, charged, static black holes with non-linear electrodynamics source. We have obtained the angle of deflection and compared it to a Schwarzschild black hole and Reissner Nordström black hole with similar properties. We have also done a graphical study of the relativistic image positions and magnifications. We hope that this method may be useful in the detection of non-luminous bodies like this current black hole.

On low-energy effective action in three-dimensional = 2 and = 4 supersymmetric electrodynamics

NASA Astrophysics Data System (ADS)

Buchbinder, I. L.; Merzlikin, B. S.; Samsonov, I. B.

2013-11-01

We discuss general structure of low-energy effective actions in = 2 and = 4 three-dimensional supersymmetric electrodynamics (SQED) in gauge superfield sector. There are specific terms in the effective action having no four-dimensional analogs. Some of these terms are responsible for the moduli space metric in the Coulomb branch of the theory. We find two-loop quantum corrections to the moduli space metric in the = 2 SQED and show that in the = 4 SQED the moduli space does not receive two-loop quantum corrections.

Non-perturbative aspects of particle acceleration in non-linear electrodynamics

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

Burton, David A.; Flood, Stephen P.; Wen, Haibao

2015-04-15

We undertake an investigation of particle acceleration in the context of non-linear electrodynamics. We deduce the maximum energy that an electron can gain in a non-linear density wave in a magnetised plasma, and we show that an electron can “surf” a sufficiently intense Born-Infeld electromagnetic plane wave and be strongly accelerated by the wave. The first result is valid for a large class of physically reasonable modifications of the linear Maxwell equations, whilst the second result exploits the special mathematical structure of Born-Infeld theory.

Convergence of quantum electrodynamics in a curved modification of Minkowski space.

PubMed Central

Segal, I E; Zhou, Z

1994-01-01

The interaction and total hamiltonians for quantum electrodynamics, in the interaction representation, are entirely regular self-adjoint operators in Hilbert space, in the universal covering manifold M of the conformal compactification of Minkowski space Mo. (M is conformally equivalent to the Einstein universe E, in which Mo may be canonically imbedded.) In a fixed Lorentz frame this may be expressed as convergence in a spherical space with suitable periodic boundary conditions in time. The traditional relativistic theory is the formal limit of the present variant as the space curvature vanishes. PMID:11607455

The evolution of consciousness

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

Stapp, H.P.

1996-08-16

It is argued that the principles of classical physics are inimical to the development of an adequate science of consciousness. The problem is that insofar as the classical principles are valid consciousness can have no effect on the behavior, and hence on the survival prospects, of the organisms in which it inheres. Thus within the classical framework it is not possible to explain in natural terms the development of consciousness to the high-level form found in human beings. In quantum theory, on the other hand, consciousness can be dynamically efficacious: quantum theory does allow consciousness to influence behavior, and thencemore » to evolve in accordance with the principles of natural selection. However, this evolutionary requirement places important constraints upon the details of the formulation of the quantum dynamical principles.« less

Mathematical Modeling of Electrodynamics Near the Surface of Earth and Planetary Water Worlds

NASA Technical Reports Server (NTRS)

Tyler, Robert H.

2017-01-01

An interesting feature of planetary bodies with hydrospheres is the presence of an electrically conducting shell near the global surface. This conducting shell may typically lie between relatively insulating rock, ice, or atmosphere, creating a strong constraint on the flow of large-scale electric currents. All or parts of the shell may be in fluid motion relative to main components of the rotating planetary magnetic field (as well as the magnetic fields due to external bodies), creating motionally-induced electric currents that would not otherwise be present. As such, one may expect distinguishing features in the types of electrodynamic processes that occur, as well as an opportunity for imposing specialized mathematical methods that efficiently address this class of application. The purpose of this paper is to present and discuss such specialized methods. Specifically, thin-shell approximations for both the electrodynamics and fluid dynamics are combined to derive simplified mathematical formulations describing the behavior of these electric currents as well as their associated electric and magnetic fields. These simplified formulae allow analytical solutions featuring distinct aspects of the thin-shell electrodynamics in idealized cases. A highly efficient numerical method is also presented that is useful for calculations under inhomogeneous parameter distributions. Finally, the advantages as well as limitations in using this mathematical approach are evaluated. This evaluation is presented primarily for the generic case of bodies with water worlds or other thin spherical conducting shells. More specific discussion is given for the case of Earth, but also Europa and other satellites with suspected oceans.

Role of magnetic and diamagnetic interactions in molecular optics and scattering

NASA Astrophysics Data System (ADS)

Forbes, Kayn A.

2018-05-01

This paper aims to explicitly clarify the role and interpretation of diamagnetic interactions between molecules and light in quantum electrodynamics. In contrast to their electric and magnetic counterparts, the diamagnetic couplings between light and matter have received relatively little interest in the field of molecular optics. This intriguing disregard of an interaction term is puzzling. The diamagnetic couplings possess unique physical properties that warrant their inclusion in any multiphoton process, and the lack of gauge invariance for paramagnetic and diamagnetic susceptibilities necessitates their inclusion. Their role and importance within nonrelativistic molecular quantum electrodynamics in the Coulomb gauge is illuminated, and it is highlighted how for any multiphoton process their inclusion should be implicit. As an indicative example of the theory presented, the diamagnetic contributions to both forward and nonforward Rayleigh scattering are derived and put into context alongside the electric and magnetic molecular responses. The work represents clarification of diamagnetic couplings in molecular quantum electrodynamics, which subsequently should proffer the study of diamagnetic interactions in molecular optics due to their unique physical attributes and necessary inclusion in multiphoton processes.

Covariant electrodynamics in linear media: Optical metric

NASA Astrophysics Data System (ADS)

Thompson, Robert T.

2018-03-01

While the postulate of covariance of Maxwell's equations for all inertial observers led Einstein to special relativity, it was the further demand of general covariance—form invariance under general coordinate transformations, including between accelerating frames—that led to general relativity. Several lines of inquiry over the past two decades, notably the development of metamaterial-based transformation optics, has spurred a greater interest in the role of geometry and space-time covariance for electrodynamics in ponderable media. I develop a generally covariant, coordinate-free framework for electrodynamics in general dielectric media residing in curved background space-times. In particular, I derive a relation for the spatial medium parameters measured by an arbitrary timelike observer. In terms of those medium parameters I derive an explicit expression for the pseudo-Finslerian optical metric of birefringent media and show how it reduces to a pseudo-Riemannian optical metric for nonbirefringent media. This formulation provides a basis for a unified approach to ray and congruence tracing through media in curved space-times that may smoothly vary among positively refracting, negatively refracting, and vacuum.

Middle atmospheric electrodynamic modification by particle precipitation at the South Atlantic magnetic anomaly

NASA Technical Reports Server (NTRS)

Gonzalez, W. D.; Dutra, S. L. G.; Pinto, O., Jr.

1987-01-01

Evidence for a localized middle atmospheric electrodynamic modification at low latitudes (southern Brazilian coast) of the South Atlantic Magnetic Anomaly (SAMA), in association with enhanced geomagnetic activity, are presented in a unified way combining recent observational efforts and related numerical studies. They involve a distortion effect in the fair weather electric field at balloon altitudes. This effect is attributed to a local intensification of energetic electron precipitation through a related middle atmospheric ionization enhancement and is elucidated by numeric simulation. From the electric field measurements and the numeric simulation, the intensification of precipitation is considered to occur in fairly narrow regions at the observed low L values (around L = 1.13) of the SAMA, with horizontal extensions of the order of a few hundred kilometers. A physical mechanism that could be responsible for this sort of intensification is suggested. Furthermore, a comparison of the phenomenon of middle atmospheric electrodynamic modification at the SAMA with a similar one at auroral latitudes, in response to enhanced solar and geomagnetic activity, is also given.

Propulsive Small Expendable Deployer System (ProSEDS)

NASA Technical Reports Server (NTRS)

1999-01-01

This Quick Time movie is of NASA's Propulsive Small Expendable Deployer System experiment (ProSEDS). ProSEDS will demonstrate the use of an electrodynamic tether, basically a long, thin wire, for propulsion. An electrodynamic tether uses the same principles as electric motors in toys, appliances and computer disk drives, and generators in automobiles and power plants. When electrical current is flowing through the tether, a magnetic field is produced that pushes against the magnetic field of the Earth. For ProSEDS, the current in the tether results by virtue of the voltage generated when the tether moves through the Earth's magnetic field at more than 17,000 mph. This approach can produce drag thrust generating useable power. Since electrodynamic tethers require no propellant, they could substantially reduce the weight of the spacecraft and provide a cost-effective method of reboosting spacecraft. The tether would be a 3.1-mile (5 kilometer) long, ultrathin base-wire tether connected with a 6.2-mile (10 kilometer) long nonconducting tether. The ProSEDS experiment is managed by the Space Transportation Directorate at the Marshall Space Flight Center.

Thermodynamic properties of asymptotically Reissner–Nordström black holes

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

Hendi, S.H., E-mail: hendi@shirazu.ac.ir

2014-07-15

Motivated by possible relation between Born–Infeld type nonlinear electrodynamics and an effective low-energy action of open string theory, asymptotically Reissner–Nordström black holes whose electric field is described by a nonlinear electrodynamics (NLED) are studied. We take into account a four dimensional topological static black hole ansatz and solve the field equations, exactly, in terms of the NLED as a matter field. The main goal of this paper is investigation of thermodynamic properties of the obtained black holes. Moreover, we calculate the heat capacity and find that the nonlinearity affects the minimum size of stable black holes. We also use Legendre-invariantmore » metric proposed by Quevedo to obtain scalar curvature divergences. We find that the singularities of the Ricci scalar in Geometrothermodynamics (GTD) method take place at the Davies points. -- Highlights: •We examine the thermodynamical properties of black holes in Einstein gravity with nonlinear electrodynamics. •We investigate thermodynamic stability and discuss about the size of stable black holes. •We obtain analytical solutions of higher dimensional theory.« less

System engineering study of electrodynamic tether as a spaceborne generator and radiator of electromagnetic waves in the ULF/ELF frequency band

NASA Technical Reports Server (NTRS)

Estes, Robert D.

1987-01-01

An electrodynamic tether deployed from a satellite in low-Earth orbit can perform, if properly instrumented, as a partially self-powered generator of electromagnetic waves in the ULF/ELF band, potentially at power levels high enough to be of practical use. Two basic problems are examined. The first is that of the level of wave power that the system can be expected to generate in the ULF/ELF radiation band. The second major question is whether an electrodynamic tethered satellite system for transmitting waves can be made partially self-powering so that power requirements for drag compensation can be met within economical constraints of mass, cost, and complexity. The theoretical developments and the system applications study are presented. The basic design criteria, the drag-compensation method, the effects on the propagation paths from orbit to Earth surface of high-altitude nuclear debris patches, and the estimate of masses and sizes are covered. An outline of recommended analytical work, to be performed as a follow-on to the present study, is contained.

Magnetobraking: Use of tether electrodynamic drag for Earth return from Mars

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

1994-01-01

It has often been proposed that a vehicle returning from Mars will use aerobraking in the Earth's atmosphere to dissipate hyperbolic excess velocity to capture into Earth orbit. Here a different system for dissipating excess velocity without expenditure of reaction mass, magnetobraking, is proposed. Magnetobraking uses the force on an electrodynamic tether in the Earth's magnetic field to produce thrust. An electrodynamic tether is deployed from the spacecraft as it approaches the Earth. The Earth's magnetic field produces a force on electrical current in the tether. If the tether is oriented perpendicularly to the Earth's magnetic field and to the direction of motion of the spacecraft, force produced by the Earth's magnetic field can be used to either brake or accelerate the spacecraft without expenditure of reaction mass. The peak acceleration on the Mars return is 0.007 m/sq sec, and the amount of braking possible is dependent on the density and current-carrying capacity of the tether, but is independent of length. A superconducting tether is required. The required critical current is shown to be within the range of superconducting technology now available in the laboratory.

Electrodynamics of quantum spin liquids

NASA Astrophysics Data System (ADS)

Dressel, Martin; Pustogow, Andrej

2018-05-01

Quantum spin liquids attract great interest due to their exceptional magnetic properties characterized by the absence of long-range order down to low temperatures despite the strong magnetic interaction. Commonly, these compounds are strongly correlated electron systems, and their electrodynamic response is governed by the Mott gap in the excitation spectrum. Here we summarize and discuss the optical properties of several two-dimensional quantum spin liquid candidates. First we consider the inorganic material herbertsmithite ZnCu3(OH)6Cl2 and related compounds, which crystallize in a kagome lattice. Then we turn to the organic compounds -EtMe3Sb[Pd(dmit)2]2, κ-(BEDT-TTF)2Ag2(CN)3 and κ-(BEDT-TTF)2Cu2(CN)3, where the spins are arranged in an almost perfect triangular lattice, leading to strong frustration. Due to differences in bandwidth, the effective correlation strength varies over a wide range, leading to a rather distinct behavior as far as the electrodynamic properties are concerned. We discuss the spinon contributions to the optical conductivity in comparison to metallic quantum fluctuations in the vicinity of the Mott transition.

Electrodynamic properties of the semimetallic Dirac material SrMnB i2 : Two-carrier-model analysis

NASA Astrophysics Data System (ADS)

Park, H. J.; Park, Byung Cheol; Lee, Min-Cheol; Jeong, D. W.; Park, Joonbum; Kim, Jun Sung; Ji, Hyo Seok; Shim, J. H.; Kim, K. W.; Moon, S. J.; Kim, Hyeong-Do; Cho, Deok-Yong; Noh, T. W.

2017-10-01

The electrodynamics of free carriers in the semimetallic Dirac material SrMnB i2 was investigated using optical spectroscopy and first-principles calculations. Using a two-carrier-model analysis, the total free-carrier response was successfully decomposed into individual contributions from Dirac fermions and non-Dirac free carriers. Possible roles of chiral pseudospin, spin-orbit interaction (SOI), antiferromagnetism, and electron-phonon (e -p h ) coupling in the Dirac fermion transport were also addressed. The Dirac fermions possess a low scattering rate of ˜10 meV at low temperature and thereby experience coherent transport. However, at high temperatures, we observed that the Dirac fermion transport becomes significantly incoherent, possibly due to strong e -p h interactions. The SOI-induced gap and antiferromagnetism play minor roles in the electrodynamics of the free carriers in SrMnB i2 . We also observed a seemingly optical-gap-like feature near 120 meV, which emerges at low temperatures but becomes filled in with increasing temperature. This gap-filling phenomenon is ascribed to phonon-assisted indirect transitions promoted at high temperatures.

Exponential nonlinear electrodynamics and backreaction effects on holographic superconductor in the Lifshitz black hole background

NASA Astrophysics Data System (ADS)

Sherkatghanad, Z.; Mirza, B.; Lalehgani Dezaki, F.

We analytically describe the properties of the s-wave holographic superconductor with the exponential nonlinear electrodynamics in the Lifshitz black hole background in four-dimensions. Employing an assumption the scalar and gauge fields backreact on the background geometry, we calculate the critical temperature as well as the condensation operator. Based on Sturm-Liouville method, we show that the critical temperature decreases with increasing exponential nonlinear electrodynamics and Lifshitz dynamical exponent, z, indicating that condensation becomes difficult. Also we find that the effects of backreaction has a more important role on the critical temperature and condensation operator in small values of Lifshitz dynamical exponent, while z is around one. In addition, the properties of the upper critical magnetic field in Lifshitz black hole background using Sturm-Liouville approach is investigated to describe the phase diagram of the corresponding holographic superconductor in the probe limit. We observe that the critical magnetic field decreases with increasing Lifshitz dynamical exponent, z, and it goes to zero at critical temperature, independent of the Lifshitz dynamical exponent, z.

Spacecraft Solar Sails Containing Electrodynamic Tethers

NASA Technical Reports Server (NTRS)

Johnson, Les; Matloff, Greg

2005-01-01

A report discusses a proposal to use large, lightweight solar sails embedded with electrodynamic tethers (essentially, networks of wires) to (1) propel robotic spacecraft to distant planets, then (2) exploit the planetary magnetic fields to capture the spacecraft into orbits around the planets. The purpose of the proposal is, of course, to make it possible to undertake long interplanetary missions without incurring the large cost and weight penalties of conventional rocket-type propulsion systems. Through transfer of momentum from reflected solar photons, a sail would generate thrust outward from the Sun. Upon arrival in the vicinity of a planet, the electrodynamic tethers would be put to use: Motion of the spacecraft across the planetary magnetic field would induce electric currents in the tether wires, giving rise to an electromagnetic drag force that would be exploited to brake the spacecraft for capture into orbit. The sail with embedded tethers would be made to spin to provide stability during capture. Depending upon the requirements of a particular application, it could be necessary to extend the tether to a diameter greater than that of the sail.

Lifelong Learning Tendencies of Prospective Teachers

ERIC Educational Resources Information Center

Cetin, Saban; Cetin, Filiz

2017-01-01

Stunning developments in this era have brought different meanings in both educational conditions and time and space in education. Developing technologies have made education applicable everywhere. In other words, education has been taken outside of the known space (classic school walls). Individuals' constant innovation has caused the development…

Quantum Electrodynamical Shifts in Multivalent Heavy Ions.

PubMed

Tupitsyn, I I; Kozlov, M G; Safronova, M S; Shabaev, V M; Dzuba, V A

2016-12-16

The quantum electrodynamics (QED) corrections are directly incorporated into the most accurate treatment of the correlation corrections for ions with complex electronic structure of interest to metrology and tests of fundamental physics. We compared the performance of four different QED potentials for various systems to access the accuracy of QED calculations and to make a prediction of highly charged ion properties urgently needed for planning future experiments. We find that all four potentials give consistent and reliable results for ions of interest. For the strongly bound electrons, the nonlocal potentials are more accurate than the local potential.

Plasma issues associated with the use of electrodynamic tethers

NASA Technical Reports Server (NTRS)

Hastings, D. E.

1986-01-01

The use of an electrodynamic tether to generate power or thrust on the space station raises important plasma issues associted with the current flow. In addition to the issue of current closure through the space station, high power tethers (equal to or greater than tens of kilowatts) require the use of plasma contactors to enhance the current flow. They will generate large amounts of electrostatic turbulence in the vicinity of the space station. This is because the contactors work best when a large amount of current driven turbulence is excited. Current work is reviewed and future directions suggested.

Space Environmental Testing of the Electrodynamic Dust Shield Technology

NASA Technical Reports Server (NTRS)

Calle, Carlos I.; Mackey, P. J.; Hogue, M. D.; Johansen, M .R.; Yim, H.; Delaune, P. B.; Clements, J. S.

2013-01-01

NASA's exploration missions to Mars and the moon may be jeopardized by dust that will adhere to surfaces of (a) Optical systems, viewports and solar panels, (b) Thermal radiators, (c) Instrumentation, and (d) Spacesuits. We have developed an active dust mitigation technology, the Electrodynamic Dust Shield, a multilayer coating that can remove dust and also prevents its accumulation Extensive testing in simulated laboratory environments and on a reduced gravity flight shows that high dust removal performance can be achieved Long duration exposure to the space environment as part of the MISSE-X payload will validate the technology for lunar missions.

8-Spinors and structure of solitons in generalized Mie electrodynamics

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

Rybakov, Yu. P., E-mail: soliton4@mail.ru

2013-02-15

A generalization of Mie electrodynamics is considered. It includes a 8-spinor field and higher powers of the Mie invariant A{sub {mu}}A{sup {mu}}. Particular topological properties of 8-spinors are indicated and are associated with the existence of the remarkable Brioschi identity of eight squares, which permits deriving a natural 8-spinor unification of the Skyrme model of baryons and the Faddeev model of leptons, these particles being treated as topological solitons. Two types of soliton configurations admitted by the model are constructed. These are charged static and neutral lightlike (luxons) ones.

Electrodynamic Dust Shields on the International Space Station: Exposure to the Space Environment

NASA Technical Reports Server (NTRS)

Calle, C. I.; Hogue, M. D.; Johansen, M. R.; Yim, H.; Delaune, P. B.; Clements, J. S.

2012-01-01

Electrodynamic Dust Shields (EDS) have been in development at NASA as a dust mitigation method for lunar and Martian missions. An active dust mitigation strategy. such as that provided by the EDS, that can remove dust from surfaces, is of crucial importance to the planetary exploration program. We report on the development of a night experiment to fully ex pose four EDS panels to the space environment. This flight experiment is part of the Materials International Space Station experiment X(MISSE-X). an external platform on the International Space Station that will expose materials to the space environment.

Electromagnetic miniactuators using thin magnetic layers

NASA Astrophysics Data System (ADS)

Kube, H.; Zoeppig, V.; Hermann, R.; Hoffmann, A.; Kallenbach, E.

2000-06-01

This paper presents two examples of miniactuators based on the electromagnetic and electrodynamic force generation principle respectively. They use modern high-energy polymer-bonded permanent magnetic layers basing on NdFeB. The first example is a linear drive with an integrated magnetic bearing. It generates electrodynamic forces to lift and move a lightweight platen. The position of the platen is measured and controlled. The second example is a miniature pneumatic valve with a fully integrated polarized electromagnetic actuator. The valve consumes power only when the armature position is changed. The holding force is generated without consumption of power.

Electro-impulse de-icing electrodynamic solution by discrete elements

NASA Technical Reports Server (NTRS)

Bernhart, W. D.; Schrag, R. L.

1988-01-01

This paper describes a technique for analyzing the electrodynamic phenomena associated with electro-impulse deicing. The analysis is done in the time domain and utilizes a discrete element formulation concept expressed in state variable form. Calculated results include coil current, eddy currents in the target (aircraft leading edge skin), pressure distribution on the target, and total force and impulse on the target. Typical results are presented and described. Some comparisons are made between calculated and experimental results, and also between calculated values from other theoretical approaches. Application to the problem of a nonrigid target is treated briefly.

Strongly disordered TiN and NbTiN s-wave superconductors probed by microwave electrodynamics.

PubMed

Driessen, E F C; Coumou, P C J J; Tromp, R R; de Visser, P J; Klapwijk, T M

2012-09-07

We probe the effects of strong disorder (2.4

Lyapunov Orbits in the Jupiter System Using Electrodynamic Tethers

NASA Technical Reports Server (NTRS)

Bokelmann, Kevin; Russell, Ryan P.; Lantoine, Gregory

2013-01-01

Various researchers have proposed the use of electrodynamic tethers for power generation and capture from interplanetary transfers. The effect of tether forces on periodic orbits in Jupiter-satellite systems are investigated. A perturbation force is added to the restricted three-body problem model and a series of simplifications allows development of a conservative system that retains the Jacobi integral. Expressions are developed to find modified locations of equilibrium positions. Modified families of Lyapunov orbits are generated as functions of tether size and Jacobi integral. Zero velocity curves and stability analyses are used to evaluate the dynamical properties of tether-modified orbits.

Book Review:

NASA Astrophysics Data System (ADS)

Poisson, E.

2006-09-01

The motion of a charged particle interacting with its own electromagnetic field is an area of research that has a long history; this problem has never ceased to fascinate its investigators. On the one hand the theory ought to be straightforward to formulate: one has Maxwell's equations that tell the field how to behave (given the motion of the particle), and one has the Lorentz-force law that tells the particle how to move (given the field). On the other hand the theory is fundamentally ambiguous because of the field singularities that necessarily come with a point particle. While each separate sub-problem can easily be solved, to couple the field to the particle in a self-consistent treatment turns out to be tricky. I believe it is this dilemma (the theory is straightforward but tricky) that has been the main source of the endless fascination. For readers of Classical and Quantum Gravity, the fascination does not end there. For them it is also rooted in the fact that the electromagnetic self-force problem is deeply analogous to the gravitational self-force problem, which is of direct relevance to future gravitational wave observations. The motion of point particles in curved spacetime has been the topic of a recent Topical Review [1], and it was the focus of a recent Special Issue [2]. It is surprising to me that radiation reaction is a subject that continues to be poorly covered in the standard textbooks, including Jackson's bible [3]. Exceptions are Rohrlich's excellent text [4], which makes a very useful introduction to radiation reaction, and the Landau and Lifshitz classic [5], which contains what is probably the most perfect summary of the foundational ideas (presented in characteristic terseness). It is therefore with some trepidation that I received Herbert Spohn's book, which covers both the classical and quantum theories of a charged particle coupled to its own field (the presentation is limited to flat spacetime). Is this the text that graduate students and researchers should turn to in order to get a complete and accessible education in radiation reaction? My answer is that while the book does indeed contain a lot of useful material, it is not a very accessible source of information, and it is certainly not a student-friendly textbook. Instead, the book presents a technical account of the author's personal take on the theory, and represents a culminating summary of the author's research contributions over more than a decade. The book is written in a fairly mathematical style (the author is Professor of Mathematical Physics at the Technische Universitat in Munich), and it very much emphasises mathematical rigour. This makes the book less accessible than I would wish it to be, but this is perhaps less a criticism than a statement about my taste, expectation, and attitude. The presentation of the classical theory begins with a point particle, but Spohn immediately smears the charge distribution to eliminate the vexing singularities of the retarded field. He considers both the nonrelativistic Abraham model (in which the extended particle is spherically symmetric in the laboratory frame) and the relativistic Lorentz model (in which the particle is spherical in its rest frame). In Spohn's work, the smearing of the charge distribution is entirely a mathematical procedure, and I would have wished for a more physical discussion. A physically extended body, held together against electrostatic repulsion by cohesive forces (sometimes called Poincaré stresses) would make a sound starting point for a classical theory of charged particles, and would have nicely (and physically) motivated the smearing operation adopted in the book. Spohn goes on to derive energy momentum relations for the extended objects, and to obtain their equations of motion. A compelling aspect of his presentation is that he formally introduces the 'adiabatic limit', the idea that the external fields acting on the charged body should have length and time scales that are long compared with the particle's internal scales (respectively the electrostatic classical radius and its associated time scale). As a consequence, the equations of motion do not involve a differentiated acceleration vector (as is the case for the Abraham Lorentz Dirac equations) but are proper second-order differential equations for the position vector. In effect, the correct equations of motion are obtained from the Abraham Lorentz Dirac equations by a reduction-of-order procedure that was first proposed (as far as I know) by Landau and Lifshitz [5]. In Spohn's work this procedure is not {\\it ad hoc}, but a natural consequence of the adiabatic approximation. An aspect of the classical portion of the book that got me particularly excited is Spohn's proposal for an experimental test of the predictions of the Landau Lifshitz equations. His proposed experiment involves a Penning trap, a device that uses a uniform magnetic field and a quadrupole electric field to trap an electron for very long times. Without radiation reaction, the motion of an electron in the trap is an epicycle that consists of a rapid (and small) cyclotron orbit superposed onto a slow (and large) magnetron orbit. Spohn shows that according to the Landau Lifshitz equations, the radiation reaction produces a damping of the cyclotron motion. For reasonable laboratory situations this damping occurs over a time scale of the order of 0.1 second. This experiment might well be within technological reach. The presentation of the quantum theory is based on the nonrelativistic Abraham model, which upon quantization leads to the well-known Pauli-Fierz Hamiltonian of nonrelativistic quantum electrodynamics. This theory, an approximation to the fully relativistic version of QED, has a wide domain of validity that includes many aspects of quantum optics and laser-matter interactions. As I am not an expert in this field, my ability to review this portion of Spohn's book is limited, and I will indeed restrict myself to a few remarks. I first admit that I found Spohn's presentation to be tough going. Unlike the pair of delightful books by Cohen-Tannoudji, Dupont-Roc, and Grynberg [6, 7], this is not a gentle introduction to the quantum theory of a charged particle coupled to its own electromagnetic field. Instead, Spohn proceeds rather quickly through the formulation of the theory (defining the Hamiltonian and the Hilbert space) and then presents some applications (for example, he constructs the ground states of the theory, he examines radiation processes, and he explores finite-temperature aspects). There is a lot of material in the eight chapters devoted to the quantum theory, but my insufficient preparation and the advanced nature of Spohn's presentation were significant obstacles; I was not able to draw much appreciation for this material. One of the most useful resources in Spohn's book are the historical notes and literature reviews that are inserted at the end of each chapter. I discovered a wealth of interesting articles by reading these, and I am grateful that the author made the effort to collect this information for the benefit of his readers. References [1] Poisson E 2004 Radiation reaction of point particles in curved spacetime Class. Quantum Grav 21 R153 R232 [2] Lousto C O 2005 Special issue: Gravitational Radiation from Binary Black Holes: Advances in the Perturbative Approach, Class. Quantum Grav22 S543 S868 [3] Jackson J D 1999 Classical Electrodynamics Third Edition (New York: Wiley) [4] Rohrlich F 1990 Classical Charged Particles (Redwood City, CA: Addison Wesley) [5] Landau L D and Lifshitz E M 2000 The Classical Theory of Fields Fourth Edition (Oxford: Butterworth Heinemann) [6] Cohen-Tannoudji C Dupont-Roc J and Grynberg G 1997 Photons and Atoms - Introduction to Quantum Electrodynamics (New York: Wiley-Interscience) [7] Cohen-Tannoudji C, Dupont-Roc J and G Grynberg G 1998 Atom Photon Interactions: Basic Processes and Applications (New York: Wiley-Interscience)

Chromosome engineering for alien gene introgression in wheat: Progress and prospective

USDA-ARS?s Scientific Manuscript database

Chromosome engineering is a useful strategy for introgression of desirable genes from wild relatives into cultivated wheat. However, it has been a challenge to transfer a small amount of alien chromatin containing the gene of interest from one genome to another non-homologous genome through classic...

Host plant oviposition preference of Ceratapion basicorne (Coleoptera:Apionidae), a potential biological control agent of yellow starthistle

USDA-ARS?s Scientific Manuscript database

Ceratapion basicorne (Coleoptera: Apionidae) is a weevil native to Europe and western Asia that is being evaluated as a prospective classical biological control agent of Centaurea solstitialis (yellow starthistle) in the United States. Choice oviposition experiments were conducted under laboratory ...

Prospects for Classical Biological Control of Saharan Mustard (Brassica tournefortii)

USDA-ARS?s Scientific Manuscript database

Saharan mustard (Brassica tournefortii) is a winter annual plant that is native to the Mediterranean Basin and is becoming highly invasive in the Sonoran and Mojave Deserts and adjacent areas and has spread great distances along highways from its original infestation. It is becoming a serious probl...

Reverse Engineering from Eminent Exemplars: How about a Retrospective Study Too?

ERIC Educational Resources Information Center

Simonton, Dean Keith

2017-01-01

In his target article, Sternberg (2017) quite rightly criticizes the approach to identifying giftedness that was initiated by Terman's (1925-1959) classic prospective study of high-IQ children. Sternberg then recommends a number of novel approaches to both identification and education. Nonetheless, this commentator recommends that future…

Prospective randomized clinical trial: single and weekly viscosupplementation

PubMed Central

Zóboli, Alejandro Agustin Carri; de Rezende, Márcia Uchôa; de Campos, Gustavo Constantino; Pasqualin, Thiago; Frucchi, Renato; de Camargo, Olavo Pires

2013-01-01

OBJECTIVE: To compare two different dosages of an intermediate molecular weight sodium hyaluronate (HA) (Osteonil®-TRB Pharma) assessing whether a single 6 ml application of this HA has the same effectiveness as the classical three-weekly 2 ml dose. METHODS: 108 patients with knee osteoarthritis were randomized into two groups of 54 patients each. The groups were designated "single" (S) and "weekly" (W). Patients in group S underwent a viscosupplementation procedure by application of only 6 ml of sodium hyaluronate and 1 ml triamcinolone hexacetonide. Patients in group W underwent the procedure of viscosupplementation through three applications with 2 ml sodium hyaluronate with a week interval between them, and the first application was also performed with the infiltration of 1 ml (20 mg) of Triamcinolone Hexacetonide. Both groups were assessed before, at one month and three months after application, by responding to the WOMAC, Lequesne, IKDC and VAS questionnaires. RESULTS: There was no statistical difference between the single application of 6 ml of sodium hyaluronate and classic application with three weekly injections. However, only the classical regime showed statistically significant improvement in baseline pain (WOMAC pain and VAS). CONCLUSION: Our results suggest that both application schemes improve application function, but the three-weekly regimen of 2 ml was more effective in reducing pain. Level of Evidence I, Prospective Randomized, Clinical Trial. PMID:24453681

Evaluation of a six-DOF electrodynamic shaker system.

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

Gregory, Danny Lynn; Smallwood, David Ora

2009-03-01

The paper describes the preliminary evaluation of a 6 degree of freedom electrodynamic shaker system. The 8 by 8 inch (20.3 cm) table is driven by 12 electrodynamic shakers producing motion in all 6 rigid body modes. A small electrodynamic shaker system suitable for small component testing is described. The principal purpose of the system is to demonstrate the technology. The shaker is driven by 12 electrodynamic shakers each with a force capability of about 50 lbs (220 N). The system was developed through an informal cooperative agreement between Sandia National Laboratories, Team Corp. and Spectral Dynamics Corporation. Sandia providedmore » the laboratory space and some development funds. Team provided the mechanical system, and Spectral Dynamics provided the control system. Spectral Dynamics was chosen to provide the control system partly because of their experience in MIMO control and partly because Sandia already had part of the system in house. The shaker system was conceived and manufactured by TEAM Corp. Figure 1 shows the overall system. The vibration table, electrodynamic shakers, hydraulic pumps, and amplifiers are all housed in a single cabinet. Figure 2 is a drawing showing how the electrodynamic shakers are coupled to the table. The shakers are coupled to the table through a hydraulic spherical pad bearing providing 5 degrees of freedom and one stiff degree of freedom. The pad bearing must be preloaded with a static force as they are unable to provide any tension forces. The horizontal bearings are preloaded with steel springs. The drawing shows a spring providing the vertical preload. This was changed in the final design. The vertical preload is provided by multiple strands of an O-ring material as shown in Figure 4. Four shakers provide excitation in each of the three orthogonal axes. The specifications of the shaker are outlined in Table 1. Four shakers provide inputs in each of the three orthogonal directions. By choosing the phase relationships between the shakers all six rigid body modes (three translation, and three rotations) can be excited. The system is over determined. There are more shakers than degrees of freedom. This provided an interesting control problem. The problem was approached using the input-output transformation matrices provided in the Spectral control system. Twelve accelerometers were selected for the control accelerometers (a tri-axial accelerometer at each corner of the table (see Figure 5). Figure 6 shows the nomenclature used to identify the shakers and control accelerometers. A fifth tri-axial accelerometer was placed at the center of the table, but it was not used for control. Thus we had 12 control accelerometers and 12 shakers to control a 6-dof shaker. The 12 control channels were reduced to a 6-dof control using a simple input transformation matrix. The control was defined by a 6x6 spectral density matrix. The six outputs in the control variable coordinates were transformed to twelve physical drive signals using another simple output transformation matrix. It was assumed that the accelerometers and shakers were well matched such that the transformation matrices were independent of frequency and could be deduced from rigid body considerations. The input/output transformations are shown in Equations 1 and 2.« less

Radiation forces and the Abraham-Minkowski problem

NASA Astrophysics Data System (ADS)

Brevik, Iver

2018-04-01

Recent years have witnessed a number of beautiful experiments in radiation optics. Our purpose with this paper is to highlight some developments of radiation pressure physics in general, and thereafter to focus on the importance of the mentioned experiments in regard to the classic Abraham-Minkowski problem. That means, what is the “correct” expression for electromagnetic momentum density in continuous matter. In our opinion, one often sees that authors over-interpret the importance of their experimental findings with respect to the momentum problem. Most of these experiments are actually unable to discriminate between these energy-momentum tensors at all, since they can be easily described in terms of force expressions that are common for Abraham and Minkowski. Moreover, we emphasize the inherent ambiguity in applying the formal conservation principles to the radiation field in a dielectric, the reason being that the electromagnetic field in matter is only a subsystem which has to be supplemented by the mechanical subsystem to be closed. Finally, we make some suggestions regarding the connection between macroscopic electrodynamics and the Casimir effect, suggesting that there is a limit for the magnitudes of the cutoff parameters in QFT related to surface tension in ordinary hydromechanics.

Quantum singularities in (2+1) dimensional matter coupled black hole spacetimes

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

Unver, O.; Gurtug, O.

2010-10-15

Quantum singularities considered in the 3D Banados-Teitelboim-Zanelli (BTZ) spacetime by Pitelli and Letelier [Phys. Rev. D 77, 124030 (2008)] is extended to charged BTZ and 3D Einstein-Maxwell-dilaton gravity spacetimes. The occurrence of naked singularities in the Einstein-Maxwell extension of the BTZ spacetime both in linear and nonlinear electrodynamics as well as in the Einstein-Maxwell-dilaton gravity spacetimes are analyzed with the quantum test fields obeying the Klein-Gordon and Dirac equations. We show that with the inclusion of the matter fields, the conical geometry near r=0 is removed and restricted classes of solutions are admitted for the Klein-Gordon and Dirac equations. Hence,more » the classical central singularity at r=0 turns out to be quantum mechanically singular for quantum particles obeying the Klein-Gordon equation but nonsingular for fermions obeying the Dirac equation. Explicit calculations reveal that the occurrence of the timelike naked singularities in the considered spacetimes does not violate the cosmic censorship hypothesis as far as the Dirac fields are concerned. The role of horizons that clothes the singularity in the black hole cases is replaced by repulsive potential barrier against the propagation of Dirac fields.« less

PTB’s radiometric scales for UV and VUV source calibration based on synchrotron radiation

NASA Astrophysics Data System (ADS)

Klein, Roman; Kroth, Simone; Paustian, Wolfgang; Richter, Mathias; Thornagel, Reiner

2018-06-01

The radiant intensity of synchrotron radiation can be accurately calculated with classical electrodynamics. This primary realization of the spectral radiant intensity has been used by PTB at several electron storage rings which have been optimized to be operated as primary source standards for the calibration of transfer sources in the spectral range of UV and VUV for almost 30 years. The transfer sources are compared to the primary source standard by means of suitable wavelength-dispersive transfer stations. The spectral range covered by deuterium lamps, which represent transfer sources that are easy to handle, is of particular relevance in practice. Here, we report on developments in the realization and preservation of the radiometric scales for spectral radiant intensity and spectral radiance in the wavelength region from 116 nm to 400 nm, based on a set of deuterium reference lamps, over the last few decades. An inside view and recommendations on the operation of the D2 lamps used for the realization of the radiometric scale are presented. The data has been recently compiled to illustrate the chronological behaviour at various wavelengths. Moreover, an overview of the internal and external validation measurements and intercomparisons is given.

Pure single-photon emission from In(Ga)As QDs in a tunable fiber-based external mirror microcavity

NASA Astrophysics Data System (ADS)

Herzog, T.; Sartison, M.; Kolatschek, S.; Hepp, S.; Bommer, A.; Pauly, C.; Mücklich, F.; Becher, C.; Jetter, M.; Portalupi, S. L.; Michler, P.

2018-07-01

Cavity quantum electrodynamics is widely used in many solid-state systems for improving quantum emitter performances or accessing specific physical regimes. For these purposes it is fundamental that the non-classical emitter, like a quantum dot or an NV center, matches the cavity mode, both spatially and spectrally. In the present work, we couple single photons stemming from In(Ga)As quantum dots into an open fiber-based Fabry–Pérot cavity. Such a system allows for reaching an optimal spatial and spectral matching for every present emitter and every optical transition, by precisely tuning the cavity geometry. In addition to that, the capability of deterministically and repeatedly locating a single quantum dot enables to compare the behavior of the quantum emitter inside the cavity with respect to before it is placed inside. The presented open-cavity system shows full flexibility by precisely tuning in resonance different QD transitions, namely excitons, biexcitons and trions. A measured Purcell enhancement of 4.4 ± 0.5 is obtained with a cavity finesse of about 140, while still demonstrating a single-photon source with vanishing multi-photon emission probability.

Quantum Field Theory Approach to Condensed Matter Physics

NASA Astrophysics Data System (ADS)

Marino, Eduardo C.

2017-09-01

Preface; Part I. Condensed Matter Physics: 1. Independent electrons and static crystals; 2. Vibrating crystals; 3. Interacting electrons; 4. Interactions in action; Part II. Quantum Field Theory: 5. Functional formulation of quantum field theory; 6. Quantum fields in action; 7. Symmetries: explicit or secret; 8. Classical topological excitations; 9. Quantum topological excitations; 10. Duality, bosonization and generalized statistics; 11. Statistical transmutation; 12. Pseudo quantum electrodynamics; Part III. Quantum Field Theory Approach to Condensed Matter Systems: 13. Quantum field theory methods in condensed matter; 14. Metals, Fermi liquids, Mott and Anderson insulators; 15. The dynamics of polarons; 16. Polyacetylene; 17. The Kondo effect; 18. Quantum magnets in 1D: Fermionization, bosonization, Coulomb gases and 'all that'; 19. Quantum magnets in 2D: nonlinear sigma model, CP1 and 'all that'; 20. The spin-fermion system: a quantum field theory approach; 21. The spin glass; 22. Quantum field theory approach to superfluidity; 23. Quantum field theory approach to superconductivity; 24. The cuprate high-temperature superconductors; 25. The pnictides: iron based superconductors; 26. The quantum Hall effect; 27. Graphene; 28. Silicene and transition metal dichalcogenides; 29. Topological insulators; 30. Non-abelian statistics and quantum computation; References; Index.

Quantum simulation of the spin-boson model with a microwave circuit

NASA Astrophysics Data System (ADS)

Leppäkangas, Juha; Braumüller, Jochen; Hauck, Melanie; Reiner, Jan-Michael; Schwenk, Iris; Zanker, Sebastian; Fritz, Lukas; Ustinov, Alexey V.; Weides, Martin; Marthaler, Michael

2018-05-01

We consider superconducting circuits for the purpose of simulating the spin-boson model. The spin-boson model consists of a single two-level system coupled to bosonic modes. In most cases, the model is considered in a limit where the bosonic modes are sufficiently dense to form a continuous spectral bath. A very well known case is the Ohmic bath, where the density of states grows linearly with the frequency. In the limit of weak coupling or large temperature, this problem can be solved numerically. If the coupling is strong, the bosonic modes can become sufficiently excited to make a classical simulation impossible. Here we discuss how a quantum simulation of this problem can be performed by coupling a superconducting qubit to a set of microwave resonators. We demonstrate a possible implementation of a continuous spectral bath with individual bath resonators coupling strongly to the qubit. Applying a microwave drive scheme potentially allows us to access the strong-coupling regime of the spin-boson model. We discuss how the resulting spin relaxation dynamics with different initialization conditions can be probed by standard qubit-readout techniques from circuit quantum electrodynamics.

Polarization characteristics of radiation in both 'light' and conventional undulators

NASA Astrophysics Data System (ADS)

Potylitsyn, A. P.; Kolchuzhkin, A. M.; Strokov, S. A.

2017-07-01

As a rule, an intensity spectrum of undulator radiation (UR) is calculated by using the classical approach, even for electron energy higher than 10 GeV. Such a spectrum is determined by an electron trajectory in an undulator while neglecting radiation loss. Using Planck's law, the UR photon spectrum can be calculated from the obtained intensity spectrum, for both linear and nonlinear regimes. The electron radiation process in a field of strong electromagnetic waves is considered within the quantum electrodynamics framework, using the Compton scattering process or radiation in a 'light' undulator. A comparison was made of the results from using these two approaches, for UR spectra generated by 250-GeV electrons in an undulator with a 11.5-mm period; this comparison shows that they coincide with high accuracy. The characteristics of the collimated UR beam (i.e. spectrum and circular polarization) were simulated while taking into account the discrete process of photon emission along an electron trajectory in both undulator types. Both spectral photon distributions and polarization dependence on photon energy are 'smoothed', in comparison to that expected for a long undulator-the latter of which considers the ILC positron source (ILC Technical Design Report).

Active measurement-based quantum feedback for preparing and stabilizing superpositions of two cavity photon number states

NASA Astrophysics Data System (ADS)

Berube-Lauziere, Yves

The measurement-based quantum feedback scheme developed and implemented by Haroche and collaborators to actively prepare and stabilize specific photon number states in cavity quantum electrodynamics (CQED) is a milestone achievement in the active protection of quantum states from decoherence. This feat was achieved by injecting, after each weak dispersive measurement of the cavity state via Rydberg atoms serving as cavity sensors, a low average number classical field (coherent state) to steer the cavity towards the targeted number state. This talk will present the generalization of the theory developed for targeting number states in order to prepare and stabilize desired superpositions of two cavity photon number states. Results from realistic simulations taking into account decoherence and imperfections in a CQED set-up will be presented. These demonstrate the validity of the generalized theory and points to the experimental feasibility of preparing and stabilizing such superpositions. This is a further step towards the active protection of more complex quantum states than number states. This work, cast in the context of CQED, is also almost readily applicable to circuit QED. YBL acknowledges financial support from the Institut Quantique through a Canada First Research Excellence Fund.

Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

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

Aaboud, M.; Aad, G.; Abbott, B.

Light-by-light scattering (γγ → γγ) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 μb -1 of lead–lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 ± 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pbmore » + Pb (γγ) → Pb(*) + Pb(*)γγ, for photon transverse energy E T > 3 GeV, photon absolute pseudorapidity |η| < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 ± 24 (stat.) ± 17 (syst.) nb, which is in agreement with the standard model predictions.« less

Evidence for light-by-light scattering in heavy-ion collisions with the ATLAS detector at the LHC

DOE PAGES

Aaboud, M.; Aad, G.; Abbott, B.; ...

2017-08-14

Light-by-light scattering (γγ → γγ) is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics. This reaction is accessible at the Large Hadron Collider thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 μb -1 of lead–lead collision data recorded at a centre-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, here we report evidence for light-by-light scattering. A total of 13 candidate events were observed with an expected background of 2.6 ± 0.7 events. After background subtraction and analysis corrections, the fiducial cross-section of the process Pbmore » + Pb (γγ) → Pb(*) + Pb(*)γγ, for photon transverse energy E T > 3 GeV, photon absolute pseudorapidity |η| < 2.4, diphoton invariant mass greater than 6 GeV, diphoton transverse momentum lower than 2 GeV and diphoton acoplanarity below 0.01, is measured to be 70 ± 24 (stat.) ± 17 (syst.) nb, which is in agreement with the standard model predictions.« less

Finite difference computation of Casimir forces

NASA Astrophysics Data System (ADS)

Pinto, Fabrizio

2016-09-01

In this Invited paper, we begin by a historical introduction to provide a motivation for the classical problems of interatomic force computation and associated challenges. This analysis will lead us from early theoretical and experimental accomplishments to the integration of these fascinating interactions into the operation of realistic, next-generation micro- and nanodevices both for the advanced metrology of fundamental physical processes and in breakthrough industrial applications. Among several powerful strategies enabling vastly enhanced performance and entirely novel technological capabilities, we shall specifically consider Casimir force time-modulation and the adoption of non-trivial geometries. As to the former, the ability to alter the magnitude and sign of the Casimir force will be recognized as a crucial principle to implement thermodynamical nano-engines. As to the latter, we shall first briefly review various reported computational approaches. We shall then discuss the game-changing discovery, in the last decade, that standard methods of numerical classical electromagnetism can be retooled to formulate the problem of Casimir force computation in arbitrary geometries. This remarkable development will be practically illustrated by showing that such an apparently elementary method as standard finite-differencing can be successfully employed to numerically recover results known from the Lifshitz theory of dispersion forces in the case of interacting parallel-plane slabs. Other geometries will be also be explored and consideration given to the potential of non-standard finite-difference methods. Finally, we shall introduce problems at the computational frontier, such as those including membranes deformed by Casimir forces and the effects of anisotropic materials. Conclusions will highlight the dramatic transition from the enduring perception of this field as an exotic application of quantum electrodynamics to the recent demonstration of a human climbing vertically on smooth glass.

Force law in material media, hidden momentum and quantum phases

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

Kholmetskii, Alexander L., E-mail: alkholmetskii@gmail.com; Missevitch, Oleg V.; Yarman, T.

We address to the force law in classical electrodynamics of material media, paying attention on the force term due to time variation of hidden momentum of magnetic dipoles. We highlight that the emergence of this force component is required by the general theorem, deriving zero total momentum for any static configuration of charges/currents. At the same time, we disclose the impossibility to add this force term covariantly to the Lorentz force law in material media. We further show that the adoption of the Einstein–Laub force law does not resolve the issue, because for a small electric/magnetic dipole, the density ofmore » Einstein–Laub force integrates exactly to the same equation, like the Lorentz force with the inclusion of hidden momentum contribution. Thus, none of the available expressions for the force on a moving dipole is compatible with the relativistic transformation of force, and we support this statement with a number of particular examples. In this respect, we suggest applying the Lagrangian approach to the derivation of the force law in a magnetized/polarized medium. In the framework of this approach we obtain the novel expression for the force on a small electric/magnetic dipole, with the novel expression for its generalized momentum. The latter expression implies two novel quantum effects with non-topological phases, when an electric dipole is moving in an electric field, and when a magnetic dipole is moving in a magnetic field. These phases, in general, are not related to dynamical effects, because they are not equal to zero, when the classical force on a dipole is vanishing. The implications of the obtained results are discussed.« less

A Concise Introduction to Quantum Mechanics

NASA Astrophysics Data System (ADS)

Swanson, Mark S.

2018-02-01

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

Generating single microwave photons in a circuit.

PubMed

Houck, A A; Schuster, D I; Gambetta, J M; Schreier, J A; Johnson, B R; Chow, J M; Frunzio, L; Majer, J; Devoret, M H; Girvin, S M; Schoelkopf, R J

2007-09-20

Microwaves have widespread use in classical communication technologies, from long-distance broadcasts to short-distance signals within a computer chip. Like all forms of light, microwaves, even those guided by the wires of an integrated circuit, consist of discrete photons. To enable quantum communication between distant parts of a quantum computer, the signals must also be quantum, consisting of single photons, for example. However, conventional sources can generate only classical light, not single photons. One way to realize a single-photon source is to collect the fluorescence of a single atom. Early experiments measured the quantum nature of continuous radiation, and further advances allowed triggered sources of photons on demand. To allow efficient photon collection, emitters are typically placed inside optical or microwave cavities, but these sources are difficult to employ for quantum communication on wires within an integrated circuit. Here we demonstrate an on-chip, on-demand single-photon source, where the microwave photons are injected into a wire with high efficiency and spectral purity. This is accomplished in a circuit quantum electrodynamics architecture, with a microwave transmission line cavity that enhances the spontaneous emission of a single superconducting qubit. When the qubit spontaneously emits, the generated photon acts as a flying qubit, transmitting the quantum information across a chip. We perform tomography of both the qubit and the emitted photons, clearly showing that both the quantum phase and amplitude are transferred during the emission. Both the average power and voltage of the photon source are characterized to verify performance of the system. This single-photon source is an important addition to a rapidly growing toolbox for quantum optics on a chip.

Classical boson sampling algorithms with superior performance to near-term experiments

NASA Astrophysics Data System (ADS)

Neville, Alex; Sparrow, Chris; Clifford, Raphaël; Johnston, Eric; Birchall, Patrick M.; Montanaro, Ashley; Laing, Anthony

2017-12-01

It is predicted that quantum computers will dramatically outperform their conventional counterparts. However, large-scale universal quantum computers are yet to be built. Boson sampling is a rudimentary quantum algorithm tailored to the platform of linear optics, which has sparked interest as a rapid way to demonstrate such quantum supremacy. Photon statistics are governed by intractable matrix functions, which suggests that sampling from the distribution obtained by injecting photons into a linear optical network could be solved more quickly by a photonic experiment than by a classical computer. The apparently low resource requirements for large boson sampling experiments have raised expectations of a near-term demonstration of quantum supremacy by boson sampling. Here we present classical boson sampling algorithms and theoretical analyses of prospects for scaling boson sampling experiments, showing that near-term quantum supremacy via boson sampling is unlikely. Our classical algorithm, based on Metropolised independence sampling, allowed the boson sampling problem to be solved for 30 photons with standard computing hardware. Compared to current experiments, a demonstration of quantum supremacy over a successful implementation of these classical methods on a supercomputer would require the number of photons and experimental components to increase by orders of magnitude, while tackling exponentially scaling photon loss.

Understanding Plasma Interactions with the Atmosphere: The Geospace Electrodynamic Connections (GEC) Mission

NASA Technical Reports Server (NTRS)

2001-01-01

The Geospace Electrodynamic Connections (GEC) mission is a multispacecraft Solar-Terrestrial Probe that has been specifically designed to advance the level of physical insight of our understanding of the coupling among the ionosphere, thermosphere, and magnetosphere. GEC is NASA's fifth Solar-Terrestrial Probe. Through multipoint measurements in the Earth's ionosphere-thermosphere (I-T) system, GEC will (i) discover the spatial and temporal scales on which magnetospheric energy input into the I-T region occurs, (ii) determine the spatial and temporal scales for the response of the I-T system to this input of energy, and (iii) quantify the altitude dependence of the response.

Regular black holes in f(T) Gravity through a nonlinear electrodynamics source

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

Junior, Ednaldo L.B.; Rodrigues, Manuel E.; Houndjo, Mahouton J.S., E-mail: ednaldobarrosjr@gmail.com, E-mail: esialg@gmail.com, E-mail: sthoundjo@yahoo.fr

2015-10-01

We seek to obtain a new class of exact solutions of regular black holes in f(T) Gravity with non-linear electrodynamics material content, with spherical symmetry in 4D. The equations of motion provide the regaining of various solutions of General Relativity, as a particular case where the function f(T)=T. We developed a powerful method for finding exact solutions, where we get the first new class of regular black holes solutions in the f(T) Theory, where all the geometrics scalars disappear at the origin of the radial coordinate and are finite everywhere, as well as a new class of singular black holes.

Compact Q-balls and Q-shells in a scalar electrodynamics

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

Arodz, H.; Lis, J.

2009-02-15

We investigate spherically symmetric nontopological solitons in electrodynamics with a scalar field self-interaction U{approx}|{psi}| taken from the complex signum-Gordon model. We find Q-balls for small absolute values of the total electric charge Q, and Q-shells when |Q| is large enough. In both cases the charge density exactly vanishes outside certain compact regions in the three-dimensional space. The dependence of the total energy E of small Q-balls on the total electric charge has the form E{approx}|Q|{sup 5/6}, while in the case of very large Q-shells, E{approx}|Q|{sup 7/6}.

Electrodynamics of the middle atmosphere: Superpressure balloon program

NASA Technical Reports Server (NTRS)

Holzworth, Robert H.

1987-01-01

In this experiment a comprehensive set of electrical parameters were measured during eight long duration flights in the southern hemisphere stratosphere. These flight resulted in the largest data set ever collected from the stratosphere. The stratosphere has never been electrodynamically sampled in the systematic manner before. New discoveries include short term variability in the planetary scale electric current system, the unexpected observation of stratospheric conductivity variations over thunderstorms and the observation of direct stratospheric conductivity variations following a relatively small solar flare. Major statistical studies were conducted of the large scale current systems, the stratospheric conductivity and the neutral gravity waves (from pressure and temperature data) using the entire data set.

The investigation of tethered satellite system dynamics

NASA Technical Reports Server (NTRS)

Lorenzini, E.

1985-01-01

The tether control law to retrieve the satellite was modified in order to have a smooth retrieval trajectory of the satellite that minimizes the thruster activation. The satellite thrusters were added to the rotational dynamics computer code and a preliminary control logic was implemented to simulate them during the retrieval maneuver. The high resolution computer code for modelling the three dimensional dynamics of untensioned tether, SLACK3, was made fully operative and a set of computer simulations of possible tether breakages was run. The distribution of the electric field around an electrodynamic tether in vacuo severed at some length from the shuttle was computed with a three dimensional electrodynamic computer code.

Electrodynamic tether system study

NASA Technical Reports Server (NTRS)

1987-01-01

The purpose of this program is to define an Electrodynamic Tether System (ETS) that could be erected from the space station and/or platforms to function as an energy storage device. A schematic representation of the ETS concept mounted on the space station is presented. In addition to the hardware design and configuration efforts, studies are also documented involving simulations of the Earth's magnetic fields and the effects this has on overall system efficiency calculations. Also discussed are some preliminary computer simulations of orbit perturbations caused by the cyclic/night operations of the ETS. System cost estimates, an outline for future development testing for the ETS system, and conclusions and recommendations are also provided.

Applications of the Electrodynamic Tether to Interstellar Travel

NASA Technical Reports Server (NTRS)

Matloff, Gregory L.; Johnson, Les

2005-01-01

After considering relevant properties of the local interstellar medium and defining a sample interstellar mission, this paper considers possible interstellar applications of the electrodynamic tether, or EDT. These include use of the EDT to provide on-board power and affect trajectory modifications and direct application of the EDT to starship acceleration. It is demonstrated that comparatively modest EDTs can provide substantial quantities of on-board power, if combined with a large-area electron-collection device such as the Cassenti toroidal-field ramscoop. More substantial tethers can be used to accomplish large-radius thrustless turns. Direct application of the EDT to starship acceleration is apparently infeasible.

Modelling nonlinear viscoelastic behaviours of loudspeaker suspensions-like structures

NASA Astrophysics Data System (ADS)

Maillou, Balbine; Lotton, Pierrick; Novak, Antonin; Simon, Laurent

2018-03-01

Mechanical properties of an electrodynamic loudspeaker are mainly determined by its suspensions (surround and spider) that behave nonlinearly and typically exhibit frequency dependent viscoelastic properties such as creep effect. The paper aims at characterizing the mechanical behaviour of electrodynamic loudspeaker suspensions at low frequencies using nonlinear identification techniques developed in recent years. A Generalized Hammerstein based model can take into account both frequency dependency and nonlinear properties. As shown in the paper, the model generalizes existing nonlinear or viscoelastic models commonly used for loudspeaker modelling. It is further experimentally shown that a possible input-dependent law may play a key role in suspension characterization.

Electromagnetically induced transparency in circuit quantum electrodynamics

NASA Astrophysics Data System (ADS)

Ku, Hsiang-Sheng; Long, Junling; Wu, Xian; Lake, Russell; Gu, Xiu; Liu, Yu-Xi; Pappas, David

Electromagnetically induced transparency (EIT) is a phenomenon caused by quantum interference between distinct transition paths in a three-level system. In general, it is difficult to realize EIT in a system of three-level superconducting quantum circuit, because the decay rates and the Rabi frequency of the driving field do not normally satisfy the conditions for EIT. However, we propose to achieve EIT within a driven circuit quantum electrodynamics (cQED) system by creating polariton states and engineering the decay rates of their levels with the driving field. In this talk we present spectroscopic measurements of the polariton states that will enable demonstration of EIT within cQED.

The gj factor of a bound electron and the hyperfine structure splitting in hydrogenlike ions

NASA Astrophysics Data System (ADS)

Beier, Thomas

2000-12-01

The comparison between theory and experiment of the hyperfine structure splitting and the electronic gj factor in heavy highly charged ions provides a unique testing ground for quantum electrodynamics in the presence of strong electric and magnetic fields. A theoretical evaluation is presented of all quantum electrodynamical contributions to the ground-state hfs splitting in hydrogenlike and lithiumlike atoms as well as to the gj factor. Binding and nuclear effects are discussed as well. A comparison with the available experimental data is performed, and a detailed discussion of theoretical sources of uncertainty is included which is mainly due to insufficiently known nuclear properties.

Free Re-boost Electrodynamic Tether on the International Space Station

NASA Technical Reports Server (NTRS)

Bonometti, Joseph A.; Sorenson, Kirk F.; Jansen, Ralph H.; Dankanich, John W.; Frame, Kyle L.

2005-01-01

The International Space Station (ISS) currently experiences significant orbital drag that requires constant make up propulsion or the Station will quickly reenter the Earth's Atmosphere. The reboost propulsion is presently achieved through the firing of hydrazine rockets at the cost of considerable propellant mass. The problem will inevitably grow much worse as station components continue to be assembled, particularly when the full solar panel arrays are deployed. This paper discusses many long established themes on electrodynamic propulsion in the context of Exploration relevance, shows how to couple unique ISS electrical power system characteristics and suggests a way to tremendously impact ISS's sustainability. Besides allowing launch mass and volume presently reserved for reboost propellant to be reallocated for science experiments and other critically needed supplies, there are a series of technology hardware demonstrations steps that can be accomplished on ISS, which are helpful to NASA s Exploration mission. The suggested ElectroDynamic (ED) tether and flywheel approach is distinctive in its use of free energy currently unusable, yet presently available from the existing solar array panels on ISS. The ideas presented are intended to maximize the utility of Station and radically increase orbital safety.

A gridded global description of the ionosphere and thermosphere for 1996 - 2000

NASA Astrophysics Data System (ADS)

Ridley, A.; Kihn, E.; Kroehl, H.

The modeling and simulation community has asked for a realistic representation of the near-Earth space environment covering a significant number of years to be used in scientific and engineering applications. The data, data management systems, assimilation techniques, physical models, and computer resources are now available to construct a realistic description of the ionosphere and thermosphere over a 5 year period. DMSP and NOAA POES satellite data and solar emissions were used to compute Hall and Pederson conductances in the ionosphere. Interplanetary magnetic field measurements on the ACE satellite define average electrostatic potential patterns over the northern and southern Polar Regions. These conductances, electric field patterns, and ground-based magnetometer data were input to the Assimilative Mapping of Ionospheric Electrodynamics model to compute the distribution of electric fields and currents in the ionosphere. The Global Thermosphere Ionosphere Model (GITM) used the ionospheric electrodynamic parameters to compute the distribution of particles and fields in the ionosphere and thermosphere. GITM uses a general circulation approach to solve the fundamental equations. Model results offer a unique opportunity to assess the relative importance of different forcing terms under a variety of conditions as well as the accuracies of different estimates of ionospheric electrodynamic parameters.

Two-dimensional Yukawa interactions from nonlocal Proca quantum electrodynamics

NASA Astrophysics Data System (ADS)

Alves, Van Sérgio; Macrı, Tommaso; Magalhães, Gabriel C.; Marino, E. C.; Nascimento, Leandro O.

2018-05-01

We derive two versions of an effective model to describe dynamical effects of the Yukawa interaction among Dirac electrons in the plane. Such short-range interaction is obtained by introducing a mass term for the intermediate particle, which may be either scalar or an abelian gauge field, both of them in (3 +1 ) dimensions. Thereafter, we consider that the fermionic matter field propagates only in (2 +1 ) dimensions, whereas the bosonic field is free to propagate out of the plane. Within these assumptions, we apply a mechanism for dimensional reduction, which yields an effective model in (2 +1 ) dimensions. In particular, for the gauge-field case, we use the Stueckelberg mechanism in order to preserve gauge invariance. We refer to this version as nonlocal-Proca quantum electrodynamics (NPQED). For both scalar and gauge cases, the effective models reproduce the usual Yukawa interaction in the static limit. By means of perturbation theory at one loop, we calculate the mass renormalization of the Dirac field. Our model is a generalization of Pseudo quantum electrodynamics (PQED), which is a gauge-field model that provides a Coulomb interaction for two-dimensional electrons. Possibilities of application to Fermi-Bose mixtures in mixed dimensions, using cold atoms, are briefly discussed.

Tethers

NASA Technical Reports Server (NTRS)

Cutler, Andrew Hall; Carroll, Joseph A.

1992-01-01

A tether of sufficient strength, capable of being lengthened or shortened and having appropriate apparatuses for capturing and releasing bodies at its ends, may be useful in propulsion applications. For example, a tether could allow rendezvous between spacecraft in substantially different orbits without using propellant. A tether could also allow co-orbiting spacecraft to exchange momentum and separate. Thus, a reentering spacecraft (such as the Shuttle) could give its momentum to one remaining on orbit (such as the space station). Similarly, a tether facility could gain momentum from a high I(sub sp)/low thrust mechanism (which could be an electrodynamics tether) and transfer than momentum by means of a tether to payloads headed for many different orbits. Such a facility would, in effect, combine high I(sub sp) with high thrust, although only briefly. An electrodynamic tether could propel a satellite from its launch inclination to a higher or lower inclination. Tethers could also allow samples to be taken from bodies such as the Moon. Three types of tether operations are illustrated. The following topics are discussed: (1) tether characteristics; (2) tether propulsion methods--basics, via momentum transfer, and electrodynamic tether propulsion; and (3) their use in planetary exploration.

Space Station Reboost with Electrodynamic Tethers

NASA Technical Reports Server (NTRS)

Vas, Irwin E.; Kelly, Thomas J.; Scarl, Ethan A.

1999-01-01

This paper presents the results of a study of an electrodynamic tether system to reboost the International Space Station (ISS). One recommendation is to use a partially bare tether for electron collection. Locations are suggested as to where the tether system is to be attached at the space station. The effects of the tether system on the microgravity environment may actually be beneficial, because the system can neutralize aerodrag during quiescent periods and, if deployed from a movable boom, can permit optimization of laboratory positioning with respect to acceleration contours. Alternative approaches to tether deployment and retrieval are discussed. It is shown that a relatively short tether system, 7 km long, operating at a power level of 5 kW could provide cumulative savings or over a billion dollars during a 10-year period ending in 2012. This savings is the direct result of a reduction in the number or nights that would otherwise be required to deliver propellant for reboost, with larger cost savings for higher tether usage. In addition to economic considerations, an electrodynamic tether promises a practical backup system that could ensure ISS survival in the event of an (otherwise) catastrophic delay in propellant delivery.

Hidden in Plain View: The Material Invariance of Maxwell-Hertz-Lorentz Electrodynamics

NASA Astrophysics Data System (ADS)

Christov, C. I.

2006-04-01

Maxwell accounted for the apparent elastic behavior of the electromagnetic field through augmenting Ampere's law by the so-called displacement current much in the same way that he treated the viscoelasticity of gases. Original Maxwell constitutive relations for both electrodynamics and fluid dynamics were not material invariant, while combin- ing Faraday's law and the Lorentz force makes the first of Maxwell's equation material invariant. Later on, Oldroyd showed how to make a viscoelastic constitutive law mate- rial invariant. The main assumption was that the proper description of a constitutive law must be material invariant. Assuming that the electromagnetic field is a material field, we show here that if the upper convected Oldroyd derivative (related to Lie derivative) is used, the displacement current becomes material invariant. The new formulation ensures that the equation for conser- vation of charge is also material invariant which vindicates the choice of Oldroyd derivative over the standard convec- tive derivative. A material invariant field model is by ne- cessity Galilean invariant. We call the material field (the manifestation of which are the equations of electrodynam- ics the metacontinuum), in order to distinguish it form the standard material continua.

STS-75 Flight Day 1

NASA Technical Reports Server (NTRS)

1996-01-01

On this first day of the STS-75 mission, the flight crew, Cmdr. Andrew Allen, Pilot Scott Horowitz, Payload Cmdr. Franklin Chang-Diaz, Payload Specialist Umberto Guidoni (Italy), and Mission Specialists Jeffrey Hoffman, Maurizio Cheli (ESA) and Claude Nicollier (ESA), were shown performing pre-launch and launching activities. This international space mission's primary objective is the deployment of the Tethered Satellite System Reflight (TSS-1R) to a 12 mile length from the shuttle, a variety of experiments, and the satellite retrieval. These experiments include: Research on Orbital Plasma Electrodynamics (ROPE); TSS Deployer Core Equipment and Satellite Core Equipment (DCORE/SCORE); Research on Electrodynamic Tether Effects (RETE); Magnetic Field Experiments for TSS Missions (TEMAG); Shuttle Electrodynamic Tether Systems (SETS); Shuttle Potential and Return Electron Experiment (SPREE); Tether Optical Phenomena Experiment (TOP); and Observations at the Earth's Surface of Electromagnetic Emissions by TSS (OESSE). The mission's secondary objectives were those experiments found in the United States Microgravity Payload-3 (USMP-3), which include: Advanced Automated Directional Solidification Furnace (AADSF); Material pour l'Etude des Phenomenes Interessant la Solidification sur Terre et en Orbite (MEPHISTO); Space Acceleration Measurement System (SAMS); Orbital Acceleration Research Experiment (OARE); Critical Fluid Scattering Experiment (ZENO); and Isothermal Dendritic Growth Experiment (IDGE).

Design and analysis of a high power moderate band radiator using a switched oscillator

NASA Astrophysics Data System (ADS)

Armanious, Miena Magdi Hakeem

Quarter-wave switched oscillators (SWOs) are an important technology for the generation of high-power, moderate bandwidth (mesoband) wave forms. The use of SWOs in high power microwave sources has been discussed for the past 10 years [1--6], but a detailed discussion of the design of this type of oscillators for particular waveforms has been lacking. In this dissertation I develop a design methodology for a realization of SWOs, also known as MATRIX oscillators in the scientific community. A key element in the design of SWOs is the self-breakdown switch, which is created by a large electric field. In order for the switch to close as expected from the design, it is essential to manage the electrostatic field distribution inside the oscillator during the charging time. This enforces geometric constraints on the shape of the conductors inside MATRIX. At the same time, the electrodynamic operation of MATRIX is dependent on the geometry of the structure. In order to generate a geometry that satisfies both the electrostatic and electrodynamic constraints, a new approach is developed to generate this geometry using the 2-D static solution of the Laplace equation, subject to a particular set of boundary conditions. These boundary conditions are manipulated to generate equipotential lines with specific dimensions that satisfy the electrodynamic constraints. Meanwhile, these equipotential lines naturally support an electrostatic field distribution that meets the requirements for the switch operation. To study the electrodynamic aspects of MATRIX, three different (but interrelated) numerical models are built. Depending on the assumptions made in each model, different information about the electrodynamic properties of the designed SWO are obtained. In addition, the agreement and consistency between the different models, validate and give confidence in the calculated results. Another important aspect of the design process is understanding the relationship between the geometric parameters of MATRIX and the output waveforms. Using the numerical models, the relationship between the dimensions of MATRIX and its calculated resonant parameters are studied. For a given set of geometric constraints, this provides more flexibility to the output specifications. Finally, I present a comprehensive design methodology that generates the geometry of a MATRIX system from the desired specification then calculates the radiated waveform.

Urban Teaching: The Essentials. Third Edition

ERIC Educational Resources Information Center

Weiner, Lois; Jerome, Daniel

2016-01-01

This significantly revised edition will help prospective and new city teachers navigate the realities of city teaching. Now the classic introduction to urban teaching, this book explains how global, national, state, and local reforms have impacted what teachers need to know to not only survive, but to do their jobs well. The Third Edition melds…

Pigskin Payday

ERIC Educational Resources Information Center

Seymour, Add, Jr.

2006-01-01

Southern University Athletic Director Greg LaFleur was smiling long before his Jaguars defeated rival Grambling State University in the State Farm Bayou Classic on Thanksgiving weekend. It wasn't the prospect of winning the game that had him giddy. It was the financial windfall his athletic department was about to get out of the game. With their…

Successful prospective management of neonatal citrullinemia.

PubMed

Go, Hayato; Imamura, Takashi; Hashimoto, Koichi; Ogasawara, Kei; Sakamoto, Osamu; Takubo, Noriyuki; Momoi, Nobuo; Hosoya, Mitsuaki

2012-01-01

Classical citrullinemia generally involves hyperammonemic coma in the first few days of life and leads to neurological sequelae in survivors. We report a case of an elder sister who fell into a hyperammonemic coma on the fifth day after birth. She was successfully treated with intravenous benzoate and hemodialysis, and was subsequently diagnosed with citrullinemia on the basis of biochemical analysis. Two years later, a younger sister was born without prenatal diagnosis. We monitored plasma ammonia and citrulline levels after birth, and again diagnosed her with CTLN1 on the basis of biochemical and DNA analyses. There have been few reports of the prospective treatment of citrullinemia; however, our experience indicates the need for the prospective management and the rapid reduction of ammonia levels to avoid neonatal hyperammonemic coma and subsequent sequelae.

A Newtonian interpretation of configurational forces on dislocations and cracks

NASA Astrophysics Data System (ADS)

Ballarini, Roberto; Royer-Carfagni, Gianni

2016-10-01

Configurational forces are fundamental concepts in the description of the motion of dislocations, cracks and other defects that introduce singularities within the solid state. They are defined by considering variations in energies associated with the movement of such defects, and are therefore different from the classical forces that enter the balance laws of classical Newtonian mechanics. Here, it is demonstrated how a configurational force can be viewed as the resultant of the (Newtonian) contact forces acting on the perturbed shape of an object of substance equivalent to the defect, and evaluated in the limit of the shape being restored to the primitive configuration. The expressions for the configurational forces on the paradigmatic examples of cracks and dislocations are in agreement with those determined using classical variational arguments. This finding opens a new prospective in the use of configurational forces by permitting their physical and intuitive visualization.

Cisgenics - A Sustainable Approach for Crop Improvement

PubMed Central

Telem, R.S.; Wani, Shabir. H.; Singh, N.B.; Nandini, R.; Sadhukhan, R.; Bhattacharya, S.; Mandal, N.

2013-01-01

The implication of molecular biology in crop improvement is now more than three decades old. Not surprisingly, technology has moved on, and there are a number of new techniques that may or may not come under the genetically modified (GM) banner and, therefore, GM regulations. In cisgenic technology, cisgenes from crossable plants are used and it is a single procedure of gene introduction whereby the problem of linkage drag of other genes is overcome. The gene used in cisgenic approach is similar compared with classical breeding and cisgenic plant should be treated equally as classically bred plant and differently from transgenic plants. Therefore, it offers a sturdy reference to treat cisgenic plants similarly as classically bred plants, by exemption of cisgenesis from the current GMO legislations. This review covers the implications of cisgenesis towards the sustainable development in the genetic improvement of crops and considers the prospects for the technology. PMID:24396278

Rydberg Dipole Antennas

NASA Astrophysics Data System (ADS)

Stack, Daniel; Rodenburg, Bradon; Pappas, Stephen; Su, Wangshen; St. John, Marc; Kunz, Paul; Simon, Matt; Gordon, Joshua; Holloway, Christopher

2017-04-01

Measurements of microwave frequency electric fields by traditional methods (i.e. engineered antennas) have limited sensitivity and can be difficult to calibrate properly. A useful tool to address this problem are highly-excited (Rydberg) neutral atoms which have very large electric-dipole moments and many dipole-allowed transitions in the range of 1-500 GHz. Using Rydberg states, it is possible to sensitively probe the electric field in this frequency range using the combination of two quantum interference phenomena: electromagnetically induced transparency and the Autler-Townes effect. This atom-light interaction can be modeled by the classical description of a harmonically bound electron. The classical damped, driven, coupled-oscillators model yields significant insights into the deep connections between classical and quantum physics. We will present a detailed experimental analysis of the noise processes in making such measurements in the laboratory and discuss the prospects for building a practical atomic microwave receiver.

The Rat Model in Microsurgery Education: Classical Exercises and New Horizons

PubMed Central

Shurey, Sandra; Akelina, Yelena; Legagneux, Josette; Malzone, Gerardo; Jiga, Lucian

2014-01-01

Microsurgery is a precise surgical skill that requires an extensive training period and the supervision of expert instructors. The classical training schemes in microsurgery have started with multiday experimental courses on the rat model. These courses have offered a low threat supervised high fidelity laboratory setting in which students can steadily and rapidly progress. This simulated environment allows students to make and recognise mistakes in microsurgery techniques and thus shifts any related risks of the early training period from the operating room to the lab. To achieve a high level of skill acquisition before beginning clinical practice, students are trained on a comprehensive set of exercises the rat model can uniquely provide, with progressive complexity as competency improves. This paper presents the utility of the classical rat model in three of the earliest microsurgery training centres and the new prospects that this versatile and expansive training model offers. PMID:24883268

New Precise Measurement of the Hyperfine Splitting of Positronium

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

Ishida, A., E-mail: ishida@icepp.s.u-tokyo.ac.jp

Positronium (Ps) is an ideal system for precision test of bound state quantum electrodynamics. The hyperfine splitting (HFS) of the ground state of Ps, which is one of the most precisely tested quantity, has a large discrepancy of 16 ppm (4.5 σ) between previous experiments and theoretical calculation up to O(α{sup 3}lnα{sup −1}) and part of O(α{sup 3}) corrections. A new experiment which reduces possible systematic uncertainties of Ps thermalization effect and nonuniformity of magnetic field was performed. It revealed that the Ps thermalization effect was as large as 10 ± 2 ppm. Treating the thermalization effect correctly, a newmore » result of 203.3942 ± 0.0016(stat., 8.0 ppm) ± 0.0013(sys., 6.4 ppm) GHz was obtained. This result is consistent with theory within 1.1 σ, whereas it disfavors the previous experimental result by 2.6 σ. It shows that the Ps thermalization effect is crucial for precision measurement of HFS. Future prospects for improved precision are briefly discussed.« less

Laser driven nuclear science and applications: The need of high efficiency, high power and high repetition rate Laser beams

NASA Astrophysics Data System (ADS)

Gales, S.

2015-10-01

Extreme Light Infrastructure (ELI) is a pan European research initiative selected on the European Strategy Forum on Research Infrastructures Roadmap that aims to close the gap between the existing laboratory-based laser driven research and international facility-grade research centre. The ELI-NP facility, one of the three ELI pillars under construction, placed in Romania and to be operational in 2018, has as core elements a couple of new generation 10 PW laser systems and a narrow bandwidth Compton backscattering gamma source with photon energies up to 19 MeV. ELI-NP will address nuclear photonics, nuclear astrophysics and quantum electrodynamics involving extreme photon fields. Prospective applications of high power laser in nuclear astrophysics, accelerator physics, in particular towards future Accelerator Driven System, as well as in nuclear photonics, for detection and characterization of nuclear material, and for nuclear medicine, will be discussed. Key issues in these research areas will be at reach with significant increase of the repetition rates and of the efficiency at the plug of the high power laser systems as proposed by the ICAN collaboration.

Adipose stromal cells improve healing of vocal fold scar: Morphological and functional evidences.

PubMed

de Bonnecaze, Guillaume; Chaput, Benoit; Woisard, Virginie; Uro-Coste, Emmanuelle; Swider, Pascal; Vergez, Sebastien; Serrano, Elie; Casteilla, Louis; Planat-Benard, Valerie

2016-08-01

Adipose derived stromal cells (ASCs) are abundant and easy to prepare. Such cells may be useful for treating severe vocal disturbance caused by acute vocal fold scars. Prospective animal experiments with controls. Twenty New-Zealand white rabbits were used in the present study. We evaluated vocal fold healing, with or without injection of autologous ASCs, after acute scarring. A defined lesion was created and the ASCs were immediately injected. Vocal fold regeneration was evaluated histomorphometrically and via viscoelastic analysis using an electrodynamic shaker. Six weeks after ASC injection, vocal folds exhibited significantly less inflammation than control folds (P < 0.005). In addition, hypertrophy of the lamina propria and fibrosis were significantly reduced upon ASC injection (P < 0.02). The decrease in viscoelastic parameters was less important in the ASC injected group compared to the noninjected group (P = 0.08). Injection of autologous ASCs improved vocal fold healing in our preclinical model. Further studies are needed, but this method may be useful in humans. NA. Laryngoscope, 126:E278-E285, 2016. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

The impact of spine stability on cervical spinal cord injury with respect to demographics, management, and outcome: a prospective cohort from a national spinal cord injury registry.

PubMed

Paquet, Jérôme; Rivers, Carly S; Kurban, Dilnur; Finkelstein, Joel; Tee, Jin W; Noonan, Vanessa K; Kwon, Brian K; Hurlbert, R John; Christie, Sean; Tsai, Eve C; Ahn, Henry; Drew, Brian; Bailey, Christopher S; Fourney, Daryl R; Attabib, Najmedden; Johnson, Michael G; Fehlings, Michael G; Parent, Stefan; Dvorak, Marcel F

2018-01-01

Emergent surgery for patients with a traumatic spinal cord injury (SCI) is seen as the gold standard in acute management. However, optimal treatment for those with the clinical diagnosis of central cord syndrome (CCS) is less clear, and classic definitions of CCS do not identify a unique population of patients. The study aimed to test the authors' hypothesis that spine stability can identify a unique group of patients with regard to demographics, management, and outcomes, which classic CCS definitions do not. This is a prospective observational study. The sample included participants with cervical SCI included in a prospective Canadian registry. The outcome measures were initial hospitalization length of stay, change in total motor score from admission to discharge, and in-hospital mortality. Patients with cervical SCI from a prospective Canadian SCI registry were grouped into stable and unstable spine cohorts. Bivariate analyses were used to identify differences in demographic, injury, management, and outcomes. Multivariate analysis was used to better understand the impact of spine stability on motor score improvement. No conflicts of interest were identified. Compared with those with an unstable spine, patients with cervical SCI and a stable spine were older (58.8 vs. 44.1 years, p<.0001), more likely male (86.4% vs. 76.1%, p=.0059), and have more medical comorbidities. Patients with stable spine cervical SCI were more likely to have sustained their injury by a fall (67.4% vs. 34.9%, p<.0001), and have high cervical (C1-C4; 58.5% vs. 43.3%, p=.0009) and less severe neurologic injuries (ASIA Impairment Scale C or D; 81.3% vs. 47.5%, p<.0001). Those with stable spine injuries were less likely to have surgery (67.6% vs. 92.6%, p<.0001), had shorter in-hospital lengths of stay (median 84.0 vs. 100.5 days, p=.0062), and higher total motor score change (20.7 vs. 19.4 points, p=.0014). Multivariate modeling revealed that neurologic severity of injury and spine stability were significantly related to motor score improvement; patients with stable spine injuries had more motor score improvement. We propose that classification of stable cervical SCI is more clinically relevant than classic CCS classification as this group was found to be unique with regard to demographics, neurologic injury, management, and outcome, whereas classic CCS classifications do not . This classification can be used to assess optimal management in patients where it is less clear if and when surgery should be performed. Copyright © 2017 Elsevier Inc. All rights reserved.

Circulating interleukin-10 and risk of cardiovascular events: a prospective study in the elderly at risk.

PubMed

Welsh, Paul; Murray, Heather M; Ford, Ian; Trompet, Stella; de Craen, Anton J M; Jukema, J Wouter; Stott, David J; McInnes, Iain B; Packard, Chris J; Westendorp, Rudi G J; Sattar, Naveed

2011-10-01

The goal of this study was to examine the association of the antiinflammatory interleukin-10 (IL-10) with risk of cardiovascular disease (CVD). In the PROSPER (PROspective Study of Pravastatin in the Elderly at Risk) cohort, we related baseline concentrations of circulating IL-10 to risk of CVD events in a nested case (n=819)-control (n=1618) study of 3.2 years of follow-up. Circulating IL-10 showed few strong associations with classical risk factors but was positively correlated with IL-6 and C-reactive protein. IL-10 was positively associated with risk of CVD events (odds ratio [OR] 1.17, 95% CI 1.05 to 1.31 per unit increase in log IL-10) after adjusting for classical risk factors and C-reactive protein. Furthermore, IL-10 was associated more strongly with CVD risk among those with no previous history of CVD (OR 1.42, 95% CI 1.18 to 1.70), compared with those with previous CVD (OR 1.04, 95% CI 0.90 to 1.19; P=0.018). Overall, IL-10 showed a modest ability to add discrimination to classical risk factors (C-statistic +0.005, P=0.002). Baseline circulating levels of the antiinflammatory IL-10 are positively associated with risk of CVD among the elderly without prior CVD events, although the association is less evident in those with a history of CVD. Additional epidemiological and mechanistic studies investigating the role of IL-10 in CVD are warranted.

Theoretical investigation of the generation and injection of electromagnetic waves in space plasma by means of a long-orbiting tether

NASA Technical Reports Server (NTRS)

Dobrowolny, M.

1981-01-01

Analysis of the various mechanisms of electromagnetic wave generation by the shuttle-borne orbiting tether of the T.S.S. Facility shows that significant electrodynamic power levels are available even when overestimating the loss mechanisms expected to intervene. This electrodynamic power is in part dissipated by Joule losses in the tether, in part goes to accelerate electrons through the sheath surrounding the balloon (when in a downward deployment), and in part goes into e.m. wave generation. A preliminary estimate shows that a 100 km tether in orbit would produce ULF/ELF signals that are detectable on the ground with state-of-the-art magnetometric instrumentation.

Plasma Motor Generator (PMG) electrodynamic tether experiment

NASA Technical Reports Server (NTRS)

Grossi, Mario D.

1995-01-01

The Plasma Motor Generator (PMG) flight of June 26, 1993 has been the most sophisticated and most successful mission that has been carried out thus far with an electrodynamic tether. Three papers from the Smithsonian Astrophysical Observatory, Washington, DC concerned with the PMG, submitted at the Fourth International Space Conference on Tethers in Space, in Washington, DC, in April 1995, are contained in this document. The three papers are (1) Electromagnetic interactions between the PMG tether and the magneto-ionic medium of the Ionosphere; (2) Tether-current-voltage characteristics, as determined by the Hollow Cathode Operation Modes; and (3) Hawaii-Hilo ground observations on the occasion for the PMG flight of June 23, 1993.

One-dimensional backreacting holographic superconductors with exponential nonlinear electrodynamics

NASA Astrophysics Data System (ADS)

Ghotbabadi, B. Binaei; Zangeneh, M. Kord; Sheykhi, A.

2018-05-01

In this paper, we investigate the effects of nonlinear exponential electrodynamics as well as backreaction on the properties of one-dimensional s-wave holographic superconductors. We continue our study both analytically and numerically. In analytical study, we employ the Sturm-Liouville method while in numerical approach we perform the shooting method. We obtain a relation between the critical temperature and chemical potential analytically. Our results show a good agreement between analytical and numerical methods. We observe that the increase in the strength of both nonlinearity and backreaction parameters causes the formation of condensation in the black hole background harder and critical temperature lower. These results are consistent with those obtained for two dimensional s-wave holographic superconductors.

Laboratory and field experimental evaluation of host plant specificity of Aceria solstitialis, a prospective biological control agent of yellow starthistle

USDA-ARS?s Scientific Manuscript database

Yellow starthistle (Centaurea solstitialis) is an invasive annual weed in the western USA that is native to the Mediterranean Region and is a target for classical biological control. Aceria solstitialis is an eriophyid mite that has been found exclusively in association with yellow starthistle in I...

The New Responsibility and Challenge of Education: The Current and Prospective Situation of Philosophy for Children

ERIC Educational Resources Information Center

Karikó, Sándor

2016-01-01

Douglas Martin (an editor) wrote a memoir in New York Times about Matthew Lipman, the founder of philosophy for children, today's classic thinker. Lipman's death brought attention again for the philosophy for children's status among professionals. Later one of the most prestigious international educational periodical review, the "Journal of…

Applications of Tethers in Space, Volume 2

NASA Technical Reports Server (NTRS)

Cron, A. C. (Compiler)

1985-01-01

Topics discussed include tethered satellites, tether deployment, satellite systems, science applications, electrodynamic interactions, transportation applications, artificial gravity, constellations, and technology and testing.

Electrodynamics of relativistic electron beam x-ray sources

NASA Astrophysics Data System (ADS)

Niknejadi, Pardis

Probing matter at atomic scales provides invaluable information about its structure; as a result interest in sources of x-rays and gamma-rays with high spectral resolution, low angular divergence and small source size has been on the rise. Explorations in this domain require x-ray or gamma-ray sources with high brightness. In the past decade, relativistic electron sources such as synchrotron rings and free electron lasers have proven to be the best technology available for the production of such beams. We1 start with an introduction to the physics of radiation and provide a summary of the theoretical grounds this work is based on. This dissertation is dedicated to different aspects of both fundamental processes of radiation in relativistic electron sources, and critical control and diagnostics that are required for the operation of these sources. Therefore this work is broken into two main parts. In the first part, the electron source that is currently set up at University of Hawai`i at Manoa will be introduced in detail. This source has unique capabilities as it is an inverse-Compton scattering (ICS) source that uses a free electron laser (FEL) with pulses of picosecond duration at ˜ 3 GHz rate for production of a coherent/semi-coherent x-ray beam by means of an optical cavity. After introducing the essential elements of the system and what was achieved prior to this work, we will focus on the requirements for achieving an optimum electron beam matched for the operation of the system which is the main focus of part I of this dissertation. The transport beam line of our system is unique and complex. For this reason, a simulation module has been developed for the study and delivery of an optimal beam. We will discuss the capabilities of this system and its compatibility with other elements that were already installed on the beam line. Finally, we will present results and experimental data as well as guidelines for future operation of the system when the microwave gun has been enhanced and/or the optical cavity (the final step of this proof-of-principle experiment) has been commissioned. Due to the complexity of this integrated system, one of the goals of this work is to serve the future members and staff of the UH FEL laboratory in configuring and operating this complex system. The final goal of the UH ICS project is to establish the principles on which producing a successful turn-key commercial inverse-Compton x-ray source will depend on. In the second part of this work we start with the discussion of coherent radiation at its most fundamental level, with emphasis on conservation of energy. We show that for coherently radiating particles the failure of conventional classical electrodynamics (CED) is far more serious than the well-known failure of CED at small scales. We will present a covariant picture of radiation in terms of the theory of action-at-a-distance and introduce a time-symmetric approach to electrodynamics. We demonstrate that this time symmetric approach provides a perfect match to the energy radiated by two coherently oscillating charged particles. This work is novel, as this was an unsolved problem in classical electrodynamics up until now. We also discuss how the conceptual implication of this work is demanding. For this purpose, we will propose two different experiments that can further our understanding of the presented problem. The first experiment involves a small (lambda/10) antenna, and the goal is to measure the advanced field of the absorber at distances of 5lambda or less. Calculation and precise measurement of the antenna field/potential at distances of order lambda is challenging, causing this experiment to be a difficult yet possible task. In the second experiment, we discuss in some detail the experimental setup that would verify and/or further our understanding of the underlying physics of Self Amplified Spontaneous Emission (SASE) FELs. We provide an analytical verification as a first step toward better understanding the process, and provide a list of required parameters for the SASE test. These parameters are at the edge of current technology of current light sources, making this experiment also a demanding and challenging task. We conclude that further detailed studies by means of simulation or analytical approaches can reduce the strain of SASE test. 1Even though this dissertation was completed by one person, as hardly any scientific work is ever completed by one, it is written in first person plural. Only in this way, it is possible to give credit to those who have contributed to this research by spending their time till the late hours of the night and sometimes even early morning in the control room. For the theoretical work, the hope is to also invite the reader to follow the work closely and check its validity as they read along, as well as to acknowledge the fruitful conversations that have led to the discussions and conclusions presented here.

Artist's Concept of Propulsive Small Expendable Deployer System (ProSEDS)

NASA Technical Reports Server (NTRS)

1999-01-01

Pictured is an artist's concept of NASA's Propulsive Small Expendable Deployer System experiment (ProSEDS). ProSEDS will demonstrate the use of an electrodynamic tether, basically a long, thin wire, for propulsion. An electrodynamic tether uses the same principles as electric motors in toys, appliances and computer disk drives, and generators in automobiles and power plants. When electrical current is flowing through the tether, a magnetic field is produced that pushes against the magnetic field of the Earth. For ProSEDS, the current in the tether results by virtue of the voltage generated when the tether moves through the Earth's magnetic field at more than 17,000 mph. This approach can produce drag thrust generating useable power. Since electrodynamic tethers require no propellant, they could substantially reduce the weight of the spacecraft and provide a cost-effective method of reboosting spacecraft. The initial flight of ProSEDS is scheduled to fly aboard an Air Force Delta II rocket in summer of 2002. In orbit, ProSEDS will deploy from a Delta II second stage. It will be a 3.1-mile (5 kilometer) long, ultrathin base-wire tether cornected with a 6.2-mile (10 kilometer) long nonconducting tether. The ProSEDS experiment is managed by the Space Transportation Directorate at the Marshall Space Flight Center.

Experimental Evaluation of Three Designs of Electrodynamic Flexural Transducers

PubMed Central

Eriksson, Tobias J. R.; Laws, Michael; Kang, Lei; Fan, Yichao; Ramadas, Sivaram N.; Dixon, Steve

2016-01-01

Three designs for electrodynamic flexural transducers (EDFT) for air-coupled ultrasonics are presented and compared. An all-metal housing was used for robustness, which makes the designs more suitable for industrial applications. The housing is designed such that there is a thin metal plate at the front, with a fundamental flexural vibration mode at ∼50 kHz. By using a flexural resonance mode, good coupling to the load medium was achieved without the use of matching layers. The front radiating plate is actuated electrodynamically by a spiral coil inside the transducer, which produces an induced magnetic field when an AC current is applied to it. The transducers operate without the use of piezoelectric materials, which can simplify manufacturing and prolong the lifetime of the transducers, as well as open up possibilities for high-temperature applications. The results show that different designs perform best for the generation and reception of ultrasound. All three designs produced large acoustic pressure outputs, with a recorded sound pressure level (SPL) above 120 dB at a 40 cm distance from the highest output transducer. The sensitivity of the transducers was low, however, with single shot signal-to-noise ratio (SNR)≃15 dB in transmit–receive mode, with transmitter and receiver 40 cm apart. PMID:27571075

The TSS-1R Electrodynamic Tether Experiment: Scientific and Technological Results

NASA Technical Reports Server (NTRS)

Stone, Nobie H.; Raitt, John

1998-01-01

The bi-national, US-Italian, Tethered Satellite System (TSS) program was designed to provide a unique opportunity to explore certain space plasma- electrodynamic processes and the orbital mechanics of a gravity-gradient stabilized system of two satellites linked by a long conducting tether. The second flight, TSS-LR, was launched February 22, 1996 on STS-75 and satellite deployment began at MET 3/00:27. A unique data set was obtained over the next five hours, as the tether was deployed to a length of 19695 meters, which has allowed significant science to be accomplished. This presentation will focus on electrodynamic processes generated by the tether--in particular, the collection of electrical current from the ionospheric plasma. Of particular significance is an apparent transition of the physics of current collection when the potential of the collecting body becomes greater than the ram energy of the ionospheric atomic oxygen ions. Previous theoretical models of current collection were electrostatic--assuming that the orbital motion of the system, which is highly subsonic with respect to electron thermal motion, was un- important. This may still be acceptable for the case of relatively slow-moving sounding rockets. However, the TSS-LR results show that motion relative to the plasma must be accounted for in orbiting systems.

Lift to Drag Ratio Analysis in Magnetic Levitation with an Electrodynamic Wheel

NASA Astrophysics Data System (ADS)

Gutarra-Leon, Angel; Cordrey, Vincent; Majewski, Walerian

Our experiments explored inductive magnetic levitation (MagLev) using simple permanent magnets and conductive tracks. Our investigations used a circular Halbach array with a 1 Tesla variable magnetic field on the outer rim of the ring. Such a system is usually called an Electrodynamic Wheel (EDW). Rotating this wheel around a horizontal axis above or below a flat conducting surface should induce eddy currents in said surface through the variable magnetic flux. The eddy currents produce, in turn, their own magnetic fields, which interact with the magnets of the EDW. We constructed a four-inch diameter Electrodynamic Wheel using twelve Neodymium permanent magnets and demonstrated that the magnetic interactions produce both lift and drag forces on the EDW. These forces can be used for levitation and propulsion of the EDW to produce magnetic levitation without coils and complex control circuitry. We achieved full levitation of the non-magnetic aluminum and copper plates. Our results confirm the expected behavior of lift to drag ratio as proportional to (L/R) ω, with L and R being the inductance and resistance of the track plate, and ω being the angular velocity of the magnetic flux. Supported by grants from the Virginia Academy of Science, Society of Physics Students, Virginia Community College System, and the NVCC Educational Foundation.

Visualization of Space-Time Ambiguities to be Explored by NASA GEC Mission with a Critique of Synthesized Measurements for Different GEC Mission Scenarios

NASA Technical Reports Server (NTRS)

Sojka, Jan J.

2003-01-01

The Grant supported research addressing the question of how the NASA Solar Terrestrial Probes (STP) Mission called Geospace electrodynamics Connections (GEC) will resolve space-time structures as well as collect sufficient information to solve the coupled thermosphere-ionosphere- magnetosphere dynamics and electrodynamics. The approach adopted was to develop a high resolution in both space and time model of the ionosphere-thermosphere (I-T) over altitudes relevant to GEC, especially the deep-dipping phase. This I-T model was driven by a high- resolution model of magnetospheric-ionospheric (M-I) coupling electrodynamics. Such a model contains all the key parameters to be measured by GEC instrumentation, which in turn are the required parameters to resolve present-day problems in describing the energy and momentum coupling between the ionosphere-magnetosphere and ionosphere-thermosphere. This model database has been successfully created for one geophysical condition; winter, solar maximum with disturbed geophysical conditions, specifically a substorm. Using this data set, visualizations (movies) were created to contrast dynamics of the different measurable parameters. Specifically, the rapidly varying magnetospheric E and auroral electron precipitation versus the slower varying ionospheric F-region electron density, but rapidly responding E-region density.

Pathfinder

NASA Image and Video Library

1999-03-25

Pictured is an artist's concept of NASA's Propulsive Small Expendable Deployer System experiment (ProSEDS). ProSEDS will demonstrate the use of an electrodynamic tether, basically a long, thin wire, for propulsion. An electrodynamic tether uses the same principles as electric motors in toys, appliances and computer disk drives, and generators in automobiles and power plants. When electrical current is flowing through the tether, a magnetic field is produced that pushes against the magnetic field of the Earth. For ProSEDS, the current in the tether results by virtue of the voltage generated when the tether moves through the Earth's magnetic field at more than 17,000 mph. This approach can produce drag thrust generating useable power. Since electrodynamic tethers require no propellant, they could substantially reduce the weight of the spacecraft and provide a cost-effective method of reboosting spacecraft. The initial flight of ProSEDS is scheduled to fly aboard an Air Force Delta II rocket in summer of 2002. In orbit, ProSEDS will deploy from a Delta II second stage. It will be a 3.1-mile (5 kilometer) long, ultrathin base-wire tether cornected with a 6.2-mile (10 kilometer) long nonconducting tether. The ProSEDS experiment is managed by the Space Transportation Directorate at the Marshall Space Flight Center.

A two-dimensional theory of plasma contactor clouds used in the ionosphere with an electrodynamic tether

NASA Technical Reports Server (NTRS)

Hastings, D. E.; Gatsonis, N. A.; Rivas, D. A.

1988-01-01

Plasma contactors have been proposed as a means of making good electrical contact between biased surfaces such as found at the ends of an electrodynamic tether and the space environment. A plasma contactor is a plasma source which emits a plasma cloud which facilitates the electrical connection. The physics of this plasma cloud is investigated for contactors used as electron collectors and it is shown that contactor clouds in space will consist of a spherical core possibly containing a shock wave. Outside of the core the cloud will expand anisotropically across the magnetic field leading to a turbulent cigar shape structure along the field. This outer region is itself divided into two regions by the ion response to the electric field. A two-dimensional theory of the motion of the cloud across the magnetic field is developed. The current voltage characteristic of an Argon plasma contactor cloud is estimated for several ion currents in the range of 1-100 Amperes. It is shown that small ion current contactors are more efficient than large ion current contactors. This suggests that if a plasma contactor is used on an electrodynamic tether then a miltiple tether array will be more efficient than a single tether.

Field-aligned currents in the undisturbed polar ionosphere

NASA Astrophysics Data System (ADS)

Kroehl, H. W.

1989-09-01

Field-aligned currents, FAC's, which couple ionospheric currents at high latitudes with magnetospheric currents have become an essential cornerstone to our understanding of plasma dynamics in the polar region and in the earth's magnetosphere. Initial investigators of polar electrodynamics including the aurora were unable to distinguish between the ground magnetic signatures of a purely two-dimensional current and those from a three-dimensional current system, ergo many scientists ignored the possible existence of these vertical currents. However, data from magnetometers and electrostatic analyzers flown on low-altitude, polar-orbiting satellites proved beyond any reasonable doubt that field-aligned currents existed, and that different ionospheric regions were coupled to different magnetospheric regions which were dominated by different electrodynamic processes, e.g., magnetospheric convection electric fields, magnetospheric substorms and parallel electric fields. Therefore, to define the “undisturbed” polar ionosphere and its structure and dynamics, one needs to consider these electrodynamic processes, to select times for analysis when they are not strongly active and to remember that the polar ionosphere may be disturbed when the equatorial, mid-latitude and sub-auroral ionospheres are not. In this paper we will define the principle high-latitude current systems, describe the effects of FAC's associated with these systems, review techniques which would minimize these effects and present our description of the “undisturbed” polar ionosphere.

A Process Algebra Approach to Quantum Electrodynamics

NASA Astrophysics Data System (ADS)

Sulis, William

2017-12-01

The process algebra program is directed towards developing a realist model of quantum mechanics free of paradoxes, divergences and conceptual confusions. From this perspective, fundamental phenomena are viewed as emerging from primitive informational elements generated by processes. The process algebra has been shown to successfully reproduce scalar non-relativistic quantum mechanics (NRQM) without the usual paradoxes and dualities. NRQM appears as an effective theory which emerges under specific asymptotic limits. Space-time, scalar particle wave functions and the Born rule are all emergent in this framework. In this paper, the process algebra model is reviewed, extended to the relativistic setting, and then applied to the problem of electrodynamics. A semiclassical version is presented in which a Minkowski-like space-time emerges as well as a vector potential that is discrete and photon-like at small scales and near-continuous and wave-like at large scales. QED is viewed as an effective theory at small scales while Maxwell theory becomes an effective theory at large scales. The process algebra version of quantum electrodynamics is intuitive and realist, free from divergences and eliminates the distinction between particle, field and wave. Computations are carried out using the configuration space process covering map, although the connection to second quantization has not been fully explored.

Quantum statistical relation for black holes in nonlinear electrodynamics coupled to Einstein-Gauss-Bonnet AdS gravity

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

Miskovic, Olivera; Olea, Rodrigo

2011-03-15

We consider curvature-squared corrections to Einstein-Hilbert gravity action in the form of a Gauss-Bonnet term in D>4 dimensions. In this theory, we study the thermodynamics of charged static black holes with anti-de Sitter (AdS) asymptotics, and whose electric field is described by nonlinear electrodynamics. These objects have received considerable attention in recent literature on gravity/gauge dualities. It is well-known that, within the framework of anti-de Sitter/conformal field theory (AdS/CFT) correspondence, there exists a nonvanishing Casimir contribution to the internal energy of the system, manifested as the vacuum energy for global AdS spacetime in odd dimensions. Because of this reason, wemore » derive a quantum statistical relation directly from the Euclidean action and not from the integration of the first law of thermodynamics. To this end, we employ a background-independent regularization scheme which consists, in addition to the bulk action, of counterterms that depend on both extrinsic and intrinsic curvatures of the boundary (Kounterterm series). This procedure results in a consistent inclusion of the vacuum energy and chemical potential in the thermodynamic description for Einstein-Gauss-Bonnet AdS gravity regardless of the explicit form of the nonlinear electrodynamics Lagrangian.« less

Citation classics in neuro-oncology: assessment of historical trends and scientific progress.

PubMed

Hachem, Laureen D; Mansouri, Alireza; Juraschka, Kyle; Taslimi, Shervin; Pirouzmand, Farhad; Zadeh, Gelareh

2017-09-01

Citation classics represent the highest cited works in a field and are often regarded as the most influential literature. Analyzing thematic trends in citation classics across eras enables recognition of important historical advances within a field. We present the first analysis of the citation classics in neuro-oncology. The Web of Science database was searched using terms relevant to "neuro-oncology." Articles with >400 citations were identified and the top 100 cited articles were evaluated. The top 100 neuro-oncology citation classics consisted of 43 clinical studies (17 retrospective, 10 prospective, 16 randomized trials), 43 laboratory investigations, 8 reviews/meta-analyses, and 6 guidelines/consensus statements. Articles were classified into 4 themes: 13 pertained to tumor classification, 37 to tumor pathogenesis/clinical presentation, 6 to imaging, 44 to therapy (15 chemotherapy, 10 radiotherapy, 5 surgery, 14 new agents). Gliomas were the most common tumor type examined, with 70 articles. There was a significant increase in the number of citation classics in the late 1990s, which was paralleled by an increase in studies examining tumor pathogenesis, chemotherapy, and new agents along with laboratory and randomized studies. The majority of citation classics in neuro-oncology are related to gliomas and pertain to tumor pathogenesis and treatment. The rise in citation classics in recent years investigating tumor biology, new treatment agents, and chemotherapeutics may reflect increasing scientific interest in nonsurgical treatments for CNS tumors and the need for fundamental investigations into disease processes. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Application of the NASCAP Spacecraft Simulation Tool to Investigate Electrodynamic Tether Current Collection in LEO

NASA Technical Reports Server (NTRS)

Adams, Mitzi; HabashKrause, Linda

2012-01-01

Recent interest in using electrodynamic tethers (EDTs) for orbital maneuvering in Low Earth Orbit (LEO) has prompted the development of the Marshall ElectroDynamic Tether Orbit Propagator (MEDTOP) model. The model is comprised of several modules which address various aspects of EDT propulsion, including calculation of state vectors using a standard orbit propagator (e.g., J2), an atmospheric drag model, realistic ionospheric and magnetic field models, space weather effects, and tether librations. The natural electromotive force (EMF) attained during a radially-aligned conductive tether results in electrons flowing down the tether and accumulating on the lower-altitude spacecraft. The energy that drives this EMF is sourced from the orbital energy of the system; thus, EDTs are often proposed as de-orbiting systems. However, when the current is reversed using satellite charged particle sources, then propulsion is possible. One of the most difficult challenges of the modeling effort is to ascertain the equivalent circuit between the spacecraft and the ionospheric plasma. The present study investigates the use of the NASA Charging Analyzer Program (NASCAP) to calculate currents to and from the tethered satellites and the ionospheric plasma. NASCAP is a sophisticated set of computational tools to model the surface charging of three-dimensional (3D) spacecraft surfaces in a time-varying space environment. The model's surface is tessellated into a collection of facets, and NASCAP calculates currents and potentials for each one. Additionally, NASCAP provides for the construction of one or more nested grids to calculate space potential and time-varying electric fields. This provides for the capability to track individual particles orbits, to model charged particle wakes, and to incorporate external charged particle sources. With this study, we have developed a model of calculating currents incident onto an electrodynamic tethered satellite system, and first results are shown here.

The Ptolemaic Approach to Ionospheric Electrodynamics

NASA Astrophysics Data System (ADS)

Vasyliunas, V. M.

2010-12-01

The conventional treatment of ionospheric electrodynamics (as expounded in standard textbooks and tutorial publications) consists of a set of equations, plus verbal descriptions of the physical processes supposedly represented by the equations. Key assumptions underlying the equations are: electric field equal to the gradient of a potential, electric current driven by an Ohm's law (with both electric-field and neutral-wind terms), continuity of current then giving a second-order elliptic differential equation for calculating the potential; as a separate assumption, ion and electron bulk flows are determined by ExB drifts plus collision effects. The verbal descriptions are in several respects inconsistent with the equations; furthermore, both the descriptions and the equations are not compatible with the more rigorous physical understanding derived from the complete plasma and Maxwell's equations. The conventional ionospheric equations are applicable under restricted conditions, corresponding to a quasi-steady-state equilibrium limit, and are thus intrinsically incapable of answering questions about causal relations or dynamic developments. Within their limited range of applicability, however, the equations are in most cases adequate to explain the observations, despite the deficient treatment of plasma physics. (A historical precedent that comes to mind is that of astronomical theory at the time of Copernicus and for some decades afterwards, when the Ptolemaic scheme could explain the observations at least as well if not better than the Copernican. Some of the verbal descriptions in conventional ionospheric electrodynamics might be considered Ptolemaic also in the more literal sense of being formulated exclusively in terms of a fixed Earth.) I review the principal differences between the two approaches, point out some questions where the conventional ionospheric theory does not provide unambiguous answers even within its range of validity (e.g., topside and bottomside boundary conditions on electrodynamics), and illustrate with some simple examples of how a neutral-wind dynamo really develops.

Chiral dynamos and magnetogenesis induced by torsionful Maxwell-Chern Simons electrodynamics

NASA Astrophysics Data System (ADS)

de Andrade, L. C. Garcia

2018-03-01

Recently chiral anomalous currents have been investigated by Boyarsky et al. and Brandenburg et al. with respect to applications to the early universe. In this paper we show that these magnetic field anomalies, which can give rise to dynamo magnetic field amplification can also be linked to spacetime torsion through the use of a chemical potential and Maxwell electrodynamics with torsion firstly proposed by de Sabbata and Gasperini. When the axial torsion is constant this electrodynamics acquires the form of a Maxwell-Chern-Simmons (MCS) equations where the chiral current appears naturally and the zero component of torsion plays the role of a chemical potential, while the other components play the role of anisotropic conductivity. The chiral dynamo equation in torsionful spacetime is derived here from MSC electrodynamics. Here we have used a recently derived a torsion LV bound of T0˜ {10^{-26}} GeV and the constraint that this chiral magnetic field is a seed for galactic dynamo. This estimate is weaker than the one obtained from the chiral battery seed of ˜ {10^{30}} G without making use of Cartan torsion. The torsion obtained here was derived at 500 pc coherence scale. When a chiral MF is forced to seed a galactic dynamo one obtains a yet weaker MF, of the order of B˜ {10^{12}} G, which is the value of a MF at nucleosynthesis. By the use of chiral dynamo equations from parity-violating torsion one obtains a seed field of B˜ {10^{27}} G, which is a much stronger MF closer to the one obtained by making use of chiral batteries. Chiral vortical currents in non-Riemannian spacetimes derived in Riemannian spaces previously by Flaschi and Fukushima are extended to include minimal coupling with torsion. The present universe yields B˜ {10^{-24}} G, still sufficient to seed galactic dynamos.

Velior Petrovich

NASA Astrophysics Data System (ADS)

Ness, Norman

Dr. Velior Petrovich Shabansky, aged 58, the head of the Laboratory of Cosmic Electrodynamics, Institute of Nuclear Physics, Moscow State University, suddenly passed away on November 16, 1985, of a heart attack. He was one of the founders of theoretical ideas in physics of interplanetary and near-earth space. Shabansky obtained his education at the Moscow State University and joined the P. N. Lebedev Physical Institute, Academy of Sciences of the U.S.S.R., as a postgraduate. He obtained his Candidate's Degree in theory of conductivity of metals in strong electric fields, with V. L. Ginsburg as his advisor, in 1954. During 1954-1958, Shabansky continued investigation of nonlinear properties of plasma in metals. For the next 2 years, he worked at the Crimean Astrophysical Observatory. Shabansky left the Crimean Observatory to go to the Institute of Nuclear Physics, Moscow State University, where he investigated the earth's radiation belts, the plasma of the earth's magnetosphere, finished his doctoral dissertation, and received his degree in 1966. From 1966, he headed the Laboratory of Cosmic Electrodynamics, Institute of Nuclear Physics, Moscow State University. He is best known to the scientific community in the Soviet Union as chief of the Seminar on Cosmic Electrodynamics. Shabansky elaborated a special course of lectures on space physics that has been delivered for many years at the Physical Faculty, Moscow State University. He taught a large number of Soviet physicists, experts in cosmic electrodynamics. An enthusiastic, talented, and many-sided personality, he carried away everybody who knew him. He was known to the U.S. space physics community because of his own work, because of the work of his colleagues and students, a n d because of his infectious and spirited personality. Having died an untimely death, he left a deeply mourning widow and a 23-year-old son. Friends and colleagues will keep the bright image of Dr. Shabansky in their memory forever.

Global modeling of storm-time thermospheric dynamics and electrodynamics

NASA Astrophysics Data System (ADS)

Fuller-Rowell, T. J.; Richmond, A. D.; Maruyama, N.

Understanding the neutral dynamic and electrodynamic response of the upper atmosphere to geomagnetic storms, and quantifying the balance between prompt penetration and disturbance dynamo effects, are two of the significant challenges facing us today. This paper reviews our understanding of the dynamical and electrodynamic response of the upper atmosphere to storms from a modeling perspective. After injection of momentum and energy at high latitude during a geomagnetic storm, the neutral winds begin to respond almost immediately. The high-latitude wind system evolves quickly by the action of ion drag and the injection of kinetic energy; however, Joule dissipation provides the bulk of the energy source to change the dynamics and electrodynamics globally. Impulsive energy injection at high latitudes drives large-scale gravity waves that propagate globally. The waves transmit pressure gradients initiating a change in the global circulation. Numerical simulations of the coupled thermosphere, ionosphere, plasmasphere, and electrodynamic response to storms indicate that although the wind and waves are dynamic, with significant apparent "sloshing" between the hemispheres, the net effect is for an increased equatorward wind. The dynamic changes during a storm provide the conduit for many of the physical processes that ensue in the upper atmosphere. For instance, the increased meridional winds at mid latitudes push plasma parallel to the magnetic field to regions of different composition. The global circulation carries molecular rich air from the lower thermosphere upward and equatorward, changing the ratio of atomic and molecular neutral species, and changing loss rates for the ionosphere. The storm wind system also drives the disturbance dynamo, which through plasma transport modifies the strength and location of the equatorial ionization anomaly peaks. On a global scale, the increased equatorward meridional winds, and the generation of zonal winds at mid latitudes via the Coriolis effects, produce a current system opposing the normal quiet-time Sq current system. At the equator, the storm-time zonal electric fields reduce or reverse the normal upward and downward plasma drift on the dayside and nightside, respectively. In the numerical simulations, on the dayside, the disturbance dynamo appears fairly uniform, whereas at night a stronger local time dependence is apparent with increased upward drift between midnight and dawn. The simulations also indicate the possibility for a rapid dynamo response at the equator, within 2 h of storm onset, before the arrival of the large-scale gravity waves. All these wind-driven processes can result in dramatic ionospheric changes during storms. The disturbance dynamo can combine and interact with the prompt penetration of magnetospheric electric fields to the equator.

Quantum Optics in Astrophysics: The Potential of a New Window

NASA Astrophysics Data System (ADS)

Solomos, Nikolaos H.

2006-08-01

The entire optical astronomy relies upon the detection of light. In this contribution, we put emphasis to the fact that a new window to the universe could be opened with the obvious idea of applying the ...Quantum Theory to describe incoming light Quanta (!). It is clearly the appropriate approach but, nevertheless, it never deemed necessary in main stream astrophysics: Customarily, traditional astronomy not only prefers time-averaged quantities, (although fluctuations in time of a measurement can be a source of information which is getting entirely lost in any time-averaged value) but misses much more information content by continuing to use old semi-classical approaches to treat photon detection processes. Thus, we fail to describe and appreciate in full very important properties of cosmic light, like spatiotemporal coherence. Nevertheless, 45 years of knowledge accumulation in Quantum Optics and technology can now result to the development of instruments capable to extract intimate quantum information scrambled in the incoming optical light fields from celestial sources, provided their ability to detect light emission alterations in the

Theory of atomic spectral emission intensity

NASA Astrophysics Data System (ADS)

Yngström, Sten

1994-07-01

The theoretical derivation of a new spectral line intensity formula for atomic radiative emission is presented. The theory is based on first principles of quantum physics, electrodynamics, and statistical physics. Quantum rules lead to revision of the conventional principle of local thermal equilibrium of matter and radiation. Study of electrodynamics suggests absence of spectral emission from fractions of the numbers of atoms and ions in a plasma due to radiative inhibition caused by electromagnetic force fields. Statistical probability methods are extended by the statement: A macroscopic physical system develops in the most probable of all conceivable ways consistent with the constraining conditions for the system. The crucial role of statistical physics in transforming quantum logic into common sense logic is stressed. The theory is strongly supported by experimental evidence.

Study on figure-eight-shaped coil electrodynamic suspension magnetic levitation systems without cross-connection

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

Ribani, P.L.; Urbano, N.

2000-01-01

Two figure-eight-shaped coils for electrodynamic suspension (EDS) magnetic levitation (MAGLEV) systems without cross-connection are proposed and analyzed. The guideway coils are positioned under the MAGLEV vehicle; they are parallel to the horizontal plane. The interaction of a magnetic module on the vehicle, composed of three or four superconducting (SC) coils, with a guideway module, comprised of two figure-eight coils, is studied by means of the dynamic circuit theory. The currents in the SC coils are supposed to be constant in time while they move as a rigid body, with a constant velocity. Some results are presented and compared with thosemore » for a standard side-wall cross-connected system.« less

Mode analysis for energetics of a moving charge in Lorentz- and C P T -violating electrodynamics

NASA Astrophysics Data System (ADS)

DeCosta, Richard; Altschul, Brett

2018-03-01

In isotropic but Lorentz- and C P T -violating electrodynamics, it is known that a charge in uniform motion does not lose any energy to Cerenkov radiation. This presents a puzzle, since the radiation appears to be kinematically allowed for many modes. Studying the Fourier transforms of the most important terms in the modified magnetic field and Poynting vector, we confirm the vanishing of the radiation rate. Moreover, we show that the Fourier transform of the field changes sign between small and large wave numbers. This enables modes with very long wavelengths to carry negative energies, which cancel out the positive energies carried away by modes with shorter wavelengths. This cancelation had previously been inferred but never explicitly demonstrated.

Integration of the Electrodynamic Dust Shield on a Lunar Habitat Demonstration Unit

NASA Technical Reports Server (NTRS)

Calle, C. I.; Immer, C. D.; Ferreira, J.; Hogue, M. D.; Chen, A.; Csonka, M. W.; VanSuetendael, N.; Snyder, S. J.

2010-01-01

NASA is developing a Habitat Demonstration Unit (HDU) to investigate the feasibility of lunar surface technologies and lunar ground operations. The HDU will define and validate lunar scenario architecture through field analog testing. It will contain a four-port vertical habitat module with docking demonstration capabilities. The Electrodynamic Oust Shield (EDS) is being incorporated into the HDU to demonstrate dust removal from a viewport and from a door prior to docking procedures. In this paper, we will describe our efforts to scale up the EDS to protect a viewport 20 cm in diameter. We will also describe the development of several 20 cm x 25 cm EDS patches to demonstrate dust removal from one of the HDU doors.

Electrodynamic response of the type-II Weyl semimetal YbMnBi 2

DOE PAGES

Chinotti, M.; Pal, A.; Ren, W. J.; ...

2016-12-01

Weyl fermions play a major role in quantum field theory but have been quite elusive as fundamental particles. These quasi-two-dimensional bismuth layers based materials were recently designed and provide an arena for studying the interplay between anisotropic Dirac fermions, magnetism, and structural changes, allowing the formation of Weyl fermions in condensed matter. We perform an optical investigation of YbMnBi 2 , a representative type-II Weyl semimetal, and contrast its excitation spectrum with the optical response of the more conventional semimetal EuMnBi 2 . This comparative study allows us to disentangle the optical fingerprints of type-II Weyl fermions, but also challengesmore » the present theoretical understanding of their electrodynamic response.« less

Local-Field Distribution of Two Dielectric Inclusions at Small Separation

NASA Astrophysics Data System (ADS)

Siu, Yuet-Lun; Yu, Kin-Wah

2001-03-01

When two dielectric inclusions approach to each other in a composite medium, significant mutual polarization effects must occur. These effects are multipolar in nature and are difficult to treat from first principles(J. D. Jackson, Classical Electrodynamics), 2nd edition, (Wiley, New York, 1975).. In this work, we employ the discrete-dipole theory(B. T. Draine and P. J. Flatau, J. Opt. Soc. Am. A 11) 1491 (1994). to account for the mutual polarization effects by dividing the inclusions into many small subparts. We begin the calculation at small inclusion sizes and large separation, where the point-dipole limit being valid, and proceed to larger inclusion sizes and small separation, for which the mutual polarization effect becomes important. Then, we apply the theory to determine the dipole moment of each subpart self-consistently. In this way, each dipole moment yields the local electric field, which in turn polarizes the neighboring dipoles. We also begin the calculation at small inclusion sizes and large separation, where the point-dipole limit being valid, and proceed to larger inclusion sizes and small separation. Our resluts indicate that convergence is achieved with moderate computational effects. The results produce valuable information about the local electric field distribution, which is relevant to optical absorption due to surface phonon-polaritons of ionic microcrystals.

Demonstration of two-qubit algorithms with a superconducting quantum processor.

PubMed

DiCarlo, L; Chow, J M; Gambetta, J M; Bishop, Lev S; Johnson, B R; Schuster, D I; Majer, J; Blais, A; Frunzio, L; Girvin, S M; Schoelkopf, R J

2009-07-09

Quantum computers, which harness the superposition and entanglement of physical states, could outperform their classical counterparts in solving problems with technological impact-such as factoring large numbers and searching databases. A quantum processor executes algorithms by applying a programmable sequence of gates to an initialized register of qubits, which coherently evolves into a final state containing the result of the computation. Building a quantum processor is challenging because of the need to meet simultaneously requirements that are in conflict: state preparation, long coherence times, universal gate operations and qubit readout. Processors based on a few qubits have been demonstrated using nuclear magnetic resonance, cold ion trap and optical systems, but a solid-state realization has remained an outstanding challenge. Here we demonstrate a two-qubit superconducting processor and the implementation of the Grover search and Deutsch-Jozsa quantum algorithms. We use a two-qubit interaction, tunable in strength by two orders of magnitude on nanosecond timescales, which is mediated by a cavity bus in a circuit quantum electrodynamics architecture. This interaction allows the generation of highly entangled states with concurrence up to 94 per cent. Although this processor constitutes an important step in quantum computing with integrated circuits, continuing efforts to increase qubit coherence times, gate performance and register size will be required to fulfil the promise of a scalable technology.

Mass analysis addition to the Differential Ion Flux Probe (DIFP) study

NASA Technical Reports Server (NTRS)

Wright, K. H., Jr.; Jolley, Richard

1994-01-01

The objective of this study is to develop a technique to measure the characteristics of space plasmas under highly disturbed conditions; e.g., non-Maxwellian plasmas with strong drifting populations and plasmas contaminated by spacecraft outgassing. The approach, conducted in conjunction with current MSFC activities, is to extend the capabilities of the Differential Ion Flux Probe (DIFP) to include a high throughput mass measurement that does not require either high voltage or contamination sensitive devices such as channeltron electron multipliers or microchannel plates. This will significantly reduce the complexity and expense of instrument fabrication, testing, and integration of flight hardware compared to classical mass analyzers. The feasibility of the enhanced DIFP has been verified by using breadboard test models in a controlled plasma environment. The ability to manipulate particles through the instrument regardless of incident angle, energy, or ionic component has been amply demonstrated. The energy analysis mode is differential and leads directly to a time-of-flight mass measurement. With the new design, the DIFP will separate multiple ion streams and analyze each stream independently for ion flux intensity, velocity (including direction of motion), mass, and temperature (or energy distribution). In particular, such an instrument will be invaluable on follow-on electrodynamic TSS missions and, possibly, for environmental monitoring on the space station.

Proceedings of a Workshop on the Applications of Tethers in Space, Volume 1

NASA Technical Reports Server (NTRS)

1983-01-01

Project overview; tether deployment; satellite system description; tether fundamentals; science applications; electrodynamic interactions; transportation; artificial gravity; and constellations; were described.

Theory of nonclassical photonic states in driven-dissipative circuit quantum electrodynamics

NASA Astrophysics Data System (ADS)

Elliott, Matthew

Superconducting circuits provide an architecture upon which cavity quantum electrodynamics (QED) can be implemented at microwave frequencies in a highly tunable environment. Known as circuit QED, these systems can achieve larger nonlinearities, stronger coupling and greater controllability than can be achieved in cavity QED, all in a customisable, solid state device, making this technology an exciting test bed for both quantum optics and quantum information processing. These new parameter regimes open up new avenues for quantum technology, while also allowing older quantum optics results to finally be tested. In particular is is now possible to experimentally produce nonclassical states, such as squeezed and Schrodinger cat states, relatively simply in these devices. Using open quantum systems methods, in this thesis we investigate four problems which involve the use of nonclassical states in circuit QED. First we investigate the effects of a Kerr nonlinearity on the ability to preserve transported squeezed states in a superconducting cavity, and whether this setup permits us to generate, and perform tomography, of a highly squeezed field using a qubit, with possible applications in the characterisation of sources of squeezed microwaves. Second, we present a novel scheme for the amplification of cat states using a coupled qubit and external microwave drives, inspired by the stimulated Raman adiabatic passage. This scheme differs from similar techniques in circuit QED in that it is deterministic and therefore compatible with a protocol for stabilising cat states without the need for complex dissipation engineering. Next we use solutions of Fokker-Planck equations to study the exact steady-state response of two nonlinear systems: a transmon qubit coupled to a readout resonator, where we find good agreement with experiments and see simultaneous bistability of the cavity and transmon; and a parametrically driven nonlinear resonator, where we compare the classical and quantum phases of the system and discuss applications in the generation of squeezed states and stabilisation of cat states. Finally, we investigate the use of two different types of superconducting qubits in a single experiment, seeing that this enables engineering of the self- and cross-Kerr effects in a line of cavities. This could provide a valuable means of entangling cavity states, in addition to a resource for quantum simulation.

Application of electrical geophysics to the release of water resources, case of Ain Leuh (Morocco)

NASA Astrophysics Data System (ADS)

Zitouni, A.; Boukdir, A.; El Fjiji, H.; Baite, W.; Ekouele Mbaki, V. R.; Ben Said, H.; Echakraoui, Z.; Elissami, A.; El Maslouhi, M. R.

2018-05-01

Being seen needs in increasing waters in our contry for fine domestics, manufactures and agricultural, the prospecting of subterranean waters by geologic and hydrogeologic classic method remains inaplicable in the cases of the regions where one does not arrange drillings or polls (soundings) of gratitude (recongnition) in very sufficient (self-important) number. In that case of figure, the method of prospecting geophysics such as the method of nuclear magnetic resonance (NMR) and the method of the geophysics radar are usually used most usually because they showed, worldwide, results very desive in the projects of prospecting and evaluation of the resources in subterranean waters. In the present work, which concerns only the methodology of the electric resistivity, we treat the adopted methodological approach and the study of the case of application in the tray of Ajdir Ain Leuh.

Prospect theory on the brain? Toward a cognitive neuroscience of decision under risk.

PubMed

Trepel, Christopher; Fox, Craig R; Poldrack, Russell A

2005-04-01

Most decisions must be made without advance knowledge of their consequences. Economists and psychologists have devoted much attention to modeling decisions made under conditions of risk in which options can be characterized by a known probability distribution over possible outcomes. The descriptive shortcomings of classical economic models motivated the development of prospect theory (D. Kahneman, A. Tversky, Prospect theory: An analysis of decision under risk. Econometrica, 4 (1979) 263-291; A. Tversky, D. Kahneman, Advances in prospect theory: Cumulative representation of uncertainty. Journal of Risk and Uncertainty, 5 (4) (1992) 297-323) the most successful behavioral model of decision under risk. In the prospect theory, subjective value is modeled by a value function that is concave for gains, convex for losses, and steeper for losses than for gains; the impact of probabilities are characterized by a weighting function that overweights low probabilities and underweights moderate to high probabilities. We outline the possible neural bases of the components of prospect theory, surveying evidence from human imaging, lesion, and neuropharmacology studies as well as animal neurophysiology studies. These results provide preliminary suggestions concerning the neural bases of prospect theory that include a broad set of brain regions and neuromodulatory systems. These data suggest that focused studies of decision making in the context of quantitative models may provide substantial leverage towards a fuller understanding of the cognitive neuroscience of decision making.

Quantum correction to classical gravitational interaction between two polarizable objects

NASA Astrophysics Data System (ADS)

Wu, Puxun; Hu, Jiawei; Yu, Hongwei

2016-12-01

When gravity is quantized, there inevitably exist quantum gravitational vacuum fluctuations which induce quadrupole moments in gravitationally polarizable objects and produce a quantum correction to the classical Newtonian interaction between them. Here, based upon linearized quantum gravity and the leading-order perturbation theory, we study, from a quantum field-theoretic prospect, this quantum correction between a pair of gravitationally polarizable objects treated as two-level harmonic oscillators. We find that the interaction potential behaves like r-11 in the retarded regime and r-10 in the near regime. Our result agrees with what were recently obtained in different approaches. Our study seems to indicate that linearized quantum gravity is robust in dealing with quantum gravitational effects at low energies.

[Comparison of efficacy of heel ulcer prevention between classic padded bandage and polyurethane heel in a medium-stay hospital: randomized controlled trial].

PubMed

Ferrer Solà, Marta; Espaulella Panicot, Joan; Altimires Roset, Jacint; Ylla-Català Borè, Elisenda; Moreno Susi, María

2013-01-01

The aim of the study is to determine the incidence of heel pressure ulcers (UPPT) and to compare the two systems for UPPT prevention: classic padded bandage and polyurethane heel. Prospective intervention study in a medium-long hospital stay of all people admitted that had no UPPT but had a risk of UPPT according to the Braden Scale or clinical judgment. The patients were randomized to prevention with classic padded bandage or polyurethane heel. The outcome variable was the incidence of UPPT for each study group, which was recorded every 15 days or when there were clinical changes. Of the 940 patients evaluated, 409 with a mean age of 80.5 years and 59.1% women,were included in the study. Of these, 78% had Barthel score ≤30; 28.6% dementia; delirium 37.6%; 27.6% diabetes; and 19.6% other UPP. The overall incidence was 2.9% UPPT; 2.49% in the classic padded bandage and 3.37% in the polyurethane heel group (p=0.82). No statistically significant differences were observed between the group with the classical dressing and the group with the polyurethane heel dressing. The use of multiple measures to prevent UPPT achieved a low incidence of these. Copyright © 2011 SEGG. Published by Elsevier Espana. All rights reserved.

Tuned mass damping system for a pendulum in gravity and microgravity fields

NASA Astrophysics Data System (ADS)

Atour, Farah

2016-07-01

An electrodynamic tether is a simple idea, but one with an amazing number of uses. Electrodynamic tether is a long conductor wire that is attached to the satellite, which can act as a generator or motor, from its motion through the earth's magnetic field. And it has the potential to make space travel significantly cheaper. The lack of electrodynamic tether's widespread in common applications can be attributed to the variable Lorentz forces occuring on the tethers, which will cause them to oscillate and may go out of control, de-orbit the satellite and fall to Earth. A tuned mass damper system, for short refered as tilger, is suggested as damper of oscillations of tethers. A system composed of a tuned mass damper and a simple pendulum simulating the tether was therefore constructed. 350 sets of experimental trials were done on the system, while it was installed inside a drop tower capsule resting on the ground, in order to pick four optimum setup experiments that will undergo a series of microgravity experiments at the Bremen Drop Tower in Bremen, Germany. The GJU Bachelor Research students found that the oscillations of the simple pendulum will not be affected by the tilger during the free fall experiment, except if a feedback mechanism is installed between the simple pendulum and the tilger. In this case, the tilger will dampen the simple pendulum oscillations during free fall.

Propulsive Small Expendable Deployer System (ProSEDS)

NASA Technical Reports Server (NTRS)

1999-01-01

NASA's Propulsive Small Expendable Deployer System experiment (ProSEDS) will demonstrate the use of an electrodynamic tether, basically a long, thin wire, for propulsion. An electrodynamic tether uses the same principles as electric motors in toys, appliances and computer disk drives, and generators in automobiles and power plants. When electrical current is flowing through the tether, a magnetic field is produced that pushes against the magnetic field of the Earth. For ProSEDS, the current in the tether results by virtue of the voltage generated when the tether moves through the Earth's magnetic field at more than 17,000 mph. This approach can produce drag thrust generating useable power. Since electrodynamic tethers require no propellant, they could substantially reduce the weight of the spacecraft and provide a cost-effective method of reboosting spacecraft. The initial flight of ProSEDS is scheduled to fly aboard an Air Force Delta II rocket in the summer of 2002. In orbit, ProSEDS will deploy from a Delta II second stage. It will be a 3.1-mile (5 kilometer) long, ultrathin base-wire cornected with a 6.2-mile (10 kilometer) long nonconducting tether. This photograph shows Less Johnson, a scientist at MSFC inspecting the nonconducting part of a tether as it exits a deployer similar to the one to be used in the ProSEDS experiment. The ProSEDS experiment is managed by the Space Transportation Directorate at MSFC.

The Effect of Organic Compounds on the Hygroscopic Properties of Inorganic Aerosol

NASA Astrophysics Data System (ADS)

Krieger, U. K.; Zardini, A. A.; Marcolli, C.

2006-12-01

The hygroscopicity of the aerosols plays a major role for the direct and indirect effect on the climate. It is known that aerosols are often a mixture of inorganic and organic matter. A significant fraction of the organic matter is water soluble (WSOC) and affects light scattering, water uptake and phase transitions of multicomponent aerosols. Additionally, organic matter can act as a surfactant around an inorganic particle, affecting the evaporation-condensation time scale. This research project benefits from the combined measurements performed by two different instrumentations: the electrodynamic trap at IACETH, Zürich, Switzerland, and a Tandem Differential Mobility Analizer (TDMA) at the Paul Scherrer Institute, Switzerland. The Electrodynamic Trap consists of a chamber in which a levitated particle can experience all the atmospherically relevant conditions of temperature, pressure, and humidity. All these parameters can be continuously varied so that the hygroscopic curve of the aerosol particle can be measured. Additional tools help to better characterize the aerosol particle: 90 degrees angular scattering of lasers (for radius measurements) and intensity fluctuation of the scattered light with time (for phase changes detection). In this poster the results obtained through the electrodynamic balance technique will be shown and compared with the TDMA. In particular, bicomponent ammonium sulphate with adipic acid bicomponent particles are studied, with different mixing ratios. Particular emphasis is put on assessing the water uptake and the phase changes of the particles.

Tethered Satellite System (TSS) core equipment

NASA Technical Reports Server (NTRS)

Bonifazi, C.

1986-01-01

To date, three Tethered Satellite System (TSS) missions of the Italian provided scientific satellite orbiting in the ionosphere connected to U.S. Space Shuttle is foreseen. The first mission will use an electrically conductive tether of 20 km deployed upward from the orbiter flying at 300 km altitude. This mission will allow investigation of the TSS electrodynamic interaction with the ionosphere due to the high voltage induced across the two terminators of the system during its motion throughout the geomagnetic field. The second mission will use a dielectric tether of 100 km deployed downward from the Orbiter flying at 230 km altitude. Tethered-vehicle access to altitude as low as 120 to 150 km from the Orbiter would permit direct long term observation of phenomena in the lower thermosphere and determination of other dynamical physical processes. The third mission would use the same configuration of the first electrodynamic mission with the complete Core Equipment. Study of power generation by tethered systems would be possible by operating the Core Equipment in the inverted current mode. This mode of operation would allow ion current collection upon the TSS satellite by controlling its potential with respect to the ambient ionospheric plasma. The main requirements of the Core Equipment configuration to date foreseen for the first TSS electrodynamic mission is described. Besides the Core Equipment purposes, its hardware and operational sub-modes of operation are described.

Electrodynamics and radiofrequency antenna concepts for human magnetic resonance at 23.5 T (1 GHz) and beyond.

PubMed

Winter, Lukas; Niendorf, Thoralf

2016-06-01

This work investigates electrodynamic constraints, explores RF antenna concepts and examines the transmission fields (B 1 (+) ) and RF power deposition of dipole antenna arrays for (1)H magnetic resonance of the human brain at 1 GHz (23.5 T). Electromagnetic field (EMF) simulations are performed in phantoms with average tissue simulants for dipole antennae using discrete frequencies [300 MHz (7.0 T) to 3 GHz (70.0 T)]. To advance to a human setup EMF simulations are conducted in anatomical human voxel models of the human head using a 20-element dipole array operating at 1 GHz. Our results demonstrate that transmission fields suitable for (1)H MR of the human brain can be achieved at 1 GHz. An increase in transmit channel density around the human head helps to enhance B 1 (+) in the center of the brain. The calculated relative increase in specific absorption rate at 23.5 versus 7.0 T was below 1.4 (in-phase phase setting) and 2.7 (circular polarized phase setting) for the dipole antennae array. The benefits of multi-channel dipole antennae at higher frequencies render MR at 23.5 T feasible from an electrodynamic standpoint. This very preliminary finding opens the door on further explorations that might be catalyzed into a 20-T class human MR system.

Pathfinder

NASA Image and Video Library

1999-03-01

NASA's Propulsive Small Expendable Deployer System experiment (ProSEDS) will demonstrate the use of an electrodynamic tether, basically a long, thin wire, for propulsion. An electrodynamic tether uses the same principles as electric motors in toys, appliances and computer disk drives, and generators in automobiles and power plants. When electrical current is flowing through the tether, a magnetic field is produced that pushes against the magnetic field of the Earth. For ProSEDS, the current in the tether results by virtue of the voltage generated when the tether moves through the Earth's magnetic field at more than 17,000 mph. This approach can produce drag thrust generating useable power. Since electrodynamic tethers require no propellant, they could substantially reduce the weight of the spacecraft and provide a cost-effective method of reboosting spacecraft. The initial flight of ProSEDS is scheduled to fly aboard an Air Force Delta II rocket in the summer of 2002. In orbit, ProSEDS will deploy from a Delta II second stage. It will be a 3.1-mile (5 kilometer) long, ultrathin base-wire cornected with a 6.2-mile (10 kilometer) long nonconducting tether. This photograph shows Less Johnson, a scientist at MSFC inspecting the nonconducting part of a tether as it exits a deployer similar to the one to be used in the ProSEDS experiment. The ProSEDS experiment is managed by the Space Transportation Directorate at MSFC.

Space weather forecasting with a Multimodel Ensemble Prediction System (MEPS)

NASA Astrophysics Data System (ADS)

Schunk, R. W.; Scherliess, L.; Eccles, V.; Gardner, L. C.; Sojka, J. J.; Zhu, L.; Pi, X.; Mannucci, A. J.; Butala, M.; Wilson, B. D.; Komjathy, A.; Wang, C.; Rosen, G.

2016-07-01

The goal of the Multimodel Ensemble Prediction System (MEPS) program is to improve space weather specification and forecasting with ensemble modeling. Space weather can have detrimental effects on a variety of civilian and military systems and operations, and many of the applications pertain to the ionosphere and upper atmosphere. Space weather can affect over-the-horizon radars, HF communications, surveying and navigation systems, surveillance, spacecraft charging, power grids, pipelines, and the Federal Aviation Administration (FAA's) Wide Area Augmentation System (WAAS). Because of its importance, numerous space weather forecasting approaches are being pursued, including those involving empirical, physics-based, and data assimilation models. Clearly, if there are sufficient data, the data assimilation modeling approach is expected to be the most reliable, but different data assimilation models can produce different results. Therefore, like the meteorology community, we created a Multimodel Ensemble Prediction System (MEPS) for the Ionosphere-Thermosphere-Electrodynamics (ITE) system that is based on different data assimilation models. The MEPS ensemble is composed of seven physics-based data assimilation models for the ionosphere, ionosphere-plasmasphere, thermosphere, high-latitude ionosphere-electrodynamics, and middle to low latitude ionosphere-electrodynamics. Hence, multiple data assimilation models can be used to describe each region. A selected storm event that was reconstructed with four different data assimilation models covering the middle and low latitude ionosphere is presented and discussed. In addition, the effect of different data types on the reconstructions is shown.

2006 Status of the Momentum eXchange Electrodynamic Re-Boost (MXER) Tether Development

NASA Technical Reports Server (NTRS)

Bonometti, Joseph A.; Sorensen, Kirk F.; Dankanich, John W.; Frame, Kyle L.

2006-01-01

The MXER Tether technology development is a high-payoff/high-risk investment area within the NASA In-Space Propulsion Technology (ISPT) Program. The ISPT program is managed by the NASA Headquarters Science Mission Directorate and implemented by the Marshall Space Flight Center in Huntsville, Alabama. The MXER concept was identified and competitively ranked within NASA's comprehensive Integrated In-Space Transportation Plan (IISTP); an agency-wide technology assessment activity. The objective of the MXER tether project within ISPT is to advance the technological maturation level for the MXER system, and its subsystems, as well as other space and terrestrial tether applications. Recent hardware efforts have focused on the manufacturability of space-survivable high-strength tether material and coatings, high-current electrodynamic tether, lightweight catch mechanism, high-accuracy propagator/predictor code, and efficient electron collection/current generation. Significant technical progress has been achieved with modest ISPT funding to the extent that MXER has evolved to a well-characterized system with greater capability as the design has been matured. Synergistic efforts in high-current electrodynamic tethers and efficient electron collection/current generation have been made possible through SBIR and STTR support. The entire development endeavor was orchestrated as a collaborative team effort across multiple individual contracts and has established a solid technology resource base, which permits a wide variety of future space cable/tether applications to be realized.

Autism in Adults: Symptom Patterns and Early Childhood Predictors. Use of the DISCO in a Community Sample Followed from Childhood

ERIC Educational Resources Information Center

Billstedt, Eva; Gillberg, I. Carina; Gillberg, Christopher

2007-01-01

Background: Few studies have looked at the very long-term outcome of individuals with autism who were diagnosed in childhood. Methods: A longitudinal, prospective, community-based follow-up study of adults who had received the diagnosis of autism (classic and atypical) in childhood (n = 105) was conducted. A structured interview (the Diagnostic…

Effect of mechanical damage on emission of volatile organic compounds from plant leaves and implications for evaluation of host plant specificity of prospective biological control agents of weeds

USDA-ARS?s Scientific Manuscript database

Assessment of host plant specificity is a critical step in the evaluation of classical biological control agents of weeds, which is necessary for avoiding possible damage to nontarget plants. Volatile organic compounds (VOC) emitted by plants likely play an important role in determining which plant...

Five-year follow-up of a prospective non-randomised study comparing duodenum-preserving pancreatic head resection with classic Whipple procedure in the treatment of chronic pancreatitis.

PubMed

Möbius, C; Max, D; Uhlmann, D; Gumpp, K; Behrbohm, J; Horvath, K; Hauss, J; Witzigmann, H

2007-05-01

Three prospective randomised studies were conducted to compare pancreatoduodenectomy (PD) with duodenum-preserving pancreatic head resection (DPPHR) in patients suffering from chronic pancreatitis (cP). In these three series, the superiority of the duodenum-preserving technique with regard to quality of life (QOL) and pain relief has been demonstrated. Long-term follow-up investigations have not been published so far. The present paper reports on a 5-year follow-up study of a prospective, non-randomised trial comparing classic Whipple procedure (PD) with Beger DPPHR. Seventy patients were initially enrolled in this study. Fifty-one patients were left for the present long-term outcome analysis (PD, n = 24; DPPHR, n = 27). The follow-up included the following parameters: QOL, pain intensity, endocrine and exocrine function, and body mass index (BMI). The median follow-up was 63.5 (range 56-67) months. Two patients in the DPPHR group and none in the PD group underwent a re-operation. The QOL scores of the relevant symptom scales (nausea, pain, diarrhoea) and functional parameters (physical status, working ability, global QOL) were significantly better in the DPPHR group than in the PD group. Pain intensity as self-assessed by the patients was less pronounced in the DPPHR group (P < 0.001), whereas the frequency of acute episodes and analgesic medication did not differ between the two groups. No difference was observed between the two groups with regard to endocrine and exocrine function. The values of the median body mass index (BMI) in the PD group [23.4 (range 18.5-25.0) kg/m(2)] and in the DPPHR group [24.2 (range 17.9-27.8) kg/m(2)] were comparable. The 5-year outcome remained stable compared to the early post-operative data published elsewhere. This 5-year long-term outcome analysis documents the superiority of the Beger duodenum-preserving technique over the classic Whipple procedure in terms of QOL and pain intensity as self-assessed by the patients.

Proceedings of a Workshop on Applications of Tethers in Space, Volume 2

NASA Technical Reports Server (NTRS)

1983-01-01

The panel conclusions for each of the following panels (science applications; electrodynamic interactions; transportation applications; artificial gravity; constellations; and technology and test) are given.

Dynamometer Facilities | Water Power | NREL

Science.gov Websites

, mechanical or electro-dynamic brakes, power electronics, control systems, and software. Manufacturers and power electronics with the electric grid, to perform accelerated lifetime certification, and to develop

Electrodynamic properties of a hypercrystal with ferrite and semiconductor layers in an external magnetic field

NASA Astrophysics Data System (ADS)

Fedorin, Illia V.

2018-01-01

Electrodynamic properties of a photonic hypercrystal formed by periodically alternating two types of anisotropic metamaterials are studied. The first metamaterial consists of ferrite and dielectric layers, while the second metamaterial consists of semiconductor and dielectric layers. The system is assumed to be placed in an external magnetic field, which applied parallel to the boundaries of the layers. An effective medium theory which is suitable for calculation of properties of long-wavelength electromagnetic modes is applied in order to derive averaged expressions for effective constitutive parameters. It has been shown that providing a conscious choice of the constitutive parameters and material fractions of magnetic, semiconductor, and dielectric layers, the system under study shows hypercrystal properties for both TE and TM waves in the different frequency ranges.

de Broglie-Proca and Bopp-Podolsky massive photon gases in cosmology

NASA Astrophysics Data System (ADS)

Cuzinatto, R. R.; de Morais, E. M.; Medeiros, L. G.; Naldoni de Souza, C.; Pimentel, B. M.

2017-04-01

We investigate the influence of massive photons on the evolution of the expanding universe. Two particular models for generalized electrodynamics are considered, namely de Broglie-Proca and Bopp-Podolsky electrodynamics. We obtain the equation of state (EOS) P=P(\\varepsilon) for each case using dispersion relations derived from both theories. The EOS are inputted into the Friedmann equations of a homogeneous and isotropic space-time to determine the cosmic scale factor a(t). It is shown that the photon non-null mass does not significantly alter the result a\\propto t1/2 valid for a massless photon gas; this is true either in de Broglie-Proca's case (where the photon mass m is extremely small) or in Bopp-Podolsky theory (for which m is extremely large).

KSC-2013-3900

NASA Image and Video Library

2013-11-07

CAPE CANAVERAL, Fla. -- Dr. Carlos Calle, senior research scientist on the Electrodynamic Dust Shield for Dust Mitigation project, manages the Electrostatics and Surface Physics Laboratory in the SwampWorks at NASA's Kennedy Space Center in Florida. Electrodynamic dust shield, or EDS, technology is based on concepts originally developed by NASA as early as 1967 and later by the University of Tokyo. In 2003, NASA, in collaboration with the University of Arkansas at Little Rock, started development of the EDS for dust particle removal from solar panels to be used on future missions to the moon, an asteroid or Mars. A flight experiment to expose the dust shields to the space environment currently is under development. For more information, visit: http://www.nasa.gov/content/scientists-developing-ways-to-mitigate-dust-problem-for-explorers/ Photo credit: NASA/Dan Casper

Research on Orbital Plasma Electrodynamics (ROPE)

NASA Technical Reports Server (NTRS)

Intriligator, Devrie S.

1998-01-01

This final report summarizes some of the important scientific contributions to the Research on Orbital Plasma Electrodynamics (ROPE) investigation, to the Tethered Satellite System (TSS) mission, and to NASA that resulted from the work carried out under this contract at Carmel Research Center. These include Dr. Intriligator's participation in the PIT for the TSS-1R simulations and flight, her participation in ROPE team meetings and IWG meetings, her scientific analyses, and her writing and submitting technical papers to scientific journals. The scientific analyses concentrated on the characterization of energetic ions and their possible relation to pickup ion effects, correlation of particle and other effects (e.g., magnetic field, satellite surface), and collaboration with theorists including with ROPE co-investigators. In addition, scientific analyses were carried out of the effects due to satellite gas releases.

Thermodynamics of third-order Lovelock-AdS black holes in the presence of Born-Infeld type nonlinear electrodynamics

NASA Astrophysics Data System (ADS)

Hendi, S. H.; Dehghani, A.

2015-03-01

In this paper, we obtain topological black hole solutions of third-order Lovelock gravity coupled with two classes of Born-Infeld-type nonlinear electrodynamics with anti-de Sitter asymptotic structure. We investigate geometric and thermodynamics properties of the solutions and obtain conserved quantities of the black holes. We examine the first law of thermodynamics and find that the conserved and thermodynamic quantities of the black hole solutions satisfy the first law of thermodynamics. Finally, we calculate the heat capacity and determinant of the Hessian matrix to evaluate thermal stability in both canonical and grand canonical ensembles. Moreover, we consider the extended phase space thermodynamics to obtain a generalized first law of thermodynamics as well as the extended Smarr formula.

Tethered constellations

NASA Technical Reports Server (NTRS)

Lorenzini, E.

1986-01-01

The studies that have been carried out on Tethered Constellations are briefly addressed. A definition of a tethered constellation is any number of masses/platforms greater that two connected by tethers in a stable configuration. Configurations and stability constraints are reviewed. Conclusions reached are: (1) The 1-D, horizontal, passively stabilized constellations have been ruled out; (2) Fishbone constellations have been also ruled out; (3) Alternative stable 2-D configurations have been devised such as the quadrangular configuration stabilized by electrodynamic forces (ESC), the quadrangular configuration stabilized by differential air drag (DSC), and the pseudo elliptical configuration stabilized by electrodynamic forces (PEC). Typical dimensions for these constellations are 10 km (horizontal) by 20 km (vertical) with balloon diameters around 100 m in the case of a DSC and a power consumption around 7 KW for an ESC or PEC.

Improving the Sensitivity of Mass Spectrometer using a High-Pressure Electrodynamic Ion Funnel Interface

PubMed Central

Ibrahim, Yehia; Tang, Keqi; Tolmachev, Aleksey V.; Shvartsburg, Alexandre A.

2006-01-01

We report on a new electrodynamic ion funnel that operates at a pressure of 30 Torr with no loss of ion transmission. The enhanced performance compared to previous ion funnel designs optimized for pressures of <5 Torr was achieved by reducing the ion funnel capacitance and increasing the RF drive frequency (1.7 MHz) and amplitude (100-170 V peak-to-peak). No degradation of ion transmission was observed for pressures from 2 - 30 Torr. The ability to operate at higher pressure enabled a new tandem ion funnel mass spectrometer (MS) interface design that can accommodate a greater gas load. When combined with a multicapillary inlet, the interface provided more efficient introduction of ions, resulting in a significant enhancement in MS sensitivity and detection limits. PMID:16839773

The investigation of tethered satellite system dynamics

NASA Technical Reports Server (NTRS)

Lorenzini, E.

1985-01-01

Progress in tethered satellite system dynamics research is reported. A retrieval rate control law with no angular feedback to investigate the system's dynamic response was studied. The initial conditions for the computer code which simulates the satellite's rotational dynamics were extended to a generic orbit. The model of the satellite thrusters was modified to simulate a pulsed thrust, by making the SKYHOOK integrator suitable for dealing with delta functions without loosing computational efficiency. Tether breaks were simulated with the high resolution computer code SLACK3. Shuttle's maneuvers were tested. The electric potential around a severed conductive tether with insulator, in the case of a tether breakage at 20 km from the Shuttle, was computed. The electrodynamic hazards due to the breakage of the TSS electrodynamic tether in a plasma are evaluated.

Dielectric Properties and Electrodynamic Process of Natural Ester-Based Insulating Nanofluid

NASA Astrophysics Data System (ADS)

Zou, Ping; Li, Jian; Sun, Cai-Xin; Zhang, Zhao-Tao; Liao, Rui-Jin

Natural ester is currently used as an insulating oil and coolant for medium-power transformers. The biodegradability of insulating natural ester makes it a preferable insulation liquid to mineral oils. In this work, Fe3O4 nanoparticles were used along with oleic acid to improve the performance of insulating natural ester. The micro-morphology of Fe3O4 nanoparticles before and after surface modification was observed through transmission electron microscopy. Attenuated total reflection-Fourier transform infrared spectroscopy, thermal gravimetric analysis, and differential thermal analysis were employed to investigate functional groups and their thermal stability on the surface-modified Fe3O4 nanoparticles. Basic dielectric properties of natural ester-based insulating nanofluid were measured. The electrodynamic process in the natural ester-based insulating nanofluid is also presented.

Entangling distant resonant exchange qubits via circuit quantum electrodynamics

NASA Astrophysics Data System (ADS)

Srinivasa, V.; Taylor, J. M.; Tahan, Charles

2016-11-01

We investigate a hybrid quantum system consisting of spatially separated resonant exchange qubits, defined in three-electron semiconductor triple quantum dots, that are coupled via a superconducting transmission line resonator. Drawing on methods from circuit quantum electrodynamics and Hartmann-Hahn double resonance techniques, we analyze three specific approaches for implementing resonator-mediated two-qubit entangling gates in both dispersive and resonant regimes of interaction. We calculate entangling gate fidelities as well as the rate of relaxation via phonons for resonant exchange qubits in silicon triple dots and show that such an implementation is particularly well suited to achieving the strong coupling regime. Our approach combines the favorable coherence properties of encoded spin qubits in silicon with the rapid and robust long-range entanglement provided by circuit QED systems.

Electromagnetic Showers at High Energy

ERIC Educational Resources Information Center

Loos, J. S.; Dawson, S. L.

1978-01-01

Some of the properties of electromagnetic showers observed in an experimental study are illustrated. Experimental data and results from quantum electrodynamics are discussed. Data and theory are compared using computer simulation. (BB)

Fundamental physical theories: Mathematical structures grounded on a primitive ontology

NASA Astrophysics Data System (ADS)

Allori, Valia

In my dissertation I analyze the structure of fundamental physical theories. I start with an analysis of what an adequate primitive ontology is, discussing the measurement problem in quantum mechanics and theirs solutions. It is commonly said that these theories have little in common. I argue instead that the moral of the measurement problem is that the wave function cannot represent physical objects and a common structure between these solutions can be recognized: each of them is about a clear three-dimensional primitive ontology that evolves according to a law determined by the wave function. The primitive ontology is what matter is made of while the wave function tells the matter how to move. One might think that what is important in the notion of primitive ontology is their three-dimensionality. If so, in a theory like classical electrodynamics electromagnetic fields would be part of the primitive ontology. I argue that, reflecting on what the purpose of a fundamental physical theory is, namely to explain the behavior of objects in three-dimensional space, one can recognize that a fundamental physical theory has a particular architecture. If so, electromagnetic fields play a different role in the theory than the particles and therefore should be considered, like the wave function, as part of the law. Therefore, we can characterize the general structure of a fundamental physical theory as a mathematical structure grounded on a primitive ontology. I explore this idea to better understand theories like classical mechanics and relativity, emphasizing that primitive ontology is crucial in the process of building new theories, being fundamental in identifying the symmetries. Finally, I analyze what it means to explain the word around us in terms of the notion of primitive ontology in the case of regularities of statistical character. Here is where the notion of typicality comes into play: we have explained a phenomenon if the typical histories of the primitive ontology give rise to the statistical regularities we observe.

Representing massive gravitons, as a way to quantify early universe magnetic field contributions to space-time, created by non linear electrodynamics

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

Beckwith, Andrew Walcott, E-mail: Rwill9955b@gmail.com

We review a relationship between cosmological vacuum energy and massive gravitons as given by Garattini and also the nonlinear electrodynamics of Camara et.al (2004) for a non singular universe and NLED. . In evaluating the Garattini result, we find that having the scale factor close to zero due to a given magnetic field value in, an early universe magnetic field affects how we would interpret Garattini’s linkage of the ‘cosmological constant’ value and non zero graviton mass.. We close as to how these initial conditions affect the issue of an early universe initial pressure and its experimental similarities and differencesmore » with results by Corda and Questa as to negative pressure at the surface of a star. Note, that in theDupays et.al. article , the star in question is rapidly spinning, which is not. assumed in the Camara et.al article , for an early universe. Also, Corda and Questa do not assume a spinning star. We conclude with a comparison between the Lagrangian Dupays and other authors bring up for non linear electrodynamics which is for rapidly spinning neutron stars , and a linkage between the Goldstone theorem and NLED. Our conclusion is for generalizing results seen in the Dupays neutron star Lagrangian with conditions which may confirm C. A. Escobar and L. F. Urrutia’s work on the Goldstone theorem and non linear electrodynamics, for some future projects we have in mind. If the universe does not spin, then we will stick with the density analogy given by adapting density as proportional to one over the fourth power of the minimum value of the scale factor as computed by adaptation of the Camara et.al.(2004) theory for non spinning universes. What may happen is that the Camara (2004) density and Quintessential density are both simultaneously satisfied, which would put additional restrictions on the magnetic field, which is one of our considerations, regardless if a universe spins, akin to spinning neutron stars. The spinning universe though may allow for easier reconciliation of the ‘Goldstone’ behavior of gravity and NLED though.« less

GEC - a mission to explore the coupling between the lower boundary of geospace and the magnetosphere

NASA Astrophysics Data System (ADS)

Grebowsky, J.; Sojka, J.; Heelis, R.; Wu, C.

The Geospace Electrodynamic Connections (GEC) mission of NASA's Solar Terrestrial Probes Program is the first mission to comprehensively focus on the electrodynamics in the threshold of the Earth's atmosphere -- i.e., in the transition region where the neutral gas changes from being the sink and driver of electrodynamic processes to being mainly driven by the Geospace charged particles and electric fields. In order to resolve how this region responds to and affects magnetospheric drivers, multiple, deep dipping spacecraft are needed. The GEC mission concept consists of three identical spacecraft with ˜ 200 X 2000 km, 830 inclination parking orbits (i.e., in a ``pearls-on-a-string'' configuration). Using onboard propulsion, the inter-spacecraft spacings can be controlled during the mission to sample different spatial/temporal scales. In addition, the spacecraft are designed to be capable of deep dipping campaigns, of approximately one week durations, down to ˜ 130 km perigee altitude or lower, where the neutral atmosphere causes the ion motions to depart significantly from the magnetosphere-driven EXB motion. The spacecraft can also be configured in a ``petal'' formation where the spacecraft perigees are separated in latitude, allowing simultaneous measurements over he same point on Earth at different altitudes. All spacecraft would carry identical instrument suites to measure in situ all the parameters (i.e., plasma, neutral gas temperatures, densities and composition; electric/magnetic fields; and energetic particle distributions) needed for intensive investigation of the electrodynamic coupling processes between the magnetosphere and the atmosphere. In recent months, the GEC mission definition has been brought to the point where it is ready for implementation, dependent only on the availability of funds. Several industry engineering studies were completed that provided detailed multi-spacecraft, deep-dipping mission concepts. These identified the technical challenges and showed how the challenges could be met. Further, the GEC Science Definition Team has recently refined the mission science rationale with a prioritization of the mission objectives and has defined the orbit scenarios most needed to accomplish the science goals.

Self-consistent Model of Magnetospheric Electric Field, RC and EMIC Waves

NASA Technical Reports Server (NTRS)

Gamayunov, K. V.; Khazanov, G. V.; Liemohn, M. W.; Fok, M.-C.

2007-01-01

Electromagnetic ion cyclotron (EMIC) waves are an important magnetospheric emission, which is excited near the magnetic equator with frequencies below the proton gyro-frequency. The source of bee energy for wave growth is provided by temperature anisotropy of ring current (RC) ions, which develops naturally during inward convection from the plasma sheet These waves strongly affect the dynamic s of resonant RC ions, thermal electrons and ions, and the outer radiation belt relativistic electrons, leading to non-adiabatic particle heating and/or pitch-angle scattering and loss to the atmosphere. The rate of ion and electron scattering/heating is strongly controlled by the Wave power spectral and spatial distributions, but unfortunately, the currently available observational information regarding EMIC wave power spectral density is poor. So combinations of reliable data and theoretical models should be utilized in order to obtain the power spectral density of EMIC waves over the entire magnetosphere throughout the different storm phases. In this study, we present the simulation results, which are based on two coupled RC models that our group has developed. The first model deals with the large-scale magnetosphere-ionosphere electrodynamic coupling, and provides a self-consistent description of RC ions/electrons and the magnetospheric electric field. The second model is based on a coupled system of two kinetic equations, one equation describes the RC ion dynamics and another equation describes the power spectral density evolution of EMIC waves, and self-consistently treats a micro-scale electrodynamic coupling of RC and EMIC waves. So far, these two models have been applied independently. However, the large-scale magnetosphere-ionosphere electrodynamics controls the convective patterns of both the RC ions and plasmasphere altering conditions for EMIC wave-particle interaction. In turn, the wave induced RC precipitation Changes the local field-aligned current distributions and the ionospheric conductances, which are crucial for a large-scale electrodynamics. The initial results from this new self-consistent model of the magnetospheric electric field, RC and EMIC waves will be shown in this presentation.

How does the predicted geomagnetic main field variation alter the thermosphere-ionosphere storm-time response?

NASA Astrophysics Data System (ADS)

Maute, A. I.; Lu, G.; Richmond, A. D.

2017-12-01

Earth's magnetic main field plays an important role in the thermosphere-ionosphere (TI) system, as well as its coupling to Earth's magnetosphere. The ionosphere consists of a weakly ionized plasma strongly influenced by the main field and embedded in the thermosphere. Therefore, ion-neutral coupling and ionospheric electrodynamics can influence the plasma distribution and neutral dynamics. There are strong longitude variations of the TI storm response. At high latitude magnetosphere-ionosphere coupling is organized by the geomagnetic main field, leading in general to stronger northern middle latitude storm time response in the American sector due to the geomagnetic dipole location. In addition, the weak geomagnetic main field in the American sector leads to larger local ExB drift and can alter the plasma densities. During geomagnetic storms the intense energy input into the high latitude region is redistributed globally, leading to thermospheric heating, wind circulation changes and alterations of the ionospheric electrodynamics. The storm time changes are measurable in the plasma density, ion drift, temperature, neutral composition, and other parameters. All these changes depend, to some degree, on the geomagnetic main field which changes on decadal time scales. In this study, we employ a forecast model of the geomagnetic main field based on data assimilation and geodynamo modeling [Aubert et al., 2015]. The main field model predicts that in 50 years the South Atlantic Anomaly is further weakened by 2 mT and drifts westward by approximately 10o. The dipole axis moves northward and westward by 2o and 6o, respectively. Simulating the March 2015 geomagnetic storm with the Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIE-GCM) driven by the Assimilative Mapping of Ionospheric Electrodynamics (AMIE), we evaluate the thermosphere-ionosphere response using the geomagnetic main field of 2015, 2065, and 2115. We compare the TI response for 2015 with available satellite data, e.g. Swarm and COSMIC, and discuss the changes in the TI response due to the predicted main field changes to identify regions of potential increase and decrease in the storm time response. Aubert, J., Geophys. J. Int. 203, 1738-1751, 2015, doi: 10.1093/gji/ggv394 .

Lunar tides in the Thermosphere-Ionosphere-Electrodynamics General Circulation Model

NASA Astrophysics Data System (ADS)

Stening, R. J.; Richmond, A. D.; Roble, R. G.

1999-01-01

Lunar semidiurnal tides are introduced at the lower boundary of the National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM). The tides are derived from the model of Vial and Forbes [1994] and interesting properties of these tides are found when they are subjected to Hough decomposition; there is considerable hemispherical antisymmetry in the September tides, and the March and September modal compositions are significantly different. A differencing method is used to isolate the lunar tidal effects in the TIEGCM, and these are compared with lunar tidal analyses of ionospheric data. The model reproduces the broad features of the lunar tide in foF2 (maximum frequency of the F region) with phase changes around 7° magnetic dip latitude during daytime. The model and data analysis both give variations of the amplitude and phase of the lunar tide with local time. Near the equator the variation of phase with local time changes with latitude as the equatorial anomaly develops during the day. Comparison between the model predictions and analyses of data at observatories at midlatitudes produces mixed results. Here the effects of the lunar components of both electrodynamic drifts and of neutral winds need to be taken into account. Several cases of day to night changes in the phase of the lunar tide in foF2 are noted. Large nighttime amplitudes of the lunar tide in hmF2 (height of the maximum density), more than 4 km, seem to be due to inphase action of the electrodynamic and neutral wind effects while during daytime they are out of phase. The lunar tide in the ratio of oxygen to nitrogen density [O]/[N2] is estimated and found to be of relatively minor importance. Amplitudes of the lunar tide in foF2 may be measured at more than 0.4 MHz at some local times, but the model values are less than this. Comparison is also made with ion drift measurements made by the San Marco D satellite. The several uncertainties which underlie this work are discussed in detail.

Risk factors for classical hysterotomy by gestational age.

PubMed

Osmundson, Sarah S; Garabedian, Matthew J; Lyell, Deirdre J

2013-10-01

To examine the likelihood of classical hysterotomy across preterm gestational ages and to identify factors that increase its occurrence. This is a secondary analysis of a prospective observational cohort collected by the Maternal-Fetal Medicine Network of all women with singleton gestations who underwent a cesarean delivery with a known hysterotomy. Comparisons were made based on gestational age. Factors thought to influence hysterotomy type were studied, including maternal age, body mass index, parity, birth weight, small for gestational age (SGA) status, fetal presentation, labor preceding delivery, and emergent delivery. Approximately 36,000 women were eligible for analysis, of whom 34,454 (95.7%) underwent low transverse hysterotomy and 1,562 (4.3%) underwent classical hysterotomy. The median gestational age of women undergoing a classical hysterotomy was 32 weeks and the incidence peaked between 24 0/7 weeks and 25 6/7 weeks (53.2%), declining with each additional week of gestation thereafter (P for trend <.001). In multivariable regression, the likelihood of classical hysterotomy was increased with SGA (n=258; odds ratio [OR] 2.71; confidence interval [CI] 1.78-4.13), birth weight 1,000 g or less (n=467; OR 1.51; CI 1.03-2.24), and noncephalic presentation (n=783; OR 2.03; CI 1.52-2.72). The likelihood of classical hysterotomy was decreased between 23 0/7 and 27 6/7 weeks of gestation and after 32 weeks of gestation when labor preceded delivery, and increased between 28 0/7 and 31 6/7 weeks of gestation and after 32 weeks of gestation by multiparity and previous cesarean delivery. Emergent delivery did not predict classical hysterotomy. Fifty percent of women at 23-26 weeks of gestation who undergo cesarean delivery have a classical hysterotomy, and the risk declines steadily thereafter. This likelihood is increased by fetal factors, especially SGA and noncephalic presentation. : II.

Genomics-Driven Precision Medicine for Advanced Pancreatic Cancer: Early Results from the COMPASS Trial.

PubMed

Aung, Kyaw L; Fischer, Sandra E; Denroche, Robert E; Jang, Gun-Ho; Dodd, Anna; Creighton, Sean; Southwood, Bernadette; Liang, Sheng-Ben; Chadwick, Dianne; Zhang, Amy; O'Kane, Grainne M; Albaba, Hamzeh; Moura, Shari; Grant, Robert C; Miller, Jessica K; Mbabaali, Faridah; Pasternack, Danielle; Lungu, Ilinca M; Bartlett, John M S; Ghai, Sangeet; Lemire, Mathieu; Holter, Spring; Connor, Ashton A; Moffitt, Richard A; Yeh, Jen Jen; Timms, Lee; Krzyzanowski, Paul M; Dhani, Neesha; Hedley, David; Notta, Faiyaz; Wilson, Julie M; Moore, Malcolm J; Gallinger, Steven; Knox, Jennifer J

2018-03-15

Purpose: To perform real-time whole genome sequencing (WGS) and RNA sequencing (RNASeq) of advanced pancreatic ductal adenocarcinoma (PDAC) to identify predictive mutational and transcriptional features for better treatment selection. Experimental Design: Patients with advanced PDAC were prospectively recruited prior to first-line combination chemotherapy. Fresh tumor tissue was acquired by image-guided percutaneous core biopsy for WGS and RNASeq. Laser capture microdissection was performed for all cases. Primary endpoint was feasibility to report WGS results prior to first disease assessment CT scan at 8 weeks. The main secondary endpoint was discovery of patient subsets with predictive mutational and transcriptional signatures. Results: Sixty-three patients underwent a tumor biopsy between December 2015 and June 2017. WGS and RNASeq were successful in 62 (98%) and 60 (95%), respectively. Genomic results were reported at a median of 35 days (range, 19-52 days) from biopsy, meeting the primary feasibility endpoint. Objective responses to first-line chemotherapy were significantly better in patients with the classical PDAC RNA subtype compared with those with the basal-like subtype ( P = 0.004). The best progression-free survival was observed in those with classical subtype treated with m-FOLFIRINOX. GATA6 expression in tumor measured by RNA in situ hybridization was found to be a robust surrogate biomarker for differentiating classical and basal-like PDAC subtypes. Potentially actionable genetic alterations were found in 30% of patients. Conclusions: Prospective genomic profiling of advanced PDAC is feasible, and our early data indicate that chemotherapy response differs among patients with different genomic/transcriptomic subtypes. Clin Cancer Res; 24(6); 1344-54. ©2017 AACR . ©2017 American Association for Cancer Research.

Dynamics explorer data analysis

NASA Technical Reports Server (NTRS)

Reiff, Patricia H.

1993-01-01

Work in the following areas is discussed: plasma physics of the auroral acceleration region; electrodynamic coupling as a function of substorm phase and interplanetary magnetic field (IMF) direction; and particle injection in the magnetospheric cusp.

Image of a moving sphere and the FitzGerald Lorentz contraction

NASA Astrophysics Data System (ADS)

Redzic, Dragan V.

2004-01-01

An asymmetry in Maxwell's electrodynamics concerning the electromagnetic image of a moving spherical conductor is pointed out. The asymmetry, if properly understood, opens the door to special relativity.

DNA translocation across protein channels: How does a polymer worm through a hole?

NASA Astrophysics Data System (ADS)

Muthukumar, M.

2001-03-01

Free energy barriers control the translocation of polymers through narrow channels. Based on an analogy with the classical nucleation and growth process, we have calculated the translocation time and its dependencies on the length, stiffness, and sequence of the polymer, solution conditions, and the strength of the driving electrochemical potential gradient. Our predictions will be compared with experimental results and prospects of reading polymer sequences.

The Pedagogical Value of Leo Brouwer's "Etudes Simples": A Perspective on Preserving an Exquisite, Yet Neglected Custom

ERIC Educational Resources Information Center

Kronenberg, Clive W.

2013-01-01

The decline in the status of the classical guitar is, for many, a cause of concern, calling for viable answers to restore its place in the expressive arts tradition. In this article, I explore a pedagogical style specifically intended for young and/or inexperienced players. It is argued that this endeavor could prospectively benefit a range of…

[Physiological aspects of music and longevity].

PubMed

Dymnikowa, M

The article provides an overview of the results of studies on the effect of music on the function of various physiological systems of the organism including the nervous, cardiovascular and endocrine systems, also on the effect of Mozart's music and the later mature Baroque music. Particular attention is paid to information on the influence of different kinds of music (classical, jazz and rock), of the nature and of the degree of musical activity (listeners, amateurs and professional performers) on cognitive and behavioral function, on health status, life expectancy and longevity. Structural acoustical attributes of music defining its treatment effect, are described with the comparison of aspects of rock music and of classical music. The article also considers the prospects for using of music in the treatment and prevention of age-associated diseases.

Restablished Accretion in Post-outburst Classical Novae Revealed by X-rays

NASA Astrophysics Data System (ADS)

Hernanz, Margarita; Ferri, Carlo; Sala, Glòria

2009-05-01

Classical novae are explosions on accreting white dwarfs (hereinafter WDs) in cataclysmic variables (hereinafter CVs) a hydrogen thermonuclear runaway on top of the WD is responsible for the outburst. X-rays provide a unique way to study the turn-off of H-burning, because super soft X-rays reveal the hot WD photosphere, but also to understand how accretion is established again in the binary system. Observations with XMM-Newton of some post-outburst novae have revealed such a process, but a coverage up to larger energies -as Simbol-X will provide- is fundamental to well understand the characteristics of the binary system and of the nova ejecta. We present a brief summary of our results up to now and prospects for the Simbol-X mission.

Quantum Order-by-Disorder in Strongly Correlated Metals

NASA Astrophysics Data System (ADS)

Green, Andrew G.; Conduit, Gareth; Krüger, Frank

2018-03-01

Entropic forces in classical many-body systems, e.g., colloidal suspensions, can lead to the formation of new phases. Quantum fluctuations can have similar effects: spin fluctuations drive the superfluidity of helium-3, and a similar mechanism operating in metals can give rise to superconductivity. It is conventional to discuss the latter in terms of the forces induced by the quantum fluctuations. However, focusing directly upon the free energy provides a useful alternative perspective in the classical case and can also be applied to study quantum fluctuations. Villain first developed this approach for insulating magnets and coined the term order-by-disorder to describe the observed effect. We discuss the application of this idea to metallic systems, recent progress made in doing so, and the broader prospects for the future.

Energy Pooling Upconversion in Free Space and Optical Cavities

NASA Astrophysics Data System (ADS)

LaCount, Michael D.

The ability to efficiently convert the wavelength of light has value in a wide range of disciplines that include the fields of photovoltaics, plant growth, optics and medicine. The processes by which such transformations are carried out are known as upconversions and downconversions. There are several ways to up/down convert light, each with its own attributes, issues, and competing mechanisms. Most are associated with one-body or two-body processes. Three-body dynamics are also possible though, going by the names of quantum cutting (downconversion) and energy pooling (upconversion). These use virtual excited electronic states to mediate conversions as has been experimentally realized using lanthanide ions embedded in wide bandgap materials. The use of lanthanides to convert light is not ideal due to their relative scarcity, toxicity, and the limited range of light frequencies that can be absorbed and emitted. Organic molecules, on the other hand, are typically non-toxic, are made up of abundant elements, and can be designed with tailored spectral properties. At issue is whether or not they can be used to carry out efficient energy pooling, the central question to be answered in this thesis. The research presented here draws on a perturbative quantum electrodynamics framework previously established for generic energy pooling. It was used to develop a computational methodology for determining the rate of energy pooling and its competing processes. This, in turn, draws on a combination of time-dependent density functional theory, quantum electrodynamics, and perturbation theory to generate the requisite material property data. This computational model was applied to two test systems consisting of stilbene-fluorescein and hexabenzocoronene-oligothiophene. The stilbene-fluorescein system was found to have a maximum energy pooling rate efficiency (as compared to competing processes) of 17% and the hexabenzocoronene-oligothiophene system was found to have a maximum energy pooling rate efficiency of 99%. This demonstrates that the energy pooling rate can be made faster than its competing processes. Based on the results of this study, a set of design rules was developed to optimize the rate efficiency of energy pooling. Prior to this research, no attempt had been made to determine if energy pooling could be made to out-pace competing processes--i.e. whether or not a molecular system could be designed to utilize energy pooling as an efficient means of upconversion. This initial investigation was part of a larger effort involving a team of researchers at the University of Colorado, Boulder and at the National Renewable Energy Laboratory. After establishing our computational proof-of-concept, we collectively used the new design rules to select an improved system for energy pooling. This consisted of rhodamine 6G and stilbene-420. These molecules were fabricated into a thin film, and the maximum internal quantum yield was measured to be 36% under sufficiently high intensity light. To further increase the efficiency of energy pooling, encapsulation within optical cavities was considered as a way of changing the rate of processes characterized by electric dipole-dipole coupling. This was carried out using a combination of classical electromagnetism, quantum electrodynamics, and perturbation theory. It was found that, in the near field, if the distance of the energy transfer is smaller than the distance from the energy transfer site and the cavity wall, then the electric dipole-dipole coupling tensor is not influenced by the cavity environment and the rates of energy transfer processes are the same as those in free space. Any increase in energy transfer efficiencies that are experimentally measured must therefore be caused by changing the rate of light absorption and emission. This is an important finding because earlier, less rigorous studies had concluded otherwise. It has been previously demonstrated that an optical cavity can be used to inhibit the spontaneous emission of atoms or molecules placed within it. This too was examined as a possible means of increasing energy pooling efficiency. Using first-principles methods, quantum electrodynamics, perturbation theory, and a kinetic model, the efficiency of energy pooling upconversion within a tuned rectangular cavity was found to be significantly larger than in free space. A model system with a free-space energy pooling upconversion efficiency of 23% was found to increase to 47% when placed in a tuned rectangular cavity.

Some current views on the origins and prospects of correlation optics.

PubMed

Angelsky, O V; Felde, Ch V; Polyanskii, P V

2016-04-20

The state of the art modern branch of optics and photonics now referred to as correlation optics is discussed in connection with both its origins and promising prospects. We use here the term "correlation" not only as a synonym of the term "coherence," but also for emphasizing the necessity of taking into account fine, sometimes enigmatic, phase relations among the components of complex optical fields, even if such fields are conventionally defined as completely coherent. Selection of topics for this brief review of correlation optics outlooks was not dictated by intention of comprehensive representation of this field of research, but rather by the scientific interests of the authors, ranging from classical theory of diffraction, holography, and light-scattering to modern singular optics.

Electrodynamic actuators for rocket engine valves

NASA Technical Reports Server (NTRS)

Fiet, O.; Doshi, D.

1972-01-01

Actuators, employed in acoustic loudspeakers, operate liquid rocket engine valves by replacing light paper cones with flexible metal diaphragms. Comparative analysis indicates better response time than solenoid actuators, and improved service life and reliability.

Applications of Tethers in Space: Workshop Proceedings, Volume 2

NASA Technical Reports Server (NTRS)

Baracat, W. A. (Compiler)

1986-01-01

Topics addressed include: tethered orbital transfer vehicle operations, Centaur and Shuttle tether technology; tethered constellations, gravitational effects; Shuttle continuous open wind tunnel; optimal control laws, electrodynamic tether technology; and space station facilities.

Performance analysis of hybrid vibrational energy harvesters with experimental verification

NASA Astrophysics Data System (ADS)

Sriramdas, Rammohan; Pratap, Rudra

2018-07-01

In the present work, performance indices for a hybrid energy harvester (HEH) that is composed of piezoelectric and electrodynamic or electromagnetic mechanisms of energy conversion are analyzed. Performance of a HEH is defined in terms of Q-normalized power factor and efficiency of conversion. They are observed to acutely depend on coupling strength or figures of merit in both piezoelectric and electrodynamic domains. The influence of figures of merit on the Q-normalized power factor, and the limits of conversion efficiency are explored. Based on the studies, a suitable range for figures of merit that would maximize both Q-normalized power factor and conversion efficiency in hybrid harvesters is proposed. The proposed idea is verified experimentally for the appropriate values of figures of merit and efficiencies by fabricating and testing four experimental models of the HEHs.

Asymmetric DE3 causes WN3 in the ionosphere

NASA Astrophysics Data System (ADS)

Jiang, Jinzhe; Wan, Weixing; Ren, Zhipeng; Yue, Xinan

2018-08-01

This study investigates a mechanism to generate the wavenumber-3 longitude variation in the ionosphere, using the simulations with the Global Coupled Ionosphere Thermosphere Electrodynamics Model, developed by the Institute of Geology and Geophysics, Chinese Academy of Sciences (GCITEM-IGGCAS). Due to the asymmetry of geomagnetic field, the asymmetric Hough mode of diurnal eastward wavenumber-3 (DE3) also produces the WN3 structure in the ionosphere by coupling with the magnetic line. The densities of the neutral mass and the plasmas in the ionosphere are studied in detail. The results show a clear WN3 pattern driven by tide's electro-dynamical coupling. We then conclude that the asymmetric component of the DE3 can also cause the WN3 structure in the ionosphere, which confirms the assumption that more than one source could generate WN3 structure in previous studies.

KSC-2013-3901

NASA Image and Video Library

2013-11-07

CAPE CANAVERAL, Fla. -- Dr. Carlos Calle, senior research scientist on the Electrodynamic Dust Shield for Dust Mitigation project, demonstrates equipment used in his experiments in the Electrostatics and Surface Physics Laboratory in the SwampWorks at NASA's Kennedy Space Center in Florida. Electrodynamic dust shield, or EDS, technology is based on concepts originally developed by NASA as early as 1967 and later by the University of Tokyo. In 2003, NASA, in collaboration with the University of Arkansas at Little Rock, started development of the EDS for dust particle removal from solar panels to be used on future missions to the moon, an asteroid or Mars. A flight experiment to expose the dust shields to the space environment currently is under development. For more information, visit: http://www.nasa.gov/content/scientists-developing-ways-to-mitigate-dust-problem-for-explorers/ Photo credit: NASA/Dan Casper

Electrodynamic Dust Shield for Space Applications

NASA Technical Reports Server (NTRS)

Mackey, Paul J.; Johansen, Michael R.; Olsen, Robert C.; Raines, Matthew G.; Phillips, James R., III; Cox, Rachel E.; Hogue, Michael D.; Pollard, Jacob R. S.; Calle, Carlos I.

2016-01-01

Dust mitigation technology has been highlighted by NASA and the International Space Exploration Coordination Group (ISECG) as a Global Exploration Roadmap (GER) critical technology need in order to reduce life cycle cost and risk, and increase the probability of mission success. The Electrostatics and Surface Physics Lab in Swamp Works at the Kennedy Space Center has developed an Electrodynamic Dust Shield (EDS) to remove dust from multiple surfaces, including glass shields and thermal radiators. Further development is underway to improve the operation and reliability of the EDS as well as to perform material and component testing outside of the International Space Station (ISS) on the Materials on International Space Station Experiment (MISSE). This experiment is designed to verify that the EDS can withstand the harsh environment of space and will look to closely replicate the solar environment experienced on the Moon.

Flux-canceling electrodynamic maglev suspension. Part 1: Test fixture design and modeling

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

Thompson, M.T.; Thornton, R.D.; Kondoleon, A.

1999-05-01

The design and analysis of a scale-model suspension test facility for magnetic levitation (maglev) is discussed. The authors describe techniques for the design, construction, and testing of a prototype electrodynamic suspension (EDS) levitation system. The viability of future high-temperature superconducting magnet designs for maglev has been investigated with regard to their application to active secondary suspensions. In order to test the viability of a new flux-canceling EDS suspension, a 1/5-scale suspension magnet and guideway was constructed. The suspension was tested by using a high-speed rotating test wheel facility with linear peripheral speed of up to 84 m/s (300 km/h). Amore » set of approximate design tools and scaling laws has been developed in order to evaluate forces and critical velocities in the suspension.« less

Magnetized black holes and nonlinear electrodynamics

NASA Astrophysics Data System (ADS)

Kruglov, S. I.

2017-08-01

A new model of nonlinear electrodynamics with two parameters is proposed. We study the phenomenon of vacuum birefringence, the causality and unitarity in this model. There is no singularity of the electric field in the center of pointlike charges and the total electrostatic energy is finite. We obtain corrections to the Coulomb law at r →∞. The weak, dominant and strong energy conditions are investigated. Magnetized charged black hole is considered and we evaluate the mass, metric function and their asymptotic at r →∞ and r → 0. The magnetic mass of the black hole is calculated. The thermodynamic properties and thermal stability of regular black holes are discussed. We calculate the Hawking temperature of black holes and show that there are first-order and second-order phase transitions. The parameters of the model when the black hole is stable are found.

Modelling of electron beam induced nanowire attraction

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

Bitzer, Lucas A.; Benson, Niels, E-mail: niels.benson@uni-due.de; Schmechel, Roland

2016-04-14

Scanning electron microscope (SEM) induced nanowire (NW) attraction or bundling is a well known effect, which is mainly ascribed to structural or material dependent properties. However, there have also been recent reports of electron beam induced nanowire bending by SEM imaging, which is not fully explained by the current models, especially when considering the electro-dynamic interaction between NWs. In this article, we contribute to the understanding of this phenomenon, by introducing an electro-dynamic model based on capacitor and Lorentz force interaction, where the active NW bending is stimulated by an electromagnetic force between individual wires. The model includes geometrical, electrical,more » and mechanical NW parameters, as well as the influence of the electron beam source parameters and is validated using in-situ observations of electron beam induced GaAs nanowire (NW) bending by SEM imaging.« less

Force-free electrodynamics in dynamical curved spacetimes

NASA Astrophysics Data System (ADS)

McWilliams, Sean

2015-04-01

We present results on our study of force-free electrodynamics in curved spacetimes. Specifically, we present several improvements to what has become the established set of evolution equations, and we apply these to study the nonlinear stability of analytically known force-free solutions for the first time. We implement our method in a new pseudo-spectral code built on top of the SpEC code for evolving dynamic spacetimes. Finally, we revisit these known solutions and attempt to clarify some interesting properties that render them analytically tractable. Finally, we preview some new work that similarly revisits the established approach to solving another problem in numerical relativity: the post-merger recoil from asymmetric gravitational-wave emission. These new results may have significant implications for the parameter dependence of recoils, and consequently on the statistical expectations for recoil velocities of merged systems.

A thermosphere-ionosphere-mesosphere-electrodynamic general circulation model (time-GCM): Equinox solar cycle minimum simulations (30-500 km)

NASA Technical Reports Server (NTRS)

Roble, R. G.; Ridley, E. C.

1994-01-01

A new simulation model of the mesosphere, thermosphere, and ionosphere with coupled electrodynamics has been developed and used to calculate the global circulation, temperature and compositional structure between 30-500 km for equinox, solar cycle minimum, geomagnetic quiet conditions. The model incorporates all of the features of the National Center for Atmospheric Research (NCAR) thermosphere-ionosphere- electrodynamics general circulation model (TIE-GCM) but the lower boundary has been extended downward from 97 to 30 km (10 mb) and it includes the physical and chemical processes appropriate for the mesosphere and upper stratosphere. The first simulation used Rayleigh friction to represent gravity wave drag in the middle atmosphere and although it was able to close the mesospheric jets it severely damped the diurnal tide. Reduced Rayleigh friction allowed the tide to penetrate to thermospheric heights but did not close the jets. A gravity wave parameterization developed by Fritts and Lu (1993) allows both features to exist simultaneously with the structure of tides and mean flow dependent upon the strength of the gravity wave source. The model calculates a changing dynamic structure with the mean flow and diurnal tide dominant in the mesosphere, the in-situ generated semi-diurnal tide dominating the lower thermosphere and an in-situ generated diurnal tide in the upper thermosphere. The results also show considerable interaction between dynamics and composition, especially atomic oxygen between 85 and 120 km.

Propulsive Small Expendable Deployer System (ProSEDS)

NASA Technical Reports Server (NTRS)

Curtis, Leslie; Johnson, Les; Brown, Norman S. (Technical Monitor)

2002-01-01

The Propulsive Small Expendable Deployer System (ProSEDS) space experiment will demonstrate the use of an electrodynamic tether propulsion system to generate thrust in space by decreasing the orbital altitude of a Delta 11 Expendable Launch Vehicle second stage. ProSEDS, which is planned on an Air Force GPS Satellite replacement mission in June 2002, will use the flight proven Small Expendable Deployer System (SEDS) to deploy a tether (5 km bare wire plus 10 km non-conducting Dyneema) from a Delta 11 second stage to achieve approx. 0.4N drag thrust. ProSEDS will utilize the tether-generated current to provide limited spacecraft power. The ProSEDS instrumentation includes Langmuir probes and Differential Ion Flux Probes, which will determine the characteristics of the ambient ionospheric plasma. Two Global Positioning System (GPS) receivers will be used (one on the Delta and one on the endmass) to help determine tether dynamics and to limit transmitter operations to occasions when the spacecraft is over selected ground stations. The flight experiment is a precursor to the more ambitious electrodynamic tether upper stage demonstration mission, which will be capable of orbit raising, lowering and inclination changes-all using electrodynamic thrust. An immediate application of ProSEDS technology is for the removal of spent satellites for orbital debris mitigation. In addition to the use of this technology to provide orbit transfer and debris mitigation it may also be an attractive option for future missions to Jupiter and any other planetary body with a magnetosphere.

Propulsive Small Expendable Deployer System (ProSEDS)

NASA Technical Reports Server (NTRS)

Ballance, Judy; Johnson, Les; Rogacki, John R. (Technical Monitor)

2000-01-01

The Propulsive Small Expendable Deployer System (ProSEDS) space experiment will demonstrate the use of an electrodynamic tether propulsion system to generate thrust in space by decreasing the orbital altitude of a Delta II Expendable Launch Vehicle (ELV) second stage. ProSEDS, which is planned to fly in 2001, will use the flight proven Small Expendable Deployer System (SEDS) to deploy a tether (5km bare wire plus 10 km spectra or dyneema) from a Delta II second stage to achieve approximately 0.4N drag thrust. ProSEDS will utilize the tether-generated current to provide limited spacecraft power. The ProSEDs instrumentation includes a Langmuir probe and Differential Ion Flux Probe, which will determine the characteristics of the ambient ionospheric plasma. Two Global Positioning System (GPS) receivers will be used (one on the Delta and one on the endmass) to help determine tether dynamics and to limit transmitter operations to occasions when the spacecraft is over selected ground stations, The flight experiment is a precursor to the more ambitious electrodynamic tether upper stage demonstration mission, which will be capable of orbit raising, lowering and inclination changes-all using electrodynamic thrust. An immediate application of ProSEDS technology is for the deorbit of spent satellites for orbital debris mitigation. In addition to the use of this technology to provide orbit transfer and debris mitigation it may also be an attractive option for future missions to Jupiter and any other planetary body with a magnetosphere.

Economic decision-making compared with an equivalent motor task.

PubMed

Wu, Shih-Wei; Delgado, Mauricio R; Maloney, Laurence T

2009-04-14

There is considerable evidence that human economic decision-making deviates from the predictions of expected utility theory (EUT) and that human performance conforms to EUT in many perceptual and motor decision tasks. It is possible that these results reflect a real difference in decision-making in the 2 domains but it is also possible that the observed discrepancy simply reflects typical differences in experimental design. We developed a motor task that is mathematically equivalent to choosing between lotteries and used it to compare how the same subject chose between classical economic lotteries and the same lotteries presented in equivalent motor form. In experiment 1, we found that subjects are more risk seeking in deciding between motor lotteries. In experiment 2, we used cumulative prospect theory to model choice and separately estimated the probability weighting functions and the value functions for each subject carrying out each task. We found no patterned differences in how subjects represented outcome value in the motor and the classical tasks. However, the probability weighting functions for motor and classical tasks were markedly and significantly different. Those for the classical task showed a typical tendency to overweight small probabilities and underweight large probabilities, and those for the motor task showed the opposite pattern of probability distortion. This outcome also accounts for the increased risk-seeking observed in the motor tasks of experiment 1. We conclude that the same subject distorts probability, but not value, differently in making identical decisions in motor and classical form.

Outcomes of liver-first strategy and classical strategy for synchronous colorectal liver metastases in Sweden.

PubMed

Valdimarsson, Valentinus T; Syk, Ingvar; Lindell, Gert; Norén, Agneta; Isaksson, Bengt; Sandström, Per; Rizell, Magnus; Ardnor, Bjarne; Sturesson, Christian

2018-05-01

Patients with synchronous colorectal liver metastases (sCRLM) are increasingly operated with liver resection before resection of the primary cancer. The aim of this study was to compare outcomes in patients following the liver-first strategy and the classical strategy (resection of the bowel first) using prospectively registered data from two nationwide registries. Clinical, pathological and survival outcomes were compared between the liver-first strategy and the classical strategy (2008-2015). Overall survival was calculated. A total of 623 patients were identified, of which 246 were treated with the liver-first strategy and 377 with the classical strategy. The median follow-up was 40 months. Patients chosen for the classical strategy more often had T4 primary tumours (23% vs 14%, P = 0.012) and node-positive primaries (70 vs 61%, P = 0.015). The liver-first patients had a higher liver tumour burden score (4.1 (2.5-6.3) vs 3.6 (2.2-5.1), P = 0.003). No difference was seen in five-year overall survival between the groups (54% vs 49%, P = 0.344). A majority (59%) of patients with rectal cancer were treated with the liver-first strategy. The liver-first strategy is currently the dominant strategy for sCRLM in patients with rectal cancer in Sweden. No difference in overall survival was noted between strategies. Copyright © 2017 International Hepato-Pancreato-Biliary Association Inc. Published by Elsevier Ltd. All rights reserved.

Schrödinger-Poisson-Vlasov-Poisson correspondence

NASA Astrophysics Data System (ADS)

Mocz, Philip; Lancaster, Lachlan; Fialkov, Anastasia; Becerra, Fernando; Chavanis, Pierre-Henri

2018-04-01

The Schrödinger-Poisson equations describe the behavior of a superfluid Bose-Einstein condensate under self-gravity with a 3D wave function. As ℏ/m →0 , m being the boson mass, the equations have been postulated to approximate the collisionless Vlasov-Poisson equations also known as the collisionless Boltzmann-Poisson equations. The latter describe collisionless matter with a 6D classical distribution function. We investigate the nature of this correspondence with a suite of numerical test problems in 1D, 2D, and 3D along with analytic treatments when possible. We demonstrate that, while the density field of the superfluid always shows order unity oscillations as ℏ/m →0 due to interference and the uncertainty principle, the potential field converges to the classical answer as (ℏ/m )2. Thus, any dynamics coupled to the superfluid potential is expected to recover the classical collisionless limit as ℏ/m →0 . The quantum superfluid is able to capture rich phenomena such as multiple phase-sheets, shell-crossings, and warm distributions. Additionally, the quantum pressure tensor acts as a regularizer of caustics and singularities in classical solutions. This suggests the exciting prospect of using the Schrödinger-Poisson equations as a low-memory method for approximating the high-dimensional evolution of the Vlasov-Poisson equations. As a particular example we consider dark matter composed of ultralight axions, which in the classical limit (ℏ/m →0 ) is expected to manifest itself as collisionless cold dark matter.

Computational algorithms dealing with the classical and statistical mechanics of celestial scale polymers in space elevator technology

NASA Astrophysics Data System (ADS)

Knudsen, Steven; Golubovic, Leonardo

Prospects to build Space Elevator (SE) systems have become realistic with ultra-strong materials such as carbon nano-tubes and diamond nano-threads. At cosmic length-scales, space elevators can be modeled as polymer like floppy strings of tethered mass beads. A new venue in SE science has emerged with the introduction of the Rotating Space Elevator (RSE) concept supported by novel algorithms discussed in this presentation. An RSE is a loopy string reaching into outer space. Unlike the classical geostationary SE concepts of Tsiolkovsky, Artsutanov, and Pearson, our RSE exhibits an internal rotation. Thanks to this, objects sliding along the RSE loop spontaneously oscillate between two turning points, one of which is close to the Earth whereas the other one is in outer space. The RSE concept thus solves a major problem in SE technology which is how to supply energy to the climbers moving along space elevator strings. The investigation of the classical and statistical mechanics of a floppy string interacting with objects sliding along it required development of subtle computational algorithms described in this presentation

Quantum chemistry simulation on quantum computers: theories and experiments.

PubMed

Lu, Dawei; Xu, Boruo; Xu, Nanyang; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng

2012-07-14

It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.

Significantly worse survival of patients with NIH-defined chronic graft-versus-host disease and thrombocytopenia or progressive onset type: results of a prospective study.

PubMed

Kuzmina, Z; Eder, S; Böhm, A; Pernicka, E; Vormittag, L; Kalhs, P; Petkov, V; Stary, G; Nepp, J; Knobler, R; Just, U; Krenn, K; Worel, N; Greinix, H T

2012-04-01

Chronic graft-versus-host disease (GVHD) remains a serious complication after allogeneic hematopoietic stem cell transplantation (HCT). In 2005 the National Institutes of Health (NIH) established new criteria for chronic GVHD based on retrospective data and expert recommendations. We prospectively evaluated the incidence of NIH-defined chronic GVHD and its prognostic impact in 178 consecutive patients. The cumulative incidence of chronic GVHD at 3 years was 64, 48 and 16% for chronic classic GVHD and overlap syndrome. Prior acute GVHD and myeloablative conditioning were significantly associated with increased risk of chronic GVHD. Three-year survival (overall survival (OS)) for late-acute GVHD, chronic classic and overlap chronic GVHD when assigned on day 100 were 69, 83 and 73%. OS was significantly worse for patients with platelet counts below 100 g/l at onset of chronic GVHD (35% versus 86%, P<0.0001) and progressive as compared with de novo and quiescent onset of chronic GVHD (54.5% versus 89.5% versus 84%, P = 0.022 and 0.001). Peak severity of chronic GVHD had no impact on non-relapse mortality (NRM) and OS. Recurrent acute GVHD, platelet counts below 100 g/l at diagnosis of chronic GVHD, progressive onset of chronic GVHD and advanced disease stage prior to HCT were significantly associated with increased NRM. This prospective analysis provides for the first-time data on the incidence rates of NIH-defined chronic GVHD categories and identified risk factors for the occurrence of chronic GVHD. A prognostic value of thrombocytopenia and progressive onset type of chronic GVHD for survival after HCT was observed in NIH-defined chronic GVHD.

Comparison of 2 cuff inflation methods of laryngeal mask airway Classic for safe use without cuff manometer in adults.

PubMed

Kim, Min-Soo; Lee, Jeong-Rim; Shin, Yang-Sik; Chung, Ji-Won; Lee, Kyu-Ho; Ahn, Ki Ryang

2014-03-01

This single-center, prospective, randomized, double-blind, 2-arm, parallel group comparison trial was performed to establish whether the adult-sized laryngeal mask airway (LMA) Classic (The Laryngeal Mask Company Ltd, Henley-on-Thames, UK) could be used safely without any consideration of cuff hyperinflation when a cuff of the LMA Classic was inflated using half the maximum inflation volume or the resting volume before insertion of device. Eighty patients aged 20 to 70 years scheduled for general anesthesia using the LMA Classic were included. Before insertion, the cuff was partially filled with half the maximum inflation volume in the half volume group or the resting volume created by opening the pilot balloon valve to equalize with atmospheric pressure in the resting volume group. Several parameters regarding insertion, intracuff pressure, airway leak pressure, and leakage volume/fraction were collected after LMA insertion. The LMA Classic with a partially inflated cuff was successfully inserted in all enrolled patients. Both groups had the same success rate of 95% at the first insertion attempt. The half volume group had a lower mean intracuff pressure compared with the resting volume group (54.5 ± 16.1 cm H2O vs 61.8 ± 16.1 cm H2O; P = .047). There was no difference in airway leak pressure or leakage volume/fraction between the 2 groups under mechanical ventilation. The partially inflated cuff method using half the maximum recommended inflation volume or the resting volume is feasible with the adult-sized LMA Classic, resulting in a high success rate of insertion and adequate range of intracuff pressures. Copyright © 2014 Elsevier Inc. All rights reserved.

Morphology dependent near-field response in atomistic plasmonic nanocavities.

PubMed

Chen, Xing; Jensen, Lasse

2018-06-21

In this work we examine how the atomistic morphologies of plasmonic dimers control the near-field response by using an atomistic electrodynamics model. At large separations, the field enhancement in the junction follows a simple inverse power law as a function of the gap separation, which agrees with classical antenna theory. However, when the separations are smaller than 0.8 nm, the so-called quantum size regime, the field enhancement is screened and thus deviates from the simple power law. Our results show that the threshold distance for the deviation depends on the specific morphology of the junction. The near field in the junction can be localized to an area of less than 1 nm2 in the presence of an atomically sharp tip, but the separation distances leading to a large confinement of near field depend strongly on the specific atomistic configuration. More importantly, the highly confined fields lead to large field gradients particularly in a tip-to-surface junction, which indicates that such a plasmonic structure favors observing strong field gradient effects in near-field spectroscopy. We find that for atomically sharp tips the field gradient becomes significant and depends strongly on the local morphology of a tip. We expect our findings to be crucial for understanding the origin of high-resolution near-field spectroscopy and for manipulating optical cavities through atomic structures in the strongly coupled plasmonic systems.

Preparation and measurement of three-qubit entanglement in a superconducting circuit.

PubMed

Dicarlo, L; Reed, M D; Sun, L; Johnson, B R; Chow, J M; Gambetta, J M; Frunzio, L; Girvin, S M; Devoret, M H; Schoelkopf, R J

2010-09-30

Traditionally, quantum entanglement has been central to foundational discussions of quantum mechanics. The measurement of correlations between entangled particles can have results at odds with classical behaviour. These discrepancies grow exponentially with the number of entangled particles. With the ample experimental confirmation of quantum mechanical predictions, entanglement has evolved from a philosophical conundrum into a key resource for technologies such as quantum communication and computation. Although entanglement in superconducting circuits has been limited so far to two qubits, the extension of entanglement to three, eight and ten qubits has been achieved among spins, ions and photons, respectively. A key question for solid-state quantum information processing is whether an engineered system could display the multi-qubit entanglement necessary for quantum error correction, which starts with tripartite entanglement. Here, using a circuit quantum electrodynamics architecture, we demonstrate deterministic production of three-qubit Greenberger-Horne-Zeilinger (GHZ) states with fidelity of 88 per cent, measured with quantum state tomography. Several entanglement witnesses detect genuine three-qubit entanglement by violating biseparable bounds by 830 ± 80 per cent. We demonstrate the first step of basic quantum error correction, namely the encoding of a logical qubit into a manifold of GHZ-like states using a repetition code. The integration of this encoding with decoding and error-correcting steps in a feedback loop will be the next step for quantum computing with integrated circuits.

Implementation of single-photon quantum routing and decoupling using a nitrogen-vacancy center and a whispering-gallery-mode resonator-waveguide system.

PubMed

Cao, Cong; Duan, Yu-Wen; Chen, Xi; Zhang, Ru; Wang, Tie-Jun; Wang, Chuan

2017-07-24

Quantum router is a key element needed for the construction of future complex quantum networks. However, quantum routing with photons, and its inverse, quantum decoupling, are difficult to implement as photons do not interact, or interact very weakly in nonlinear media. In this paper, we investigate the possibility of implementing photonic quantum routing based on effects in cavity quantum electrodynamics, and present a scheme for single-photon quantum routing controlled by the other photon using a hybrid system consisting of a single nitrogen-vacancy (NV) center coupled with a whispering-gallery-mode resonator-waveguide structure. Different from the cases in which classical information is used to control the path of quantum signals, both the control and signal photons are quantum in our implementation. Compared with the probabilistic quantum routing protocols based on linear optics, our scheme is deterministic and also scalable to multiple photons. We also present a scheme for single-photon quantum decoupling from an initial state with polarization and spatial-mode encoding, which can implement an inverse operation to the quantum routing. We discuss the feasibility of our schemes by considering current or near-future techniques, and show that both the schemes can operate effectively in the bad-cavity regime. We believe that the schemes could be key building blocks for future complex quantum networks and large-scale quantum information processing.

How does the plasmonic enhancement of molecular absorption depend on the energy gap between molecular excitation and plasmon modes: a mixed TDDFT/FDTD investigation.

PubMed

Sun, Jin; Li, Guang; Liang, WanZhen

2015-07-14

A real-time time-dependent density functional theory coupled with the classical electrodynamics finite difference time domain technique is employed to systematically investigate the optical properties of hybrid systems composed of silver nanoparticles (NPs) and organic adsorbates. The results demonstrate that the molecular absorption spectra throughout the whole energy range can be enhanced by the surface plasmon resonance of Ag NPs; however, the absorption enhancement ratio (AER) for each absorption band differs significantly from the others, leading to the quite different spectral profiles of the hybrid complexes in contrast to those of isolated molecules or sole NPs. Detailed investigations reveal that the AER is sensitive to the energy gap between the molecular excitation and plasmon modes. As anticipated, two separate absorption bands, corresponding to the isolated molecules and sole NPs, have been observed at a large energy gap. When the energy gap approaches zero, the molecular excitation strongly couples with the plasmon mode to form the hybrid exciton band, which possesses the significantly enhanced absorption intensity, a red-shifted peak position, a surprising strongly asymmetric shape of the absorption band, and the nonlinear Fano effect. Furthermore, the dependence of surface localized fields and the scattering response functions (SRFs) on the geometrical parameters of NPs, the NP-molecule separation distance, and the external-field polarizations has also been depicted.

The R.I. Pimenov unified gravitation and electromagnetism field theory as semi-Riemannian geometry

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

Gromov, N. A., E-mail: gromov@dm.komisc.r

2009-05-15

More than forty years ago R.I. Pimenov introduced a new geometry-semi-Riemannian one-as a set of geometrical objects consistent with a fibering pr: M{sub n} {yields} M{sub m}. He suggested the heuristic principle according to which the physically different quantities (meter, second, Coulomb, etc.) are geometrically modelled as space coordinates that are not superposed by automorphisms. As there is only one type of coordinates in Riemannian geometry and only three types of coordinates in pseudo-Riemannian one, a multiple-fibered semi-Riemannian geometry is the most appropriate one for the treatment of more than three different physical quantities as unified geometrical field theory. Semi-Euclideanmore » geometry {sup 3}R{sub 5}{sup 4} with 1-dimensional fiber x{sup 5} and 4-dimensional Minkowski space-time as a base is naturally interpreted as classical electrodynamics. Semi-Riemannian geometry {sup 3}V{sub 5}{sup 4} with the general relativity pseudo-Riemannian space-time {sup 3}V{sub 4}, and 1-dimensional fiber x{sup 5}, responsible for the electromagnetism, provides the unified field theory of gravitation and electromagnetism. Unlike Kaluza-Klein theories, where the fifth coordinate appears in nondegenerate Riemannian or pseudo-Riemannian geometry, the theory based on semi-Riemannian geometry is free from defects of the former. In particular, scalar field does not arise.« less

Fuzzy correlation analysis with realization

NASA Astrophysics Data System (ADS)

Tang, Yue Y.; Fan, Xinrui; Zheng, Ying N.

1998-10-01

The fundamental concept of fuzzy correlation is briefly discussed. Based on the correlation coefficient of classic correlation, polarity correlation and fuzzy correlation, the relationship between the correlations are analyzed. A fuzzy correlation analysis has the merits of both rapidity and accuracy as some amplitude information of random signals has been utilized. It has broad prospects for application. The form of fuzzy correlative analyzer with NLX 112 fuzzy data correlator and single-chip microcomputer is introduced.

Characteristic functions of quantum heat with baths at different temperatures

NASA Astrophysics Data System (ADS)

Aurell, Erik

2018-06-01

This paper is about quantum heat defined as the change in energy of a bath during a process. The presentation takes into account recent developments in classical strong-coupling thermodynamics and addresses a version of quantum heat that satisfies quantum-classical correspondence. The characteristic function and the full counting statistics of quantum heat are shown to be formally similar. The paper further shows that the method can be extended to more than one bath, e.g., two baths at different temperatures, which opens up the prospect of studying correlations and heat flow. The paper extends earlier results on the expected quantum heat in the setting of one bath [E. Aurell and R. Eichhorn, New J. Phys. 17, 065007 (2015), 10.1088/1367-2630/17/6/065007; E. Aurell, Entropy 19, 595 (2017), 10.3390/e19110595].

Steroid hormone and epidermal growth factor receptors in meningiomas.

PubMed

Horsfall, D J; Goldsmith, K G; Ricciardelli, C; Skinner, J M; Tilley, W D; Marshall, V R

1989-11-01

A prospective study of steroid hormone and epidermal growth factor receptor expression in 57 meningiomas is presented. Scatchard analysis of radioligand binding identified 20% of meningiomas as expressing classical oestrogen receptors (ER) at levels below that normally accepted for positivity, the remainder being negative. ER could not be visualized in any meningioma using immunocytochemistry. Alternatively, 74% of meningiomas demonstrated the presence of progesterone receptors (PR) by Scatchard analysis, the specificity of which could not be attributed to glucocorticoid or androgen receptors. Confirmation of classical PR presence was determined by immunocytochemical staining. The presence of epidermal growth factor receptor (EGFR) was demonstrated in 100% of meningiomas using immunocytochemical staining. These data are reviewed in the context of previously reported results and are discussed in relation to the potential for medical therapy as an adjunct to surgery.

Structural, biochemical and non-traditional cardiovascular risk markers in PCOS.

PubMed

Christakou, Charikleia; Diamanti-Kandarakis, Evanthia

2013-01-01

Polycystic ovary syndrome (PCOS) is a heterogeneous syndrome of reproductive and metabolic derangements. The combination of anovulation and hyperandrogenism signifies the classic form of PCOS which displays the adverse metabolic phenotype of the syndrome. This phenotype includes visceral obesity and insulin resistance as well as a constellation of other traditional cardiovascular risk factors, mainly low grade inflammation, disturbances of glucose metabolism and dyslipidemia. The resultant increased risk for cardiovascular disease may affect not only obese but also lean women with classic PCOS. The mechanisms underlying the increased cardiovascular risk in the context of PCOS may include not only metabolic aberrations, but also hormonal factors, in particular hyperandrogenemia. However, the consequences in terms of CV morbidity remain questionable due to the difficulties in conducting long-term, prospective studies aimed at identifying potential late-arriving clinical outcomes.

Quantum Optics with Superconducting Circuits: From Single Photons to Schrodinger Cats

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

Schoelkopf, Rob

Over the last decade and a half, superconducting circuits have advanced to the point where we can generate and detect highly-entangled states, and perform universal quantum gates. Meanwhile, the coherence properties of these systems have improved more than 10,000-fold. I will describe recent experiments, such as the latest advance in coherence using a three-dimensional implementation of qubits interacting with microwave cavities, called “3D circuit QED.” The control and strong interactions possible in superconducting circuits make it possible to generate non-classical states of light, including large superpositions known as “Schrodinger cat” states. This field has many interesting prospects both for applicationsmore » in quantum information processing, and fundamental investigations of the boundary between the macroscopic classical world and the microscopic world of the quantum.« less

Dark matter from a classically scale-invariant S U (3 )X

NASA Astrophysics Data System (ADS)

Karam, Alexandros; Tamvakis, Kyriakos

2016-09-01

In this work we study a classically scale-invariant extension of the Standard Model in which the dark matter and electroweak scales are generated through the Coleman-Weinberg mechanism. The extra S U (3 )X gauge factor gets completely broken by the vacuum expectation values of two scalar triplets. Out of the eight resulting massive vector bosons the three lightest are stable due to an intrinsic Z2×Z2' discrete symmetry and can constitute dark matter candidates. We analyze the phenomenological viability of the predicted multi-Higgs sector imposing theoretical and experimental constraints. We perform a comprehensive analysis of the dark matter predictions of the model solving numerically the set of coupled Boltzmann equations involving all relevant dark matter processes and explore the direct detection prospects of the dark matter candidates.

Middle Atmosphere Program. Handbook for MAP, Volume 7

NASA Technical Reports Server (NTRS)

Sechrist, C. F., Jr. (Editor)

1982-01-01

Completed and proposed research relating to the Middle Atmosphere Program is discussed. Emphasis is given to the winters in the Northern Hemisphere, the equatorial atmosphere, meteor observation, solar irradiance, atmospheric temperature, geopotential height, atmospheric circulation, and electrodynamics.

On μe-scattering at NNLO in QED

NASA Astrophysics Data System (ADS)

Mastrolia, P.; Passera, M.; Primo, A.; Schubert, U.; Torres Bobadilla, W. J.

2018-05-01

We report on the current status of the analytic evaluation of the two-loop corrections to the μescattering in Quantum Electrodynamics, presenting state-of-the art techniques which have been developed to address this challenging task.

Metallic phases from disordered (2+1)-dimensional quantum electrodynamics

DOE PAGES

Goswami, Pallab; Goldman, Hart; Raghu, S.

2017-06-15

Metallic phases have been observed in several disordered two-dimensional (2D) systems, including thin films near superconductor-insulator transitions and quantum Hall systems near plateau transitions. The existence of 2D metallic phases at zero temperature generally requires an interplay of disorder and interaction effects. Consequently, experimental observations of 2D metallic behavior have largely defied explanation. We formulate a general stability criterion for strongly interacting, massless Dirac fermions against disorder, which describe metallic ground states with vanishing density of states. We show that (2+1)-dimensional quantum electrodynamics (QED 3) with a large, even number of fermion flavors remains metallic in the presence of weakmore » scalar potential disorder due to the dynamic screening of disorder by gauge fluctuations. In conclusion, we also show that QED 3 with weak mass disorder exhibits a stable, dirty metallic phase in which both interactions and disorder play important roles.« less

Weber electrodynamics, part I. general theory, steady current effects

NASA Astrophysics Data System (ADS)

Wesley, J. P.

1990-10-01

The original Weber action at a distance theory, valid for slowly varying effects, is extended to time-retarded fields, valid for rapidly varying effects including radiation. A new law for the force on a charge moving in this field is derived (replacing the Lorentz force which violates Newton's third law). The limitations of the Maxwell theory are discussed. The Weber theory, in addition to predicting all of the usual electrodynamic results, predicts the following crucial results for slowly varying effects (where Maxwell theory fails): 1) the force on Ampere's bridge in agreement with the measurements of Moyssides and Pappas, 2) the tension required to rupture current carrying wires as observed by Graneau, 3) the force to drive the Graneau-Hering submarine, 4) the force to drive the mercury in Hering's pump, and 5) the force to drive the oscillations in a current carrying mercury wedge as observed by Phipps.

On equilibrium positions and stabilization of electrodynamic tether system in the orbital frame

NASA Astrophysics Data System (ADS)

Tikhonov, A. A.; Shcherbakova, L. F.

2018-05-01

An electrodynamic tether system (EDTS) in a near-Earth circular orbit is considered. EDTS contains conductive tether with lumped masses attached to it at the ends. Possible equilibrium positions of the stretched tether under the influence of gravity gradient, Ampere and Lorentz forces in orbital frame are investigated. It is shown that in addition to the vertical equilibrium position, the "inclined" equilibrium positions of the tensioned tether are also possible. Conditions are obtained for the EDTS parameters, under which there is only one vertical position of the tether equilibrium. On the basis of nonlinear differential equations of motion, using the Lyapunov functions method, sufficient conditions for the stability of the vertical position of the tether equi-librium are obtained. It is shown that stabilization of the tether in this position is possible in the presence of damping in the EDTS system. The results of numerical simulation are presented.