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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

QED with the electron as a very small black-hole-like object

We pursue a simple semi-classical particle-based picture of QED in which the electron is assumed to contain a point massless and chargeless core that interacts with the electromagnetic vacuum in ways that are not dissimilar to the manner in which small black holes may interact with photons. Modifications are made to obtain known properties of the electron including the presence of rest energy, Lamb shift, magnetic moments (both free and bound), charge, Larmor emission, and vacuum polarization. The present study does not provide proofs but is rather an attempt to reverse-engineer the photon-electron and black-hole-electron interaction properties needed to match experimental observations. The ease by which many QED observables can be reproduced suggests further study of the presented framework may be warranted. Future detailed analysis of the exchange of long wavelength Hawking radiation between a pair of small black holes will be of particular interest.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

K{sub l3{gamma}}{sup +} decays revisited: Branching ratios and T-ODD momenta correlations

We calculate the branching ratios of the K{sup +} {yields} {pi}{sup 0}l{sup +}{nu}{sub l{gamma}} (l = e, Micro-Sign ) decays, and the T-odd triple momenta correlations {xi} = q {center_dot} [p{sub l} Multiplication-Sign p{sub {pi}}]/M{sub K}{sup 3}, due to the electromagnetic final-state interaction, in these processes. The contributions on the order of {omega}{sup -1} and {omega}{sup 0} to the corresponding amplitudes are treated exactly. For the branching ratios, the corrections on the order of {omega} are estimated and demonstrated to be small. We compare the results with those of other authors. In some cases our results differ considerably from the previous ones.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

Interactions for massive mixed symmetry field

Here we give a first two examples of non-trivial interactions for simplest massive mixed symmetry field (hook) in general (A ) dS space with arbitrary value of cosmological constant including flat Minkowski space. For that purpose using frame-like gauge invariant description of massive higher spin particles we extend Fradkin-Vasiliev approach initially developed for investigations of gravitational and other interactions for massless higher spin particles in AdS space to the case of arbitrary combinations of massive and/or massless particles including e.g. electromagnetic and gravitational interactions for massive higher spin ones.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Tunable Three-Body Loss in a Nonlinear Rydberg Medium

Long-range Rydberg interactions, in combination with electromagnetically induced transparency (EIT), give rise to strongly interacting photons where the strength, sign, and form of the interactions are widely tunable and controllable. Such control can be applied to both coherent and dissipative interactions, which provides the potential for generating novel few-photon states. Recently it has been shown that Rydberg-EIT is a rare system in which three-body interactions can be as strong or stronger than two-body interactions. In this work, we study three-body scattering loss for Rydberg-EIT in a wide regime of single and two-photon detunings. We report our numerical simulations of the full three-body wave function and analytical estimates based on Fermi’s golden rule strongly suggest that the observed features in the outgoing photonic correlations are caused by the resonant enhancement of the three-body losses.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2018

Mössbauer Studies and the Microwave Properties of Al{sup 3+}- and In{sup 3+}-Substituted Barium Hexaferrites

The correlation of the chemical composition, the structure, and the microwave characteristic of solid solutions of the BaFe{sub 12–x}D{sub x}O{sub 19} (0.1 ≤ x ≤ 1.2) barium hexaferrite substituted with diamagnetic Al{sup 3+} and In{sup 3+} ions has been studied. The precise data on the crystal structure have been obtained by powder neutron diffraction using a high-resolution Fourier diffractometer (Dubna, JINR). The data on the distribution of the diamagnetic substituting ions in the hexaferrite structure have been obtained by Mössbauer spectroscopy. The microwave properties (the transmittance and the reflectance) have been studied in the frequency range 20–65 GHz and in external magnetic fields to 8 kOe. It is found that the transmission spectra are characterized by a peak that corresponds to the resonant frequency of the electromagnetic energy absorption, which is due to the ferromagnetic resonance phenomenon. The correlation of the chemical composition, the features of the ion distribution in the structure, and the electromagnetic properties has been revealed. It is shown that external magnetic fields shift the absorption peak of electromagnetic radiation to higher frequencies due to an increase in the magnetocrystal anisotropy. The results enable the conclusion that the features of the intrasublattice interactions and the electromagnetic properties should be explained using the phenomenological Goodenough–Kanamori model.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Nonlinear dispersion and transverse profile of intense electromagnetic waves, propagating through electron-positron-ion hot magnetoplasma

Self-guided nonlinear propagation of intense circularly-polarized electromagnetic waves in a hot electron-positron-ion magnetoplasma is studied. Using a relativistic fluid model, a nonlinear equation is derived, which describes the interaction of the electromagnetic wave with the plasma in the quasi-neutral approximation. Transverse Eigen modes, the nonlinear dispersion relation and the group velocity are obtained. Results show that the transverse profile in the case of magnetized plasma with cylindrical symmetry has a radially damping oscillatory form. Effect of applying external magnetic fields, existence of the electron-positron pairs, changing the amplitude of the electromagnetic wave, and its polarization on the nonlinear dispersion relation and Eigen modes are studied.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Nonlinear susceptibilities for weakly turbulent magnetized plasma: Electromagnetic formalism

This is a companion paper to the previous work [P. H. Yoon, Phys. Plasmas 31, 032309 (2024)] in which the nonlinear susceptibilities of weakly turbulent magnetized plasma are derived under a simplifying assumption of electrostatic interaction. The present paper extends the analysis to a general situation of electromagnetic interaction. The main novelty of the previous and present papers is that by employing the Bessel function addition theorem, the mathematical definitions for the susceptibilities are substantially simplified, a procedure that has not been discussed in the existing literature. In the present paper, a full set of Maxwell’s equations are considered in conjunction with the nonlinear Vlasov equation, which is solved by a perturbative method. The result is a fully general nonlinear susceptibility, given in tensorial form, which is applicable for weakly turbulent magnetized plasmas.

Materials Science↗
DOE OSTI2016

Materials perspective on Casimir and van der Waals interactions

Interactions induced by electromagnetic fluctuations, such as van der Waals and Casimir forces, are of universal nature present at any length scale between any types of systems. In such interactions these are important not only for the fundamental science of materials behavior, but also for the design and improvement of micro- and nanostructured devices. In the past decade, many new materials have become available, which has stimulated the need for understanding their dispersive interactions. The field of van der Waals and Casimir forces has experienced an impetus in terms of developing novel theoretical and computational methods to provide new insights into related phenomena. The understanding of such forces has far reaching consequences as it bridges concepts in materials, atomic and molecular physics, condensed-matter physics, high-energy physics, chemistry, and biology. Our review summarizes major breakthroughs and emphasizes the common origin of van der Waals and Casimir interactions. Progress related to novel ab initio modeling approaches and their application in various systems, interactions in materials with Dirac-like spectra, force manipulations through nontrivial boundary conditions, and applications of van der Waals forces in organic and biological matter are examined. Finally, the outlook of the review is to give the scientific community a materials perspective of van der Waals and Casimir phenomena and stimulate the development of experimental techniques and applications.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Ehrenfest+R dynamics. I. A mixed quantum–classical electrodynamics simulation of spontaneous emission

The dynamics of an electronic system interacting with an electromagnetic field is investigated within mixed quantum–classical theory. Beyond the classical path approximation (where we ignore all feedback from the electronic system on the photon field), we consider all electron–photon interactions explicitly according to Ehrenfest (i.e., mean-field) dynamics and a set of coupled Maxwell–Liouville equations. Because Ehrenfest dynamics cannot capture certain quantum features of the photon field correctly, we propose a new Ehrenfest+R method that can recover (by construction) spontaneous emission while also distinguishing between electromagnetic fluctuations and coherent emission.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Central vortex steady states and dynamics of Bose–Einstein condensates interacting with a microwave field

Here we study central vortex steady states and dynamics of a two-dimensional (2D), two-component, Gross–Pitaevskii equation (CGPE) system for two pseudo-spinor Bose Einstein condensates (BECs) interacting with an electromagnetic field (microwave) analytically and numerically. For the central vortex steady state at any given winding number S, we prove its existence in a reduced, single component detuning limit when contact-interaction strength β < β b , and nonexistence when β > β b , respectively, where β b is a threshold value, whose value is given in Theorem 3.1 in the paper. We extend the existence and nonexistence result to the general two pseudo-spinor case and prove that a central vortex steady state exists for any given S if β ≤ β b while it does not exist when β > 2β b . We then derive dynamical equations for some observables (expectations of the matter wave function) such as the center-of-mass, position of dispersion, the linear and angular momentum of the two pseudo-spinor CGPEs. Finally, numerical computations are brought in to validate and extend the existence of vortex steady state results to β b ≤ β < 2β b for the two pseudo-spinor case and to explore transient dynamics of the observables.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Study of a Single-Power Two-Circuit ESR Process with Current-Carrying Mold: Mathematical Simulation of the Process and Experimental Verification

A novel single-power two-circuit ESR process (ESR-STCCM) with current-carrying mold has been investigated via numerical simulation and experimental research in this paper. A 2D quasi-steady-state mathematical model is developed to describe ESR-STCCM. The electromagnetic field, flow field, slag pool temperature distribution, and the shape of a molten steel pool in ESR-STCCM have been investigated by FLUENT software as well as user-defined functions (UDF). The results indicate that ESR-STCCM is different from the conventional ESR process. The maximum electromagnetic force, current density, Joule heat, and slag pool flow velocity are located in the lower part of the conductor in the ESR-STCCM process. The direction of the maximum electromagnetic force inclines upward. There are two distinct vortices in the slag pool. The larger swirl rotates counterclockwise near the conductor, with a value of 0.0263 m s{sup −1} due to the interaction of the electromagnetic force and gravity. The maximum temperature of the slag pool is 2070 K (1797 °C) and is located in the center of the swirl with a filling ratio of 0.6 and a 20 mm electrode immersion depth. The depth of a molten steel pool is shallower, which is conducive to improving solidification quality. In addition, the filling ratio of 0.6 is conducive to controlling steel solidification quality. Some experiments have been done, and the numerical model is confirmed by experimental results.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Plasma parameters and electromagnetic forces induced by the magneto hydro dynamic interaction in a hypersonic argon flow experiment

This work proposes an experimental analysis on the magneto hydro dynamic (MHD) interaction induced by a magnetic test body immersed into a hypersonic argon flow. The characteristic plasma parameters are measured. They are related to the voltages arising in the Hall direction and to the variation of the fluid dynamic properties induced by the interaction. The tests have been performed in a hypersonic wind tunnel at Mach 6 and Mach 15. The plasma parameters are measured in the stagnation region in front of the nozzle of the wind tunnel and in the free stream region at the nozzle exit. The test body has a conical shape with the cone axis in the gas flow direction and the cone vertex against the flow. It is placed at the nozzle exit and is equipped with three permanent magnets. In the configuration adopted, the Faraday current flows in a closed loop completely immersed into the plasma of the shock layer. The electric field and the pressure variation due to MHD interaction have been measured on the test body walls. Microwave adsorption measurements have been used for the determination of the electron number density and the electron collision frequency. Continuum recombination radiation and line radiation emissions have been detected. The electron temperature has been determined by means of the spectroscopic data by using different methods. The electron number density has been also determined by means of the Stark broadening of H{sub {alpha}} and the H{sub {beta}} lines. Optical imaging has been utilized to visualize the pattern of the electric current distribution in the shock layer around the test body. The experiments show a considerable effect of the electromagnetic forces produced by the MHD interaction acting on the plasma flow around the test body. A comparison of the experimental data with simulation results shows a good agreement.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2013

Effect of electromagnetic radiation on an array of weakly interacting carbon nanotubes in the presence of nanosecond pulses

For metallic 'zigzag'-type carbon nanotubes, the dependence of a nonlinear current on an ac electric field with an inclined-leading-edge width of {Delta}T = 3 Multiplication-Sign 10{sup -11} s and wavelength of {lambda} Almost-Equal-To 1 mm is studied. It is theoretically and numerically shown that the surface current is almost independent of the nanotube radius. In the case of semiconductor zigzag-type nanotubes, the radiation of a two-frequency CO{sub 2} laser with a constant amplitude is considered as an ac electric field. The dependence on the relaxation time in the Boltzmann kinetic equation is studied. The optimal conditions for terahertz-radiation generation are achieved when the relaxation time is 40 fs. It is numerically found that the amplified radiation amplitude behaves as beats.

36 MATERIALS SCIENCE↗
DOE OSTI2011

Effect on cavity optomechanics of the interaction between a cavity field and a one-dimensional interacting bosonic gas

We investigate optomechanical coupling between one-dimensional interacting bosons and the electromagnetic field in a high-finesse optical cavity. We show that by tuning interatomic interactions, one can realize effective optomechanics with mechanical resonators ranging from side-mode excitations of a Bose-Einstein condensate (BEC) to particle-hole excitations of a Tonks-Girardeau (TG) gas. We propose that this unique feature can be formulated to detect the BEC-TG gas crossover and measure the sine-Gordon transition continuously and nondestructively.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2017

Casimir force phase transitions in the graphene family

The Casimir force is a universal interaction induced by electromagnetic quantum fluctuations between any types of objects. We found that the expansion of the graphene family by adding silicene, germanene and stanene (2D allotropes of Si, Ge, and Sn), lends itself as a platform to probe Dirac-like physics in honeycomb staggered systems in such a ubiquitous interaction. Here, we discover Casimir force phase transitions between these staggered 2D materials induced by the complex interplay between Dirac physics, spin-orbit coupling and externally applied fields. Particularly, we find that the interaction energy experiences different power law distance decays, magnitudes and dependences on characteristic physical constants. Furthermore, due to the topological properties of these materials, repulsive and quantized Casimir interactions become possible.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Gravitational scattering and beyond from extreme mass ratio effective field theory

We explore a recently proposed effective field theory describing electromagnetically or gravitationally interacting massive particles in an expansion about their mass ratio, also known as the self-force (SF) expansion. By integrating out the deviation of the heavy particle about its inertial trajectory, we obtain an effective action whose only degrees of freedom are the lighter particle together with the photon or graviton, all propagating in a Coulomb or Schwarzschild background. The 0SF dynamics are described by the usual background field method, which at 1SF is supplemented by a “recoil operator” that encodes the wobble of the heavy particle, and similarly computable corrections appearing at 2SF and higher. Our formalism exploits the fact that the analytic expressions for classical backgrounds and particle trajectories encode dynamical information to all orders in the couplings, and from them we extract multiloop integrands for perturbative scattering. As a check, we study the two-loop classical scattering of scalar particles in electromagnetism and gravity, verifying known results. We then present new calculations for the two-loop classical scattering of dyons, and of particles interacting with an additional scalar or vector field coupling directly to the lighter particle but only gravitationally to the heavier particle.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Search for the standard model Higgs boson in $l\nu+b\bar{b}$ final states in 9.7 fb$^{-1}$ of $p\bar{p}$ collisions with the DØ detector

Humans have always attempted to understand the mystery of Nature, and more recently physicists have established theories to describe the observed phenomena. The most recent theory is a gauge quantum field theory framework, called Standard Model (SM), which proposes a model comprised of elementary matter particles and interaction particles which are fundamental force carriers in the most unified way. The Standard Model contains the internal symmetries of the unitary product group SU(3) c ⓍSU(2) L Ⓧ U(1) Y , describes the electromagnetic, weak and strong interactions; the model also describes how quarks interact with each other through all of these three interactions, how leptons interact with each other through electromagnetic and weak forces, and how force carriers mediate the fundamental interactions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗