Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Proceedings of the Physical Society Section A

Coherent Scattering of Light by an Atom and Negative Energy States

K. J. Le Couteur, S. Zienau

Published Nov 1, 1950• 0 citations
Publisher

Abstract

It is proved that the difference between the single electron theory and the positron theory for the coherent scattering of light by an atom represents the scattering of light by the atomic potential. In the practical cases the effect is negligible. The gauge invariance of the perturbation formulae for this effect is discussed.
DOI
10.1088/0370-1298/63/11/306

Related papers

Electron scattering from atoms in the presence of a laser field. III

Marvin H. Mittleman

The development of the theory of the effect of a laser on electron-atom scattering is continued by the derivation of explicit relations between the observed electron-atom scattering cross sections in the presence of a laser and exact electron-atom scattering cross sections with no laser present. No approximation concerning the scattering interaction is made. The only approximations concerning the laser are that (1) the laser-atom interaction energy is small compared to atomic energies, (2) the Rabi frequency times the collision time is small, and (3) the laser intensity in appropriate units is small.

Physical Review A•Oct 1, 1977•21 citations

Permutation Symmetry in Coherent Electrons Scattering by Disordered Media

E. V. Orlenko, Fedor E. Orlenko

A non-Anderson weak localization of an electron beam scattered from disordered matter is considered with respect to the principle of electron indistinguishability. A weak localization of electrons of a new type is essentially associated with inelastic processing. The origin of inelasticity is not essential. We take into account the identity principle for electron beam and electrons of the atom of the scatterer with an open shell. In spite of isotropic scattering by each individual scatterer, the electron exchange contribution has a hidden parameters effect on the resulting angular dependence of the scattering cross-section. In this case, the electrons of the open shell of an atomic scatterer can be in the s-state, that is, the atomic shell remains spherically symmetric. The methods of an invariant time-dependent exchange perturbation theory and a Green functions with exchange were applied. An additional angular dependence of the scattering cross-section appears during the coherent scattering process. It is shown exactly for the helium scatterer that the role of exchange effects in the case of a singlet is negligible, while for the triplet state, it is decisive, especially for those values of the energy of incident electrons when de Broglie’s waves are commensurate with the atomic.

Symmetry•Nov 28, 2020•2 citations

Strong coupling of virtual negative states in the Kapitza-Dirac effect

Qianlong Wang, Sven Ahrens, Baifei Shen

Negative states are an intrinsic property of relativistic quantum theory and related to anti-particles in the context of the Dirac sea concept. We show that negative states can dominantly contribute to the diffraction amplitude in the quantum dynamics of the two-photon Kapitza-Dirac effect. We draw our conclusion by investigating solutions from time-dependent perturbation theory, where the perturbative solutions are in match with numeric solutions of the relativistic quantum system and also with the numeric and analytic solutions from the relativistic equations of motion of a classical point-like electron in an external standing wave light field. While our numeric solutions assume a strong laser field, the analytic solutions indicate that negative state coupling remains dominant for arbitrary low field amplitudes, where in the single-photon case (Compton scattering) negative state coupling can be mathematically associated with the interaction of a virtual electron-positron pair in the context of a quantized theory in old-fashioned perturbation theory.

quant-pharXiv:2601.07157•Jan 13, 2026

Generalized optical theorem in coherent scattering

Ming Chiang Li

It is shown that the generalized optical theorem in quantum mechanics is a useful theorem in the scattering of two coherent beams.

Physical Review A•Mar 1, 1975•3 citations

Coherent Scattering of Photons by Atomic Hydrogen

Marvin H. Mittleman, Fred A. Wolf

The cross section for the coherent scattering of light by atomic hydrogen is evaluated numerically below the first excitation thershold. The evaluation above threshold is discussed.Received 10 May 1962DOI:https://doi.org/10.1103/PhysRev.128.2686©1962 American Physical Society

Physical Review•Dec 15, 1962•25 citations

Scattering of low-energy electrons and positrons by atomic beryllium: Ramsauer–Townsend effect

David D. Reid, J. M. Wadehra

Total cross sections for the scattering of low-energy electrons and positrons by atomic beryllium in the energy range below the first inelastic thresholds are calculated. A Ramsauer–Townsend minimum is seen in the electron scattering cross sections, while no such effect is found in the case of positron scattering. A minimum total cross section of 0.016 a 0 2 at 0.0029 eV is observed for the electron case. In the limit of zero energy, the cross sections yield a scattering length of −0.61 a 0 for electron and a 0 for positron scattering.

arXiv:1408.1389•Journal of Physics B Atomic Molecular and Optical Physics•Nov 7, 2014•23 citations
The development of the theory of the effect of a laser on electron-atom scattering is continued by the derivation of explicit relations between the observed electron-atom scattering cross sections in the presence of a laser and exact electron-atom scattering cross sections with no laser present. No approximation concerning the scattering interaction is made. The only approximations concerning the laser are that (1) the laser-atom interaction energy is small compared to atomic energies, (2) the Rabi frequency times the collision time is small, and (3) the laser intensity in appropriate units is small.
A non-Anderson weak localization of an electron beam scattered from disordered matter is considered with respect to the principle of electron indistinguishability. A weak localization of electrons of a new type is essentially associated with inelastic processing. The origin of inelasticity is not essential. We take into account the identity principle for electron beam and electrons of the atom of the scatterer with an open shell. In spite of isotropic scattering by each individual scatterer, the electron exchange contribution has a hidden parameters effect on the resulting angular dependence of the scattering cross-section. In this case, the electrons of the open shell of an atomic scatterer can be in the s-state, that is, the atomic shell remains spherically symmetric. The methods of an invariant time-dependent exchange perturbation theory and a Green functions with exchange were applied. An additional angular dependence of the scattering cross-section appears during the coherent scattering process. It is shown exactly for the helium scatterer that the role of exchange effects in the case of a singlet is negligible, while for the triplet state, it is decisive, especially for those values of the energy of incident electrons when de Broglie’s waves are commensurate with the atomic.
Negative states are an intrinsic property of relativistic quantum theory and related to anti-particles in the context of the Dirac sea concept. We show that negative states can dominantly contribute to the diffraction amplitude in the quantum dynamics of the two-photon Kapitza-Dirac effect. We draw our conclusion by investigating solutions from time-dependent perturbation theory, where the perturbative solutions are in match with numeric solutions of the relativistic quantum system and also with the numeric and analytic solutions from the relativistic equations of motion of a classical point-like electron in an external standing wave light field. While our numeric solutions assume a strong laser field, the analytic solutions indicate that negative state coupling remains dominant for arbitrary low field amplitudes, where in the single-photon case (Compton scattering) negative state coupling can be mathematically associated with the interaction of a virtual electron-positron pair in the context of a quantized theory in old-fashioned perturbation theory.
Total cross sections for the scattering of low-energy electrons and positrons by atomic beryllium in the energy range below the first inelastic thresholds are calculated. A Ramsauer–Townsend minimum is seen in the electron scattering cross sections, while no such effect is found in the case of positron scattering. A minimum total cross section of 0.016 a 0 2 at 0.0029 eV is observed for the electron case. In the limit of zero energy, the cross sections yield a scattering length of −0.61 a 0 for electron and a 0 for positron scattering.