Photon self-energy at all temperatures and densities in all of phase space
arXiv:2405.18466 · doi:10.1007/JHEP11(2024)139
Abstract
In an isotropic background comprised of free charges, the transverse and longitudinal modes of the photon acquire large corrections to their dispersion relations, described by the in-medium photon self-energy. Previous work has developed simple approximations that describe the propagation of on-shell photons in plasmas of varying temperatures and densities. However, off-shell excitations can also receive large medium-induced corrections, and the on-shell approximations have often been used in an effort to capture these effects. In this work we show that the off-shell self-energy can be qualitatively very different than the on-shell case. We develop analytic approximations that are accurate everywhere in phase space, especially in classical and degenerate plasmas. From these, we recover the on-shell expressions in the appropriate limit. Our expressions also reproduce the well-known Lindhard response function from solid-state physics for the longitudinal mode.
13 pages, 4 figures
References in corpus (8)
- Array Programming with NumPy
- Stellar cooling bounds on new light particles: plasma mixing effects
- Making dark matter out of light: freeze-in from plasma effects
- Microwave Background Constraints on Mixing of Photons with Hidden Photons
- Determining Dark Matter-Electron Scattering Rates from the Dielectric Function
- Effects of Axion-Photon Mixing on Gamma-Ray Spectra from Magnetized Astrophysical Sources
- DarkELF: A python package for dark matter scattering in dielectric targets
- Probing dark photons with plasma haloscopes