Chiral Cherenkov and chiral transition radiation in anisotropic matter

TL;DR

This paper derives the frequency spectrum and angular distribution of chiral Cherenkov radiation caused by a fast charge in anisotropic chiral matter, analyzing quantum effects in quark-gluon plasma and Weyl semimetals.

Contribution

It provides the first detailed derivation of the spectrum and angular distribution of chiral Cherenkov radiation in anisotropic chiral media, including quantum effects.

Findings

Chiral Cherenkov radiation spectrum is derived for high-energy particles.

Quantum effects and fermion mass influence the radiation characteristics.

Analysis includes applications to quark-gluon plasma and Weyl semimetals.

Abstract

A significant contribution to the electromagnetic radiation by a fast electric charge moving in anisotropic chiral matter arises from spontaneous photon radiation due to the chiral anomaly. While such a process, also known as the "vacuum Cherenkov radiation", is forbidden in the QED vacuum, it can occur in chiral matter, where it is more appropriate to call it the "chiral Cherenkov radiation". Its contribution to the radiation spectrum is of order $\alpha^2$ compared to $\alpha^3$ of the bremsstrahlung. I derive the frequency spectrum and the angular distribution of this radiation in the high energy limit. The quantum effects due to the hard photon emission and the fermion mass are taken into account. The obtained spectra are analyzed in the case the quark-gluon plasma and a Weyl semimetal.