Electromagnetic spectral properties and Debye screening of a strongly magnetized hot medium

TL;DR

This paper analyzes electromagnetic spectral functions and Debye screening in a hot, strongly magnetized medium, revealing dimensional reduction effects and enhanced dilepton production at low invariant mass.

Contribution

It provides a detailed computation of spectral functions and Debye mass considering strong magnetic fields, highlighting the effects of Landau level dynamics and magnetic catalysis.

Findings

Spectral strength peaks at low photon energy due to Landau level effects.

Debye mass depends on quark mass, temperature, and magnetic field strength.

Enhanced dilepton rate observed at low invariant mass in strong magnetic fields.

Abstract

We have evaluated the electromagnetic spectral function and its spectral properties by computing the one-loop photon polarization tensor in presence of magnetic field, particularly in a strong field approximation compared to the thermal scale. When the magnetic scale is higher than the thermal scale the lowest Landau level (LLL) becomes effectively (1+1) dimensional strongly correlated system that provides a kinematical threshold based on the mass scale. Beyond this threshold the photon strikes the LLL and the spectral strength starts with a high value due to the dimensional reduction and then falls off with increase of the photon energy due to LLL dynamics in a strong field approximation. This strongly enhances the dilepton rate over the thermal perturbative leading order (Born) rate at very low invariant mass. We have also investigated the electromagnetic screening by computing the Debye screening mass and it depends distinctively on three different scales (mass of the quasiquark, temperature and the magnetic field strength) of a hot magnetized system. The mass dependence of the Debye screening supports the occurrence of a magnetic catalysis effect in the strong field approximation.