# Lorentz violation and black-hole thermodynamics: Compton scattering process

## TL;DR

This paper explores how Lorentz-violating modifications to quantum electrodynamics in a black hole background can lead to unique Compton scattering events that might challenge the generalized second law of thermodynamics.

## Contribution

It introduces a Lorentz-violating QED model with photons having an effective horizon outside the Schwarzschild horizon and analyzes scattering processes that could violate thermodynamic laws.

## Key findings

- Photons can have an effective horizon outside the black hole horizon.
- Compton scattering in the photonic ergoregion can decrease black hole mass.
- Possible violation of the generalized second law of thermodynamics.

## Abstract

A Lorentz-noninvariant modification of quantum electrodynamics (QED) is considered, which has photons described by the nonbirefringent sector of modified Maxwell theory and electrons described by the standard Dirac theory. These photons and electrons are taken to propagate and interact in a Schwarzschild spacetime background. For appropriate Lorentz-violating parameters, the photons have an effective horizon lying outside the Schwarzschild horizon. A particular type of Compton scattering event, taking place between these two horizons (in the photonic ergoregion) and ultimately decreasing the mass of the black hole, is found to have a nonzero probability. These events perhaps allow for a violation of the generalized second law of thermodynamics in the Lorentz-noninvariant theory considered.