Resetting photons

TL;DR

This paper introduces a photon resetting process that lowers photon frequency at random times, resulting in a modified equilibrium distribution with increased low-frequency photons, relevant for nonequilibrium photon gas studies.

Contribution

It presents a novel nonlinear Markov process modeling photon frequency resetting, extending the understanding of nonequilibrium photon distributions beyond the classical Planck law.

Findings

Stationary distribution shows increased low-frequency photon occupation.

Two resetting models demonstrate different impacts on the photon spectrum.

The process models nonequilibrium effects in photon gases.

Abstract

Starting from a frequency diffusion process for a tagged photon which simulates relaxation to the Planck law, we introduce a resetting where photons lower their frequency at random times. We consider two versions, one where the resetting to low frequency is independent of the existing frequency and a second case where the reduction in frequency scales with the original frequency. The result is a nonlinear Markov process where the stationary distribution modifies the Planck law by abundance of low-frequency occupation. The physical relevance of such photon resetting processes can be found in explorations of nonequilibrium effects, e.g., via random expansions of a confined plasma or photon gas or via strongly inelastic scattering with matter.