Nonequilibrium Dynamics in Noncommutative Spacetime

TL;DR

This paper investigates how spacetime noncommutativity influences the nonequilibrium behavior of particles in a thermal bath, revealing momentum-dependent effects on decay and thermalization that could impact early universe processes.

Contribution

It demonstrates that noncommutative thermal baths avoid IR/UV mixing issues and shows how noncommutativity can alter particle decay and thermalization depending on momentum.

Findings

Noncommutative thermal quantities are free from infrared singularities.

Noncommutativity can switch decay and thermalization on or off depending on momentum.

Potential implications for early universe phenomena like reheating and dark matter freeze-out.

Abstract

We study the effects of spacetime noncommutativity on the nonequilibrium dynamics of particles in a thermal bath. We show that the noncommutative thermal bath does not suffer from any further IR/UV mixing problem in the sense that all the finite-temperature non-planar quantities are free from infrared singularities. We also point out that the combined effect of finite temperature and noncommutative geometry has a distinct effect on the nonequilibrium dynamics of particles propagating in a thermal bath: depending on the momentum of the mode of concern, noncommutative geometry may switch on or switch off their decay and thermalization. This momentum dependent alternation of the decay and thermalization rates could have significant impacts on the nonequilibrium phenomena in the early universe at which spacetime noncommutativity may be present. Our results suggest a re-examination of some of the important processes in the early universe such as reheating after inflation, baryogenesis and the freeze-out of superheavy dark matter candidates.