Kinetic theory for nongeodesic particle motion: Selfinteracting equilibrium states and effective viscous fluid pressures

TL;DR

This paper develops a kinetic theory for relativistic gases with self-interacting forces, revealing how such forces induce effective viscous pressures and may explain phenomena like cosmic inflation.

Contribution

It introduces a kinetic framework for nongeodesic particle motion with self-interactions, linking microscopic forces to macroscopic cosmological effects.

Findings

Self-interacting forces produce effective viscous pressures in relativistic gases.

Generalized equilibrium states can lead to accelerated cosmic expansion.

Power law inflation may result from specific self-interacting forces.

Abstract

The particles of a classical relativistic gas are supposed to move under the influence of a quasilinear (in the particle four-momenta), self-interacting force inbetween elastic, binary collisions. This force which is completely fixed by the equilibrium conditions of the gas, gives rise to an effective viscous pressure on the fluid phenomenological level. Earlier results concerning the possibility of accelerated expansion of the universe due to cosmological particle production are reinterpreted. A phenomenon such as power law inflation may be traced back to specific self-interacting forces keeping the particles of a gas universe in states of generalized equilibrium.