Irreversibility and decoherence in an ideal gas

TL;DR

This paper explores how non-interacting particles in an ideal gas can produce dissipative forces through mode mixing, using the Closed Time Path formalism to unify classical and quantum descriptions of dissipation.

Contribution

It introduces a novel application of the Closed Time Path formalism to classical mechanics, providing a unified approach to dissipative forces in both classical and quantum systems.

Findings

Effective action for dissipative models derived within the CTP formalism

Demonstrates mode mixing leads to irreversibility in ideal gases

Unifies classical and quantum descriptions of dissipation

Abstract

Different models are described where non-interacting particles generate dissipative effective forces by the mixing of infinitely many soft normal modes. The effective action is calculated for these models within the Closed Time Path formalism. This is a well known scheme for quantum systems but its application in classical mechanics presents a new, more unified derivation and treatment of dissipative forces within classical and quantum physics.