Quantum kinetic equation before and after Big Bang

TL;DR

This paper explores how microscopic operator ordering leads to macroscopic irreversibility in kinetic processes, applying a general approach that spans from cosmological events like the Big Bang to molecular gas dissipation.

Contribution

It introduces a formalism linking microscopic operator ordering to macroscopic irreversibility, applicable across diverse physical processes without specific spacetime assumptions.

Findings

Operator ordering explains irreversibility in kinetic processes

Applicable to cosmological and molecular systems

No special spacetime assumptions required

Abstract

The energy dissipation in a gas of structured objects, e.g. molecules, is considered in density matrix formalism. It is shown that the macroscopic irreversibility of the kinetic processes can be considered as a consequence of the microscopic operator ordering. Our approach is free of any special assumptions on the space-time geometry, except for the general causality assumptions, so it can be applied to a wide variety of processes, from the cosmological processes at Big Bang stage till the energy dissipation in molecular gases.