Equilibration of quasi-isolated quantum systems

TL;DR

This paper investigates how quasi-isolated quantum systems evolve from nonequilibrium states, showing that they tend toward equilibrium with properties influenced by initial conditions, and explaining irreversibility through information dynamics.

Contribution

It provides a general framework for describing the evolution and equilibration of quasi-isolated quantum systems without detailed system specifics.

Findings

Systems tend toward equilibrium states influenced by initial conditions.

Average information in the system does not increase over time.

Partial equilibration and information behavior explain irreversibility.

Abstract

The evolution of a quasi-isolated finite quantum system from a nonequilibrium initial state is considered. The condition of quasi-isolation allows for the description of the system dynamics on the general basis, without specifying the system details and for arbitrary initial conditions. The influence of surrounding results in (at least partial) equilibration and decoherence. The resulting equilibrium state bears information on initial conditions and is characterized by a representative ensemble. It is shown that the system average information with time does not increase. The partial equilibration and non-increase of average information explain the irreversibility of time.