Thermalization in one- plus two-body ensembles for dense interacting boson systems

TL;DR

This paper investigates how temperature and entropy behave in dense bosonic systems modeled by random matrix ensembles, identifying a thermalization region where different definitions converge, and analyzing the dependence on system parameters.

Contribution

It introduces a detailed analysis of thermalization in bosonic systems using one plus two-body random matrix ensembles, including the identification of a thermalization region and parameter dependence.

Findings

Temperature and entropy converge in the thermalization region.

The thermalization threshold mbda_t is significantly larger than other transition points.

Derived mbda_t dependence on system size and levels.

Abstract

Employing one plus two-body random matrix ensembles for bosons, temperature and entropy are calculated, using different definitions, as a function of the two-body interaction strength \lambda for a system with 10 bosons (m=10) in five single particle levels (N=5). It is found that in a region \lambda \sim \lambda_t, different definitions give essentially same values for temperature and entropy, thus defining a thermalization region. Also, (m,N) dependence of \lambda_t has been derived. It is seen that \lambda_t is much larger than the \lambda values where level fluctuations change from Poisson to GOE and strength functions change from Breit-Wigner to Gaussian.