Theory of thermalization in an isolated Bose-Einstein condensate

TL;DR

This paper investigates how an isolated Bose-Einstein condensate thermalizes through disorder-induced scattering, highlighting the role of Shannon entropy and resolving Loschmidt's paradox in this context.

Contribution

It introduces Shannon entropy as a key measure for thermalization and explains the process of disorder-induced scattering leading to thermal equilibrium in an isolated condensate.

Findings

Shannon entropy in position or momentum space describes thermalization.

Multiple scattering with disorder increases incoherent thermal particles.

Condensed and thermal particles act as mutual heat baths.

Abstract

Thermalization in an isolated oscillating Bose-Einstein condensate in a disordered trap is investigated. We show Shannon entropy in $x$ or $p$ representation is the eligible one to describe the thermalization. Besides, we show that multiple scattering with the disorder generates more and more incoherent thermal particles and condensed and thermal particles act as mutual heat bath that results in the thermalization of the whole system. We also demonstrate that Loschmidt's paradox can be resolved in the present system.