The peculiarities of Bose-condensation of quasiparticles

TL;DR

This paper explores the unique aspects of Bose-Einstein condensation in quasiparticles, deriving equations for condensate particle number and analyzing the effects of pumping and thermal excitations on the condensation process.

Contribution

It introduces a new equation for quasiparticle condensate number considering pumping and thermal effects, highlighting differences from particle Bose-Einstein condensation.

Findings

Condensation can occur at arbitrary high temperatures for low-energy quasiparticles.

Derived equations relate condensate number to pumping intensity and thermal excitations.

The chemical potential of pumped quasiparticles is characterized as a function of system parameters.

Abstract

An attempt is made to consider the difference between the proccesses of the Bose-Einstein condensation of particles and quasiparticles. An equation for particle number of the Bose-condensate as a function of the total number of particles in the system is obtained. This equation is also written for the caseof quasiparticles with taking into account their creation by pumping and the existence ofequilibriumthermal excitations in the system. From the analysis of both these equations the chemical potential of pumped quasiparticles and their number in the condensate as a function of pumping intensity is found. It is shown that for low energy quasiparticles the proccess of Bose-condensation begins and proceeds at arbitrary temperatures high enough included.