Phase diffusion in stationary state of nonequilibrium Bose gas

TL;DR

This paper investigates the low energy excitation spectrum of a nonequilibrium Bose gas in a stationary state, revealing that noise induces a diffusive spectrum unlike the sound-like spectrum in equilibrium systems.

Contribution

It demonstrates that noise in nonequilibrium Bose gases causes the excitation spectrum to become diffusive, contrasting with the sound spectrum observed in equilibrium.

Findings

The spectrum exhibits diffusion due to noise effects.

Contrasts with thermodynamic equilibrium where spectrum is sound-like.

Stationary nonequilibrium state maintains dynamical particle exchange.

Abstract

Properties of low energy spectrum of elementary excitations in nonequilibrium Bose gas in stationary state with the dynamical equilibrium of outgoing and incoming of particles are studied. It is shown that due to the noise effect, typical for nonequilibrium systems, this spectrum has a diffusion character, in contradiction with the thermodynamically equilibrium systems, where this spectrum has a sound form.