Collective Excitations of a Two-Component Bose Condensate at Finite Temperature

TL;DR

This paper investigates how collective excitations in a two-component Bose condensate differ at finite temperature depending on whether there is spontaneous intercomponent coherence, revealing distinct excitation spectra.

Contribution

It compares collective modes in two-component Bose condensates with and without intercomponent coherence at finite temperature using the time-dependent Hartree-Fock approximation.

Findings

Different collective excitation spectra depending on intercomponent coherence

Interaction effects between condensate and non-condensate alter excitations

Zero-temperature single-particle excitations can be probed by intercomponent excitations

Abstract

We compare the collective modes for Bose-condensed systems with two degenerate components with and without spontaneous intercomponent coherence at finite temperature using the time-dependent Hartree-Fock approximation. We show that the interaction between the condensate and non-condensate in these two cases results in qualitatively different collective excitation spectra. We show that at zero temperature the single-particle excitations of the incoherent Bose condensate can be probed by intercomponent excitations.