Goldstone modes and bifurcations in phase-separated binary condensates at finite temperature

TL;DR

This paper investigates the behavior of Goldstone modes and mode bifurcations in phase-separated binary condensates at finite temperature, revealing how these modes evolve with temperature and interaction strength.

Contribution

It introduces a detailed analysis of Goldstone mode persistence and bifurcation phenomena in binary condensates using Hartree-Fock-Bogoliubov theory at finite temperature.

Findings

Third Goldstone mode persists under certain density profiles.

Mode bifurcation occurs near the critical temperature.

Kohn mode deviates from natural frequency at finite temperature.

Abstract

We show that the third Goldstone mode, which emerges in binary condensates at phase-separation, persists to higher inter-species interaction for density profiles where one component is surrounded on both sides by the other component. This is not the case with symmetry-broken density profiles where one species is to entirely to the left and the other is entirely to the right. We, then, use Hartree-Fock-Bogoliubov theory with Popov approximation to examine the mode evolution at $T\neq0$ and demonstrate the existence of mode bifurcation near the critical temperature. The Kohn mode, however, exhibits deviation from the natural frequency at finite temperatures after the phase separation. This is due to the exclusion of the non-condensate atoms in the dynamics.