Finite temperature phase diagram of a spin-1 Bose gas

TL;DR

This paper develops a self-consistent Hartree-Fock theory for spin-1 Bose gases at finite temperature, revealing how thermal atom coherence influences the phase diagram and providing analytical tools to understand phase boundary shifts.

Contribution

It introduces a novel self-consistent Hartree-Fock framework for finite-temperature spin-1 Bose gases, emphasizing the role of thermal atom coherence in phase transitions.

Findings

Spin coherence between thermal atoms and condensed atoms affects phase boundaries.

Analytical expressions describe temperature and interaction effects on phase shifts.

Coherent collisions are key to understanding the phase diagram.

Abstract

We formulate a self-consistent Hartree-Fock theory for a spin-1 Bose gas at finite temperature and apply it to characterizing the phase diagram. We find that spin coherence between thermal atoms in different magnetic sub-levels develops via coherent collisions with the condensed atoms, and is a crucial factor in determining the phase diagram. We develop analytical expressions to characterize the interaction and temperature dependent shifts of the phase boundaries.