Signature of existence of a BEC-type state in a dilute gas above the BEC transition temperature

TL;DR

This paper investigates quantum coherence in a dilute gas above the BEC transition temperature, suggesting a BEC-type state exists and explaining previous experimental results.

Contribution

It proposes the existence of a BEC-type state above the transition temperature, providing a new perspective on quantum coherence in dilute gases.

Findings

Some atoms exhibit coherence lengths longer than average

Quantum coherence persists above the BEC transition temperature

Explains previously unexplained experimental results

Abstract

We study quantum coherence properties of a dilute gas at temperatures above, but not much above the transition temperature of Bose-Einstein condensation (BEC). In such a gas, a small proportion of the atoms may possess coherence lengths longer than the mean neighboring-atomic distance, implying the existence of quantum coherence more than that expected for thermal atoms. Conjecturing that a part of this proportion of the atoms may lie in a BEC-type state, some unexplained experimental results [Phys. Rev. A, 71, 043615 (2005)] can be explained.