Two-body anticorrelation in a harmonically trapped ideal Bose gas

TL;DR

This paper predicts a unique anticorrelation feature in the density fluctuations of a partially condensed ideal Bose gas confined in a harmonic trap, revealing new quantum statistical behavior.

Contribution

It introduces the prediction of a dip in the second-order coherence function indicating anticorrelation, specifically in a canonical ensemble for trapped ideal Bose gases.

Findings

Dip below unity in second-order coherence function observed

Anticorrelation most pronounced in highly anisotropic traps with few particles

The phenomenon is explained through fundamental physical mechanisms

Abstract

We predict the existence of a dip below unity in the second-order coherence function of a partially condensed ideal Bose gas in harmonic confinement, signaling the anticorrelation of density fluctuations in the sample. The dip in the second-order coherence function is revealed in a canonical-ensemble calculation, corresponding to a system with fixed total number of particles. In a grand-canonical ensemble description, this dip is obscured by the occupation-number fluctuation catastrophe of the ideal Bose gas. The anticorrelation is most pronounced in highly anisotropic trap geometries containing small particle numbers. We explain the fundamental physical mechanism which underlies this phenomenon, and its relevance to experiments on interacting Bose gases.