Local condensate depletion at trap center under strong interactions

TL;DR

This paper investigates the unexpected local depletion of Bose-Einstein condensate density at the trap center under strong interactions, combining Monte Carlo simulations and a self-consistent theoretical approach.

Contribution

It introduces a self-consistent theory explaining local condensate depletion due to pair correlations, contrasting with mean-field predictions.

Findings

Monte Carlo simulations show condensate depletion at trap center under strong interactions.

Self-consistent theory attributes depletion to anomalous averages and pair correlations.

Contrasts mean-field hump-shaped condensate distribution with observed depletion.

Abstract

Cold trapped Bose-condensed atoms, interacting via hard-sphere repulsive potentials are considered. Simple mean-field approximations show that the condensate distribution inside a harmonic trap always has the shape of a hump with the maximum condensate density occurring at the trap center. However Monte Carlo simulations at high density and strong interactions display the condensate depletion at the trap center. The explanation of this effect of local condensate depletion at trap center is suggested in the frame of self-consistent theory of Bose-condensed systems. The depletion is shown to be due to the existence of the anomalous average that takes into account pair correlations and appears in systems with broken gauge symmetry.