Anomalous particle-number fluctuations in a three-dimensional interacting Bose-Einstein condensate

TL;DR

This paper investigates particle-number fluctuations in a 3D interacting Bose-Einstein condensate, revealing a superlinear fluctuation law and the suppression of fluctuations near the critical temperature, with explicit quantum depletion contributions.

Contribution

It provides a detailed calculation of quantum depletion effects and explicit formulas for particle-number fluctuations in a 3D BEC, highlighting their anomalous scaling behavior.

Findings

Particle-number fluctuations scale as N^{22/15}.

Fluctuations vanish near the BEC critical temperature.

Quantum depletion significantly influences fluctuations.

Abstract

The particle-number fluctuations originated from collective excitations are investigated for a three-dimensional, repulsively interacting Bose-Einstein condensate (BEC) confined in a harmonic trap. The contribution due to the quantum depletion of the condensate is calculated and the explicit expression of the coefficient in the formulas denoting the particle-number fluctuations is given. The results show that the particle-number fluctuations of the condensate follow the law $<\delta N_0^2> \sim N^{22/15}$ and the fluctuations vanish when temperature approaches to the BEC critical temperature.