Anomalous fluctuations of two-dimensional Bose-Einstein condensates

TL;DR

This paper studies unusual particle-number fluctuations in 2D and quasi-2D Bose-Einstein condensates, revealing they scale anomalously with particle number and trapping frequency, which impacts understanding of low-dimensional quantum gases.

Contribution

It uncovers the anomalous scaling laws of particle-number fluctuations in 2D and quasi-2D BECs at low temperatures, highlighting new fluctuation behaviors.

Findings

Fluctuations in 2D BEC scale as N^2.

In quasi-2D BEC, fluctuations scale as N^2 and with the square root of trapping frequency.

Fluctuations are significantly larger than in three-dimensional BECs.

Abstract

We investigate the particle-number fluctuations due to the collective excitations created in a two-dimensional (2D) and a quasi-2D Bose-Einstein condensates (BECs) at low temperature. We find that the fluctuations display an anomalous behavior, i. e. for the 2D BEC they are proportional to $N^2$, where $N$ is the total number of particles. For the quasi-2D BEC, the particle-number fluctuations are proportional not only to $N^2$ but also to the square root of the trapping frequency in the strongly-confined direction.