Quasi 1 and 2d Dilute Bose Gas in Magnetic Traps : Existence of Off-Diagonal Order and Anomalous Quantum Fluctuations

TL;DR

This paper investigates how anisotropic magnetic traps create quasi-one and two-dimensional Bose gases, revealing that quantum phase fluctuations do not destroy off-diagonal order in trapped systems and analyzing their size-dependent quantum fluctuations.

Contribution

It demonstrates the persistence of off-diagonal order in quasi-1D and 2D trapped Bose gases and explains the size-dependent quantum fluctuations due to collective mode spectra.

Findings

Off-diagonal order persists in trapped quasi-1D and 2D Bose gases.

Quantum fluctuations vary with system size: increase in 3D, constant in 2D, decrease in 1D.

Behavior linked to finite energy gap and universal collective mode spectrum.

Abstract

Current magnetic traps can be made so anisotropic that the atomic gas trapped inside behaves like quasi one or two dimensional system. Unlike the homogeneous case, quantum phase fluctuations do not destroy macroscopic off-diagonal order of trapped Bose gases in $d\leq 2$. In the dilute limit, quantum fluctuations increase, remain constant, and decrease with size for $% 3, 2, 1d$ respectively. These behaviors are due to the combination of a finite gap and the universal spectrum of the collective mode.