Measuring the condensate fraction of rapidly rotating trapped boson systems: off-diagonal order from the density

TL;DR

This paper presents a method to determine the condensate fraction of rapidly rotating trapped bosons directly from their density profiles, enabling insights into the transition from vortex-lattice to quantum fluid states.

Contribution

It establishes a direct link between density profiles and condensate fraction in rotating bosonic systems, facilitating experimental probing of phase crossovers.

Findings

Density profile can reveal condensate fraction in rotating bosons

Method applicable to realistic finite trap systems

Useful for analyzing freely expanding boson clouds

Abstract

We demonstrate a direct connection between the density profile of a system of ultra-cold trapped bosonic particles in the rapid-rotation limit and its condensate fraction. This connection can be used to probe the crossover from condensed vortex-lattice states to uncondensed quantum fluid states that occurs in rapidly rotating boson systems as the particle density decreases or the rotation frequency increases. We illustrate our proposal with a series of examples, including ones based on models of realistic finite trap systems, and comment on its application to freely expanding boson density profile measurements.