Signature of Quantum Criticality in the Density Profiles of Cold Atom Systems

TL;DR

This paper introduces methods to identify quantum critical behavior in cold atom systems through density profiles, enabling determination of phase boundaries and scaling functions despite finite size effects.

Contribution

It presents a novel algorithm to extract quantum critical properties from experimental density data of trapped atomic gases.

Findings

Validated schemes using exactly soluble models.

Able to determine T=0 phase boundaries from density profiles.

Provided methods to remove finite size effects in experiments.

Abstract

In recent years, there is considerable experimental effort using cold atoms to study strongly correlated many-body systems. One class of phenomena of particularly interests is quantum critical (QC) phenomena. While prevalent in many materials, these phenomena are notoriously difficult theoretical problems due to the vanishing of energy scales in QC region. So far, there are no systematic ways to deduce QC behavior of bulk systems from the data of trapped atomic gases. Here, we present a simple algorithm to use the experimental density profile to determine the T=0 phase boundary of bulk systems, as well as the scaling functions in QC regime. We also present another scheme for removing finite size effects of the trap. We demonstrate the validity of our schemes using exactly soluble models.