Exploring quantum criticality based on ultracold atoms in optical lattices

TL;DR

This paper investigates quantum criticality in ultracold cesium atoms within a 2D optical lattice, focusing on thermodynamic scaling laws and transport properties near the superfluid-Mott insulator transition.

Contribution

It provides experimental insights into quantum critical behavior using in situ density measurements, testing scaling laws and exploring transport in a cold atom system.

Findings

Equation of state follows predicted scaling law at low temperatures near critical point.

Progress in measuring thermodynamic and transport properties in quantum critical regime.

Experimental validation of critical scaling in ultracold atom systems.

Abstract

Critical behavior developed near a quantum phase transition, interesting in its own right, offers exciting opportunities to explore the universality of strongly-correlated systems near the ground state. Cold atoms in optical lattices, in particular, represent a paradigmatic system, for which the quantum phase transition between the superfluid and Mott insulator states can be externally induced by tuning the microscopic parameters. In this paper, we describe our approach to study quantum criticality of cesium atoms in a two-dimensional lattice based on in situ density measurements. Our research agenda involves testing critical scaling of thermodynamic observables and extracting transport properties in the quantum critical regime. We present and discuss experimental progress on both fronts. In particular, the thermodynamic measurement suggests that the equation of state near the critical point follows the predicted scaling law at low temperatures.