Observing quantum criticality in cold atoms

Kaden R. A. Hazzard, Erich J. Mueller

Kaden R. A. Hazzard

Kaden R. A. Hazzard, Ana María Rey, Richard T. Scalettar

Kaden R. A. Hazzard, Erich J. Mueller

We describe how rescaling experimental data obtained from cold atom density profiles can reveal signatures of quantum criticality. We identify a number of important questions which can be answered by analyzing experimental data in this manner. We show that such experiments can distinguish different universality classes and that the signatures are robust against temperature, noise, and finite system size.

Xibo Zhang, Chen-Lung Hung, Shih-Kuang Tung +2 more

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 (2D) 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.

Cheng Chin