Observation of Kibble-Zurek Behavior across Topological Transitions of a Chern Band in Ultracold Atoms

TL;DR

This study experimentally demonstrates the applicability of the Kibble-Zurek mechanism to topological phase transitions in a Chern band within ultracold atomic systems, revealing characteristic defect formation scaling.

Contribution

First experimental investigation of Kibble-Zurek behavior across topological transitions in a Chern band using ultracold atoms.

Findings

Observed power-law scaling of excitation density during topological transitions

Reconstructed defect density via spin wave measurements

Established experimental relevance of Kibble-Zurek mechanism for topological phases

Abstract

The Kibble-Zurek (KZ) mechanism renders a theoretical framework for elucidating the formation of topological defects across continuous phase transitions. Nevertheless, it is not immediately clear whether the KZ mechanism applies to topological phase transitions. The direct experimental study for such a topic is hindered by quenching a certain parameter over orders of magnitude in topological materials. Instead, we investigate the KZ behavior across topological transitions of a Chern band in two-dimensional (2D) optical Raman lattices with quantum gases. Defined as the defects, excitation density is reconstructed via measuring the spin wave functions, with which the power-law scaling of total excitation density is extracted and such scaling could be interpreted within the KZ framework. Our work has heralded the commencement of experimentally exploring the KZ mechanism of the topological phase transitions.