Universal spatiotemporal dynamics of spontaneous superfluidity breakdown in the presence of synthetic gauge fields

TL;DR

This paper demonstrates that the spontaneous superfluidity breakdown in atomic Bose-Einstein condensates with synthetic gauge fields follows the Kibble-Zurek mechanism, revealing universal scaling laws linked to the Landau critical velocity.

Contribution

It establishes the applicability of the Kibble-Zurek mechanism to superfluidity breakdown in BECs with synthetic gauge fields and derives associated scalings and critical exponents.

Findings

KZM applies to superfluidity breakdown in synthetic gauge field BECs

Derived Kibble-Zurek scalings from Landau critical velocity

Numerically extracted critical exponents from vortex dynamics

Abstract

According to the famous Kibble-Zurek mechanism (KZM), the universality of spontaneous defect generation in continuous phase transitions (CPTs) can be understood by the critical slowing down. In most CPTs of atomic Bose-Einstein condensates (BECs), the universality of spontaneous defect generations has been explained by the divergent relaxation time associated with the nontrivial gapless Bogoliubov excitations. However, for atomic BECs in synthetic gauge fields, their spontaneous superfluidity breakdown is resulted from the divergent correlation length associated with the zero Landau critical velocity. Here, by considering an atomic BEC ladder subjected to a synthetic magnetic field, we reveal that the spontaneous superfluidity breakdown obeys the KZM. The Kibble-Zurek scalings are derived from the Landau critical velocity which determines the correlation length. In further, the critical exponents are numerically extracted from the critical spatial-temporal dynamics of the bifurcation delay and the spontaneous vortex generation. Our study provides a general way to explore and understand the spontaneous superfluidity breakdown in CPTs from a single-well dispersion to a double-well one, such as, BECs in synthetic gauge fields, spin-orbit coupled BECs, and BECs in shaken optical lattices.