Spatial inversion symmetry breaking of vortex current in biased-ladder superfluid

TL;DR

This paper studies the dynamics of interacting bosons in a biased ladder superfluid, revealing spontaneous spatial inversion symmetry breaking and asymmetric vortex current spreading, with implications for many-body localization.

Contribution

It uncovers the spontaneous breaking of spatial inversion symmetry in vortex currents of a biased-ladder superfluid and analyzes the robustness of particle-like versus wave-like currents.

Findings

Asymmetric vortex current spreading observed

Particle-like current more robust than wave-like

Entanglement entropy shows logarithmic growth indicating localization

Abstract

We investigate the quench dynamics of interacting bosons on a two-leg ladder in presence of a uniform Abelian gauge field. The model hosts a variety of emergent quantum phases, and we focus on the superfluid biased-ladder phase breaking the $Z_{2}$ symmetry of two legs. We observe an asymmetric spreading of vortex current and particle density, i.e., the current behaves particle-like on the right and wave-like on the left, indicating spontaneous breaking of the spatial inversion symmetry. By decreasing the repulsion strength, it is found the particle-like current is more robust than the wave-like one. The evolution of entanglement entropy manifests logarithmic growth with time suggesting many-body localization matters.