Topological Condensate in an Interaction Induced Gauge Potential

TL;DR

This paper explores how many-body effects induce a synthetic gauge potential in a Bose-Einstein Condensate, revealing topological ground states, phase transitions, and anisotropic superfluid properties with potential experimental signatures.

Contribution

It demonstrates the emergence of topological states and phase transitions in a BEC due to interaction-induced gauge potentials, combining analytical and numerical methods.

Findings

Identification of a ferromagnetic transition driven by interactions and gauge coupling.

Prediction of topological ground states with vortex structures in traps.

Analysis of anisotropic critical velocities in superfluid flow.

Abstract

We systematically investigate the ground state and elementary excitations of a Bose-Einstein Condensate with a synthetic vector potential, which is induced by the many-body effects and atom-light coupling. For a sufficiently strong inter-atom interaction, we find the condensate undergoes a Stoner-type ferromagnetic transition through the self-consistent coupling with the vector potential. For a weak interaction, the critical velocity of a supercurrent is found anisotropic due to the density fluctuations affecting the gauge field. We further analytically demonstrate the topological ground state with a coreless vortex ring in a 3D harmonic trap and a coreless vortex-antivortex pair in a 2D trap. The circulating persistent current is measurable in the time-of-flight experiment or in the dipolar oscillation through the violation of Kohn theorem.