Topological Condensate in an Interaction-induced Gauge Potential
Jun-hui Zheng1*, Bo Xiong1, Gediminas Juzeliunas2, Daw-Wei Wang1,3
1Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
2Institute of Theoretical Physics and Astronomy, Vilnius University, A. Gostauto 12, Vilnius 01108, Lithuania
3Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan
* presenting author:Jun-hui Zheng,
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 suffciently 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-light experiment or in the dipolar oscillation through the violation of Kohn theorem.

Keywords: Ultracold gases, Bose-Einstein condensate, Spin-orbital coupling