Topological Condensate in an Interaction-induced Gauge Potential Jun-hui Zheng ^{1*}, Bo Xiong^{1}, Gediminas Juzeliunas^{2}, Daw-Wei Wang^{1,3}^{1}Department of Physics, National Tsing Hua University, Hsinchu, Taiwan^{2}Institute of Theoretical Physics and Astronomy, Vilnius University, A. Gostauto 12, Vilnius 01108, Lithuania^{3}Physics Division, National Center for Theoretical Sciences, Hsinchu, Taiwan* presenting author:Jun-hui Zheng, email:jhzheng24@gmail.com 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 |