Title: Synthetic gauge fields in ultracold atoms

Guest Speaker: Prof. Zhifang Xu

Time: 2015-1-21 (Wednesday), 9:30－10:30 
Location: Conference Room (7205), School of Science 

Abstract

       Synthetic abelian and non-abelian gauge fields for ultracold atoms have attracted a huge interest. Recent experiments on ultracold atomic gases have made remarkable breakthroughs in realizing synthetic magnetic fields and 1D spin-orbit coupling for neutral atoms. In this talk, I will show you two different schemes on generating gauge fields in spinor quantum gases. First, I will present a general scheme for dynamically creating a 2D Rashba-type spin-orbit coupling for neutral atoms with arbitrary hyperfine spin by using only magnetic-field-gradient pulses. Second, I will show you that a U(1) gauge field can spontaneously emerge in a mixture of spinor Bose-Fermi mixtures loaded into a frustrated triangular optical lattice. The underline mechanism is that Fermi surface nesting at 3/4 filling leads to spontaneous formation of various bosonic spin textures. Most significantly, in one non-coplanar state the mixture is found to exhibit a spontaneous quantum Hall effect in fermions and a finite-momentum condensation in bosons.