“Fermions in synthetic non-Abelian gauge fields’ by Vijay B. Shenoy (Indian Institute of Science)

Monday, March 25, 2013 - 4:00pm
Condensed Matter Physics Seminar in PAB 4-330


The ability of cold atoms to simulate condensed-matter systems has been bolstered by the recent spectcular experimental advances in the generation of synthetic gauge fields.  After a brief review of ideas for the generation of synthetic non-Abelian gauge fields, I shall discuss the physics of interacting fermions in their presence. Such gauge fields induce a generalized spin-orbit interaction for the two component fermions. I shall demonstrate that on increasing the strength of the spin-orbit coulpling, a BCS superfluid that is realized in the presence of weak attraction in the absence of the gauge field, is driven to BEC state. The BEC state is a condensate of a new kind of nematic bosons, which we call "rashbons", whose properties are determined solely by the gauge field and not by the strength of the attraction between the fermions. The rashbon-BEC is shown to have a transition temperature of the order of the Fermi temperature suggesting a route to enhancing the transition temperature in weakly attracting systems using spin-orbit interaction. I shall then show that the rashbon-BEC is described by a Bogoliubov theory and estimate that the rashbon-rashbon scattering length which is shown to be *independent* of the scattering length between the constituent fermions. Finally, I will make a proposal of using a non-Abelian gauge field in a conjunction with another potential for the realization of interesting condensed matter Hamiltonians such as that due to a magnetic monopole. 


Work done in collaboration with J. P. Vyasanakere(IISc) and Sudeep Ghosh(IISc) References: cond-mat:1101.0411, 1104.5633, 1108.4872, 1109.5279, 1201.5332, 1211.1831, 1212.2858 Supported by DST, DAE, India