Dr. Tomoki Ozawa (INO-CNR BEC Center and University of Trento, Italy)
"Ultracold Bose gases with Rashba spin-orbit coupling"
Stimulated by recent experimental realization of spin-orbit coupling in ultracold gases, we investigate low-temperature phases of ultracold bosons in the presence of Rashba spin-orbit coupling. When a particle is subject to Rashba spin-orbit coupling, the single-particle dispersion relation is modified to give infinitely degenerate minima. Because of this degeneracy, a gas of bosons cannot condense at nonzero temperature even in three dimensions when the inter-particle interaction is absent. However, in the presence of inter-particle interactions, a Bose condensate can be stable at finite temperatures. We discuss the nature of the phase transition from normal to condensate phases in such spin-orbit coupled systems.