1211.4020 (M. Iskin et al.)

Topological superfluid phases of an atomic Fermi gas with equal
Rashba-Dresselhaus spin-orbit coupling and in- and out-of-plane Zeeman fields    [PDF]

M. Iskin, A. L. Subasi

We analyze the effects of in- and out-of-plane Zeeman fields on the BCS-BEC evolution of a spin-orbit coupled Fermi gas with an equal contribution from Rashba and Dresselhaus terms, and show that the ground-state of the system involves novel gapless superfluid phases that can be distinguished with respect to the topological structure of the momentum-space regions with zero excitation energy. Depending on the combination of Zeeman and spin-orbit fields, these topological structures correspond to one or two doubly-degenerate round spheres, two or four round spheres, two or four concave spheres, or one or two doubly-degenerate circles. Such changes in the topology signal a quantum phase transition between distinct superfluid phases, and leave their signatures on some of the thermodynamic quantities.

View original: http://arxiv.org/abs/1211.4020