Abstract

The two-component Fermi gas is the canonical fermionic system exhibiting pairing phenomena and superfluidity and, as such, has relevance to a range of different fields in physics. Ultracold atomic gases provide an exceptionally clean realization of this system, since the interatomic interactions and atom spin are both independently tuneable. In particular, we expect rich scenarios when the populations of each spin are imbalanced, because then the pairing among fermions is frustrated. Indeed, pairing and superfluidity will be destroyed entirely beyond a critical spin polarisation.

In this talk, I will discuss the behaviour of this spin-polarised Fermi superfluid, with emphasis on the current outstanding questions. Specifically, I will argue that non-equilibrium effects are the most likely cause of the discrepancy in the observed critical spin polarisation in recent cold-atom experiments.