Superfluid-Normal Quantum Phase Transitions in an Imbalanced Fermi Gas

Abstract

We investigate the superfluid-to-normal zero temperature quantum phase transitions of asymmetric two-component Fermi gases as a function of the chemical potential imbalance $h$. The calculations are performed for homogeneous and trapped imbalanced systems. We concentrate at unitarity, characterized by a divergent interaction parameter $k_F a$, where most of the current experiments are realized. For homogeneous systems, we determine the critical chemical potential imbalance $h_c$ at which possible phase transitions occur. In the case of trapped gases, we show how $h_c$ can be consistently determined from experimental observations.