Quantum phase transitions across a p-wave Feshbach resonance -: art. no. 230403

We study a single-species polarized Fermi gas tuned across a narrow p-wave Feshbach resonance. We show that in the course of a Bose-Einstein condensation (BEC)-BCS crossover, the system can undergo a magnetic-field-tuned quantum phase transition from a p(x)-wave to a p(x)+ip(y)-wave superfluid. The latter state, that spontaneously breaks time-reversal symmetry, furthermore undergoes a topological p(x)+ip(y) to p(x)+ip(y) transition at zero chemical potential mu. In two dimensions, for mu > 0 it is characterized by a Pfaffian ground state exhibiting topological order and non-Abelian excitations familiar from fractional quantum Hall systems.