Itinerant ferromagnetism in an interacting Fermi gas with mass imbalance

作者：von Keyserlingk C W^*; Conduit G J

来源：Physical Review A, 2011, 83(5): 053625.

DOI：10.1103/PhysRevA.83.053625

We study the emergence of itinerant ferromagnetism in an ultracold atomic gas with a variable mass ratio between the up- and down-spin species. Mass imbalance breaks the SU(2) spin symmetry, leading to a modified Stoner criterion. We first elucidate the phase behavior in both the grand canonical and canonical ensembles. Second, we apply the formalism to a harmonic trap to demonstrate how a mass imbalance delivers unique experimental signatures of ferromagnetism. These could help future experiments to better identify the putative ferromagnetic state. Furthermore, we highlight how a mass imbalance suppresses the three-body loss processes that handicap the formation of a ferromagnetic state. Finally, we study the time-dependent formation of the ferromagnetic phase following a quench in the interaction strength.

• 出版日期2011-5-24