Collective excitations of an imbalanced fermion gas in a 1D optical lattice
arXiv:1307.2655 · doi:10.1007/s10909-013-0926-2
Abstract
The collective excitations that minimize the Helmholtz free energy of a population-imbalanced mixture of a Li gas loaded in a quasi one-dimensional optical lattice are obtained. These excitations reveal a rotonic branch after solving the Bethe-Salpeter equation under a generalized random phase approximation based on a single-band Hubbard Hamiltonian. The phase diagram describing stability regions of Fulde-Farrell-Larkin-Ovchinnikov and Sarma phases is also analyzed.
Six pages and 3 figures