Anomalous dispersion of the collective modes of an ultracold ⁶Li- ⁴⁰K mixture in a square optical lattice

2014/10/15 by Zlatko Koinov, Shanna Pahl, Rafael Mendoza
Physics and Astronomy · #cond-mat.str-el

paper · pdf · doi:10.1007/s10909-014-1269-3

arXiv admin note: substantial text overlap with arXiv:1410.2577

arxiv created 2014/10/15 · arxiv updated 2015/06/23

Abstract

We report numerical calculations of the collective excitation spectrum and the speed of sound of the superfluid phase of an atomic Fermi-Fermi mixture of population-imbalanced Lithium-6 and Potassium-40 atoms in a square lattice. It is predicted that in the exotic states of matter, known as the Fulde-Ferrell phase, an anomalous dispersion of the collective modes may be realized at some values of polarization, interacting strength and temperature, i.e. the collective-mode dispersion initially bends upward before bending over as the quasimomentum increases.

Citations

• Low-energy theory of the Nambu-Goldstone modes of an ultracold ⁶Li- ⁴⁰K mixture in an optical lattice