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

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.

arXiv admin note: substantial text overlap with arXiv:1410.2577

References in corpus (2)

• Density Functional Theory for non-relativistic Fermions in the Unitarity Limit
• Quantum phases of Fermi-Fermi mixtures in optical lattices