%0 Journal Article
%T Collective excitations in a fermion-fermion mixture with different Fermi surfaces
%A Lan Yin
%J Physics
%D 2003
%I arXiv
%R 10.1103/PhysRevA.68.055602
%X In this paper, collective excitations in a homogeneous fermion-fermion mixture with different Fermi surfaces are studied. In the Fermi liquid phase, the zero-sound velocity is found to be larger than the largest Fermi velocity. With attractive interactions, the superfluid phase appears below a critical temperature, and the phase mode is the low-energy collective excitation. The velocity of the phase mode is proportional to the geometric mean of the two Fermi velocities. The difference between the two velocities may serve as a tool to detect the superfluid phase.
%U http://arxiv.org/abs/cond-mat/0309344v1