Coupling of hydrodynamics and quasiparticle motion in collective modes of superfluid trapped Fermi gases

Abstract

At finite temperature, the hydrodynamic collective modes of superfluid trapped Fermi gases are coupled to the motion of the normal component, which in the BCS limit behaves like a collisionless normal Fermi gas. The coupling between the superfluid and the normal components is treated in the framework of a semiclassical transport theory for the quasiparticle distribution function, combined with a hydrodynamic equation for the collective motion of the superfluid component. We develop a numerical test-particle method for solving these equations in the linear response regime. As a first application we study the temperature dependence of the collective quadrupole mode of a Fermi gas in a spherical trap. The coupling between the superfluid collective motion and the quasiparticles leads to a rather strong damping of the hydrodynamic mode already at very low temperatures. At higher temperatures the spectrum has a two-peak structure, the second peak corresponding to the quadrupole mode in the normal phase.

14 pages; v2: major changes (effect of Hartree field included)

References in corpus (4)

• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Precision Measurements of Collective Oscillations in the BEC-BCS Crossover
• Temperature and finite-size effects in collective modes of superfluid Fermi gases
• Transition to hydrodynamics in colliding fermion clouds

Cited by in corpus (5)

• Number of closed-channel molecules in the BEC-BCS crossover
• Dynamics of a strongly interacting Fermi gas: the radial quadrupole mode
• Collective modes of trapped Fermi gases with in-medium interaction
• Normal-Superfluid Interface for Polarized Fermion Gases
• Radial quadrupole and scissors modes in trapped Fermi gases across the BCS phase transition