1 Department of Physics and Astronomy, Science and Technology, Aarhus University2 Cambridge University3 Department of Physics and Astronomy, Science and Technology, Aarhus University
We derive analytical expressions for the frequency and damping of the lowest collective modes of a two-dimensional Fermi gas using kinetic theory. For strong coupling, we furthermore show that pairing correlations overcompensate the effects of Pauli blocking on the collision rate for a large range of temperatures, resulting in a rate which is larger than that of a classical gas. Our results agree well with experimental data, and they recover the observed crossover from collisionless to hydrodynamic behavior with increasing coupling for the quadruple mode. Finally, we show that a trap anisotropy within the experimental bounds results in a damping of the breathing mode which is comparable to what is observed, even for a scale-invariant system.
Physical Review a (atomic, Molecular and Optical Physics), 2013, Vol 87, Issue 4, p. 1-8