arXiv:cond-mat/0309591 · Journal of Physics B Atomic Molecular and Optical Physics

Heat capacity of a two-component superfluid Fermi gas

А. V. Avdeenkov

Published Dec 8, 2003• 6 citations

Abstract

We investigate mean-field effects in two-component trapped Fermi gases in the superfluid phase, in the vicinity of s-wave Feshbach resonances. Within the resonance superfluidity approach (Holland et al 2001 Phys. Rev. Lett. 87 120406) we calculate the ground state energy and the heat capacity as functions of temperature. Heat capacity is analysed for different trap aspect ratios. We find that trap anisotropy is an important factor in determining both the value of heat capacity near the transition temperature and the transition temperature itself.

DOI: 10.1088/0953-4075/37/1/015

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arXiv:cond-mat/0309591 · Journal of Physics B Atomic Molecular and Optical Physics

Heat capacity of a two-component superfluid Fermi gas

А. V. Avdeenkov

Published Dec 8, 2003• 6 citations

arXiv HTML PDF

Abstract

DOI: 10.1088/0953-4075/37/1/015

Related papers

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S(E)

as a function of the total energy

E

. Our results are in good agreement with both experimental data and previous analytical and numerical results for the thermodynamics of the unitary Fermi gas. The value of the Bertsch parameter at

T=0

and the superfluid transition temperature, however, differ appreciably. We show that, well in the superfluid regime, removal of atoms near the cloud edge enables cooling far below temperatures that have been reached so far.

^{6}\text{L}\text{i}

and

^{40}\text{K}

with resonant interaction.

{T}_{c}

to the superfluid state. For a homogeneous gas in the unitarity limit, the relaxation rates are increased by nearly an order of magnitude compared to their value obtained in the absence of medium effects due to the Cooper instability at

{T}_{c}

. For trapped gases the corresponding ratio is found to be about three due to the averaging over the inhomogeneous density distribution. The effect of superfluidity below

{T}_{c}

is considered to leading order in the ratio between the energy gap and the transition temperature.

{T}_{\mathrm{c}},

reflecting the change of the dominant particles going from Fermi atoms to composite bosons. In the BEC regime, these composite bosons are shown to first appear well above

{T}_{\mathrm{c}}.

We also discuss the ``phase diagram'' above

{T}_{\mathrm{c}}

as a function of the tunable threshold energy $2\ensuremath{\nu}.$ We introduce a characteristic temperature ${T}^{*}(2\ensuremath{\nu})$ describing the effective crossover in the normal phase from a Fermi gas of atoms to a gas of stable molecules.