Expansion of a Fermi Cloud in the BCS-BEC Crossover

Abstract

We study the free expansion of a dilute two-component Fermi gas with attractive interspecies interaction in the BCS-BEC crossover. We apply a time-dependent parameter-free density-functional theory by using two choices of the equation of state: an analytic formula based on Monte Carlo data and the mean-field equation of state resulting from the extended BCS equations. The calculated axial and transverse radii and the aspect ratio of the expanding cloud are compared to experimental data on vapors of ^6Li atoms. Remarkably, the mean-field theory shows a better agreement with the experiments than the theory based on the Monte Carlo equation of state. Both theories predict a measurable dependence of the aspect ratio on expansion time and on scattering length.

5 pages, 3 figures

References in corpus (5)

• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Observation of Bose-Einstein Condensation of Molecules
• Weakly bound dimers of fermionic atoms
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Collective modes and ballistic expansion of a Fermi gas in the BCS-BEC crossover

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• Superfluid Bose-Fermi mixture from weak-coupling to unitarity
• DC Josephson Effect with Fermi gases in the Bose-Einstein regime
• Macroscopic Periodic Tunneling of Fermi Atoms in the BCS-BEC Crossover
• Effective Nonlinear Schrödinger Equations for Cigar-Shaped and Disk-Shaped Fermi Superfluids at Unitarity
• Nonlinear Schroedinger equation for a superfluid Bose gas from weak coupling to unitarity: Study of vortices
• Condensate Fraction of a Two-Dimensional Attractive Fermi Gas
• Hydrodynamics of Bose and Fermi superfluids at zero temperature: the superfluid nonlinear Schrodinger equation
• Low-temperature thermodynamics of the unitary Fermi gas: superfluid fraction, first sound and second sound
• Fermi-Bose mixture across a Feshbach resonance
• DC and AC Josephson effects with superfluid Fermi atoms across a Feshbach resonance
• Mean-Field vs Monte-Carlo equation of state for the expansion of a Fermi superfluid in the BCS-BEC crossover
• Gradient corrections to the local density approximation for trapped superfluid Fermi gases
• Dynamical properties of the unitary Fermi gas: collective modes and shock waves