Endpoint thermodynamics of an atomic Fermi gas subject to a Feshbach resonance

Abstract

The entropy and kinetic, potential, and interaction energies of an atomic Fermi gas in a trap are studied under the assumption of thermal equilibrium for finite temperature. A Feshbach resonance can cause the fermions to pair into diatomic molecules. The entropy and energies of mixtures of such molecules with unpaired atoms are calculated, in relation to recent experiments on molecular Bose-Einstein condensates produced in this manner. It is shown that, starting with a Fermi gas of temperature $T=0.1T_F^0$, where $T_F^0$ is the non-interacting Fermi temperature, an extremely cold degenerate Fermi gas of temperature $T\lesssim 0.01T_F^0$ may be produced without further evaporative cooling. This requires adiabatic passage of the resonance, subsequent sudden removal of unpaired atoms, and adiabatic return. We also calculate the ratio of the interaction energy to the kinetic energy, a straightforward experimental signal which may be used to determine the temperature of the atoms and indicate condensation of the molecules.

arXiv comment12 pages, 5 figures

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Cited by in corpus (7)

• Strongly Correlated Quantum Fluids: Ultracold Quantum Gases, Quantum Chromodynamic Plasmas, and Holographic Duality
• Thermodynamics of Interacting Fermions in Atomic Traps
• Ultracold two-component Fermi gases with a magnetic field gradient near a Feshbach resonance
• Thermometry of Fermionic Atoms in an Optical Lattice
• Asymmetric Fermi superfluid in a harmonic trap
• Adiabatic Phase Diagram of an Ultracold Atomic Fermi Gas with a Feshbach Resonance
• Ultracold Fermion Cooling Cycle using Heteronuclear Feshbach Resonances