Thermodynamic Properties of Universal Fermi Gases

Abstract

We develop a simple, mean-field-like theory for the normal phase of a unitary Fermi gas by deriving a self-consistent equation for its self-energy via a momentum-dependent coupling constant for both attractive and repulsive universal fermions. For attractive universal fermions in the lower branch of a Feshbach resonance, we use zero-temperature Monte Carlo results as a starting point for one-step iteration in order to derive an analytical expression for the momentum-dependent self-energy. For repulsive universal fermions in the upper branch of a Feshbach resonance, we iteratively calculate the momentum-dependent self-energy via our self-consistent equation. Lastly, for the case of population imbalance, we propose an ansatz for higher order virial expansion coefficents. Overall, we find that our theory is in good agreement with currently available, high temperature experimental data.

7 pages, 6 figures; http://link.aps.org/doi/10.1103/PhysRevA.87.013602

References in corpus (12)

• Theory of ultracold Fermi gases
• Generalized Virial Theorem and Pressure Relation for a strongly correlated Fermi gas
• Pure Gas of Optically Trapped Molecules Created from Fermionic Atoms
• Itinerant Ferromagnetism in a Fermi Gas of Ultracold Atoms
• Normal state of a polarized Fermi gas at unitarity
• Critical Temperature and Thermodynamics of Attractive Fermions at Unitarity
• Ultra-cold Polarized Fermi Gases
• Thermodynamic Measurements in a Strongly Interacting Fermi Gas
• Quantum mechanical limitations to spin diffusion in the unitary Fermi gas
• Renormalization Group Theory for the Imbalanced Fermi Gas
• Virial expansion for a strongly correlated Fermi gas with imbalanced spin populations
• Quantum quench dynamics of the Bose-Hubbard model at finite temperatures