Isothermal compressibility and effects of multi-body molecular interactions in a strongly interacting ultracold Fermi gas

Abstract

We theoretically investigate the isothermal compressibility ${\kappa }_T$ in the normal state of an ultracold Fermi gas. Including pairing fluctuations, as well as preformed-pair formations, within the framework of the self-consistent $T$-matrix approximation (SCTMA), we evaluate the temperature dependence of this thermodynamic quantity over the entire BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein condensation) crossover region. While ${\kappa }_T$ in the weak-coupling BCS regime is dominated by Fermi atoms near the Fermi surface, correlations between tightly bound Cooper-pair molecules are found to play crucial roles in the strong-coupling BEC regime. In the latter region, besides a two-body molecular interaction, a three-body one is shown to sizably affect ${\kappa }_T$ near the superfluid phase transition temperature. Our results indicate that the strong-coupling BEC regime of an ultracold Fermi gas would provide a unique opportunity to study multi-body correlations between Cooper-pair molecules.

30 pages, 13 figures

References in corpus (24)

• Many-Body Physics with Ultracold Gases
• Theory of ultracold Fermi gases
• Weakly bound dimers of fermionic atoms
• Collective excitations of a degenerate gas at the BEC-BCS crossover
• Using photoemission spectroscopy to probe a strongly interacting Fermi gas
• The Equation of State of a Low-Temperature Fermi Gas with Tunable Interactions
• Thermodynamics of the BCS-BEC crossover
• Universal Quantum Viscosity in a Unitary Fermi Gas
• Observation of pseudogap behavior in a strongly interacting Fermi gas
• Precision Measurements of Collective Oscillations in the BEC-BCS Crossover
• Viscosity and scale invariance in the unitary Fermi gas
• BCS-BEC crossover at finite temperature in the broken-symmetry phase
• Thermodynamic Measurements in a Strongly Interacting Fermi Gas
• Evolution of the Normal State of a Strongly Interacting Fermi Gas from a Pseudogap Phase to a Molecular Bose Gas
• Goldstone mode and pair-breaking excitations in atomic Fermi superfluids
• Breakdown of Fermi liquid description for strongly interacting fermions
• Speckle Imaging of Spin Fluctuations in a Strongly Interacting Fermi Gas
• Pseudo-gap pairing in ultracold Fermi atoms
• Quantum mechanical limitations to spin diffusion in the unitary Fermi gas
• Shear viscosity of a universal Fermi gas near the superfluid phase transition
• Comparative study of strong coupling theories of a trapped Fermi gas at unitarity
• Temperature of a trapped unitary Fermi gas at finite entropy
• Cooper pairing above the critical temperature in a unitary Fermi gas
• Hetero pairing and component-dependent pseudogap phenomena in an ultracold Fermi gas with mass imbalance

Cited by in corpus (1)

• Role of the effective range in the density-induced BEC-BCS crossover