Pair correlations in the normal phase of an attractive Fermi gas

Abstract

In a recent paper [Phys. Rev. A 99, 053617 (2019)], the total number of fermion pairs in a spin-balanced two-component Fermi gas of ${}^6$Li atoms was experimentally probed in the normal phase above the superfluid critical temperature, in order to investigate the sectors of pseudogap and preformed-pair in the temperature-coupling phase diagram. Here, we present a theoretical account of these experimental results in terms of an ab-initio self-consistent $t$-matrix calculation, which emphasizes the role of the pair-correlation function between opposite-spin fermions at equilibrium. Good agreement is found between the available experimental data and the theoretical results obtained with no adjustable parameter.

arXiv comment16 pages, 11 figures

References in corpus (22)

• BCS-BEC Crossover: From High Temperature Superconductors to Ultracold Superfluids
• Large momentum part of fermions with large scattering length
• Energetics of a strongly correlated Fermi gas
• The BCS-BEC crossover: From ultra-cold Fermi gases to nuclear systems
• Homogeneous Atomic Fermi Gases
• On the correct strong-coupling limit in the evolution from BCS superconductivity to Bose-Einstein condensation
• Spectral Functions and rf Response of Ultracold Fermionic Atoms
• Viscosity and scale invariance in the unitary Fermi gas
• Modified Structure of Protons and Neutrons in Correlated Pairs
• Single-particle properties and pseudogap effects in the BCS-BEC crossover regime of an ultracold Fermi gas above Tc
• Spectral response and contact of the unitary Fermi gas
• Contact and sum-rules in a near-uniform Fermi gas at unitarity
• Self-consistent theory for molecular instabilities in a normal degenerate Fermi gas in the BEC-BCS crossover
• Evolution from BCS superconductivity to Bose-Einstein condensation: Current correlation function in the broken-symmetry phase
• Thermodynamics of a trapped unitary Fermi gas
• Fermi gas throughout the BCS-BEC crossover: Comparative study of t-matrix approaches with various degrees of self-consistency
• Thermal equilibrium and efficient evaporation of an ultracold atom-molecule mixture
• Entanglement between pairing and screening in the Gorkov-Melik-Barkhudarov correction to the critical temperature throughout the BCS-BEC crossover
• Temperature dependence of the pair coherence and healing lengths for a fermionic superfluid throughout the BCS-BEC crossover
• Detecting a preformed pair phase: The response to a pairing forcing field
• Pair fraction in a finite temperature Fermi gas on the BEC side of the BCS-BEC crossover
• From superconducting fluctuations to the bosonic limit in the response functions above the critical temperature

Cited by in corpus (10)

• Transition from a polaronic condensate to a degenerate Fermi gas of heteronuclear molecules
• Tunneling transport of unitary fermions across the superfluid transition
• Solution of the BEC to BCS Quench in One Dimension
• Beyond-mean-field description of a trapped unitary Fermi gas with mass and population imbalance
• Josephson effect at finite temperature along the BCS-BEC crossover
• Multi-Particle Tunneling Transport at Strongly-Correlated Interfaces
• Sound emission and annihilations in a programmable quantum vortex collider
• Peaks and widths of radio-frequency spectra: An analysis of the phase diagram of ultra-cold Fermi gases
• Mechanical stability of resonant Bose-Fermi mixtures
• Strong Fulde-Ferrell Larkin-Ovchinnikov pairing fluctuations in polarized Fermi systems