Critical region of the superfluid transition in the BCS-BEC crossover

Abstract

We determine the size of the critical region of the superfluid transition in the BCS-BEC crossover of a three-dimensional fermion gas, using a renormalization-group approach to a bosonic theory of pairing fluctuations. For the unitary Fermi gas, we find a sizable critical region $[T_G^{-},T_G^{+}]$, of order $T_c$, around the transition temperature $T_c$ with a pronounced asymmetry: $|T_G^{+}-T_c|/|T_G^{-}-T_c|\sim 8$. The critical region is strongly suppressed on the BCS side of the crossover but remains important on the BEC side.

v1) 7 pages, 3 figures, v2) revised version

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• Kibble-Zurek universality in a strongly interacting Fermi superfluid
• Mapping out spin and particle conductances in a quantum point contact
• Breakdown of the Wiedemann-Franz law in a unitary Fermi gas
• Thermography of the superfluid transition in a strongly interacting Fermi gas
• The pseudogap regime in the unitary Fermi gas
• Quantum critical thermal transport in the unitary Fermi gas
• Interaction-Assisted Reversal of Thermopower with Ultracold Atoms
• Quantum Lifshitz points and fluctuation-induced first-order phase transitions in imbalanced Fermi mixtures
• Collective excitations of superfluid Fermi gases near the transition temperature
• ${\mathbb{Z}}_4$-symmetric perturbations to the XY model from functional renormalization
• Beyond Gaussian pair fluctuation theory for strongly interacting Fermi gases
• Enhanced superconducting-fluctuation effects on thermodynamic properties in BCS-BEC-crossover regime
• Criticality of the $O(2)$ model with cubic anisotropies from nonperturbative renormalization
• Stabilization of vortex-liquid state by strong pairing interaction