Renormalization of the BCS-BEC crossover by order parameter fluctuations

Abstract

We use the functional renormalization group approach with partial bosonization in the particle-particle channel to study the effect of order parameter fluctuations on the BCS-BEC crossover of superfluid fermions in three dimensions. Our approach is based on a new truncation of the vertex expansion where the renormalization group flow of bosonic two-point functions is closed by means of Dyson-Schwinger equations and the superfluid order parameter is related to the single particle gap via a Ward identity. We explicitly calculate the chemical potential, the single-particle gap, and the superfluid order parameter at the unitary point and compare our results with experiments and previous calculations.

5 pages, 3 figures

References in corpus (8)

• Many-Body Physics with Ultracold Gases
• Crossover from a molecular Bose-Einstein condensate to a degenerate Fermi gas
• Quantum Fluctuations in the Superfluid State of the BCS-BEC Crossover
• Large-N expansion for unitary superfluid Fermi gases
• Collective fields in the functional renormalization group for fermions, Ward identities, and the exact solution of the Tomonaga-Luttinger model
• Particle-hole fluctuations in the BCS-BEC Crossover
• Renormalization group flow for fermionic superfluids at zero temperature
• Functional renormalization group approach to the Anderson impurity model