Superfluidity in many fermion systems: Exact renormalisation group treatment

Abstract

The application of the exact renormalisation group to symmetric as well as asymmetric many-fermion systems with a short-range attractive force is studied. Assuming an ansatz for the effective action with effective bosons, describing pairing effects a set of approximate flow equations for the effective coupling including boson and fermionic fluctuations has been derived. The phase transition to a phase with broken symmetry is found at a critical value of the running scale. The mean-field results are recovered if boson-loop effects are omitted. The calculations with two different forms of the regulator are shown to lead to a similar results. We find that, being quite small in the case of the symmetric many-fermion system the corrections to mean field approximation becomes more important with increasing mass asymmetry.

Talk given at the IVth International Conference on Quarks and Nuclear Physics (QNP06), Madrid, 5-10 June 2006

References in corpus (8)

• Non-Perturbative Renormalization Flow in Quantum Field Theory and Statistical Physics
• Interior Gap Superfluidity
• Phase separation in asymmetrical fermion superfluids
• A renormalisation-group treatment of two-body scattering
• Derivative expansion and renormalisation group flows
• Cold asymmetrical fermion superfluids
• Effective Action and Renormalization Group Flow of Anisotropic Superconductors
• Off-shell effects and consistency of many-body treatments of dense matter

Cited by in corpus (5)

• Functional renormalization group approach to correlated fermion systems
• The nonperturbative functional renormalization group and its applications
• Effective interactions and fluctuation effects in spin-singlet superfluids
• Low energy singularities in the ground state of fermionic superfluids
• Exact renormalisation group flow for ultracold Fermi gases in unitary limit