Many body exchange effects close to the s-wave Feshbach resonance in two-component Fermi systems: Is a triplet superfluid possible?

TL;DR

This paper explores how exchange fluctuations near a Feshbach resonance in two-component Fermi gases can induce p-wave attraction, potentially leading to a triplet superfluid state, and models molecular binding energies.

Contribution

It demonstrates that exchange fluctuations can create a significant p-wave attraction near the resonance, suggesting the possibility of a triplet superfluid in current experimental conditions.

Findings

Exchange fluctuations induce effective p-wave attraction.

Effective scattering length remains finite near resonance.

Modeling of molecular binding energy on the BEC side.

Abstract

We suggest that the exchange fluctuations close to a Feshbach resonance in a two-component Fermi gas can result in an effective p-wave attractive interaction. On the BCS side of a Feshbach resonance, the magnitude of this effective interaction is comparable to the s-wave interaction, therefore leading to a possible spin-triplet superfluid in the range of temperatures of actual experiments. We also show that the particle-hole exchange fluctuations introduce an effective scattering length which does not diverge, as the standard mean-field one does. Finally, using the effective interaction quantities we are able to model the molecular binding energy on the BEC side of the resonance.