Resonantly enhanced superconductivity mediated by spinor condensates

TL;DR

This paper demonstrates that resonant enhancement of fermionic superconductivity can be achieved via a two-component spinor BEC, significantly increasing pairing strength and critical temperature through tuning to a quantum critical point.

Contribution

It introduces a novel mechanism for enhancing fermion interactions by using a spinor BEC at a quantum critical point, with proposed experimental setups.

Findings

Fermion pairing gap is significantly increased near the spinodal point.

Superconducting critical temperature can be dramatically enhanced.

Resonant enhancement is achievable in exciton-polariton and ultracold atomic systems.

Abstract

Achieving strong interactions in fermionic many-body systems is a major theme of research in condensed matter physics. It is well-known that interactions between fermions can be mediated through a bosonic medium, such as a phonon bath or Bose-Einstein condensate (BEC). Here we show that such induced attraction can be resonantly enhanced when the bosonic medium is a two-component spinor BEC. The strongest interaction is achieved by tuning the boson-boson scattering to the quantum critical spinodal point of the BEC where the sound velocity vanishes. The fermion pairing gap and the superconducting critical temperature can thus be dramatically enhanced. We propose two experimental realizations of this scenario, with exciton-polariton systems in two-dimensional semiconductors and ultracold atomic Bose-Fermi mixtures.