Fermionic superfluidity: From high Tc superconductors to ultracold Fermi gases

TL;DR

This paper develops a pairing fluctuation theory for BCS-BEC crossover, applying it to high Tc superconductors and ultracold Fermi gases, highlighting the pseudogap phenomenon and experimental evidence in these systems.

Contribution

It introduces a self-consistent pairing fluctuation theory that unifies the understanding of superfluidity in high Tc superconductors and ultracold Fermi gases.

Findings

Evidence of pseudogap in ultracold Fermi gases

Phase diagrams with population imbalance analyzed

Strong similarities between unitary Fermi gases and high Tc superconductors

Abstract

We present a pairing fluctuation theory which self-consistently incorporates finite momentum pair excitations in the context of BCS--Bose-Einstein condensation (BEC) crossover, and we apply this theory to high $T_c$ superconductors and ultracold Fermi gases. There are strong similarities between Fermi gases in the unitary regime and high Tc superconductors. Here we address key issues of common interest, especially the pseudogap. In the Fermi gases we summarize recent experiments including various phase diagrams (with and without population imbalance), as well as evidence for a pseudogap in thermodynamic and other experiments.