Topological effects on transition temperatures and response functions in three-dimensional Fermi superfluids

TL;DR

This paper explores how topological order influences the transition temperature and response functions in three-dimensional fermionic superfluids with spin-orbit coupling, revealing suppressed $T_c$ and distinctive response signatures of topological phases.

Contribution

It provides a theoretical analysis of topological effects on $T_c$ and response functions in 3D Fermi superfluids, including fluctuations beyond mean-field and relevance to ultracold atomic gases.

Findings

Topological phase stabilizes away from BEC towards BCS limit.

Transition temperature $T_c$ is significantly suppressed in topological superfluids.

Response functions show signatures of topological phases through frequency-dependent peaks.

Abstract

We investigate the effects of topological order on the transition temperature, $T_c$, and response functions in fermionic superfluids with Rashba spin-orbit coupling and a transverse Zeeman field in three dimensions. Our calculations, relevant to the ultracold atomic Fermi gases, include fluctuations beyond mean-field theory and are compatible with $f$-sum rules. Reminiscent of the $p_x + i p_y$ superfluid, the topological phase is stabilized when driven away from the Bose-Einstein condensation and towards the BCS limit. Accordingly, while experimentally accessible, $T_c$ is significantly suppressed in a topological superfluid. Above $T_c$, the spin and density response functions provide signatures of topological phases via the recombination or amplification of frequency dependent peaks.