Realization, Characterization, and Detection of Novel Superfluid Phases with Pairing between Unbalanced Fermion Species

TL;DR

This paper reviews recent advances in understanding and detecting novel superfluid phases arising from pairing between unbalanced fermion species, highlighting experimental and theoretical insights into their properties and detection methods.

Contribution

It provides a comprehensive overview of experimental and theoretical developments in identifying and characterizing superfluid phases with imbalanced fermion pairing, including symmetry and topological analysis.

Findings

Identification of superfluid phases with unbalanced fermion pairing

Proposed experimental probes for detecting superfluid order parameters

Analysis of Fermi surface structures in imbalanced systems

Abstract

In this chapter we review recent experimental and theoretical work on various novel superfluid phases in fermion systems, that result from pairing fermions of different species with unequal densities. After briefly reviewing existing experimental work in superconductors subject to a strong magnetic field and trapped cold fermionic atom systems, we discuss how to characterize the possible pairing phases based on their symmetry properties, and the structure/topology of the Fermi surface(s) formed by the unpaired fermions due to the density imbalance. We also discuss possible experimental probes that can be used to directly detect the structure of the superfluid order parameter in superconductors and trapped cold atom systems, which may establish the presence of some of these phases unambiguously.