Non-Hermitian topological Fermi superfluid near the $p$-wave unitary limit

TL;DR

This paper explores the complex interplay of non-Hermitian effects, topological phase transitions, and superfluidity in a one-dimensional Fermi gas near a $p$-wave resonance, revealing loss-induced transitions and fragility of superfluid states.

Contribution

It introduces a theoretical framework for non-Hermitian superfluid phase transitions near the $p$-wave unitary limit, unifying thermodynamics, topology, and non-Hermitian physics.

Findings

Loss-induced superfluid-normal transition at exceptional points

Diffusive gapless mode as a precursor to instability

Superfluid fragility near topological transition

Abstract

We theoretically discuss the non-Hermitian superfluid phase transition in one-dimensional two-component Fermi gases near the $p$-wave Feshbach resonance accompanied by the two-body loss associated with the dipolar relaxation. For the first time we point out that this system gives us an opportunity to explore the interplay among various non-trivial properties such as universal thermodynamics at divergent $p$-wave scattering length, topological phase transition at vanishing chemical potential, and non-Hermitian Bardeen-Cooper-Schrieffer(BCS) to Bose-Einstein condensate (BEC) transition, in a unified manner. In the BCS phase, the loss-induced superfluid-normal transition occurs when the exceptional point appears in the effective non-Hermitian Hamiltonian. In the BEC phase, the diffusive gapless mode can be regarded as a precursor of the instability of the superfluid state. Moreover, we show that the superfluid state is fragile against the two-body loss near the topological phase transition point.