Pairing-induced phase transition in the non-reciprocal Kitaev chain

TL;DR

This paper explores how pairing interactions induce a phase transition in a non-reciprocal Kitaev chain, revealing new phases and behaviors in non-Hermitian quantum systems through reservoir engineering.

Contribution

It demonstrates the emergence of a pairing-induced phase transition and novel phases in a non-reciprocal Kitaev chain using reservoir engineering techniques.

Findings

Identification of a pairing-induced phase transition.

Discovery of a density wave phase at strong pairing.

Characterization of non-reciprocal correlations and dynamics.

Abstract

Investigating the robustness of non-reciprocity in the presence of competing interactions is central to understanding non-reciprocal quantum matter. In this work, we use reservoir engineering to induce non-reciprocal hopping and pairing in the fermionic Kitaev chain, and reveal the emergence of a pairing-induced phase transition. The two phases appear in the spectrum of the non-Hermitian Kitaev Hamiltonian describing the dynamics of correlations, separated by an exceptional point. In the non-reciprocal phase, dynamics are characterized by directionality and slow relaxation, and the steady state supports non-reciprocal density and spatial correlations. At strong pairing, we uncover an unexpected density wave phase, featuring short relaxation times, a modulation in particle occupation and strikingly different correlation spreading depending on pairing non-reciprocity. Our work highlights the non-trivial breakdown of non-reciprocity due to superconducting pairing and invites experimental investigation of non-reciprocal fermionic systems.