Dissipative phase transition of interacting non-reciprocal fermions

TL;DR

This paper investigates how non-reciprocal couplings in an interacting fermionic chain induce a dissipative phase transition characterized by a many-body gap, altered relaxation dynamics, and unique entanglement properties.

Contribution

It reveals the effects of dissipation and interactions on quantum criticality, demonstrating a phase transition and dynamic reciprocity restoration in non-reciprocal fermionic systems.

Findings

Dissipative phase transition with many-body gap opening

Non-reciprocal signatures like nonzero currents and skin effect

Volume-law entanglement persists despite localization

Abstract

While non-reciprocal couplings are ubiquitous in classical systems, their impact on quantum many-body criticality and entanglement remains largely unexplored. Using exact numerical simulations, we study an interacting fermionic chain subject to non-reciprocal gain and loss. We show that the interplay between dissipation and interactions drives a dissipative phase transition, marked by the opening of a many-body gap and a crossover from power-law to exponential relaxation. The weakly-interacting regime displays non-reciprocal signatures, including nonzero currents and directional charge accumulation reminiscent of the skin effect. Notably, despite this localization, quantum trajectories exhibit volume-law entanglement. Finally, reciprocity is dynamically restored above a critical interaction strength.