Nonreciprocal Amplification Transition in a Driven-Dissipative Quantum Network

TL;DR

This paper explores how nonreciprocal amplification in driven-dissipative quantum networks relates to topological and edge state phenomena, revealing new insights for long-range coupled systems.

Contribution

It uncovers the connection between nonreciprocal amplification transitions and zero-energy edge states in long-range coupled quantum networks.

Findings

Nonreciprocal amplification linked to topological phase transition in short-range coupling.

In long-range coupling, amplification transition relates to zero-energy edge states.

Analysis of stability, crossover, and bandwidth of amplification.

Abstract

We study the transport properties of a driven-dissipative quantum network, where multiple bosonic cavities such as photonic microcavities are coupled through a nonreciprocal bus with unidirectional transmission. For short-range coupling between the cavities, the occurrence of nonreciprocal amplification can be linked to a topological phase transition of the underlying dynamic Hamiltonian. However, for long-range coupling, we find that the nonreciprocal amplification transition deviates drastically from the topological phase transition. Nonetheless, we show that the nonreciprocal amplification transition can be connected to the emergence of zero-energy edge states of an auxiliary Hamiltonian with chiral symmetry even in the long-range coupling limit. We also investigate the stability, the crossover from short to long-range coupling, and the bandwidth of the nonreciprocal amplification. Our work has potential application in signal transmission and amplification, and also opens a window to non-Hermitian systems with long-range coupling and nontrivial boundary effects.