Cyclic permutation-time symmetric structure with coupled gain-loss microcavities

TL;DR

This paper investigates a cyclic permutation-time symmetric microcavity system with balanced gain and loss, revealing unique dynamical patterns, exceptional points, and the influence of quantum noise on light transport.

Contribution

It introduces a novel cyclic permutation-time symmetric structure with coupled gain-loss microcavities and analyzes its quantum dynamical properties and noise effects.

Findings

Multiple exceptional points lead to system 'phase transitions'

Quantum noise disrupts reciprocal light transport

Dynamical evolution patterns depend on symmetry and gain-loss balance

Abstract

We study the coupled even number of microcavities with the balanced gain and loss between any pair of their neighboring components. The effective non-Hermitian Hamiltonian for such structure has the cyclic permutation-time symmetry with respect to the cavity modes, and this symmetry determines the patterns of the dynamical evolutions of the cavity modes. The systems also have multiple exceptional points for the degeneracy of the existing supermodes, exhibiting the "phase transition" of system dynamics across these exceptional points. We illustrate the quantum dynamical properties of the systems with the evolutions of cavity photon numbers and correlation functions. Moreover, we demonstrate the effects of the quantum noises accompanying the amplification and dissipation of the cavity modes. The reciprocal light transportation predicted with the effective non-Hermitian models for the similar couplers is violated by the unavoidable quantum noises.