Quantum and thermal noise in coupled non-Hermitian waveguide systems with different models of gain and loss

TL;DR

This paper compares how different gain and loss mechanisms in non-Hermitian waveguide systems influence quantum and thermal noise, revealing universal properties and effects on eigenstructure, noise power, and photon statistics.

Contribution

It provides a comprehensive analysis of how various gain/loss models affect noise characteristics and eigenstructure in non-Hermitian photonic systems, highlighting universal behaviors.

Findings

Eigenvalue/eigenvector structure varies with gain/loss models

Noise power scales linearly with waveguide length

Universal properties include gain-loss compensation and phase transitions

Abstract

Non-Hermitian (NH) photonic systems leverage gain and loss to open new directions for nanophotonic technologies. However, the quantum and thermal noise intrinsically associated with gain/loss affects the eigenvalue/eigenvector structure of NH systems, as well as its practical noise performance. Here, we present a comparative analysis of the impact of different gain and loss mechanisms on the noise generated in gain-loss compensated NH waveguide systems. Our results highlight important differences in the eigenvalue/eigenvector structure, noise power, photon statistics and squeezing. At the same time, we identify some universal properties such as gain-loss compensation, broken to unbroken phase transitions, coalesce of pairs of eigenvectors, and linear scaling of the noise with the length of the waveguide. We believe that these results provide a more global understanding on the impact of the gain/loss mechanism on the noise generated in NH systems.