Sensing weak anharmonicities with a passive-active anti-PT symmetric system

TL;DR

This paper introduces a novel anti-PT symmetric cavity-magnon-waveguide system for highly sensitive detection of weak anharmonicities, leveraging linewidth suppression and tunable gain to enhance nonlinearities detection.

Contribution

It presents a new passive-active three-mode anti-PT symmetric scheme that improves sensitivity to weak nonlinearities in cavity and magnonic modes.

Findings

Linewidth suppression point can be flexibly controlled.

High sensitivity achieved for detecting weak nonlinearities.

Sensitivity is significantly enhanced with a detuned laser drive.

Abstract

We propose a scheme for enhanced sensing of weak anharmonicities based on a three-mode anti-parity-time (anti-PT) symmetric cavity-magnon-waveguide system. By tuning the optical gain to the active cavity mode, the linewidth suppression point for the anti-PT symmetric Hamiltonian can be flexibly controlled even when the two dissipative magnonic modes experience strong intrinsic decay. This essential characteristic is utilized for detecting weak nonlinearities in both the cavity and magnonic modes, with both demonstrating similar high levels of sensitivity. Moreover, the sensitivity can be greatly improved with a detuned laser drive. Based on the integrated passive-active three-mode anti-PT symmetric system, the sensing scheme can be generalized to various physical systems with anharmonicities.