<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi mathvariant="script">PT</mml:mi></mml:math>-symmetry-breaking-enhanced cavity optomechanical magnetometry
Zhucheng Zhang, Yi-Ping Wang, Xiaoguang Wang
Abstract
A $\mathcal{PT}$-symmetry-breaking-enhanced cavity optomechanical magnetometer is proposed, which is achieved by monitoring the change in intensity of a nonlinear four-wave mixing (FWM) process in a gain-cavity-assisted cavity optomechanical system (COMS). Compared with the traditional single loss COMS, the FWM intensity can be enhanced by two orders of magnitude when the gain-cavity-assisted COMS operates on the $\mathcal{PT}$-symmetry-breaking phase. Meanwhile, the sensitivity of magnetic-field sensing can be increased from ${10}^{\ensuremath{-}9}\phantom{\rule{4pt}{0ex}}\mathrm{T}$ to ${10}^{\ensuremath{-}11}\phantom{\rule{4pt}{0ex}}\mathrm{T}$. This originally comes from the fact that the effective detuning and decay of the loss cavity can be effectively modified in the $\mathcal{PT}$-symmetry-breaking phase. Our work shows that an ultrahigh-sensitivity magnetometer can be achieved in the $\mathcal{PT}$-symmetry-breaking COMS, which will have wide applications in the field of quantum sensing.