Giant emitter magnetometer

Leveraging the sensitive dependence of a giant atom's relaxation rate on its frequency [A. F. Kockum et al., Phys. Rev. A 90, 013837 (2014)], we propose an effective magnetometer model based on a single giant emitter. In this model, the emitter's frequency is proportional to the applied bias magnetic field. The self-interference effect causes the slope of the decay rate to vary linearly with the number of emitter-waveguide coupling points. The giant emitter magnetometer achieves a sensitivity as high as ${10}^{\ensuremath{-}8}--{10}^{\ensuremath{-}9}\phantom{\rule{0.28em}{0ex}}\mathrm{T}/\sqrt{\mathrm{Hz}}$, demonstrating the significant advantages of the self-interference effect compared to small emitters. We hope our proposal will expand the applications of giant emitters in precision measurement and magnetometry.