Squeezing enhanced sensing at an exceptional point
arXiv:2507.17961 · doi:10.1103/kmtx-7x9d
Abstract
Pushing the boundaries of measurement precision is central for sensing and metrology, pursued by nonclassical resources such as squeezing, and non-Hermitian degeneracies with distinct spectral response. Their convergence, however, remains challenging. We find extraordinary enhancement of sensitivity by unifying both effects in a general framework for quantum sensing in open systems. At the parametric oscillation threshold and an exceptional point, the sensing precision exhibits a unique quartic scaling with the perturbation strength. The result generalizes to multimode squeezed-state sensors with higher-order exceptional points catered to various quantum sensing platforms.
Version accepted for publication in Physical Review Letters. 3 figures in the main text, 4 figures in the Supplemental Material