Enhanced quantum sensing with hybrid exceptional-diabolic singularities

TL;DR

This paper demonstrates enhanced quantum sensing sensitivity near hybrid exceptional-diabolic singularities in a four-mode bosonic system, achieving a twofold improvement in error scaling over non-HED points.

Contribution

It introduces the concept of hybrid exceptional-diabolic singularities in quantum sensing and shows how they can be exploited for improved measurement precision.

Findings

Twofold improvement in estimation error scaling at HED singular points

Quantum Fisher information bounds the ultimate measurement precision

Heterodyne detection achieves optimal sensitivity at HED points

Abstract

We report an enhanced sensitivity for detecting linear perturbations near hybrid (doubly degenerated) exceptional-diabolic (HED) singular points in a four mode bosonic system. The sensitivity enhancement is attributed to a singular response function, with the pole order determining the scaling of estimation error. At HED singular points, the error scaling exhibits a twofold improvement over non-HED singular points. The ultimate bound on estimation error is derived via quantum Fisher information, with heterodyne detection identified as the measurement achieving this optimal scaling.