Multicritical quantum sensors driven by symmetry-breaking

TL;DR

This paper demonstrates that symmetry-breaking alone can enable quantum-enhanced sensing, achieving Heisenberg scaling without gap-to-gapless transitions, and explores multicritical systems for multiparameter quantum sensing.

Contribution

It reveals symmetry-breaking as a standalone resource for quantum sensing and extends analysis to multiparameter estimation in multicritical systems.

Findings

Heisenberg scaling achieved near multicritical points in the Kitaev model.

Symmetry-breaking alone can drive quantum-enhanced sensing without gapless transitions.

Multiparameter estimation shows $L^6$ scaling with observable consequences.

Abstract

Quantum criticality has been demonstrated as a useful quantum resource for parameter estimation. This includes second-order, topological and localization transitions. In all these works reported so far, gap-to-gapless transition at criticality has been identified as a crucial resource for achieving the quantum-enhanced sensing, although there are several important concepts associated with criticality, such as long-range correlation, symmetry breaking. In this work, we show that symmetry-breaking alone can drive a quantum-enhanced sensing, even without any gap-to-gapless transition. We analytically demonstrate that the estimation of the superconducting pairing amplitude in the one-dimensional Kitaev model achieves Heisenberg scaling when the system is prepared near a multicritical point and is varied along a gapless critical line, implying symmetry breaking as a standalone metrological resource. Extending our analysis in the realm of simultaneous multiparameter estimation of both the pairing term and the chemical potential, we show that it is possible to obtain $L^6$ scaling in a narrow parameter range, but with definite observable consequence, where the quantum advantage is assisted by gap-to-gapless transition as well. Our work thus identifies a new resource for criticality-enhanced quantum sensing, and also suggests multicritical systems as useful platform for multiparameter sensing.