Critical parametric quantum sensing

TLDR

Critical quantum systems offer a promising resource for quantum metrology because their susceptibility diverges near phase transitions. The study assesses the metrological power of parametric Kerr resonators undergoing driven‑dissipative phase transitions and designs protocols that exploit their critical behavior to improve quantum magnetometer precision and superconducting qubit readout fidelity. The authors characterize the quantum Fisher information and Helstrom bound for frequency estimation and discrimination, and design protocols that leverage the critical behavior of nonlinear resonators. They demonstrate that Heisenberg‑limited precision can be achieved with experimentally reachable parameters beyond the asymptotic regime.

Abstract

Abstract Critical quantum systems are a promising resource for quantum metrology applications, due to the diverging susceptibility developed in proximity of phase transitions. Here, we assess the metrological power of parametric Kerr resonators undergoing driven-dissipative phase transitions. We fully characterize the quantum Fisher information for frequency estimation, and the Helstrom bound for frequency discrimination. By going beyond the asymptotic regime, we show that the Heisenberg precision can be achieved with experimentally reachable parameters. We design protocols that exploit the critical behavior of nonlinear resonators to enhance the precision of quantum magnetometers and the fidelity of superconducting qubit readout.