Critical parametric quantum sensing

TL;DR

This paper investigates the use of driven-dissipative phase transitions in parametric Kerr resonators to enhance quantum sensing, demonstrating achievable Heisenberg-limited precision and practical protocols for improved quantum magnetometry and qubit readout.

Contribution

It provides a comprehensive analysis of quantum Fisher information and Helstrom bounds in critical nonlinear resonators, proposing protocols to leverage criticality for quantum metrology.

Findings

Heisenberg precision is achievable with realistic parameters.

Critical behavior enhances quantum magnetometry.

Protocols improve superconducting qubit readout fidelity.

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.