Critical Quantum Sensing

Critical quantum sensing (CQS) is by now a well-established approach, based on the exploitation of quantum properties spontaneously developed in proximity of phase transitions.

Numerous theoretical studies and first experimental demonstrations show that a quantum-enhanced sensing precision can be achieved by exploiting static or dynamical properties of many-body systems in proximity of the critical point [1]. It has been recently shown [2] that CQS protocols can also be implemented using finite-component phase transitions (FCPTs), where the thermodynamic limit is replaced with a rescaling of the system parameters. This class of phase transitions emerges in quantum resonators with atomic or Kerr-like nonlinearities, and it is of high theoretical and experimental relevance. 
Here, we show [3,4] that optimal quantum sensing protocols can be implemented using FCPTs taking place in small-scale solid-state quantum technologies, without the need to implement and control complex many-body systems. We then report on the experimental implementation [5] of a driven-dissipative CQS protocol with a parametrically pumped Kerr resonator, which has direct applications in magnetometry and superconducting-qubit readout. Finally, we discuss how these ideas could be transferred to the context of quantum optomechanics.

[1] V. Montenegro et al. arXiv:2408.15323v2 (2024) 

[2] L. Garbe et al. Phys. Rev. Lett. 124, 120504 (2020)

[3] R. Di Candia et al npj Quant. Inf. 9, 23 (2023)

[4] U. Alushi et al. Phys. Rev. Lett. 133, 040801 (2024)

[5] G. Beaulieu arXiv:2409.19968 (2024)