Continuous Sensing and Parameter Estimation with the Boundary Time Crystal

Cabot, Albert; Carollo, Federico; Lesanovsky, Igor

Abstract

A boundary time crystal is a quantum many-body system whose dynamics is governed by the competition between coherent driving and collective dissipation. It is composed of N two-level systems and features a transition between a stationary phase and an oscillatory one. The fact that the system is open allows one to continuously monitor its quantum trajectories and to analyze their dependence on parameter changes. This enables the realization of a sensing device whose performance we investigate as a function of the monitoring time T and of the system size N. We find that the best achievable sensitivity is proportional to TN, i.e., it follows the standard quantum limit in time and Heisenberg scaling in the particle number. This theoretical scaling can be achieved in the oscillatory time-crystal phase and it is rooted in emergent quantum correlations. The main challenge is, however, to tap this capability in a measurement protocol that is experimentally feasible. We demonstrate that the standard quantum limit can be surpassed by cascading two time crystals, where the quantum trajectories of one time crystal are used as input for the other one.

Citation

Cabot, A., Carollo, F., & Lesanovsky, I. (2024). Continuous Sensing and Parameter Estimation with the Boundary Time Crystal. Physical Review Letters, 132(5), Article 050801. https://doi.org/10.1103/physrevlett.132.050801

• Journal Article Type: Article
• Acceptance Date: Nov 28, 2023
• Online Publication Date: Jan 30, 2024
• Publication Date: Feb 2, 2024
• Deposit Date: Jan 22, 2024
• Publicly Available Date: Jan 30, 2024
• Journal: Physical Review Letters
• Print ISSN: 0031-9007
• Electronic ISSN: 1079-7114
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 132
• Issue: 5
• Article Number: 050801
• DOI: https://doi.org/10.1103/physrevlett.132.050801
• Keywords: Quantum parameter estimation; Quantum sensing; Time crystals
• Public URL: https://nottingham-repository.worktribe.com/output/30109641