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arXiv · 2405.00328

Discrete Time Crystal Phase as a Resource for Quantum Enhanced Sensing

Rozhin Yousefjani·Krzysztof Sacha·Abolfazl Bayat
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Abstract

Discrete time crystals are a special phase of matter in which time translational symmetry is broken through a periodic driving pulse. Here, we first propose and characterize an effective mechanism to generate a stable discrete time crystal phase in a disorder-free many-body system with indefinite persistent oscillations even in finite-size systems. Then we explore the sensing capability of this system to measure the spin exchange coupling. The results show strong quantum-enhanced sensitivity throughout the time crystal phase. As the spin exchange coupling varies, the system goes through a sharp phase transition and enters a non-time crystal phase in which the performance of the probe considerably decreases. We characterize this phase transition as a second-order type and determine its critical properties through a comprehensive finite-size scaling analysis. The performance is independent of the initial states and may even benefit from imperfections in the driving pulse. A simple set of projective measurements can capture the quantum-enhanced sensitivity.

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Rozhin Yousefjani, Krzysztof Sacha, Abolfazl Bayat. 2024-05-01. Discrete Time Crystal Phase as a Resource for Quantum Enhanced Sensing. https://doi.org/10.1103/physrevb.111.125159

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