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arXiv · 1807.04617

Quantum Critical Detector : Amplifying Weak Signals Using First-Order Dynamical Quantum Phase Transitions

Li-Ping Yang·Zubin Jacob
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Abstract

We introduce a first-order quantum-phase-transition model, which exhibits giant sensitivity $χ\propto N^2$ at the critical point. Exploiting this effect, we propose a quantum critical detector (QCD) to amplify weak input signals. The time-dynamic QCD functions by triggering a first-order dynamical quantum phase transition in a system of spins with long-range interactions coupled to a bosonic mode. We numerically demonstrate features of the dynamical quantum phase transition, which leads to a time-dependent quantum gain. We also show the linear scaling with the spin number $N$ in both the quantum gain and the corresponding signal-to-quantum noise ratio of this QCD. Our QCD can be a resource for metrology, weak signal amplification, and single photon detection.

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Li-Ping Yang, Zubin Jacob. 2018-11-26. Quantum Critical Detector : Amplifying Weak Signals Using First-Order Dynamical Quantum Phase Transitions. https://doi.org/10.1364/oe.27.010482

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