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arXiv · 2310.11013

Quantum limits of covert target detection

Guo Yao Tham·Ranjith Nair·Mile Gu
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Abstract

In covert target detection, Alice attempts to send optical or microwave probes to determine the presence or absence of a weakly-reflecting target embedded in thermal background radiation within a target region, while striving to remain undetected by an adversary, Willie, who is co-located with the target and collects all light that does not return to Alice. We formulate this problem in a realistic setting and derive quantum-mechanical limits on Alice's error probability performance in entanglement-assisted target detection for any fixed level of her detectability by Willie. We demonstrate how Alice can approach this performance limit using two-mode squeezed vacuum probes in the regime of small to moderate background brightness, and how such protocols can outperform any conventional approach using Gaussian-distributed coherent states. In addition, we derive a universal performance bound for non-adversarial quantum illumination without requiring the passive-signature assumption.

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Guo Yao Tham, Ranjith Nair, Mile Gu. 2023-10-17. Quantum limits of covert target detection. https://doi.org/10.1103/physrevlett.133.110801

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