Microwave Quantum Illumination with Correlation-To-Displacement Conversion

Entanglement is vulnerable to degradation in a noisy sensing scenario, but surprisingly, the quantum illumination protocol has demonstrated that its advantage can survive. However, designing a measurement system that realizes this advantage is challenging since the information is hidden in the weak correlation embedded in the noise at the receiver side. Recent progress in a correlation-to-displacement conversion module provides a route towards an optimal protocol for practical microwave quantum illumination. In this work, we extend the conversion module to accommodate experimental imperfections that are ubiquitous in microwave systems. To mitigate loss, we propose amplification of the return signals. In the case of ideal amplification, the entire six-decibel error-exponent advantage in target detection error can be maintained. However, in the case of noisy amplification, this advantage is reduced to three decibels. We analyze the quantum advantage under different scenarios with a Kennedy receiver in the final measurement. In the ideal case, the performance still achieves the optimal one over a fairly large range of error probability with only on-off detection. Empowered by photon-number-resolving detectors, the performance is further improved and also analyzed in terms of receiver operating characteristic curves. Our findings pave the way for the development of practical microwave quantum illumination systems.

Automated summary

Quantum entanglement is vulnerable to degradation in noisy scenarios, but the quantum illumination protocol has shown that its advantage can still be maintained. Designing a measurement system to realize this advantage is challenging due to information hidden in weak correlations and noise. Recent progress in a correlation-to-displacement conversion module provides a potential solution for practical microwave quantum illumination. This study extends the conversion module to accommodate experimental imperfections and proposes signal amplification to mitigate loss, paving the way for the development of practical microwave quantum illumination systems.