Microwave Quantum Illumination with Correlation-To-Displacement Conversion

Abstract

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.

Quantum illumination and quantum radar: a brief overview

“…The correlation-to-displacement architecture was applied to microwave QI in [64] where it was extended to accommodate experimental inefficiencies associated with this regime. By introducing a loss to to the return mode, associated with nonideal coupling with the receiver, results showed that even with amplification a good quantum advantage compared to the ideal classical system can be guaranteed.…”

Microwave Gaussian Quantum Sensing With a CNOT Gate Receiver

“…The full 6 dB advantage can be hypothetically attained with the complicated sum frequency generation (SFG) receiver and its extremely intricate upgrade, feed-forward SFG (FF-SFG) [13]. However, recent progress has been made towards saturating the full quantum advantage by proposing less demanding receiver architectures that only utilize heterodyne measurements and photodetection [14], [15]. Moreover, very recently the authors here [16] managed to achieve a 3dB advantage with only homodyne and heterodyne detection without the need for a joint signal-idler measurement.…”