A new look at quantum radar suggests it might boost accuracy more than thought

Phys.org  January 10, 2022 Despite the many proposals for quantum radar, none have delineated the ultimate quantum limit on ranging accuracy. A team of researchers in the US (University of Arizona, MIT) has derived that limit through continuous-time quantum analysis. They showed that quantum illumination ranging—a quantum pulse-compression radar that exploits the entanglement between a high time-bandwidth product transmitted signal pulse and a high time-bandwidth product retained idler pulse—achieves that limit. They also showed that quantum illumination ranging offers mean-squared range-delay accuracy that can be tens of dB better than that of a classical pulse-compression radar of the same pulse […]

Scientists demonstrate quantum radar prototype

Science Daily  May 8, 2020 Instead of using conventional microwaves, an international team of researchers (Austria, UK. USA – MIT, Italy) entangled two groups of photons, which are called the ‘signal’ and ‘idler’ photons. The ‘signal’ photons are sent out towards the object of interest, whilst the ‘idler’ photons are measured in relative isolation, free from interference and noise. When the signal photons are reflected back, true entanglement between the signal and idler photons is lost, but a small amount of correlation survives, creating a signature or pattern that describes the existence or the absence of the target object — […]