A team of Italian and Chinese researchers propose a method that uses entangled photons as radar probes.
The quantum radar methods so far proposed could determine the distance to an object more precisely than classical radar, but they offered no improvements in determining its direction. The new method does both.
The team expanded to 3D a previously proposed 1D method. They accounted for all the spatial degrees of freedom of the entangled photons, and they analyzed how the radar signal would propagate from the target object to the receiver. They found that for N entangled-photon radar probes, the 3D region of possible positions of an object narrowed by N3∕2 compared to a classical radar scheme using the same number of independent photons.
The technique does have limitations, including a high sensitivity to noise: Losing even one entangled photon would cost the system some of its advantage over the classical version. But there are ways to mitigate this problem. (Physics)
This research has published in Physical Review Letters.