Entanglement‐Enhanced Quantum Ranging in Near‐Earth Spacetime

Abstract

A quantum ranging protocol to determine the distance between an observer and a target in the near‐Earth curved spacetime is proposed. Unlike quantum illumination, the quantum ranging scheme utilizes multiple quantum hypothesis testing to simultaneously determine the presence and location of the target. The interest is in how the Earth's spacetime curvature influences photon propagation as well as the performance of the quantum ranging. It is found that the maximum potential advantage of the quantum ranging strategy in the curved spacetime outperforms its flat spacetime counterpart. It is shown that the number of transmitted modes can enhance the maximum potential advantage of the quantum ranging tasks. In contrast, the maximum potential advantage of quantum ranging cannot be significantly increased by dividing the range into multiple slices in the curved spacetime.