Quantum Ranging with Gaussian Entanglement

It is well known that entanglement can benefit quantum information processing tasks. Quantum illumination, when first proposed, was surprising as the entanglement's survived entanglement-breaking noise. Since then, many efforts have been devoted to study sensing in noisy scenarios. The applicability of such schemes, however, limited a binary hypothesis testing scenario. In terms target detection, schemes interrogate single spatiotemporal resolution bin at time, limiting impact radar detection. We resolve this binary-hypothesis limitation by proposing an entanglement-assisted ranging protocol. By formulating task multiary problem, we show enables 6-dB advantage error exponent against optimal classical scheme. Moreover, proposed protocol also be used implement pulse-position modulated communication Our reveals potential general tasks and paves way toward quantum-ranging with provable advantage.