The quantum illumination story

Abstract

Quantum Radar! Check out what Wikipedia says about it: it might render stealth aircraft obsolete. Watch YouTube videos that purport to explain all about it. Read press reports in which China claims it field tested one in 2016. But is there any fire underneath all that smoke? This talk will answer that question by telling the story of “quantum illumination”, from its beginnings through recent theoretical and experimental results. Quantum illumination is the only quantum radar concept that has been proven, theoretically, to outperform all classical radars of the same transmitted energy in detecting a weakly-reflecting target that is embedded in strong background noise. It uses a source of quadrature-entangled signal and idler beams to gain its target-detection performance improvement despite loss and noise that destroys the entanglement. A realistic assessment of that improvement's utility, however, shows that its value is severely limited. Nevertheless, the fact that entanglement can be of value on an entanglement-breaking channel — the meta-lesson of the quantum illumination story — should spur continued research on quantum radar.