Opportunities and Challenges of Quantum Radar

It has been recognized for over half a century that quantum mechanics defines the ultimate limits for sensing devices, and products of that recognition are now on the horizon of practical implementation. One of the most promising of those products is quantum radar, which offers a capability to significantly improve the tradeoff between energy and detection sensitivity compared to classical alternatives. We provide a back-of-the-envelope and implementation-agnostic analysis to glimpse the kinds of expected improvement that a quantum radar could provide for applications of interest. Our analysis relies on relatively simplistic models that are only intended to facilitate an intuitive grasp of quantum-versus-classical distinctions. Such analyses of course cannot lead to definitive conclusions, but we believe they provide evidence that in some contexts quantum radar can be expected to offer realizable practical advantages over classical alternatives. We conclude with a discussion of theoretical and practical obstacles and a high-level summary of what can be said about the present status of quantum radar.