Is Quantum Money a Waste of Time?

The idea of a universal currency realized by quantum states was first proposed by Weisner in 1983 [1]. Weisner’s proposal was quickly dismissed as little more than a novel, albeit practically useless idea, because of its lack of realizability. Since then, the idea of Quantum Money has received little attention, compared to far more popular areas of research such as quantum computation and quantum communication. However, new advancements and research in digital currencies, quantum communication, and quantum cryptography present attractive avenues which warrant revisiting the idea Quantum Money. Current cryptographic currencies solve the double-spending problem often by integrating a blockchain which is backed by hard-to-solve cryptographic hash functions. This ensures that each “coin” is unique, and also maintains the value of the underlying asset via the difficulty of “mining” such coins through the hash-solving process. The study of Quantum Information presents many concepts such as quantum teleportation, quantum digital signatures, and quantum secret sharing which make its application to such problems extremely attractive and a rich source of scientific research. In this study, we ask ourselves the question, "Is Quantum Money a waste of time?". We begin by discussing the vulnerabilities and inefficiencies of present digital currency schemes. We then proceed to a thorough literature review and categorization of research regarding quantum money since Weisner’s proposal, discussing the improvements each scheme proposes, and classifying the methods used to do so. Finally, we motivate our own proposals to incorporate quantum technology into cryptocurrency.