This theoretical project lies in the rapidly growing field of quantum information science. It brings together fundamental quantum mechanics and state-of-the-art quantum technology. We will investigate novel schemes for digital signatures that use quantum mechanics. Digital signatures ensure that messages cannot be forged or tampered with, and are widely used to provide security for electronic communications, for example in financial transactions and electronic mail. Much like quantum key distribution, quantum digital signatures can be made unconditionally secure, based on laws of quantum mechanics. Essentially, security relies on the fact that it is impossible to perfectly distinguish between non-orthogonal quantum states. Realisations of long-distance and entanglement-based schemes for quantum digital signatures are likely to include both optical and condensed-matter components. In this project, we will outline new schemes, investigate their security properties and, in collaboration with experimentalists, devise feasible realisations. 

References:  Clarke et al., Nature Communications 3, 1174 (2012) Dunjko et al. arXiv:1309.1375, to appear in Physical Review Letters  Collins et al. arXiv:1311.5760

Please send inquiry emails to Prof. Erika Andersson at