Free-Space Quantum Signatures Using Heterodyne Measurements

Croal C, Peuntinger C, Heim B, Khan I, Marquardt C, Leuchs G, Wallden P, Andersson E, Korolkova N (2016)

Publication Type: Journal article

Publication year: 2016

Journal

Physical Review Letters American Physical Society

Book Volume: 117

Article Number: 100503

Journal Issue: 10

DOI: 10.1103/PhysRevLett.117.100503

Abstract

Digital signatures guarantee the authorship of electronic communications. Currently used "classical" signature schemes rely on unproven computational assumptions for security, while quantum signatures rely only on the laws of quantum mechanics to sign a classical message. Previous quantum signature schemes have used unambiguous quantum measurements. Such measurements, however, sometimes give no result, reducing the efficiency of the protocol. Here, we instead use heterodyne detection, which always gives a result, although there is always some uncertainty. We experimentally demonstrate feasibility in a real environment by distributing signature states through a noisy 1.6 km free-space channel. Our results show that continuous-variable heterodyne detection improves the signature rate for this type of scheme and therefore represents an interesting direction in the search for practical quantum signature schemes. For transmission values ranging from 100% to 10%, but otherwise assuming an ideal implementation with no other imperfections, the signature length is shorter by a factor of 2 to 10. As compared with previous relevant experimental realizations, the signature length in this implementation is several orders of magnitude shorter.

Authors with CRIS profile

Christoph Marquardt Institut für Optik, Information und Photonik Gerhard Leuchs

Involved external institutions

Heriot-Watt University GB United Kingdom (GB) Max-Planck-Institut für die Physik des Lichts (MPL) / Max Planck Institute for the Science of Light DE Germany (DE) University of St Andrews GB United Kingdom (GB) University of Edinburgh GB United Kingdom (GB)

How to cite

APA:

Croal, C., Peuntinger, C., Heim, B., Khan, I., Marquardt, C., Leuchs, G.,... Korolkova, N. (2016). Free-Space Quantum Signatures Using Heterodyne Measurements. Physical Review Letters, 117(10). https://doi.org/10.1103/PhysRevLett.117.100503

MLA:

Croal, Callum, et al. "Free-Space Quantum Signatures Using Heterodyne Measurements." Physical Review Letters 117.10 (2016).

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