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TT: Fachverband Tiefe Temperaturen
TT 58: Poster: Superconductivity II
TT 58.10: Poster
Thursday, March 30, 2023, 15:00–18:00, P2/OG3
Microwave single-shot quantum key distribution — •Florian Fesquet1,2, Fabian Kronowetter1,2,4, Michael Renger1,2, Nadezhda Kukharchyk1,2, Hans Huebl1,2,3, Achim Marx1, Rudolf Gross1,2,3, and Kirill. G. Fedorov1,2 — 1Walther- Meißner-Institut, 85748 Garching, Germany — 2Technical University of Munich, TUM School of Natural Sciences, Physics Department, 85748 Garching, Germany — 3Munich Center for Quantum Science and Technology (MCQST), 80799 Munich, Germany — 4Rohde & Schwarz GmbH, 81671 Munich, Germany
Security of modern classical data encryption often relies on computationally hard-to-solve problems. A potential remedy for this challenge is quantum communication (QC) which takes advantage of the laws of quantum physics to provide secure exchange of information. Here, quantum key distribution (QKD) represents a powerful tool, allowing unconditionally secure QC between remote parties. A demand for QC at microwave frequencies has emerged due to the tremendous progress in quantum information processing with superconducting circuits. To this end, we present a realization of a continuous-variable QKD protocol based on displaced squeezed microwave states. We use a Josephson parametric amplifier (JPA) to generate squeezed microwave states at cryogenic temperatures. By implementing a single-shot quadrature readout with a second JPA in the phase-sensitive regime with quantum efficiency of 38 %, we demonstrate the unconditional security of this microwave QKD protocol. We analyze these results in terms of losses and noise in order to map them on possible real-world scenarios.