Security of continuous-variable quantum key distribution: towards a de Finetti theorem for rotation symmetry in phase space

• Main Authors: Leverrier, Anthony (Contributor), Karpov, Evgueni (Author), Grangier, P. (Author), Cerf, Nicolas J. (Contributor)
• Other Authors: Massachusetts Institute of Technology. Research Laboratory of Electronics (Contributor)
• Format: Article
• Language: English
• Published: Institute of Physics Publishing, 2012-05-09T20:26:32Z.
• Subjects: Article
• Online Access: Get fulltext

 Proving the unconditional security of quantum key distribution (QKD) is a highly challenging task as one needs to determine the most efficient attack compatible with experimental data. This task is even more demanding for continuous-variable QKD as the Hilbert space where the protocol is described is infinite dimensional. A possible strategy to address this problem is to make an extensive use of the symmetries of the protocol. In this paper, we investigate a rotation symmetry in phase space that is particularly relevant to continuous-variable QKD, and explore the way towards a new quantum de Finetti theorem that would exploit this symmetry and provide a powerful tool to assess the security of continuous-variable protocols. As a first step, a single-party asymptotic version of this quantum de Finetti theorem in phase space is derived.