Efficiency in Quantum Key Distribution Protocols with Entangled Gaussian States

Abstract

Quantum key distribution (QKD) refers to specific quantum strategies which permit the secure distribution of a secret key between two parties that wish to communicate secretly. Quantum cryptography has proven unconditionally secure in ideal scenarios and has been successfully implemented using quantum states with finite (discrete) as well as infinite (continuous) degrees of freedom. Here, we analyze the efficiency of QKD protocols that use as a resource entangled gaussian states and gaussian operations only. In this framework, it has already been shown that QKD is possible (M. Navascués et al. Phys. Rev. Lett. 94, 010502 (2005)) but the issue of its efficiency has not been considered. We propose a figure of merit (the efficiency $E$) to quantify the number of classical correlated bits that can be used to distill a key from a sample of $N$ entangled states. We relate the efficiency of the protocol to the entanglement and purity of the states shared between the parties.

13 pages, 2 figures, OSID style, published version

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• Efficiency in Quantum Key Distribution Protocols with Entangled Gaussian States

Cited by in corpus (11)

• High-bandwidth squeezed light at 1550 nm from a compact monolithic PPKTP cavity
• Multipartite secret key distillation and bound entanglement
• Gaussian entanglement in the turbulent atmosphere
• Gaussian Entanglement for Quantum Key Distribution from a Single-Mode Squeezing Source
• Continuous-wave non-classical light with GHz squeezing bandwidth
• Multipartite Continuous Variable Solution for the Byzantine Agreement Problem
• Continuous Variable Solution for Byzantine Agreement
• Operational Quantification of Continuous Variable Correlations
• Efficiency in Quantum Key Distribution Protocols with Entangled Gaussian States
• Fundamental limitations to key distillation from Gaussian states with Gaussian operations
• Quantum Information with Continuous Variable systems