Experimental realization of equiangular three-state quantum key distribution

TL;DR

This paper reports the experimental implementation of a three-state equiangular quantum key distribution protocol, achieving high secure key rates and demonstrating security against various attack models.

Contribution

It presents the first experimental realization of an entanglement-based three-state QKD protocol with passive optics and finite-key security analysis.

Findings

Secure key rate over 10 kbit/s achieved

Mean QBER of 1.6% measured

Security validated against collective and general attacks

Abstract

Quantum key distribution using three states in equiangular configuration combines a security threshold comparable with the one of the Bennett-Brassard 1984 protocol and a quantum bit error rate (QBER) estimation that does not need to reveal part of the key. We implement an entanglement-based version of the Renes 2004 protocol, using only passive optic elements in a linear scheme for the measurement POVM, generating an asymptotic secure key rate of more than 10 kbit/s, with a mean QBER of 1.6%. We then demonstrate its security in the case of finite key and evaluate the key rate for both collective and general attacks.