Demonstration of a 6 State-4 State Reference Frame Independent channel for Quantum Key Distribution

• Published in: arXiv.org
• Main Authors: Tannous, Ramy, Ye, Zhangdong, Jin, Jeongwan, Kuntz, Katanya B, Lütkenhaus, Norbert, Jennewein, Thomas
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 19.11.2019
• Subjects: Physics - Quantum Physics; Polarization; Quantum cryptography
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1905.09197

We study a novel protocol for reference frame independent (RFI) quantum key distribution (QKD) using six states for Alice and four states for Bob, while previous RFI protocols require a six state analyzer for Bob. Our protocol can generate a secure key for any possible phase of the entangled state, provided the variation is small compared to the measurement rate, shown by our numerical key rate analysis. We perform a proof-of-principle experiment using polarization entangled photon pairs. In the presence of a varying rotational phase, we obtain a consistently low error rate of less than \(4\%\) indicating the feasibility of this protocol for QKD. Our protocol is hence beneficial but not limited to applications in satellite or mobile free-space QKD, where a communication node must limit resources and restrict the number of measured states to four instead of six.