Alternative schemes for measurement-device-independent quantum key distribution

TL;DR

This paper introduces practical measurement-device-independent quantum key distribution schemes using phase, path, or time encoding, featuring simple modules, dead-time management, and a decoy-state variant with linear key rate scaling.

Contribution

It presents new practical MDI-QKD schemes that are simpler, more efficient, and scalable, addressing detection loopholes and detector dead-time issues.

Findings

Scheme employs only two single-photon detectors.

Decoy-state variant achieves linear key rate scaling.

Setup is immune to detection loopholes.

Abstract

Practical schemes for measurement-device-independent quantum key distribution using phase and path or time encoding are presented. In addition to immunity to existing loopholes in detection systems, our setup employs simple encoding and decoding modules without relying on polarization maintenance or optical switches. Moreover, by employing a modified sifting technique to handle the dead-time limitations in single-photon detectors, our scheme can be run with only two single-photon detectors. With a phase-postselection technique, a decoy-state variant of our scheme is also proposed, whose key generation rate scales linearly with the channel transmittance.