Reference‐Frame‐Independent Asynchronous Measurement‐Device‐Independent Quantum Key Distribution

Abstract Asynchronous quantum key distribution protocol (AMDI‐QKD) is a high performance quantum key distribution protocol while it can outperform the Pirandola–Laurenza–Ottaviani–Banchi (PLOB) bound without the need of phase‐locking and phase‐tracking techniques. However, the protocol applies the relative phase information of the communicating parties for encoding, and the drift of the reference frame inevitably affects the performance of the QKD system, whereas reference frame independent quantum key distribution (RFI‐QKD) has the advantage of tolerating the slow change of the reference frame. In this study, a reference frame‐independent asynchronous quantum key distribution (RFI‐AMDI‐QKD) scheme is proposed, which does not require phase alignment between the interferometers of both parties, and it is shown that the protocol can transmit over long distances and is robust to the drift of the reference frame.