Efficient measurement-device-independent quantum key distribution without vacuum sources

摘要

We present an efficient decoy-state protocol measurement-device-independent quantum key distribution without vacuum source, with the heralded single-photon source (HSPS) and global optimization. This protocol is able to give a high key rate and avoid the security problem caused by the vacuum source or extremely weak source. In the protocol, the heralded outcome pulse pairs in X basis are used as decoy pairs and all outcome pairs in Z basis are used as signal pairs. Each side uses three different intensities for the outcome pulses, two in X basis and one in Z basis. In order to efficiently optimize the key rate globally, we present an efficient method to estimate what values we will observe by using the HSPS. This efficient method greatly reduces the computation complexity from the fourfold summation to a single-fold summation in the numerical simulation and makes it operable to seek the optimization points globally.