Sending-or-not-sending twin field quantum key distribution with imperfect vacuum sources

Abstract The sending-or-not-sending (SNS) protocol of the twin-field (TF) quantum key distribution (QKD) can tolerant large misalignment error and its rate exceed linear bound repeaterless QKD. original SNS all variants TF-QKD require perfect vacuum sources, but in real world experiments there is no practical source. Instead, experimenters use extremely weak sources to substitute which may break security protocol. Here we propose an with imperfect give non-asymptotic decoy-state analysis this Our numerical simulation shows that when are close our obtain similar as sources. This first result closes potential loophole due TF-QKD.