Method to mitigate propagation loss in waveguide transmission of quantum states

摘要

A system comprises a source of entangled photon pairs. The source is to place a signal photon and an idler photon in individual unknown quantum states but in a known entangled quantum state. One or more transmission channels are connected to the source. Each of the one or more transmission channels transmits one of the signal photon or the idler photon. Each of the one or more transmission channels is to substantially balance an instantaneous transmission loss with an instantaneous transmission gain distributed over a transmission distance. Analysis interferometers are configured to receive a corresponding one of the signal photon or the idler photon. Each of the one or more analysis interferometers is to perform a basis measurement on one of the signal photon or the idler photon. Single-photon detectors detect one of the signal photon or the idler photon.