In a time evolving photon-entanglement, the emission time of at least one of the entangled photons is used to deduce the most probable entanglement state.

摘要

A quantum information system is disclosed with provides a source of entangled photons, in which the entanglement state evolves with time. The system also includes timing means configured to indicate the most probable entangled state, based on the emission time of one or more of the photons. The timing means could be in the form of a time switched attenuator gate for blocking photons from being transmitted at particular points in time. Alternatively, a timing signal could be applied to a detector. The quantum information system may be a quantum key distribution (QKD) system. The source of entangled photons preferably comprises a quantum dot device which emits entangled photon pairs as a result of the decay of one or more biexcitons. The relevant timing information may be the time interval between the emission of the first photon and the second photon of the pair. The entangled state may vary periodically in time.