Method and system for identifying entangled photons with one-way classical information sharing

A system for identifying entangled photons, the system comprising:

• a) an entangled photon source that generates a plurality of sets of four entangled photons wherein each of the four entangled photons appear at an output at a same time and a pair of photons in each of the plurality of sets of four entangled photons are time correlated indicating that another pair of photons in a same one of each of the plurality of sets of four entangled photons are time correlated:
• b) a coincidence detector having at least one input optically coupled to the output of the entangled photon source, the coincidence detector determining coincidences of a pair of photons of at least some of the plurality of sets of four entangled photons and generating signals at an output related to determined coincidences;
• c) a photon detector having at least one input optically coupled to the output of the entangled photon source, the photon detector determining a state value of at least one of the other pair of photons of at least some of the plurality of sets of four entangled photons and generating signals at an output related to determined state values;
• d) a first processor having an input coupled to the output of the coincidence detector, the first processor recording the determined coincidences generated by the coincidence detector and generating an ordered list of coincidences;
• e) a second processor having an input coupled to the output of the photon detector, the second processor recording the determined state values generated by the photon detector and generating an ordered list of state values;
• and
• f) a third processor having an input coupled to at least one of the first and second processors, the third processor comparing the ordered list of coincidences to the ordered list of state values to determine entangled state information that comprises determined state values that correspond to entangled sets of four entangled photons.

A system for identifying entangled photons, the system comprising:

• a) an entangled photon source that generates a plurality of sets of four entangled photons wherein each of the four entangled photons appear at an output at a same time and wherein a pair of photons in each of the plurality of sets of four entangled photons are time correlated indicating that another pair of photons in a same one of each of the plurality of sets of four entangled photons are time correlated;
• and
• b) a coincidence detector having at least one input optically coupled to the output of the entangled photon source, the coincidence detector determining coincidences of a pair of photons of at least some of the plurality of sets of four entangled photons and generating heralding signals at an output related to determined coincidences;
• and
• c) a photon detector having at least one input optically coupled to the output of the entangled photon source and an input connected to the output of the coincidence detector, the photon detector determining a state value of at least one of the other pair of photons of at least some of the plurality of sets of four entangled photons based on at least one of the generated heralding signals.

A system for identifying entangled photons, the system comprising:

• a) an entangled photon source that generates a plurality of sets of four entangled photons at an output, wherein a pair of photons in each of the plurality of sets of four entangled photons are time correlated indicating that another pair of photons in a same one of each of the plurality of sets of four entangled photons are time correlated;
• b) a coincidence detector having at least one input optically coupled to the output of the entangled photon source, the coincidence detector determining coincidences of a pair of photons of at least some of the plurality of sets of four entangled photons and generating signals at an output related to determined coincidences;
• c) a photon detector having at least one input optically coupled to the output of the entangled photon source, the photon detector determining a state value of at least one of the other pair of photons of at least some of the plurality of sets of four entangled photons and generating signals at an output related to determined state values;
• d) a first processor having an input coupled to the output of the coincidence detector, the first processor recording the determined coincidences generated by the coincidence detector and generating an ordered list of coincidences;
• e) a second processor having an input coupled to the output of the photon detector, the second processor recording the determined state values generated by the photon detector and generating an ordered list of state values;
• and
• f) a third processor having an input coupled to at least one of the first and second processors, the third processor comparing the ordered list of coincidences to the ordered list of state values to determine entangled state information that comprises determined state values that correspond to entangled sets of four entangled photons,
• wherein the at least one of the first, second, or third processors is configured to generate in response to signals generated by a meta-data collector one or more of a number of coincidences in a time window, time-windows of expected entangled pairs based on pump pulse information, background counts, expected background levels based on detector bias point, measurement start and stop times in some coordinated time frame, deterministic quantum state coherence levels, probabilistic estimates of quantum state coherence levels, or wavefunction characteristics.