That particular link is to a study that doesn’t recombine beams, and is still fully explained by a classical model. It does show that if you change the polarization of one of an entangled pair, the polarization of the other does not change.
But I’m concerned about something different. Specifically, I’m responding to the observation that if a beam is polarized to vertical, split via PBS to \ and / components, and then recombined, the recombined beam is vertically polarized (as measured by passing through a vertical/horizontal PBS and being directed to two detectors). I’m asking what happens if the beam is recombined after only one half of the beam has been delayed for longer than the beam length.
If / is delayed by 100ms (roughly the distance to geostationary orbit, although materials with a lower speed of light might be used) and the pulse length is ~30ms, I expect the detectors to indicate a 30ms pulse equally between them, followed 100ms later by another. I have not found an experiment that tests this or a closely analogous case.
If / is precise to within the limits of experimentation, but the pulse length is a single photon, I expect the detectors to detect with 50% chance. I believe that I have seen summaries of experiments that say my expectations are incorrect. I assume here that it is not within our ability to match two path lengths to within the time it takes light to travel the distance occupied by one photon, if nothing else due to Brownian motion of the lowest-temperature medium we can have.
If my expectation in the former case is incorrect, I ask what happens if there is a shutter placed in the path of /, such that iff the detectors indicate a vertically polarized beam, / is blocked before it recombines.
That particular link is to a study that doesn’t recombine beams, and is still fully explained by a classical model. It does show that if you change the polarization of one of an entangled pair, the polarization of the other does not change.
But I’m concerned about something different. Specifically, I’m responding to the observation that if a beam is polarized to vertical, split via PBS to \ and / components, and then recombined, the recombined beam is vertically polarized (as measured by passing through a vertical/horizontal PBS and being directed to two detectors). I’m asking what happens if the beam is recombined after only one half of the beam has been delayed for longer than the beam length.
If / is delayed by 100ms (roughly the distance to geostationary orbit, although materials with a lower speed of light might be used) and the pulse length is ~30ms, I expect the detectors to indicate a 30ms pulse equally between them, followed 100ms later by another. I have not found an experiment that tests this or a closely analogous case.
If / is precise to within the limits of experimentation, but the pulse length is a single photon, I expect the detectors to detect with 50% chance. I believe that I have seen summaries of experiments that say my expectations are incorrect. I assume here that it is not within our ability to match two path lengths to within the time it takes light to travel the distance occupied by one photon, if nothing else due to Brownian motion of the lowest-temperature medium we can have.
If my expectation in the former case is incorrect, I ask what happens if there is a shutter placed in the path of /, such that iff the detectors indicate a vertically polarized beam, / is blocked before it recombines.