Main Question or Discussion Point
What are the characteristics of a photon that cause it's parts to behave similarly when split in two and then to reform later ?
A photon does not "split in two". You need to be very careful with the language that you use to describe physics to avoid any confusion.What are the characteristics of a photon that cause it's parts to behave similarly when split in two and then to reform later ?
I've not read the article thoroughly, but since the second paragraph begins with "the twin-photon experiment" I don't think that one photon splits into two.This experiment splits a photon in two;
You need to be very careful when reading such a thing. The photon wasn't split, but rather two correlated photons were sent in opposite direction as part of a EPR-type experiment.This experiment splits a photon in two;
This reference rejoins quantum bits of photons after teleportation;
It seems the photon must have characteristics that allows these results.
I don't understand what they could be if a photon as a unit of energy is supposed to be an indivisble entity.
You read it correctly, but not in terms of the physics. That's why I said that you really should read up on what is meant by a parametric down conversion. Naively, the incoming photon actually causes a atomic transition, but the decay of that transition undergoes two separate energy levels, which produces the two photons. These two photons will have the total spin orientation of the original photon.This is a quote from the site.
"One way to create a pair of entangled twins is to start with a single photon of ultraviolet radiation and pass it through a peculiar artificial mineral called a "down-conversion crystal." In the Swiss experiment, the crystal consisted of potassium niobate. The crystal splits the photon in two, producing two new photons that continue on in somewhat different directions, and whose combined energy equals the energy of their parent photon."
Am I reading this incorrectly ?
I think you may need to do a lot of background reading on a lot of "water that has passed under the bridge", so to speak. You might want to look around PF for discussions (there have been a lot of threads on these) on (i) superposition and (ii) entanglement, EPR-type experiments, non-locality, etc.Actually these are some of the photon characteristics I was seeking in my original question, although maybe I didn't phrase the question clearly and implied a condition that doesn't exist.
Even though more clearly explained by the Spontaneous parametric down conversion than the site, in any event two photons are the result with the combined energy of the parent photon. But more, the photon pair make the same decisions with regard to possibly 10 different pathways to select in an interferometer even when they are separated by significant distances. It seems to me , this may imply additional characteristics that may be related to atomic transition and spin orientation when separation occurs. But, also possibly with properties not yet fully explored such as a connection or awareness not affected by distance. There seems to be something here not fully explained.
What do you think ?