According to TNG "Parallels" matter in each universe has a quantum signature unique to that universe:SPOCK: You are assuming that Nero knows how events are predicted to unfold. To the contrary, Nero's very presence has altered the flow of history, beginning with the attack on the USS Kelvin, culminating in the events of today, thereby creating an entire new chain of incidents that cannot be anticipated by either party.
UHURA: An alternate reality?
SPOCK: Precisely. Whatever our lives might have been, if the time continuum was disrupted, our destinies have changed. Mr. Sulu, plot a course to the Laurentian system warp factor three.
DATA: All matter in the universe resonates on a quantum level with a unique signature. That signature is constant. It cannot be changed through any known process. It is the basic foundation of existence.
RIKER: Are you saying that Worf's quantum signature is different from ours?
DATA: Yes, sir. I cannot explain it. It is as if he originates from a different quantum universe.
So the question I had was: Is the quantum signature of the Kelvin Universe the same as that of the Prime Universe?
In Discovery episode "Despite Yourself" they were able to determine that they were in a different universe by using this quantum signature method
SARU: I may have something.
The quantum signature of the Cooper, as well as that of the Vulcan cruiser, are inconsistent with ours.
BURNHAM: That's not possible.
All matter native to our universe resonates with the same quantum signature, nothing can change it.
Unless this is not our universe.
If the Kelvin and Prime Universe have the same quantum signature then would that make them in the same universe given that the quantum signature was supposed to be unique to each universe? Or are quantum signatures not necessarily unique to each universe if the universes are created from a branching off process? Or if they do have different quantum signatures, was it always that way? Or did the Kelvin Universe's quantum signature suddenly change when Nero traveled back in time? If that's the case then would that not be a way to change the quantum signature given the quantum signature was supposed to be unalterable?