@emergence The multiverse theory is based on the Law of Conservation of Information. When there is an event governed by quantum probability, all outcomes must occur for information to be conserved – but we only ever observe one outcome. Multiverse theory addresses this problem by saying that all other outcomes occur in universes parallel to our own. If an electron is in state A in our universe, the exact same electron is in state B in a parallel universe. The important point here is that it is the same particle, not a copy.
Quantum entanglement, according to this theory, by forcing two electrons into the same state. When you remove them from each other, they are in exactly the same state for all quantum numbers except location. Electron A is in my hand and B in yours in our universe, but in our parallel you have A and I have B. Because A is A, if I change its state in our universe, it will change state in your hand in our parallel. That will affect B due to proximity across the universes, which will in turn change the state of my B – it doesn’t matter how far away you are.
Quantum computing takes advantage of these principles to perform calculations in a way so that part of the calculation happens in each of the universes involved, and all receive the outcome.
My point with this whole question though, is that you have no antimatter self. Your self in any parallel universe is exactly like you would be with a small number of electrons in different shells – no outsider could tell the difference. There is no antimatter universe, because whatever caused the baryon asymmetry we observe would undoubtedly have acted across all universes, causing the same matter/antimatter imbalance we observe in our universe. The only antimatter we know of exists in microscopic amounts at particle accelerators or in high energy accretion rings around massive stars.