In quantum mechanics, a particle is in several places at once, yet only exists in one of those places when you look at it.
Obviously, it exists across all space-times in that point. That is why, whenever you view a particle it only appears at one point, because at all other of those points, of that inhabited space, it is in all other space-times in the dimensional universe.
This may or may not speak to concepts of travel or alternative universes. I wouldn't stick my head out.