This question already has an answer here:
Some theories propose that there are more universes.
In one of them it is said that there are parallel universes, due to inflations after the big bang that created them.
But in the two-slit experiment is also known the multiverses theorie. The probability wave is not collapsing but each possibility is creating a universe on his own.
So they both speak about other universes. But is there a link between them? Or are that just completely different things/theories?