Do you mean multiple universes existing at the same time but in other dimensions? This is a staple of science fiction and as a teenager, I use to greedily devour science fiction. The answer is no, of course not. It is a fanciful idea that has no evidence whatsoever to back it up. A bit like theology, in fact.

By the way: a good example of a science fiction alternative universe story is Bob Shaw's A Wreath of Stars. Excellent stuff.