Is there another universe out there? Possibility

Is there another universe out there where we could have the opposite of ourselves? Like an alternate/parallel universe?

Example: A girl with brunette hair( here ) would have blond hair in the other universe.

If you can catch my drift.. then that's good.

I was just reading up on this the other day as it relates to quantum computers. I don't have a clear understanding of how the calculations take place across every universe simultaneously. But I do know that dispensing with the knowledge that every universe participates is immediately reflected in the results! From what I was able to understand, the universes themselves are not the type where you and everyone you know is doing something different. The quantum state splits off, not a whole cosmos. However, that quantum state embodies the entire knowledge of the situation from which it departed and carries it into the next interaction. What is interacting? You may need to ask an expert. But it goes something like this. Waves are the building blocks of coherence. Coherence is the distinguishing nature of reality from its inscrutable partner, Superposition. Coherence is why you perceive the universe in just the way you think it truly is. Don't read too much into it. Everyone else sees the same world. These are quantum effects, not macroscopic phenomena. I'll do my best to sum it up in one sentence. Forgive my poor lexicon. The wave function of all particles in the universe corresponding to any particular world will be a product of states that do not constitute "objects". This means that brunette girl will not appear as blond girl, because the alternative world does not constitute a product. Blond girl satisfies the particular ambiguity inherent in a rigorous prediction. How then does every universe participate in the interaction? Whew. You really are giving me a work out today. Every universe crosses the time line simultaneously as a conical surface. Outside of the two inverted cones is space in the complex region; that is, it's not reachable by force. As the wave function in a universe interferes with others like it, the decomposition can be expressed as the expectation value of the projection operator on the space of quantum states corresponding to the actual values of all physical variables describing the world.