Basically, the Quantum Theory I'm talking about is the theory that there are other universes. Other dimensions or rooms.
If it is true, then they are non-existant inh our universe, but exist in some other form. It is there, infront of you, but you can't get to it and it's not there. It's pretty confusing when you get into the technical part of it though but it's easy enough to know the basics.
Some scientists who study this have took a gun to their head, and shot themselves, thinking that the bullet will degenerate and that they will exist in some other way.
Another example is the cat in the Quantum box. The cat is inside the box. Or is it?

So, what do you all think about this theory? Do you think it's true? If so, it could explain some other things like the big bang or photons.