So, the concept of parallel realities has been around for quite sometime. Although, recently a huge number of people probably believe in this concept. So, the question that comes to mind is whether parallel realities do exist of or not and how do they function.
Now, there have been experiments done in quantum mechanics related to this concept to better understand the principle.
You can see the video below to understand the science behind this principal. The video features Prof. Sean Carroll who is an expert in this subject.
To understand it in a better manner, Schrodinger conducted a cat experiment which was only a THOUGHT experiment. The cat was placed in container which had a radioactive atom. If the atom decayed, the detector detected the radiation and the poison gas would be released and the cat died. However, if the atom did not decay the detector would not detect the radiation and the gas would not be released, so the cat would survive.
So, assuming that no measurements or observations took place, the atom would be in a superposition state meaning decayed and not decayed at the same time. So, that would imply that the cat is both dead and alive at the same time when not being observed. And if we open the container then the wave function would collapse meaning it would either decay or not decay, ie. either the cat would be dead or alive. So, the cat is in superposition with the atom.
So, the idea was that why is the wave function collapsing on observation. The answer is it does not collapse. But, when we observe the cat, we become a part of the system. We are in superposition, so we see the cat both dead and alive at the same time. So, here is where the theory of the parallel worlds comes into play. If we see the cat alive, another version of us sees the cat dead. The other version of us exists in some other world.
So, the idea is that split or branching keeps happening all the time. There are different realities existing at any point. Some things might not happen for example an electron will not become a proton or vice versa, but different things could happen depending on the circumstances or whatever.
So, depending on the choices you make you will experience the timeline that you want to experience. Currently, there might be a version of you that is living the life that you want to really live. So, all you have to do is to tune into that vibration that will lead you to be that version. This is what a lot of law of attraction experts talk about. If you are able to do that, you will live the life that you would like to live.