Source: Documentary Heaven
Quantum Suicide is a thought experiment that was originally conceived in 1987 by Hans Moravec but later independently developed by Max Tegmark in 1998.
It is one of those ideas that really squeezes your brain juices in an effort to produce an elixir of profound contemplation.
The idea goes a little something like: get yourself one unobservable room, a healthy physicist and death inducing device i.e. a gun. However it so happens that this gun contains a moving particle and only fires when the particle is moving counterclockwise. There is a 50% chance of this.
The idea is that the physicist is situated in this room alone, holds the gun to his head and pulls the trigger. If the particle is moving counterclockwise we have one dead body and a hell of a mess on our hands (Quantum Suicide), otherwise a misfire is witnessed and the lucky physicist gets to have another go.
Well probability would have you believe that under these circumstances there is a 50% chance of survival for the first iteration and if you were unlucky enough to die in this sick and twisted room of disparity there is a definite 0% chance of survival, right.
Here is where it gets interesting, Quantum Immortality supposes that at this point the universe splits into two, one where the physicist is dead and one where he is alive. However because in one universe his consciousness is permanently terminated, the physicist can only consciously perceive the other, the one in which he survived. This means that the physicist will only ever experience the gun misfiring and therefore allow for immortality, in his eyes alone.
At this point however if you were to introduce an observer they may very well witness the death of a crazed suicidal physicist and think nothing more of it, as their consciousness remains unaffected by this entire bizarre and can continue going about their business in that particular universe.
This is merely a thought experiment that currently rests unproven however there are many real world examples that help provide evidence that such quantum operations may exist. One of which is Photosynthesis, it is a known fact that the process of Photosynthesis uses a quantum transport system to figure out the most efficient way to guide incoming light hitting a leaf and store it as energy in a plant or tree’s reaction centers. The light is said to travel through all routes first before choosing the most efficient and because of this it is theoretically possible that your conciseness does something similar and follows all stems of your life choices, ultimately choosing the one where you live the longest.