'In quantum mechanics, quantum suicide is a thought experiment. It was originally published independently by Hans Moravec in 1987 and Bruno Marchal in 1988 and was independently developed further by Max Tegmark in 1998.
'It attempts to distinguish between the Copenhagen interpretation of quantum mechanics and the Everett many-worlds interpretation by means of a variation of the Schrödinger's cat thought experiment, from the cat's point of view.
'Unlike the Schrödinger's cat thought experiment which used poison gas and a radioactive decay trigger, this version involves a life-terminating device and a device that measures the spin value of protons. Every 10 seconds, the spin value of a fresh proton is measured. Conditioned upon that quantum bit, the weapon is either deployed, killing the experimenter, or it makes an audible "click" and the experimenter survives.
'The theories are distinctive from the point of view of the experimenter only; their predictions are otherwise identical.
'The probability of surviving the first iteration of the experiment is 50%, under both interpretations, as given by the squared norm of the wavefunction. At the start of the second iteration, if the Copenhagen interpretation is true, the wavefunction has already collapsed, so if the experimenter is already dead, there's a 0% chance of survival. However, if the many-worlds interpretation is true, a superposition of the live experimenter necessarily exists, regardless of how many iterations or how improbable the outcome. Barring life after death, it is not possible for the experimenter to experience having been killed, thus the only possible experience is one of having survived every iteration.' (Wikipedia article).