Quantum suicide is one of the most horrifying thought experiments proposed by Hans Moravec. To be brief, rig up a gun to a device measuring the spin value of a proton every ten seconds. The spin value randomly creates a quantum bit as 1 or 0. When the trigger’s pulled and the quantum bit comes up 1, the gun fires, killing the subject. Zero? The subject survives, and will survive subsequent attempts should Hugh Everett’s many-worlds interpretation prove correct. It’s a riff on Schrödinger’s cat, where kitty is in a superposition of being alive and dead at the same time.
But who wants to risk their lives despite the prospect of quantum immortality? Isn’t there a safer way to test this?
In case you’ve been living under a rock, the most popular example of this theory is the Berenstain Bears controversy. Rap duo Run The Jewels, and many others, insist the children’s book series was originally spelled “Berenstein”.
Filian and Hope discover it’s impossible to find definitive proof, but their paper describes how to detect if a person was in a state of superposition. It’s a non-lethal take on quantum suicide. The experimenter enters a machine with pen and paper to record the state of an electron as “yes” or “no”. After noting their observation, they exit the machine, leaving the data on a table. After, say, 100 tries, the data is reviewed. Should the compiled results be roughly 50/50, then the person wasn’t in superposition. If all the results are the same, the experimenter was in superposition.
“We also note that this test relies crucially on both the ‘memory loss’ experienced by the experimenter, and the knowledge of the phase of the initial superposition. The full quantum state of the experimenter, including their memories, is being generated by the machine. This means that it is possible for them to have any memories at all, but we have shown that they must be identical across multiple branches of the superposition, and therefore cannot be correlated with the actual relevant measurement results.”
What if these memories only appear identical, and the differences are so insignificant where realities are indistinguishable from another? For example, the differences between a pair of realities might be an atom resonating at a lower energy than its parallel doppelgänger. Over these iterations, based upon the experimenter’s measurements, a universe with a significant difference like Berenstain/Berenstein could crop up and conflict with “reality”.
The possibilities are endless, like our infinite universes.