Difference between revisions of "45: Schrodinger"
(→Explanation: I couldn't stand the poor explanation of Schrodinger's cat any longer.)
(→Transcript: Added trail through lj comics.)
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Revision as of 23:17, 19 August 2012
Title text: There was no alt-text until you moused over
Under the Copenhagen interpretation, an atomic nucleus is described by a wave function that allows one to calculate the probability that it is any given state. A radioactive nucleus with a half-life of one hour, for instance, would have a wave-function that would split, showing two distinct states (decayed, undecayed) that change over time until some "observation" forced the wave-function into one state or another (called "collapsing the wave-function). Before the wave-function is collapsed, it is incorrect to say that the atom has decayed or has not decayed; it is in a "superposition" of states, effectively half-decayed and half-undecayed.
Schrödinger thought this was absurd, and devised the Schrödinger's cat thought experiment to show this. Put a cat in a box, he said, with a device triggered by the decay of an atom with a half-life of one hour that would release a poisonous gas if triggered. Then, after waiting an hour, the Copenhagen interpretation would say that the atom is in a superposition of decayed and undecayed states, and thus, by extension, the cat would be in a superposition of alive and dead states. Only when the box is opened would the wave-function for the cat collapse into either alive or dead states. Since it is absurd for a cat to be both alive and dead, it is absurd for an atom to be both decayed and undecayed. Yet that's what quantum mechanics implied.
In this comic, Black Hat and Cueball are likening the last panel to the box with the cat: until you read it, it is in a mixed state (a superposition) of both funny and unfunny, and it's wave-function won't collapse until you read it.
[The last panel of this comic is both funny and not funny at the same time.]
[Until you read it, there's no way to tell which it will end up being.]
- This is the forty-second comic posted to livejournal. The previous was xkcd 39. The next was xkcd 46
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