Question relating to Schrodinger's Cat

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Re: Question relating to Schrodinger's Cat

#21  Postby twistor59 » Sep 14, 2011 7:29 pm

eric8476 wrote:
twistor59 wrote:By "conclusions of schrodinger", you presumably mean Schroedinger's cat experiment, not the conclusions of Schroedinger himself. If so, then I wouldn't say "disproving", but rather "highlighting a problem with":

The atom is in a quantum superposition (decayed+not decayed). There would then be a long causal chain of interactions leading to the eventual state of the cat. The atom in the gamma ray detector would be in a superpostion of detected+not detected. The electric current would be in a superposition of generated+not generated. The motor would be in a superposition of in motion + not in motion etc. All the time along the chain the items are getting bigger -- less microscopic and more macroscopic.

We know that we never see cats in a superposition of states. The question is therefore - "where along the causal chain do the rules of quantum mechanics break down and superposition gets lost" ?. This is the "Measurement Problem".

There have been many proposed answers to this over the years, and if you want an animated physics coffee table discussion, this is one topic guaranteed to bring it about.

the activity of the atom does not put the other functions of the experiment in superposition.

According to the rules of quantum mechanics, it should. The pieces of the system are connected by interaction Hamiltonians, and undergo a linear time evolution equation. However we don't observe this classically. Why not ?
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Re: Question relating to Schrodinger's Cat

#22  Postby lucek » Sep 14, 2011 7:30 pm

zaybu wrote:There's one problem with these explanations: the wave function is NEVER observed. Observables in QM are operators, such as position, momentum, energy, spin. The wavefunction is just a mathematical tool that allows calculation of expectation values of these observables. Any other interpretation of the wavefunction is just pure speculation, unsupported by any evidence.

OK not quite "unsupported by any evidence" but yes the various interpretations of what the waves actually are still in debate.
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Re: Question relating to Schrodinger's Cat

#23  Postby heisenbinker » Sep 24, 2011 12:59 pm

Referring to the original post. The cat is both dead and alive when not observed .

BUT, if according to your experiment an electron( say 'A') 'looking' is called as observing, then yes the wave function will collapse relative to the electron 'A'. If somehow electron 'B' who does not 'know' whether the cat is dead or alive, is transmitted this information from 'A', then the wave function collapses dead or alive to 'B'. Again the definition of observation just changed now to 'transmitting information about the cat' to collapse the wave function.

CI just says observing is necessary.

Point is, if its your experiment define every aspect of it properly according to some rules and you will find the answer yourself. Sometimes these experiments lead to interesting insights. As far as my knowledge goes Schrodinger did not describe the experiment completely enough to answer your question.
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