Darren New <dne### [at] sanrrcom> wrote:
> As I said, the probability of finding a particle in a particular place is 
> based on multiplying complex numbers.

  Btw, I find it curious how you use the mathematical models as some kind
of evidence that photons are not waves. After all, Feynman himself stressed
that his formulation is merely a mathematical description, not an attempt to
describe a real process that we cannot meassure.

-- 
                                                          - Warp

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Darren New <dne### [at] sanrrcom> wrote:
> Warp wrote:
> >   Schrodinger's cat is a thought experiment, not an analogy.

> It's not even that hard to set up. :-)

> I think the point is that you have to question what an "observation" is. If 
> the particle gets emitted and runs into the detector when the power is 
> turned off, is it "observed"?  If the power is on but the detector isn't 
> connected to anything?  If it's connected to a speaker you can't hear? If 
> it's connected to poison but there's no cat in the box?  Etc?

> In other words, if it takes an "observer" to collapse the wave function, is 
> the cat enough of an "observer" to count? If so, how does the human get 
> involved? According to the math, the cat is still superimposed. But that 
> would imply the cat isn't sufficiently an observer to cause the collapse. 
> *Or* that the math doesn't match reality. And multi-worlds is an attempt to 
> say "no, the math really matches reality."

  AFAIK those are the things Erwin Schr?dinger questioned about the
Copenhagen interpretation with his now-famous thought experiment.

-- 
                                                          - Warp

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Warp wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> As I said, the probability of finding a particle in a particular place is 
>> based on multiplying complex numbers.
> 
>   Btw, I find it curious how you use the mathematical models as some kind
> of evidence that photons are not waves.

I believe you misunderstand me. I'm saying we never observe a wave. We just 
observe math that's the same math as a wave. That isn't what makes it "not a 
wave", that's what makes people used to think (and some people still think) 
it was a wave. :-)

I.e., just the opposite. The mathematical model is *not* evidence it's a 
wave, any more than the interference patterns are.

-- 
Darren New, San Diego CA, USA (PST)
   Human nature dictates that toothpaste tubes spend
   much longer being almost empty than almost full.

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Warp wrote:
>   AFAIK those are the things Erwin Schr?dinger questioned about the
> Copenhagen interpretation with his now-famous thought experiment.

Yes. I'm agreeing with you, and hopefully adding some more to the discussion.

-- 
Darren New, San Diego CA, USA (PST)
   Human nature dictates that toothpaste tubes spend
   much longer being almost empty than almost full.

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Darren New <dne### [at] sanrrcom> wrote:
> I.e., just the opposite. The mathematical model is *not* evidence it's a 
> wave, any more than the interference patterns are.

  I don't really know your definition of "evidence", but as I understand it,
the interference pattern *is* evidence for it to be wave. It's not *proof* of
it, but evidence is no proof anyways.

-- 
                                                          - Warp

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> Except that's exactly the point. The math says it's the latter case. And 
> the cat experiment is to point out how absurd that conclusion is. Hence, 
> the math must be mistaken.

What happens if you shut the double-slit experiment away in a box, with 
photon detector attached to each slit?  Will the interference pattern still 
be generated?

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scott wrote:
>> Except that's exactly the point. The math says it's the latter case. 
>> And the cat experiment is to point out how absurd that conclusion is. 
>> Hence, the math must be mistaken.
> 
> What happens if you shut the double-slit experiment away in a box, with 
> photon detector attached to each slit?  Will the interference pattern 
> still be generated?

No.  Worse, check out this:

http://en.wikipedia.org/wiki/Wheeler%27s_delayed_choice_experiment

Basically, the photon behaves differently even if you measure it *after* it 
has passed through the slits. Which is why it's pretty safe to assume it's 
not "going thru both slits" when you get the interference pattern.

http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraser

This one changes whether the photon went thru one or both slits *after* it 
has already been detected. Hard to see how that's the behavior of a wave 
that passes through both slits.

-- 
Darren New, San Diego CA, USA (PST)
   Human nature dictates that toothpaste tubes spend
   much longer being almost empty than almost full.

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>> What happens if you shut the double-slit experiment away in a box, with 
>> photon detector attached to each slit?  Will the interference pattern 
>> still be generated?
>
> No.  Worse, check out this:
>
> http://en.wikipedia.org/wiki/Wheeler%27s_delayed_choice_experiment
>
> Basically, the photon behaves differently even if you measure it *after* 
> it has passed through the slits. Which is why it's pretty safe to assume 
> it's not "going thru both slits" when you get the interference pattern.

But put the whole thing inside a big closed box so nobody can observe the 
patterns (exactly like the cat in a box setup).  If a cat's status is not 
decided until someone looks inside (even though there is a particle detector 
and related mechanisms inside) then why should the interference pattern not 
be there if nobody is observing it?

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scott wrote:
> If a cat's status is not decided until someone looks inside 

Since that isn't true, it's a meaningless question to ask.

-- 
Darren New, San Diego CA, USA (PST)
   Human nature dictates that toothpaste tubes spend
   much longer being almost empty than almost full.

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>> If a cat's status is not decided until someone looks inside
>
> Since that isn't true, it's a meaningless question to ask.

I thought the whole point of that experiment was that according to QM the 
cat was both alive and dead until you actually tried to look?  Maybe 
something changed since I read about it?

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