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Author Topic: Act of observation collapses the wave function, but I observed this in a book?  (Read 3664 times)

Offline davrosdalek

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Apparently in quantum physics, 'the act of observation collapses the wave function'. This seems to be as true at the quantum levels of fundamental particles, as it is at the 'Cat' level of real life theory, if I understand Schrodinger correctly. However, I only know this because I opened a book about quantum physics, collapsed the wave function and observed a sentence that read 'the act of observation collapses the wave function.' Surely this must be a paradox ?


 

Offline yor_on

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You can read about The Copenhagen definition here. But in a way it's pretty simple, without measuring we can't know what's happened. So in a way you could say it's about how to define what we can 'know'.

And that is by a measurement.
==

A way of imagining it could be:

Think of the universe as a very wide holographic beam, begetting three dimensions and time, according to us inside it. Then look at the source, the 'light bulb' if you will, that one might be without any dimensions at all, and having no 'distance'. So when the Copenhagen definition states that what we don't measure is unknowable you can find its resolution in that 'light bulb' using no 'dimensions' we know of to create what we call 'reality'.

"The wave function is a complete description of a wave/particle. Any information that cannot be derived from the wave function does not exist. For example, a wave is spread over a broad region, therefore does not have a specific location."

So in a way we create our reality by 'living it', well, if you want to take it to its limits :) It's a minimalistic approach to 'reality' in where measurements will be what defines it.
« Last Edit: 30/01/2011 16:25:41 by yor_on »
 

Offline Bill S

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Hi, davrosdalek.
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Apparently in quantum physics, 'the act of observation collapses the wave function'

As I see it, this is just one interpretation, and might not be right.

However, assuming it is right, would you not think the wave functions of all the particles in the book would have been collapsed long before you opened it?
 

Offline QuantumClue

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Apparently in quantum physics, 'the act of observation collapses the wave function'. This seems to be as true at the quantum levels of fundamental particles, as it is at the 'Cat' level of real life theory, if I understand Schrodinger correctly. However, I only know this because I opened a book about quantum physics, collapsed the wave function and observed a sentence that read 'the act of observation collapses the wave function.' Surely this must be a paradox ?

Oh where to start...

Macroscopic objects are free from observational collapse methods. The wave function of matter has ''decohered'', so there is very little left for the everyday observer to collapse: Even a cat has decohered, so the cat in the box will always be alive or dead, not a mixture of a superpositioning.

Smaller systems however interact all the time - observation in quantum physics can mean two things: It is a weak coupling of the system to another system. It is also a simple interaction between two particles. In other words, the wave function of a particle can collapse without the aid of a human observer (not that we have managed to ever observe a particle directly with the human eye).

To state that macroscopic systems are free from quantum effects therefore, resolves Schrodingers Superpositioning paradox. It also allows us to redefine what an observation in physics truely means for us and the things around us.
 

Offline yor_on

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Yes QC "the wave function of a particle can collapse without the aid of a human observer" must be true. Which brings us back to entanglements :) And how, and where, exactly? Did that spin got defined?..

But the Copenhagen definition does not discuss what is 'unknowable' as I understands it, only what can be known. Which will leave that cat in a superposition inside that remarkable box, until your measurement.
 

Offline QuantumClue

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Yes QC "the wave function of a particle can collapse without the aid of a human observer" must be true. Which brings us back to entanglements :) And how, and where, exactly? Did that spin got defined?..

But the Copenhagen definition does not discuss what is 'unknowable' as I understands it, only what can be known. Which will leave that cat in a superposition inside that remarkable box, until your measurement.


Superdeterminism solves this problem easily. Now the question is whether everything is determined or not.
 

Offline yor_on

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Ah, but now we are discussing one 'faith' against another, ain't we :)
 

Offline QuantumClue

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Ah, but now we are discussing one 'faith' against another, ain't we :)

I have faith we have solutions. We just need to learn how to apply them correctly. Just takes a small amount of concentration and imagination :)
 

Offline yor_on

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Faith is a wonderous thing. Superdeterminism, if I understands it? The idea that everything will be 'determined' in due course, even though 'hidden' for us. Then you have the Bohemian interpretation in which the observer plays no fundamental role. Bohmian mechanics describes, instead of probabilities of measurement results, objective microscopic events. In a way then similar to Superdeterminism, as it builds on a Newtonian concept of action and reaction. Then we have the wave/particle duality, and the idea of defined light quanta, as shown in black body radiation, and the two slit experiment, clashing with each other. What we can see now and here is that we count on probability's, not hidden mechanisms. We also find constants, like Feigenbaum's, showing us a linearity inside non-linearity.

To me it's more like the concept of Russian dolls, in where both a deterministic approach as well as the Copenhagen interpretation have its own existence. and the way they have it seems very much to be about from 'where' you stand looking at it. So 'free will' exist beside the Feigenbaum concept as easily shown in chaos theory with its bifurcations. The universe is both complex and simple I think. We just don't have the 'gold standard' for how to see it.

And that gold standard, if existing, might then be all of our 'approaches', or maybe none of them at all? But probability works, and give us a good tool for approximation as I understands it. And I kind of agree in that a interaction is what counts, and if you do not observe it you can't define it, more than statistically.
 

Offline davrosdalek

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thanks for all the great feedback. very interesting answers.
 

Offline Bill S

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Quote from: davrosdalek
very interesting answers.

That was a cautious response.  :) 
Was your question answered, though?
 

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