The measurement problem

Ivan Seeking

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Regarding the measurement problem in QM - clearly a charged and divisive subject - what is your take on this problem? [I hope this is appropriate for this forum.] I would like your vote on the solution to this problem. Decoherence, non-linear collapse due to gravity, multiple universes, conscious observer required, and here is one of my favorites from the Quantum Cosmologists, the wave function doesn't collapse, you jump into a superposition of eigenstates. Also, I have read recently that collapse could be relative. Given these and any ignored but reasonable contenders, what is your vote and why?

I can see the cannon fire between the ivory towers, what is the mood on the streets?
 
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selfAdjoint

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Decoherence, non-linear collapse due to gravity, multiple universes, conscious observer required, and here is one of my favorites from the Quantum Cosmologists, the wave function doesn't collapse, you jump into a superposition of eigenstates.
Another one that a lot of people like is Cramer's Transactional interpretation. And I notice you didn't include "The wavefunction describes our knowledge".

I have my own views but I'll hold off and see how the thread goes. Maybe someone else is deeper into this topic than I am.
 

Ivan Seeking

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Originally posted by selfAdjoint
I'll hold off and see how the thread goes. Maybe someone else is deeper into this topic than I am.
In my experience, anyone without a Nobel Prize who is deeply into this topic is sworn to secrecy. [zz)]
 
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My own personal theory is the measurement problem is related to the paradox of existence and isn't just a measurement problem restricted to Quantum Mechanics. The more extreme any measurement or observation, the more paradoxical it can appear to be.

There are two basic paradoxes logicians take seriously, the Cretan Liar's paradox and the Sorites Heap paradox. The Liar's paradox is the self-contradictory and self-referential kind while the Heap paradox is just plain vague. Whether exploring the origin of existence, the validity of mathematics, or the validity of logistics or any number of extremes we apparently eventually come across what appears to be increasingly paradoxical and irreconcilable.

Therefore you can claim it is merely a question of semantics, ignorance, or any number of things but, bottom line the most honest statement we can make is that we just plain can't say what it is other than to describe it as paradoxical. For example, one possibility you didn't list is that the measurement problem might just represent the ineffable.

Of course, science is not in the business of throwing it's arms up and declaring something impenetrable. That's what priests and philosophers do. A number of physicists have expressed horror at the thought that a TOE might have to be relegated to the mathematicians and philosophers to explore, but I strongly suspect even if physicists can come up with a TOE the measurement problem will remain and eventually be relegated to philosophers and theologians. That's life, if we already knew the answer to life, the universe, and everything we'd probably be bored stiff.
 

Hurkyl

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My take on the problem.

I think that position and momentum are not fundamental concepts. Underlying reality cannot be described by a unique pair of numbers that have the properties that position and momentum should have, but instead we use ways to non-uniquely specify those numbers so that the results have a statistical pattern that behaves how we think position and momentum should behave (whether or not the underlying reality is truly random).
 

drag

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Greetings !

Well, just a remark about WF collapse:
I believe that it doesn't happen because
like I suggested in my PF2 thread in different
relativistic reference frames this would imply
it can actually collapse in one's past -
and while instant action is strange enough, this
just sounds like too much to me. Then again,
this is a very strange problem too.

As for my "take" on this I just wan'na say
that the greatest minds in the world have not yet
succeeded in solving this problem, so of what
possible value would anything I say be except
demonstrate my ignorance, overgrown ego and
semantic preferences ? :wink:

Live long and prosper.
 

Ivan Seeking

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Originally posted by drag
Greetings !

Well, just a remark about WF collapse:
I believe that it doesn't happen because
like I suggested in my PF2 thread in different
relativistic reference frames this would imply
it can actually collapse in one's past -
and while instant action is strange enough, this
just sounds like too much to me. Then again,
this is a very strange problem too.

As for my "take" on this I just wan'na say
that the greatest minds in the world have not yet
succeeded in solving this problem, so of what
possible value would anything I say be except
demonstrate my ignorance, overgrown ego and
semantic preferences ? :wink:

Live long and prosper.
It is very important that we do not all follow the same
fashion... It's necessary to increase the amount of
variety... and the only way to do this is to implore you
few guys to take a risk with your lives that you will not
be heard of again, and go off into the wild blue yonder to
see if you can figure it out." Richard Feynman(1965),
Nobel prize in physics award address
 

Alexander

Originally posted by Ivan Seeking
Regarding the measurement problem in QM - clearly a charged and divisive subject - what is your take on this problem?...
Decoherence, non-linear collapse due to gravity, multiple universes, conscious observer required, and here is one of my favorites from the Quantum Cosmologists, the wave function doesn't collapse, you jump into a superposition of eigenstates.
None of the above. It is way more simple.

Everything is wave (electron, photon, newtron, etc). Wave has many related (= mathematically tied together via definitions) quantities. Say, position of wave and momentum of wave are inverse of each other - that is just how they defined. Same with energy and time, angular momentum and angle, etc.

Thus, when you limit one (say, the time of measurement), you inversly limit the other (spread of energy in this case, because energy and time are tied together by mathematical definition).

Just a matter of definitions, you know.
 
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