Implications of Quantum Physics

[TCO]

Originally posted by KrazyHorse
The fundamental axiom of quantum mechanics in question is the one which states: "any measurement of an observable puts the system into an eigenstate of the associated operator"

Is it that or is it that it is in an eigenstate but we're not sure which one without the measurement?

[TCO]

Originally posted by Dauphin
I find it amusing that PA, an economist by education, is questioning the ability of highly precise physics theories to make accurate predictions.

Ask him some questions about deadweight losses and such. I would not be surprised to find some holes on tough micro questions.

[Elok]

Okay, in order for a theory to be valid, it must be understandable by PA. PA does not understand it, and according to quantum physics truth is dependent on the observer, therefore quantum physics are false. So you'd better get out the sock puppets and start brewing the coffee, Kuci, or the universe is gonna vanish.

[Kuciwalker]

*poof*

[Atahualpa]

Coincidently the light just went black for a moment, universe must have restarted.

I think I saw a command prompt for a nanosec.

[Kuciwalker]

God got a BSoD.

[Atahualpa]

I bet he'll soon switch to Mac.

[Kuciwalker]

[KrazyHorse]

Originally posted by TCO


Is it that or is it that it is in an eigenstate but we're not sure which one without the measurement?

You yourself mentioned the double slit experiment with single electrons, dude. If it was just that we weren't sure there would be no interference pattern.

Plus, go look at Bell's theorem to see how badly hidden variable theories like the one you seem to favour have been trounced.

It is not impossible for there to be a local hidden-variable theory that is consistent with experimental results. However, we haven't found one yet, so my feeling is that any such theory will be needlessly complex.

[TCO]

I just don't like the observer being important to events. How does the double slit thing cause problems again?

[KrazyHorse]

"The observer" is only an interaction with the non-quantum world, George. No need for consciousness or even for the observation to be recorded.

Putting a particle into an eigenstate can be done without anybody ever finding out what the value of the associated observable was originally. Think about putting a single electron in a giant magnetic field (in z direction) in a sealed box. After a longish time you open the box. The magnetic moment of the electron will have aligned with the magnetic field (it will be in an eigenstate of Sz), yet you performed no "observation" in the naive sense on the original spin The axiom goes the other way: it simply says that you can't find out what its Sz is without putting it into an eigenstate of Sz (or energy or any other observable).

And as for the double slit thing, if the electron took a single path without us having to measure it (and we simply didn't know what path that was) then why would there be an interference pattern? If we throw pool balls through slits in the dark and record where they hit we don't get an interference pattern...

[Kuciwalker]

And as for the double slit thing, if the electron took a single path without us having to measure it (and we simply didn't know what path that was) then why would there be an interference pattern? If we throw pool balls through slits in the dark and record where they hit we don't get an interference pattern...

I wonder if anyone has tried

[Dauphin]

Getting a coherent beam of pool balls may be a problem.

[Az]

And as for the double slit thing, if the electron took a single path without us having to measure it (and we simply didn't know what path that was) then why would there be an interference pattern? If we throw pool balls through slits in the dark and record where they hit we don't get an interference pattern...

The electrons in the parallel universe!

Yes, I admit, I am a sucker for this theory coz I hate wave-particle duality with a passion.

[KrazyHorse]

Azazel, there's no problem with the many-universe interpretation.

However you must realise that the universe which we live in is not determined unltil the moment you make the observation.

Universes in that interpretation do not split except at observation points. So saying "the parallel universe" is naive. As a matter of fact, in that interpretation the interference pattern is the result of us remaining in a superposition of universes.