OT: QM pilot wave theory.

OK I have no idea, but if this is a "valid" as any other theory of QM (I hate "many worlds".)

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Then I'm all in. It's a nice picture.

George H.

Reply to
George Herold
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This months New Scientist Issue has a story on Bohmian Mechanics. imo, it makes more sense than Many Worlds.

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My favourite is the "non interpretation"

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-- Kevin Aylward

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- SuperSpice
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Kevin Aylward

Thanks, There was this experiment too.

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George H.

Reply to
George Herold

Thanks, There was this experiment too.

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Interesting.

-- Kevin Aylward

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- SuperSpice
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Kevin Aylward

"The fundamental issue is the failure to understand that a quantum state vector such as does not refer to a measurement of position , but only to the probability of measuring a position."

Do people really not understand that a wavefunction represents the probability amplitude of some observable?

The wavefunction can be complex-valued, how could a complex-valued function on its own represent a real-world measurement of strictly real-valued observable like momentum or energy, anyway?

Reply to
bitrex

Right I've been schooled in the Copenhagen interpretation, "shut up and calculate."

Let's just talk about the two slit experiment. Photons, no problem, (for me) electrons, well small and hard to get a hold of. He4 atoms.... It's getting real hard to see it go through both holes, I have no problem with it "knowing" about both slits. (I think someone's done two slit interference with C-60)

George H.

Reply to
George Herold

As daft as that sounds, that many Ph.D. Physicists, simply don't understand what the wave function means, despite the ability to manipulate the maths of QM 100 times better than me, that is indeed the case.

Specifically, I actually had a few minutes of a chat with Lawrence Krauss at a Darwin Humanist comedy event in London in February. He was very clear in his claim that particles can exist in two places at once. However, I believe I did sense some following thinking on his part, when I pointed out the inherent contradiction with the postulates of QM. He had to dash off though, to sign some more of the books he was flogging at the event.

Sure. Its absolutely stunning that there is this universal misunderstanding on what QM means.

Just to clarify more on what I write in my paper above .

A key idea is that, if it were possible to unequivocally conclude that a measurement or argument, however indirect or convoluted, could only be associated with with the physical fact that an object was in two places at once, it would constitute an actual measurement of that fact, hence, would contradict the postulates of QM, hence QM would be falsified.

Either you make a measurement, in which case, you can't get two values at once if QM is correct, or you don't make a measurement, in which case you can't claim anything about where the object actually is. You only have probabilities.

All media waffle always treats the quantum state, as if it is the same as a classical variable that it is describing. Its twilight zone stuff.

-- Kevin Aylward

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- SuperSpice
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Reply to
Kevin Aylward

Maybe he was being ironic/trolling? Krauss has a pretty impressive CV...

From what I've read, "hidden variable"-type theories are in vogue again among certain camps of theoretical physicists; you can get around some difficult problems with the standard formulation of QM ('firewall paradox'

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if you make the assumption that there is no _global_ "Hilbert space of the universe", but that there exist independent spaces for each division of the universe into observer and system. Or something. It's a bit above my pay grade.

Reply to
bitrex

He is quite rich...

He is pretty consistent on all his YouTube stuff on claims of two places at once stuff. Its fashionable to make such claims to lay people. It makes them appear impressive by claiming something bizarre, is proven true. The layman don't understand, its gibberish.

Understanding the math is not the same as understanding the physical meaning. That's partly why there are so many interpretations of QM.

I can't say if he *really* believes it, only that he presents it as if he does.

I will have a look...

-- Kevin Aylward

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- SuperSpice
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Kevin Aylward

The only problem IIRC is that if I'm understanding it correctly, to get the package deal you have to give up certain other fundamental assumptions we have about "the Universe", particularly that independent observers even exist in the same locally-independent system of states that can be objectively agreed upon, which seems to raise a lot more questions than it solves.

Also, the few folks working on "shape dynamics" wrt the problem of quantum gravity have noticed that there are two fairly isomorphic formulations of Einsteinian general relativity, the "shape dynamics" variation taking time rather than speed of light to be the universal invariant.

At least on the local scale both formulations seem to make the same predictions, but it's currently unknown whether something different happens on the scale of whole universes.

The difficulty with the search for "grand unified" theories seems to be hinting at the possibility that just as Newtonian dynamics and classical EM are only valid approximations above some de Broglie wavelength, velocities

Reply to
bitrex

of GR that is

Reply to
bitrex

Not quite sure what you are saying here. I don't have a problem, with no independent observers. I can't see how it can be another way. Its all relative. A mass can only be compared with another mass. Distance with another distance. Object's properties are always dependant on other objects properties. For example, two 1Kg masses separated, far apart, are not 1kg each when close together. Its a core reason, imo, why QM is contextual, that is, properties such as momentum, can only be defined with referenced with a particular "measuring" system. i.e the properties of another system. That doesn't mean that objects not exist unless measured, it just means that properties of objects are not unique.

-- Kevin Aylward

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- SuperSpice
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Reply to
Kevin Aylward

My favorite problem that I've seen and worked, from Griffiths: express the Sun-Earth system as a hydrogenic atom. Calculate the atomic number n for the system. Is there anything peculiar about the energy level going from n to n-1?

The answer is really pretty "duh", because it is equivalent -- as it must be -- to the classical case. But it's a fun, roundabout way to arrive at it.

Tim

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Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
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Reply to
Tim Williams

It's the square of the wavefunction that's the probability, and the square is always real.

Sylvia.

Reply to
Sylvia Else

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