
#181
Dec2612, 01:09 PM

P: 50

Maybe this student went on to develop IEEE standards :D




#182
Dec2612, 02:09 PM

P: 53

Speaking of intuition and instinct, QM depends critically on a pointparticle view of matter. It is this view that has, as its consequence, indefiniteness of state, nonlocality, and such.
Bell clearly shows that a pointparticle viewpoint of matter leads to nonlocality, and experiments do seem to confirm this. If you execute a "loopholefree" EPR experiment against the loopholes that are motivated only by a particle viewpoint of matter, then the results will certainly seem to confirm an ontology of randomness and nonlocality. In other words, the definitive experiment can at best claim to say (assuming success), that "If the world is made of particles, then the world is indefinite and nonlocal." <Speculation> However, if the "star stuff" are relationships, rather than particles, each end of which depends on the other at the speed of light, then there's no need for randomness or nonlocality. A definitive experiment must rule this out. I call it the "aparticle" loophole. </Speculation> Here's a link to some recent work confirming the theoretical potential of an "aparticle" based theory at the astrophysics level. Note they still model the interaction over distance as a particle. I model it as a series of step waves through the relationship with observable events the consequence of a threshold having been reached. http://physics.aps.org/synopsisfor/...ett.109.231301 



#183
Dec2612, 03:28 PM

Sci Advisor
PF Gold
P: 5,145





#184
Dec2612, 04:17 PM

P: 53

By point particle I mean in the Dirac delta sense, not in the absolute sense. Sorry for the imprecision.
Perhaps another way to look at it is as something separable from its context, or something that can exist in isolation. In the Dirac delta sense, it is something for which there is a distance beyond which the upper bound of its influence on any other thing is on the order of 1/d^2. 



#185
Dec2612, 06:55 PM

P: 741

Just out of curiosity, though: Is "Joy Christian" his original name? The one that his parents gave him? Or did he pick this name as an adult? 



#186
Dec2612, 07:09 PM

P: 53

I'm bothered by the personal attacks and speculation about mental health aimed at the subject of this thread. Can we please keep the criticism to the papers and the science?




#187
Dec2712, 01:02 AM

P: 50

If someone writes something like A(L) = 1 when L = 1 and A(L) = 1 when L = 1 and then denies that A(L) = L when L = +/1 then you start worrying about some form of mental disorder.




#188
Dec2712, 01:18 AM

P: 36

While you folks are discussing about Bell's Theorem. Are you aware of any Entanglement experiments which has disproven the theory that as entangled particles separate, they form a spacetime foliation with time synchronized to both of them from T0 until collapse (this is assuming the wave function is not just in the equations but actually there in spacetime)? Is this possible or disproven already?




#189
Dec2712, 05:00 AM

PF Gold
P: 1,999

I have been considering putting Bell's Theorem on my list of things to look at but I have been unable to get past the statement of his theorem:
"No physical theory of local hidden variables can ever reproduce all of the predictions of quantum theory" If any theory cannot predict what is observed then that theory is flawed and should not be considered as a real theory at all. Suppose that there can be such a thing as a real theory of local hidden variables.If so it will reproduce all of the observable predictions of QM. The problem is that the details of such a theory are not known and nor are the details and subtleties of any detection methods known. How then can Bell and his followers make generalised statements about all theories without a detailed knowledge of those theories? 



#190
Dec2712, 05:03 AM

P: 50

I just finished reading James Weatheralls paper (see link posted by DrChinese), very good analysis. I think Christian was trying to do a model of the type discussed in the paper where measurement results are represented by rotation orientations  this is the sort of thing everyone tries to come up with when first encountering Bell. I did it myself as a kid after reading d'Espagnet's famous paper in Scientific American (http://www.sciam.com/media/pdf/197911_0158.pdf)  I even built some contraption with cardboard disks connected by a rod to picture whats going on. I didn't know about wedge products and bivectors but got by with good old ordinary 3 vectors and a lot of sines and cosines. If you do that sort of stuff (which is an explicitly realist model) you quickly discover that you simply cannot get by the counting arguments) Now at that young age I hadn't bought into the whole eigenstate ontology (or even known its mathematical details) so nonlocality had to be the answer. But assuming relativity it was pretty clear also that some form of signaling or travelling influence couldn't be the answer  the conclusion was that there had to be something analogous to the rod between my cardboard disks in reality, but which truely behaved "rigidly" so that turning one disk turned the other and turned it instanteously not like in a real rod made up of molecules where the influence is pretty fast but not instantaneous. This I found deeply disturbing but became less disturbing over the years as I learned to appreciate that space and time is something that "emerges" from the fact that entities interact via electromagnetism and gravity, it isn't something that is just there in the first place.




#191
Dec2712, 05:35 AM

P: 50

Dadface, the notion of a "local hidden variable theory" has a very precise mathematical definition and this definition is general enough to include essentially any theory that excludes any faster than light (in particular instantaneous) connections between separated particles and assumes one can meaningfully count counterfactual values along with factual ones. The definition then allows us to calculate a numerical constraint that all such theories must obey. However QM doesn't obey that constraint and QM wins when checked experimentally.




#192
Dec2712, 05:39 AM

Sci Advisor
Thanks
P: 2,944





#193
Dec2712, 08:42 AM

P: 72





#194
Dec2712, 08:50 AM

Sci Advisor
PF Gold
P: 5,145

And while you are at it, ask yourself: what does it mean that there are hidden variables? It is only those theories which are ruled out by Bell (unless of course there are nonlocal interactions). You should go all the way back to the 1935 EPR paper to understand this point. They talk about "elements of reality" and define that specifically. Entangled particle pairs evidence EPR elements of reality, and those elements of reality imply hidden variables. Bell tackles that point head on. It turns out that it is not possible to have those elements of reality beyond what can actually be observed and expect a match to the QM predictions. Ergo there are no local hidden variables. We must live in an observer dependent universe. 



#195
Dec2712, 09:18 AM

PF Gold
P: 1,999

Thank you Mathematech and Nugatory and thank you DrChinese. DrChinese, your advice looks good. I just tried a google search to find the 1935 paper and your site on Bell came up.
I have visited your excellent site before but have just scanned it and not looked at it in enough detail to get,what I think, would be a thorough understanding. I will certainly look at the 1935 paper but I know I will have troubles with the maths.I haven't looked at that sort of maths for over fourty years. 



#196
Dec2712, 09:46 AM

Sci Advisor
PF Gold
P: 5,145

The real joy of the paper is that they define "element of reality" in a manner that it is difficult to refute. If you can predict a measurement outcome before it occurs, then there must be an element of reality somewhere associated with it. That is the case with an entangled particle pair, you can measure one to learn about the other. Next: if you think of particle spin along different axes as being different observables (different elements of reality), then these must be predetermined if we are living in an observer independent reality. In such a reality, the Heisenberg Uncertainty Principle is NOT fundamentally true  because complementary elements of reality exist. That was what EPR sought to demonstrate, and they thought they had. Of course, Bohr and others rejected their conclusion as unwarranted. In fact, the two sides were at an impass. Bell raised the bar by attempting to imagine hidden variables that would determine outcomes at many different angles. It turned out there was a major consistency conflict between the "elements of reality" criterion and the quantum predictions. 



#197
Dec2712, 10:31 AM

PF Gold
P: 1,999

Thank you DrChinese.
I will have a read up and give this some more thought. The Stanford Encyclopaedia of Philosophy seems to give a good account of EPR. 



#198
Dec2712, 11:09 AM

P: 50

I read this book years ago
http://www.amazon.com/Incompleteness.../dp/0198242387 A very good introduction to the subject. The math was at a very rigorous but nevertheless easy to understand level. As a mathematician there were some things I couild nitpick about but they were really only things a mathematician would nitpick about :) The only things missing from this book were i) a detailed examination of how probabilities of counterfactual incompatible measurements differ from probabilities of compatible measurements (he seemed to be dismissive of Arthur Fine's work or he never really understood it) and ii) a detailed discussion of how a nonlocal mechanism would work although a lot of what is said these days hadn't been said yet when this book was written. 


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