"Experiment" "Proves" "Non-Realism"

[Qwertz]

http://www.nature.com/nature/journal/v446/...ature05677.html

I do not have enough physics to wade through this, but here's the concluding paragraph. The authors are quite bold in their willingness to abandon the foundations of the very science they're trying to do. If someone with better wherewithal would like to take a critical look at this, I'd appreciate it.

-Q

We have experimentally excluded a class of important non-local hidden-variable theories. In an attempt to model quantum correlations of entangled states, the theories under consideration assume realism, a source emitting classical mixtures of polarized particles (for which Malus' law is valid) and arbitrary non-local dependencies via the measurement devices. Besides their natural assumptions, the main appealing feature of these theories is that they allow us both to model perfect correlations of entangled states and to explain all existing Bell-type experiments. We believe that the experimental exclusion of this particular class indicates that any non-local extension of quantum theory has to be highly counterintuitive. For example, the concept of ensembles of particles carrying definite polarization could fail. Furthermore, one could consider the breakdown of other assumptions that are implicit in our reasoning leading to the inequality. These include Aristotelian logic, counterfactual definiteness, absence of actions into the past or a world that is not completely deterministic. We believe that our results lend strong support to the view that any future extension of quantum theory that is in agreement with experiments must abandon certain features of realistic descriptions.

[DragonMaci]

And the translation of that quote? Well it is this, "We abandoned reality in favour of complete fantasy." Note: by "complete fantasy" I mean fantasy without any inclusion of the real. An example of fantasy with real things would be if I was to have a fantasy of sitting on a particular beach with my ideal woman. The woman might not be real, but me and the beach are. Complete fantasy, with that quote as an example, does not include that much even.

I haven't got time to read the full article right now (I am about to leave the computer so I can have dinner), but I will read it when I have the time. Also, I am not the most qualified to comment on it. However, I want to read it anyway out of curiosity and if I have anything to say on it I will.

It is a shame Prometheus98876 has not got the internet connected right now because he would love to be involved in this discussiion and he knows a lot about the "science."

EDIT: I can't read it due to access being denied due to not being a subscriper to Nature.

Edited August 7, 2007 by DragonMaci

[Qwertz]

Oh, I didn't even realize it was a subscription thing. I looked it up while VPN'd to the university network.

So if anyone wants to read the whole article, you'll need to do so through a university or public library.

-Q

[DragonMaci]

Oh, I didn't even realize it was a subscription thing. I looked it up while VPN'd to the university network.

So if anyone wants to read the whole article, you'll need to do so through a university or public library.

-Q

How would being at a university or public library make any difference?

[Qwertz]

Most of them will have institutional licenses to access Nature. As the access page says:

Most users gain access to full text articles through a site license. This is available to institutional customers only. For further information visit the Librarian Gateway.

-Q

[tnunamak]

We believe that our results lend strong support to the view that any future extension of quantum theory that is in agreement with experiments must abandon certain features of realistic descriptions.

I would take this to mean that "quantum theory" contradicts reality and thus is invalid. I'm not sure what they mean by "quantum theory that is in agreement with experiments," however. "In agreement" as in, quantum theory is supported by the experiments? Or "In agreement" as in, the results of the experiment prove that quantum theory is valid. If it is the latter, than the experiment must be invalid, since it depends on a theory that contradicts reality . Or maybe it's just getting too late and I need to go to sleep...

[y_feldblum]

They want a[n extension to] quantum theory in agreement with experiments. On the one hand, any theory being in agreement with experiments entails and implies Aristotelian logic et al, while on the other hand, this particular theory being in agreement with experiments seemingly contradicts Aristotelian logic et al.

As an aside, and I have not read the paper, the principle of locality says that it is impossible for any object having mass to move as fast as or faster than the speed of light, and it is impossible for photons to move at any other speed than the speed of light. "Bell-type experiments", assuming locality, encounter a contradiction between quantum theory and logic. A "non-local extension to quantum theory" would mean a description of some newly-discovered physical phenomena which may move faster than the speed of light.

The principle of locality is, I think, based on the interpretation of Einstein's special relativity theory offered by Minkowski, of a spacetime continuum, with space and time inextricably intertwined and, essentially, one and the same. Minkowski spacetime certainly makes the mathematical expression of relativity theory very elegant; it is also seemingly bizarre for meshing space and time so; and it also asserts locality.

[Atlas51184]

Objectivist physicist Travis Norsen deals with this kind of non-sense in this paper.

[DragonMaci]

Most of them will have institutional licenses to access Nature.

That may be true in the US, but sadly I don't think it is true here in new Zealand. At least with libraries anyway.

I would take this to mean that "quantum theory" contradicts reality and thus is invalid. Or "In agreement" as in, the results of the experiment prove that quantum theory is valid. If it is the latter, than the experiment must be invalid, since it depends on a theory that contradicts reality .

That is the wayt I interpreted it.

Y_feldblum, thatnks for explaining what local and non-local are. I hadn't understood that part before, now I do. I appreciate you clearing it up.

Atlas51184, thanks for the link. How long is that document? If it isn't too long for my tight schedule I should read it.

[DavidOdden]

That may be true in the US, but sadly I don't think it is true here in new Zealand. At least with libraries anyway.

This library does, in case they have open stacks.

[DragonMaci]

This library does, in case they have open stacks.

Thanks. I will try and find it. I hope I can find it, though it won't be easy since I don't know the title of the article. Then I have to find time. However, I doubt I will be able to get very much from it. I don't really know much about physics really.

I can't use that one either. It requires you log in. Since I am not a student of Auckland University I cannot access the articles they have online.

Edited out grammatical errors.

Edited August 7, 2007 by DragonMaci

[Qwertz]

Simon Gröblacher, Tomasz Paterek, Rainer Kaltenbaek, Časlav Brukner, Marek Żukowski, Markus Aspelmeyer & Anton Zeilinger, An Experimental Test of Non-Local Realism, 446 Nature 871, 871-875 (2007). Volume 446 spans 9 issues, and the relevant pages are found in the 19 April 2007 issue.

-Q

[DragonMaci]

Simon Gröblacher, Tomasz Paterek, Rainer Kaltenbaek, Časlav Brukner, Marek Żukowski, Markus Aspelmeyer & Anton Zeilinger, An Experimental Test of Non-Local Realism, 446 Nature 871, 871-875 (2007). Volume 446 spans 9 issues, and the relevant pages are found in the 19 April 2007 issue.

-Q

Thanks, but I can;t actually access it, which is quite a shame.

[DavidOdden]

Here is the arXiv version.

[DragonMaci]

Here is the arXiv version.

Thanks a lot. You have gone through a lot of hassle to find me a way to read it (though not as much hassle as I had to go through to get Visual Stduo Standard 2008 Beta 2 installed last night). I appreaciate that alot. I will read it later when I have time.

EDIT: Fixed a gramatical error.

Edited August 8, 2007 by DragonMaci

[Qwertz]

Wow, thanks, DavidOdden.

On a side note, what is arXiv?

[DavidOdden]

On a side note, what is arXiv?

Our friends at Cornell hosts an approval-based archive for various math-intensive sciences like Physics (primarily), Computer Science etc, where prepublication papers are posted. I don't know the standards in physics, but I get the impression that most published works are posted there. A number of them are previously published. In this case, the article was accepted in Nature on 13 February 2007 and the arXiv version was submitted 6 Aug 2007 (rather hot off the press -- maybe they got their copy from Nature and corrected some typos).

[DragonMaci]

Our friends at Cornell hosts an approval-based archive for various math-intensive sciences like Physics (primarily), Computer Science etc, where prepublication papers are posted. I don't know the standards in physics, but I get the impression that most published works are posted there. A number of them are previously published. In this case, the article was accepted in Nature on 13 February 2007 and the arXiv version was submitted 6 Aug 2007 (rather hot off the press -- maybe they got their copy from Nature and corrected some typos).

Ok, now I have to ask a question myself: what is Cornell?

[DavidOdden]

what is Cornell?

Oh, that's an elitish university in New York state, which has a pretty awesome collection of online legal resources such as the entire US legal code, all of the regulations, links to anything you'd want to know about NZ law, the Mongolian constitution (unfortunately, only in English, not Mongolian), etc. Carl Sagan used to teach there.

[DragonMaci]

Oh, that's an elitish university in New York state, which has a pretty awesome collection of online legal resources such as the entire US legal code, all of the regulations, links to anything you'd want to know about NZ law, the Mongolian constitution (unfortunately, only in English, not Mongolian), etc. Carl Sagan used to teach there.

Foregein laws such as NZ law even? That is unexpected. How often is there stuff ipdated?

[DavidOdden]

Foregein laws such as NZ law even? That is unexpected. How often is there stuff ipdated?

Okay, the US law material is directly hosted by them; it's "very current" but not as immediate as e.g. the House of Representatives page or the SCOTUS "Here's what we decided today" page is. For NZ law, I see they actually collected best links, such as courts.govt.nz and Herr Dr. Dr. Professor Tschentscher's collection. You can check the Cornell NZ link here, and see if it seems right to you or not. It's nearly definitive for US law (discrepancy of statement is not a legitimate legal defense, naturally).

[DragonMaci]

I don't really know enough about NZ law to say much about its accuracy, unless I compare what the two sites say and I don't have time to trawl through the massive tangle that NZ law no doubt is. Thanks for the links though. Now if I ever do want to find out something about the law I can easily do so without doing a Google search. Thanks for saving me the effort, I greatly appreciate it.

[Prometheus98876]

Well as far as I can gather QM is moving more and more away from a realistic view all the time. This reminds me of something Nohr Bohr said way back in the early days of QM:

"``There is no quantum world. There is only an abstract physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature.''

And this seems to be a very typical view in the field today, where it is commonly accepted that the "traditional" rules of logic, causality do not apply (!!!!).

So in other words, Quantum Science isnt about a study of reality apparently, but a mathematical description of interpreted results run through an arbitary mathematical filter that "explains" the results.

[DragonMaci]

Well as far as I can gather QM is moving more and more away from a realistic view all the time. This reminds me of something Nohr Bohr said way back in the early days of QM:

"``There is no quantum world. There is only an abstract physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature.''

And this seems to be a very typical view in the field today, where it is commonly accepted that the "traditional" rules of logic, causality do not apply (!!!!).

So in other words, Quantum Science isnt about a study of reality apparently, but a mathematical description of interpreted results run through an arbitary mathematical filter that "explains" the results.

Since Prometheus98876's time at the net cafe is up he sent me a SMS message asking me to state the following:

He does not agree with Bohr. He disagrees. He meant to say Bohr is wrong. However he says he implied he agreed even though he never blatantly said so.

Anyway, he wanted me to state that clarrification to prevent misinterpretation.

[horrid]

I'm a senior Physics major.

The Heisenberg Uncertainty Principle states that you can't know the exact momentum of a particle if you know its exact position. If you know the exact momentum, you cannot know the exact position.

several variables other than p, and x are coupled similarly (in the microscopic world).

Einstein theorized that there could be "hidden variables." Such that if you knew the

value of a certain hidden variable, you could calculate both momentum and position

exactly. (momentum and position would be a function of the hidden variable).

The scientists in that article are claiming to have proven that no such

hidden variables could ever exist.

As to whether or not its true, I can't comment because I haven't read the paper.

Even if I did, it would probably be over my head. But I hope they're wrong.

But if they are right, it means that nature is, by definition, uncertain. It will mean that man (or anything else) can NEVER know everything in the universe. He can only know probability functions of the things around him in the microscopic world.

Determinism will be destroyed because the fundamental particles that interact in this universe will forever be uncertain. They will require a measurement to ever be in one place. Until then, they are probability functions of possible places to exist.

To quote my quantum physics textbook:

"Thus determinism is a dehumanizing philosophy. It describes a universe that is infinitely predictable, holding few surprises. All can be known; nothing is unexpected. Determinism is boring. It is also wrong."

--Understanding Quantum Physics by Michael A. Morrison (pg. 6).

If that doesn't shake you to the bone, I dont know what will.