Anyone read this article in Seed Magazine?

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ossicle
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Anyone read this article in Seed Magazine?

Postby ossicle » Tue May 27, 2008 7:55 pm UTC

"The Reality Tests" about experiments being done in Vienna re: locality and realism.

http://joshuaroebke.com/Articles_files/Reality.pdf

I'd be interested in any thoughts anyone has on it.

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Turambar
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Re: Anyone read this article in Seed Magazine?

Postby Turambar » Tue May 27, 2008 9:04 pm UTC

ossicle wrote:"The Reality Tests" about experiments being done in Vienna re: locality and realism.

http://joshuaroebke.com/Articles_files/Reality.pdf

I'd be interested in any thoughts anyone has on it.


Well, I just read it. Reality as an emergent property? Seems kinda plausible. Thank God for scientists that aren't convinced by the dominant theory. They're the only reason it gets tested and improved.
"Physics is like sex. Sure, it may give some practical results, but that's not why we do it."
--Richard Feynman

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ATCG
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Re: Anyone read this article in Seed Magazine?

Postby ATCG » Tue May 27, 2008 11:59 pm UTC

Thank you for sharing the link. I found it fascinating. Zeilinger and his collaborators have an impressive record for coming up with experiments (such as keeping fair-sized molecules in quantum superposition and quantum teleportation) that show how common sense gets its butt kicked by QM. (I also liked how Zeilinger scribbles his equations on Boltzmann's old blackboard.)

Turambar wrote:Reality as an emergent property? Seems kinda plausible.

Agreed. I'd actually say it's certain if by "reality" we mean the classical, macroscopic world of our everyday perceptions. In fact there are good reasons to believe that even such intuitively fundamental notions as time and space arise from something deeper.
"The age of the universe is 100 billion, if the units are dog years." - Sean Carroll

Mettra
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Re: Anyone read this article in Seed Magazine?

Postby Mettra » Wed May 28, 2008 1:10 am UTC

ATCG wrote:
Turambar wrote:Reality as an emergent property? Seems kinda plausible.

Agreed. I'd actually say it's certain if by "reality" we mean the classical, macroscopic world of our everyday perceptions. In fact there are good reasons to believe that even such intuitively fundamental notions as time and space arise from something deeper.


If spacetime is emergent (not 'fundamental', as is hinted at by current theoretical physics), it doesn't seem too hard to think that 'reality' in the sense of information might be emergent. Zeilinger, as you said, has very pointed questions for quantum mechanics. Somehow, QM just doesn't jive with humans. Every time we think we may have figured something out, we realize we've forgotten some concept of the observer. The observer is that single quizzical object in QM that we never finish wrapping our heads around.

I love the macroscopic superposition experiments. In fact this paper reminds me of Seth Lloyd's 'the universe is a big computer' idea - that guy made a great macroscopic superposition in his work on quantum computers (the one with some electrons going clockwise around a 'corridor' and others going counter, couldn't find a good paper on it offhand).
zenten wrote:Maybe I can find a colouring book to explain it to you or something.

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ATCG
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Re: Anyone read this article in Seed Magazine?

Postby ATCG » Wed May 28, 2008 3:20 am UTC

Mettra wrote:If spacetime is emergent (not 'fundamental', as is hinted at by current theoretical physics), it doesn't seem too hard to think that 'reality' in the sense of information might be emergent. Zeilinger, as you said, has very pointed questions for quantum mechanics. Somehow, QM just doesn't jive with humans. Every time we think we may have figured something out, we realize we've forgotten some concept of the observer. The observer is that single quizzical object in QM that we never finish wrapping our heads around.

I love the macroscopic superposition experiments. In fact this paper reminds me of Seth Lloyd's 'the universe is a big computer' idea - that guy made a great macroscopic superposition in his work on quantum computers (the one with some electrons going clockwise around a 'corridor' and others going counter, couldn't find a good paper on it offhand).

Rolf Landauer's mantra of "information is physical" is alluded to in the Seed article. I'm tremendously excited by the whole notion of quantum computation and quantum information theory -- not because of the prospects of building a working quantum computer (although such a thing would be a fantastic accomplishment), but because of what it may tell us about the foundations of quantum mechanics and the structure of reality. Research into foundations languished for decades while more fashionable topics (first particle physics, then string theory) got all the glory. (Lloyd, in Programming the Universe, writes of how he, along with every other PhD student in the Rockefeller University physics department, was under enormous pressure to make string theory his thesis topic. He seems to have been the one holdout.) It would please me no end if real progress on puzzles such as quantum gravity started to come from this field. (In his previously cited book, Lloyd tells of having the beginnings of a theory of quantum gravity with its roots in quantum information theory.)

As for jiving with humans, you are right. QM has implications that make human beings bleed from the ears. Even that old war horse, the double-slit experiment, opens up a deep mystery. It defies logic that any given photon should do anything but go through just one slit (after all, the experiment can be performed with just a single photon). But where that photon winds up depends critically on whether there are one or two slits. How the hell does the photon know whether the other slit is there or not? At this point wave-particle duality gets trotted out, which is perfectly fine, except for the fact that it does nothing to reconcile experiment with the understanding of the world burned deeply into our brains by a lifetime of experience.

It just gets worse from there. I defy anyone to contemplate the Eliztur-Vaidman bomb testing problem (yet another thought experiment turned into a physical experiment by Zeilinger and his coworkers) without concluding that causality has been stood in front of a wall and shot. As with the double-slit experiment, there is a counterfactual -- a "what if" -- question being both posed and answered. In each case the answer to the question arrives to affect the outcome of the experiment, but from where?

Proponents of the many-worlds interpretation of QM (David Deutsch and Bryce deWitt being good candidates for its top two prosthelytizers) have a ready answer: The information comes from a parallel universe in which the "what if" case, rather than being just potential, is actual. I have to admit that I find their arguments compelling. Perhaps it's a measure of QM's bizarreness that someone can find MWI to be its least-strange interpretation.
"The age of the universe is 100 billion, if the units are dog years." - Sean Carroll

Mettra
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Re: Anyone read this article in Seed Magazine?

Postby Mettra » Wed May 28, 2008 4:51 pm UTC

Yes, the 'extra information' phenomenon is definitely something crazy. I've always thought it odd how, for example, some quantum states 'know' to avoid infinite negative potentials (like in some big bang theories) and suddenly reverse 'course' when they start to encounter one. It's like they have little feelers that feel out everywhere. That is very cheaty. It seems to me that we have a long way to go with quantum information theory.

I wouldn't agree that causality has been dealt a blow by concepts like this. I'd simply ask where the systems got the info. Maybe they got it from Seth Lloyd's monkeys. But how did the monkeys know >_>? Things we feel that are certain tend to be uncertain, and things that we feel to be fundamentally uncertain turn out to be... certain - such is the way of quantum mechanics.

I'd have to agree on the MWI. I find it hilarious and sad that people (including myself) can consider it seriously. Sometimes I just don't know whether to hate or love quantum mechanics. I guess there's a superposition of both somewhere in there.
zenten wrote:Maybe I can find a colouring book to explain it to you or something.

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Scigatt
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Re: Anyone read this article in Seed Magazine?

Postby Scigatt » Wed Jun 11, 2008 5:56 am UTC

A couple weeks ago I came across an interpretation that found rather interesting. The main idea of Relational Quantum Mechanics is that 'states' or 'properties' of system are not intrinsic to an object but to the relation between that system and an observer(which could be any other system, actually). (There are some good links in the References section.)


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