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PostPosted: Sun Sep 13, 2009 9:01 pm 
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The back cover of IZ 224 has an advert for Einstein's Question, by Steve and Deja Whitehouse. I read this fascinating novel several weeks ago and would like to discuss some of its deep aspects here.
The book concerns the role of living entities in our universe, the possibility that our universe is part of a unified collection of universes called a multiverse, that every entity (even each elementary particle) in each of these universes can be said to be living, how all this relates to theology, how mathematics can describe all this, and how the acts of living entities can hold the multiverse together. Much physics and social science can be learned by reading it with care.
The main idea is stability, in physics and social science. All entities in each universe must be somehow stable, this stability is needed to ensure the stability of each universe, and the latter can guarantee the stability of the multiverse itself. In fact, individual entities can act to bring this global stability about, or to keep it in place. We have a new take on the adage 'everything depends on everything else,' without the usual New Age irrationalist connotations.
The multiverse is looked over by the Guardians, beings with nearly divine powers. They enlist the Terran physicist Edward to help them intervene in an attack on our planet by a race of fanatical extraterrestrials. Stability of our universe alone demands intervention, as does fixing the ecological mess that we have made of the Earth. They succeed, but at a price that we can technically call genocidal. The moral is that anything at all can and should be sacrificed to ensure stability. For without stability nothing can exist, and preserving the proper existing entities is an overriding, ethically justified goal at any moment.
The authors now introduce another problem. This time the stability of the multiverse is threatened by the failure of one universe to enter a state conducive to global stability. This is a nearly Planck-scale Quantum Universe, which is governed by the probabilistic laws of quantum mechanics. With the help of beings even more god-like than the Guardians, humans are reduced to elementary particles, to assist in solving the problem. They do so by entering the Quantum Universe and carrying out acts of observation. These create the desired state of the entire Quantum Universe, just as (it is claimed) observation of the contents of a box determines the state--living or dead--of Schrödinger's cat. The multiverse and the Earth therein are saved.
Here I wish to state a criticism of this wonderful, strange book. The couple writes as if observation was an accepted tool in quantum theory. It is not. The notion that 'mind' and its acts of observation are essential to Quantum Mechanics was introduced by J. von Neumann, criticised by Schrödinger by using his cat, and is quite controversal. Indeed, the true interpretation of quantum mechanics is (as a mathematician told me) 'up for grabs.' Steve and Deja Whitehouse should have mentioned this.
There is much is this fine book that I am incompetant to discuss. The authors use the notion of stability in the physical and social sciences. I do not fully understand its latter use, although I believe that 'stability' is one idea that unifies the entire text. The discussions of political and social theory are too brief for me, as is the treatment of democracy therein. But this is a merely subjective criticism of this intellectually dazzling work.


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PostPosted: Tue Sep 22, 2009 5:51 pm 
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I saw the same back cover on IZ 244 this morning, and was intrigued by the book. I looked it up on Amazon UK, read a few reviews, but wasn't completely convinced.
Now after reading what you wrote, I really want to read it! Sounds like my type of SF, lots of ideas, science and philosophy. Thanks for your review!

I thought that the consequences of the act of observation in quantum physics (the collapse of the probabibility wave for example) had been more or less accepted. I'd like to check that up, to be sure.
As for the true interpretation, as in, does the universe exist because we can witness it hence collapase all its wave functions and creating "reality", I imagine that it is indeed "up for grabs"...Makes me think of many works from Greg Egan.


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PostPosted: Tue Sep 22, 2009 6:20 pm 
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Sorry we put an incorrect webpage address on the ad so here is the correct link

Roy


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PostPosted: Tue Sep 22, 2009 8:32 pm 
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Hi c-naptic. I'm glad you liked my review. Thanks for your thanks.
Here's a stab at a decent answer. Von Neumann introduced the notion of the collapse of the wave function as an addition to the other axioms of quantum mechanics. It's only justification was and is pragmatic, but it plays no role in the maths of qm. You are right to say that it connects with observation. But since there are interpretations of qm that reject collapse, the role of observation too is called into question.
The problem (a bit simplified) is how one gets from a state vector to one of its weighted components, called an eigenstate. Von N. claimed that observation does that. Today that is often doubted, for not many physicists (unless they're SF writers:) would say that observation creates eigenstates, i.e. bits of reality. That's too subjective. So some try to get rid of the reduction and interpret qm more objectively. The 'many worlds interpretation' is one example. And there my knowledge currently ends, although I could restate the above in maths terms. It really is up for grabs, as is particle theory (strings or what?).


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PostPosted: Wed Sep 23, 2009 12:09 pm 
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There is always the rather difficult question of what constitutes an observation. In those single-photon, double-slit experiments, it seems to be the presence of a particle detector that causes the wave function to collapse, rather than an observation by a conscious being. I believe the theory of quantum decoherence is thought to have resolved some of the questions around this, but I haven't got round to exploring it myself.

cheers, Mike

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PostPosted: Wed Sep 23, 2009 2:01 pm 
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Thanks Mike A., I forgot about those two topics (since I'm hardly acquainted with them). I read some popular stuff on the two-slit-type experiments in Brian Greene's The Fabric of the Cosmos. They are amazing, especially those that appear to show influences from future to past states of an experimental setup that contribute to how we can interpret the outcomes. Although my impression was that we don't know how to properly describe this type of behavior, they do support your reading. I have thought about them on and off for several years, but the puzzlement hasn't decreased.
I know nothing about decoherence except that understanding the theories that fall under that name would leave me with no time to do anything else. Do you know of any good, noncondescending, books or articles on the latter?


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PostPosted: Thu Sep 24, 2009 6:49 pm 
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C-naptil,
Concerning your question on Quantum Mechanics and hopefully adding to George Berger’s contribution. Professional physicist’s view of Quantum Mechanics breaks down into two groups: 99.9 % who use it as a wonderful calculation tool and don’t care about the philosophy (e.g. Richard Feynman) & 0.1% who try to understand the fundamentals. There is no doubt that 100% of physicist’s don’t understand the principles of QM.

It all started with Neils Bohr who developed the standard approach to “understanding” Quantum Mechanics which came to be known at the Copenhagen Interpretation, collapsing Wavefunction, apparatus being key to reality and the importance of observation, etc. When I was a student, literally a life time ago, if you did not “believe” you were thought of as dim, a poor student, there was no question of discussion – the Taliban interpretation of QM. I thought it was drivel then and I do now. I was in good company so did Einstein, Schrödinger, de Broglie, David Bohm etc..

Einstein challenged Bohr as to whether QM, namely Copenhagen Interpretation was a good description of reality, it all hinged around Quantum Entanglement and non-locality. The challenge came in terms of a paper: EPR (Einstein, Podolsky, Rosen) thought experiment.

Much later a genius based as CERN, John Bell took up the EPR challenge. His book Speakable and Upspeakable in Quantum Mechanics is the new bible, it’s technical but a must read. Essentially he proved, with the help of experiments, that Einstein interpretation of QM was correct and Bohr’s interpretation wrong. QM was consistent and experiments predicted non-local physics.

Another major figure came on the scene David Bohm, he developed a theory where there would be no need for a collapsing Wavefunction or the necessity of observations from a sentient being to reinforce reality. David Bohn was interested in the philosophy of QM.

Note here that non-locality implies the physics of Special Relativity is WRONG and the two are irreconcilable!!!

All these ideas are brought together in a very good article in Scientific America (March 2009) by David Albert and Rivka Galchen (page 26) – “A Quantum threat to Special Relativity”

Presently there is a great deal of research going on in Bohmian Mechanics, most of the papers are on the web and accessible to the public, however they are highly technical papers (look up Daumer, Durr, Tumulka, Zanghi).

I have been trying to find some time so that I can have a good look at this subject, presently not doing very well.

Finally, to paraphrase a quote from Feynman, “anyone who think they understand QM is confused.”


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PostPosted: Thu Sep 24, 2009 9:08 pm 
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Hi SpaceTime--Thanks for that bird's eye view of the main events on the recent foundational landscape. I can offer no excuse for not having read John Bell's book (it's a collection of papers by him). I shall order it soon.
I thought of mentioning Bohm but decided not to, since it's the many-worlds interpretation of qm that fascinates SF people right now. Besides, I know nothing in detail about Bohm's theory.
I'm glad you referred to the article in Scientific American. I decided not to read it upon its publication, since I already knew about the authors and their ideas. You have done the readers a service by stressing the notion that special relativity and qm are an inconsistent pair. I don't know what to believe, if only because I love the relativity theories so much. But I am quite ready to accept the falsity of special relativity. I've had no time to study these matters, and the Sci Am article gave too few technical details for my taste. But the main idea is clear, once you've learned Bell's theorem: non-locality is required by Bell, but special relativity rules it out. So something must give. Here I might disagree with you. Why not keep special relativity and modify or drop qm? Didn't Bohm keep relativity, admit a nonlocal field, and modify qm to keep a particle theory that's consistent with all experiments? Here I start to get lost!


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PostPosted: Thu Sep 24, 2009 9:32 pm 
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For practical purposes, relativity works at the large scale and QM works at the small (read: subatomic) scale. QM is inherently discrete or granular, everything happening in 'lumps' determined by Planck's Constant; by contrast relativity is inherently continuous. On their respective scales, both have been thoroughly verified experimentally. The question is, what theory could synthesise the two, explaining at what threshold, and how/why, QM switches into relativity? At the moment, nobody really knows, but there are several competing theories. Loop Quantum Gravity is the most recent one I've heard of.

The many-worlds interpretation was due to Hugh Everett III, who first formulated it in 1957. Bohm's interpretation is a kind of pilot-wave theory. There is a wikipedia page summarising the various interpretations here:
http://en.wikipedia.org/wiki/Interpretations_of_quantum_mechanics

The best book for explaining to the layman how QM works is probably Richard Feynman's "QED: The Strange Theory of Light and Matter". It simplifies somewhat by ignoring the phenomenon of polarisation, and it doesn't stray too far into the philosophical side of things, but I found it a very good primer.

Cheers, Mike

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PostPosted: Fri Sep 25, 2009 2:52 am 
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I've heard that Lee Smolin has at least one article in Scientific American that summarises the ideas of Loop Quantum Gravity. His popular, 'Three Roads To Quantum Gravity' does not do this in any depth. There's an exposition that looks ok in Roger Penrose's 'The Road To Reality,' yet another book that I 'must' read parts of. The most thorough text I have seen is Carlo Rovelli's, 'Quantum Gravity.'


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PostPosted: Fri Sep 25, 2009 2:13 pm 
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Mike, SpaceTime, etc. Here's an argument I thought up for modifying or replacing elementary qm. The latter is our second level of description, with only classical relativistic physics above it. Below are the theories of the weak and strong forces. If I understand things correctly, the latter two are relativistic quantum field theories (each with its own formulation). Now why should elementary qm be the exception here? Consider the two lower-level theories. If they are non-local, relativistic, and conceptually in order, then I'd consider it probable that something is wrong with elementary qm, not special relativity. If they don't involve non-locality, are relativistic, and are conceptually in order, then elementary qm is an exception, for all the others use special relativity in a nonobjectionable way, while elementary qm has a problem with it. It would then be reasonable (but perhaps wrong!) to modify or get rid of it.


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PostPosted: Sat Sep 26, 2009 12:45 pm 
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Mike A

Can I politely disagree with you concerning the issue of non-locality. The key issue between Special Relativity and Quantum Mechanics is not the scale, continuous versus discrete but the concept of action at a distance (AAAT). AAAT was the issue that disturbed Isaac Newton with his theory of gravity, how can any force travel faster than the speed of light, or indeed at an infinite speed, and effect particles in the real world.

All of our present theories disagree with AAAT with the exception of QM but QM is correct. Take entangled electrons for example, when one of the electrons is examined and is found to be say spin up, relatively to some measurement frame, the other entangled electron is found to be spin down, even if the second electron is the other side of the Galaxy. A Swiss group and others experiments how shown this effect to be correct (at shorter intercity distances).

Here again if I can politely disagree with George’s comments, I “believe” that QM’s is the fundamental theory of reality and all others are only approximations. Everyone knows that General Relativity, in its present formulation, is not valid at the Planck scale. Non- locality is a hard pill for physicists to swallow.

This is a fascinating and wonderful subject and I have really enjoyed reading the various contributions.
SpaceTime


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PostPosted: Sat Sep 26, 2009 5:40 pm 
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SpaceTime, you are right about the theories besides qm being approximations because of the incompatibility of General Relativity and Planck-Scale structures. I should have remembered that. Instead, I falsely assumed that as you get smaller in scale the theories must be better descriptions of reality. That's wrong, for precisely the reason you state. Something must be done at the smallest scale, and only then will we see if anything needs to be done with elementary qm. That's a bit weaker than calling qm "correct." My argument now fails to convince.


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PostPosted: Sun Sep 27, 2009 1:12 pm 
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Eat your heart out Analog Forum. This is a proper SF discussion thread, we need more of this here.


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PostPosted: Sun Sep 27, 2009 1:55 pm 
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Thanks Roy. It is a pleasure to have started this thread. I first saw that Analog forum about one year ago. It's amazing, but my heart's on this side of the Pond.


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