String theory is what?

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Is String theory a theory

Poll ended at Mon May 17, 2010 8:39 am

1) No
3
7%
2) Yes
8
17%
3) Not yet
17
37%
4) Nope and never will be its not even a hypothesis it's just religious arm waving
4
9%
5) Of course you fool it has lots of evidence you just need to understand 22 dimensional topography!?
3
7%
6) Don't know/care/ have an opinion/x/y/t/i/D5,D6,D7,dx/dy/ Cream cheese
3
7%
7) Bacon and egg sandwiches, ghgsdhsfdghawete, Bacon.
8
17%
 
Total votes: 46

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Re: String theory is what?

Post by Xamonas Chegwé » Thu Mar 18, 2010 5:13 pm

hackenslash wrote:
Xamonas Chegwé wrote:I honestly don't understand enough about it to give an opinion on its likelihood of ever being more than an hypothesis. I really need to get my head around QM before I start messing with silly string. :dono:
If you need to get your head around QM first, you're not going to bother. Nobody can get their head around QM.

Brian Greene's The Elegant Universe is an excellent introduction to M-Theory, and covers a good deal of QM and GR as well.
Found it on Amazon for 65p - over £3 with postage but still worth it at that price.

I really do want something of reasonable complexity about QM though. Not pop-sci but well written, starting from the basics and with at least the main parts of the maths intact. Any recommendations?
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Re: String theory is what?

Post by AshtonBlack » Thu Mar 18, 2010 6:02 pm

Not yet, but some nice plans for space bourne instrumentation coming on stream in the next few years, plus getting the LHC working at full power might help. But yes, it's just a hypothesis at the moment.

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Re: String theory is what?

Post by Nautilidae » Thu Mar 18, 2010 6:07 pm

Xamonas Chegwé wrote:
hackenslash wrote:
Xamonas Chegwé wrote:I honestly don't understand enough about it to give an opinion on its likelihood of ever being more than an hypothesis. I really need to get my head around QM before I start messing with silly string. :dono:
If you need to get your head around QM first, you're not going to bother. Nobody can get their head around QM.

Brian Greene's The Elegant Universe is an excellent introduction to M-Theory, and covers a good deal of QM and GR as well.
Found it on Amazon for 65p - over £3 with postage but still worth it at that price.

I really do want something of reasonable complexity about QM though. Not pop-sci but well written, starting from the basics and with at least the main parts of the maths intact. Any recommendations?
I suggest "The Quantum World"

http://www.amazon.com/Quantum-World-Phy ... 0674013425

It gives an overview of not just the science, but the history as well. It discusses quantum mechanics and even a bit of quantum field theory. I purchased a copy last year, though all I have done is skim through bits [har har har] and pieces of the book.

I also suggest Leonard Susskind's "The Black Hole War". It discuss the black hole information paradox proposed by Stephen Hawking. It discusses the quantum mechanics of the paradox and even the string theory behind the resolution.

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Re: Strings 2010 Conference - Webcast

Post by Nautilidae » Thu Mar 18, 2010 7:23 pm

If anyone is interested, in 7 minutes, Nobel prize winning physicist Steven Weinberg will be giving a lecture on gravity at high energies. To listen to the lecture, simply follow the link from the first post.

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Re: String theory is what?

Post by owtth » Thu Mar 18, 2010 7:27 pm

As a very non-scientist I can recommend Hyperspace by Kaku, most of the time I actually understood what he was saying. I think it was more concerned with superstring theory, and to be honest I can't recall the difference.
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Re: Strings 2010 Conference - Webcast

Post by The Dagda » Thu Mar 18, 2010 11:17 pm

Nautilidae wrote:
The Dagda wrote:Reminds me of a religious symposium. I don't like String Theorists or their theory not because it isn't useful or hasn't a chance of being right. Hell that would be great if it was right as well as being useful to complex systems. The problem I have is that it is as it stands pure philosophy and relies on an interpretation being falsified more or less to make it science. That is not scientific method, that is philosophy. I therefore don't agree that String theory is a theory no matter how many people say it can be falsified, because a it doesn't matter if it can (and it can't, it's background independent and so no matter what field of physics is proven wrong it is unfalsifiable) it simply would given the potential to be falsified only be a hypothesis, not a theory, theories need facts and evidence not arm waving mathematics. String theory doesn't IMHO even qualify as a hypothesis it is pure maths. Is it worth studying hell yes, does it belong in a physics department, as yet no.
1. I think that you are being a bit unreasonable. It seems to me that you think that anything that has yet to be falsified isn't physics. Using this logic, the following things don't belong in the physics department:

All theories of spontaneous symmetry breaking (including Higgs and technicolor)
All quantum gravity theories (String theory, Horava-Lifshitz, LQG, and other canonical quantum gravity theories)
All grand unification theories

Spontaneous symmetry breaking mechanisms have yet to be falsified, yet they a cornerstone of quantum field theory. Just because something has yet to be falsified doesn't mean that it isn't physics; you need hypotheses before you are able to test them.


2. String theory is background-dependent, not background-independent.

3. How on Earth does background independence show that theories are unfalsifiable? General relativity is background-independence and it is supported by much physical evidence. Unless you are suggesting that general relativity is unfalsifiable, I suggest that you rethink your argument.
No just after 30 years they should be in the pure maths departments and not sucking money from other physics areas unless they contribute scientifically, we need physics funding in theoretical physical theories but only ones that have a snow balls hell chance in hell of turning up anything, and aren't a self proclaimed only game in town money vacuum distinctly short of any likely experiment in anyone's lifetimes or even the next thousand generations maybe. Few theories that have nothing to show for themselves are given this much grace or faith. And that is why I see it as a religion after 30 years with nothing at all it must be faith keeping it alive in the science depts. I can only put that down to its cult like status.

I think Peter Woit is right it's Not Even Wrong and it is seriously disturbing to see so much physics funding thrown at a so called theory that has nothing at all to show for itself not even a falsifiable experimental set up. I don't want it to lose funding I just want it to come from maths departments not physics departments, after all these people just need a slide rule they don't need experiment.
hackenslash wrote:Special Relativity wasn't even maths when it was begun to be taken seriously. Even after that, it was still only maths until Eddington's (faulty) observation.

Again, and I have to say this every time I post about M-Theory, I'm neither a supporter nor a detractor yet, but given that predictions have arisen from it, it is science, not least because it is falsifiable as a result of those predictions. It is also, at root, an extremely simple idea, and has a degree of parsimony. I think it has excellent potential as a GUT, and for those reasons alone should be pursued.
Special relativity was proved in about 17 years, had it not gained any experimental evidence during that time it would probably have ceased to exist. It's only in the modern age that pop science mags have idolised this pretender and given it a wider audience than it deserves given what it has to show for itself, nothing directly applicable to either a standard model or a ToE.

There's a very good reason they haven't given out a Nobel Prize for anything that directly proves Strings are a viable theoretical concern, it's the same reason Special Relativity (SR) wasn't considered a strong scientific theory until Einstein was given a prize for his three seminal papers and specifically the photo electric effect. The day they do start handing out prizes to hypothesis is the day science dies, first to come is the day it starts showing us the money not the other way round.
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Re: Strings 2010 Conference - Webcast

Post by Nautilidae » Fri Mar 19, 2010 12:24 am

The Dagda wrote: No just after 30 years they should be in the pure maths departments and not sucking money from other physics areas unless they contribute scientifically, we need physics funding in theoretical physical theories but only ones that have a snow balls hell chance in hell of turning up anything, and aren't a self proclaimed only game in town money vacuum distinctly short of any likely experiment in anyone's lifetimes or even the next thousand generations maybe. Few theories that have nothing to show for themselves are given this much grace or faith. And that is why I see it as a religion after 30 years with nothing at all it must be faith keeping it alive in the science depts. I can only put that down to its cult like status.
Okay. Either you are a troll or you are completely ignorant.

String theory makes many falsifiable predictions. Let's list some:

1. Supersymmetry
2. Extra dimensions
3. String harmonics
4. Special properties of quantum gravity, such as the holographic principle

Now let's list some of it's applications:

1. Quantum gravity
2. High-temperature superconductors
3. Condensed matter physics,
4. Applications in quantum chromodynamics
5. Grand Unification

For a theory that has nothing going for it, it sure has a lot going for it!
I think Peter Woit is right it's Not Even Wrong and it is seriously disturbing to see so much physics funding thrown at a so called theory that has nothing at all to show for itself not even a falsifiable experimental set up. I don't want it to lose funding I just want it to come from maths departments not physics departments, after all these people just need a slide rule they don't need experiment.
This is simply insulting. See above.
Special relativity was proved in about 17 years, had it not gained any experimental evidence during that time it would probably have ceased to exist. It's only in the modern age that pop science mags have idolised this pretender and given it a wider audience than it deserves given what it has to show for itself, nothing directly applicable to either a standard model or a ToE.
... String theory is used to study quantum chromodynamics all of the time. It also creates a framework with which to model quantum gravity, something at which even the standard model fails.
There's a very good reason they haven't given out a Nobel Prize for anything that directly proves Strings are a viable theoretical concern, it's the same reason Special Relativity (SR) wasn't considered a strong scientific theory until Einstein was given a prize for his three seminal papers and specifically the photo electric effect. The day they do start handing out prizes to hypothesis is the day science dies, first to come is the day it starts showing us the money not the other way round.
:drunk:

... You fool and double-damned fool.

Let us view some Nobel laureates that have received prizes for hypotheses:

Sheldon Glashow
Steven Weinberg
Abdus Salam
Yoichiro Nambu

Just because has yet to be tested doesn't mean that it doesn't offer testable predictions. The hypothesis is one of the core aspects of the scientific method.
I suggest, before you make a mockery of brilliant men, that you become more informed on the subject that you are mocking

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Re: String theory is what?

Post by JimC » Fri Mar 19, 2010 5:02 am

hackenslash wrote:It's a hypothesis. I would tend to call it something like a 'metatheory' except that I run away from the 'meta' prefix as it makes anything sound like wibble.

I'm neither a supporter nor a detractor, but I do think it has the potential to explain a great deal, and at bottom it's actually quite parsimonious, although the mathematics is quite esoteric. At the moment, I'm happy to wait for the experimental evidence arising from the first predictions.
:tup:

Although you could really call it a speculative model, containing a whole heap of hypotheses and an intricate web of mathematical reasoning that few can grasp in its entirety...

I'm not really against it, just waiting for it to generate experimentally testable predictions, whether via cosmological data, or high energy particle physics.
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Re: Strings 2010 Conference - Webcast

Post by lpetrich » Fri Mar 19, 2010 5:11 am

Anything interesting yet?

I'm particularly interested in whether one can get the Standard Model out of string theory. There are three possibilities:
  1. It is not possible to get the Standard Model out of string theory.
  2. It is possible to get the Standard Model out of string theory, but also lots of similar theories resulting from different space-time topologies and boundary conditions.
  3. It is possible to get the Standard Model out of string theory, but no similar theory.
The impression I get is that string theory partially fits case 2, with little progress toward demonstrating or rejecting either case 1 or case 3. Is that a fair statement?

I think that we will be in a better position when the LHC has run for a while. We will either see particles predicted by supersymmetric extensions of the Standard Model, or else we will push lower limits up by at least a factor of 3. Either possibility will help improve constraints on GUT-scale physics and make possibilities 1 and 3 more testable.

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Re: Strings 2010 Conference - Webcast

Post by The Dagda » Fri Mar 19, 2010 7:30 am

1. Supersymmetry
How would you test for this in what experiment have you shown this?
2. Extra dimensions
How do you test for dimensions we can't see nor probably never will? It disappears into x is not a proof.
3. String harmonics
so far beyond the planck scale that it would take a colider the size of the solar system to see them.
4. Special properties of quantum gravity, such as the holographic principle
What test? Which experiment shows this?
Now let's list some of it's applications:

1. Quantum gravity
2. High-temperature superconductors
3. Condensed matter physics,
4. Applications in quantum chromodynamics
5. Grand Unification
Nah I'm sorry but what experiment would distinguish any of these to string theory alone above any other model from the standard to LQG?

I'm not talking about the maths being useles, I'm talking about its claims being a TOE. Nowhere have I claimed it is useless in fact if its used for something it wasn't designed even if it isn't any more than modelling complex systems then it is science even if it has nothing to do with what it was originally intended to do. However that doesn't make a proof of a GUT or TOE at all. Another favourite tactic of the Witch Doctors of String voodoo is to claim credit for predictions other back ground dependent models make as if them being falsified would falsify a model that has to have no relation to actual events ie it isn't inductive it is deductive. All it has to do is fit experimental results, it doesn't have to be provable that the equations are pictorially real. Still it is still pure maths and no amount of arm waving will change the fact that a model of everything aught to at least predict something that can be shown in experiment. There will be no evidence of strings at CERN. Those who work there questioned about it (Theoretical/experimental physics) said in their opinion the chances of evidence of strings turning up were 1 in a thousand to impossible. That was all of them. String theory is slowly sliding out of view, it's time it showed us something other than talk.
Nautilidae wrote:
The Dagda wrote: No just after 30 years they should be in the pure maths departments and not sucking money from other physics areas unless they contribute scientifically, we need physics funding in theoretical physical theories but only ones that have a snow balls hell chance in hell of turning up anything, and aren't a self proclaimed only game in town money vacuum distinctly short of any likely experiment in anyone's lifetimes or even the next thousand generations maybe. Few theories that have nothing to show for themselves are given this much grace or faith. And that is why I see it as a religion after 30 years with nothing at all it must be faith keeping it alive in the science depts. I can only put that down to its cult like status.
Okay. Either you are a troll or you are completely ignorant.


For a theory that has nothing going for it, it sure has a lot going for it!
I think Peter Woit is right it's Not Even Wrong and it is seriously disturbing to see so much physics funding thrown at a so called theory that has nothing at all to show for itself not even a falsifiable experimental set up. I don't want it to lose funding I just want it to come from maths departments not physics departments, after all these people just need a slide rule they don't need experiment.
This is simply insulting. See above.
Special relativity was proved in about 17 years, had it not gained any experimental evidence during that time it would probably have ceased to exist. It's only in the modern age that pop science mags have idolised this pretender and given it a wider audience than it deserves given what it has to show for itself, nothing directly applicable to either a standard model or a ToE.
... String theory is used to study quantum chromodynamics all of the time. It also creates a framework with which to model quantum gravity, something at which even the standard model fails.
There's a very good reason they haven't given out a Nobel Prize for anything that directly proves Strings are a viable theoretical concern, it's the same reason Special Relativity (SR) wasn't considered a strong scientific theory until Einstein was given a prize for his three seminal papers and specifically the photo electric effect. The day they do start handing out prizes to hypothesis is the day science dies, first to come is the day it starts showing us the money not the other way round.
:drunk:

... You fool and double-damned fool.

Let us view some Nobel laureates that have received prizes for hypotheses:

Sheldon Glashow
Steven Weinberg
Abdus Salam
Yoichiro Nambu

Just because has yet to be tested doesn't mean that it doesn't offer testable predictions. The hypothesis is one of the core aspects of the scientific method.
I suggest, before you make a mockery of brilliant men, that you become more informed on the subject that you are mocking

-Nautilidae
No it doesn't make any falsifiable predictions. Please if I am a troll then so is Peter Woight.

I know you are enamoured of your God but I really don't care what half baked stuff you want to claim makes your theory a real theory. It's punching above its weight and a non background independent theory cannot be falsified by proving a back ground dependant theory wrong, end of story. Sorry but if you think scientific criticism levelled by the best people in high energy physics is trolling then you should take it up with them.

How many people have recieved a Nobel prize for string theory?

It is not even wrong. Please read the book before you come your self righteous religious ire at me.

I may be more concise than Dr Woights 300 page attack on the state of physics. But I'm not saying anything hundreds and thousands of other people haven't said. Put up or shut up.

And I may be pointed but I wouldn't troll about this subject unless someone else was trolling, then I'd troll them.
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Review of "Not Even Wrong" by Peter Woit and
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Not Even Wrong by Peter Woit. Basic Books, 2006. 278 pp. $26.00 / $34.95 (hardcover). ISBN 0-465-09275-6.

The Trouble with Physics by Lee Smolin. Houghton Mifflin, 2006. 343 pp. $xx.xx (hardcover). ISBN x-xxx-xxxxx-x.

Throughout human history, we have had, among us, an intellectual elite whose members kindly advise the rest of us as to “what it all means.” These advisors have, typically, been the priests of the current religion. And we the people have always been glad to have those priests’ potent insight! Genuinely glad, because, although we are not so naïve as to expect their advice to be perfect, we are mature enough to know that it is likely the best advice that we are going to get.

So, how are we doing today, in this regard? Well, nothing has changed in the sphere of religious advice, but there is, of course, a significant new element, that of “scientific” insight. Considering the fantastic practical successes of science, combined with the essentially total lack of any practical successes on the side of the priests, it is, perhaps, surprising that most people still do stick with those priests (to get what they feel is the real skinny). How can this be?

I think it is because people naturally sense that everything that we scientists are discovering, important as it is, is essentially superficial. And, it is superficial, in my opinion.

The last truly grand success of physics was in 1925, with the discovery of quantum mechanics. There have been many important advances since then, but nothing of the same epochal character.

Until now? Well, this is a book review! I am reviewing two books that take on superstring theory. If superstring theory turns out to be correct (if that is even possible), then, superstring theory is, just maybe, in the class of quantum mechanics, in terms of its epochal impact.

Both of the books that I am reviewing suggest that that will never happen; that superstring theory is without a future; that it is in fact a failed theory. And both authors are concerned that continued fixation on this failed theory, by professors who won their tenure as its advocates, will retard advances in other directions.

Until very recently, I was a mainstream advocate of superstrings, glibly mouthing the party line: that superstrings produce quantum gravity; that it is the only game in town; and so on. But, I never spent much time teaching it to students. As I explained to the students, “I do like it, but it might not be right. There are other things that are right, that are so fantastic in their implications that I don’t want to waste a great deal of your time on superstrings: I am here of course referring to Special Relativity, General Relativity, and Quantum Mechanics.” I concentrate on teaching these three glories, as being things that we know are true, and that deeply offend our intuition⎯which must therefore be suppressed as simply wrong. That is enough to keep me, and the young people, busy! Don’t bother me with superstrings and M-theory!

What has changed my mind? An evolution. One important step was hearing Raman Sundrum’s wonderful talk at the Albuquerque APS meeting in 2002, in which he clearly brought out that we have no identified avenue to understand the value of the cosmological constant. His exposition produced a big impact on me, because the calculation of the value is so simple, and produces such a horribly wrong answer. The simple calculation is closely analogous to that which produced the ultraviolet catastrophe, which required the quantum to fix. I decided that something just as fundamental as the quantum was needed here, and … forgive me! … I ordered my brain to find it.

What am I talking about? Well, we have NO understanding of how our brains work. But we do have plenty of examples of peoples’ brains actually working, and producing, sometimes, great answers. My favorite example, of both failure and success, is our discovery of vectors.

I ask students, “how hard was it, for you, to learn vectors?” They reply, in agreement with my own experience, “not totally easy, but no big deal.” Well⎯I then tell them⎯for our human race to discover vectors was very close to impossible. Our greatest mathematician, Gauss, tried his hand, and he failed dismally. And, when Hamilton did succeed, he did so only via a “lightning bolt,” as he and Mrs. Hamilton approached Broughm bridge.

Was Hamilton’s discovery of quaternions (essentially, vectors) a gift from God? I think not!

Hamilton had, by working on it, “ordered” his brain to find it, and years of growing synapses in his sleep eventually produced it. That is my petty “theory!” I do not believe that we can think anything that is not already wired in our synapses. You have to grow it.

So, my brain, such as it is, has been “under orders” for some years now! Any result? Yes, I think so. Perhaps not the brass ring, but, I think, something! In 2006 April I stumbled across an internet paper by Curt Renshaw pointing out that NASA’s planned Space Interferometry Mission (SIM) could test the “contraction of length” predicted as part of Special Relativity. I am very interested in physics outreach and student involvement, and I thought that “Was Einstein Right?” would be a great student experiment for SIM. So, I went through the simple mathematics ... and discovered that the conventional interpretation of length contraction is wrong, and that space is not contracted in the direction of motion, but instead is curled. A different topology.

Well, my paper on the subject is still in the hands of the editors at Physical Review Letters. We shall see!

But there is something else that made me think that superstring theory might be wrong (before reading the two reviewed books), and that is new experimental investigations into the reach of Newtonian gravitation. Many theories of extra dimensions suggest that Newtonian gravitation might fail on scales of about a millimeter! Well, it doesn’t. It does not fail down to nanometer scales. This we find from dropping neutrons, and watching them bounce under gravity. Brilliant, and conclusive.

But, the theory can be adjusted, to evade this new result! Well, that is a chief complaint by both our authors, Voit and Smolin: that superstring theory is so plastic that it can fit any experimental results at all, and hence has neither any ability to predict, nor the strength of being falsifiable. It is argued that this means that superstring theory is no more a part of science than is Intelligent Design.

You should probably read these two books in the opposite order to what I did. That is, read “Not Even Wrong” first. It is denser, and it will prepare your mind, filling you with all kinds of good ammunition. And, it accelerates, becoming somewhat polemical toward the end, and thus firing you up for Lee Smolin’s rather more accessible book.

Now, what is all this about? Well, over the decades, physicists have had a rough ride, as they attempted to read the book of nature. Sir Arthur Stanley Eddington in 1927 painted a clear picture of how this “progress” occurs: “Scientific discovery is like the fitting together of the pieces of a giant jig-saw puzzle; a revolution of science does not mean that the pieces already arranged and interlocked have to be dispersed; it means that in fitting on fresh pieces we have had to revise our impression of what the puzzle-picture is going to be like. One day you ask the scientist how he is getting on; he replies, “Finely. I have very nearly finished this piece of blue sky.” Another day you ask how the sky is progressing and are told, “I have added a lot more, but it was sea, not sky; there’s a boat floating on the top of it”. Perhaps the next time it will have turned out to be a parasol upside down; but our friend is still enthusiastically delighted with the progress he is making.”

So how are superstrings coping with the astonishing discovery of a small non-zero positive cosmological constant (by the guys just down the hall from me, with their colleagues)? Why, finely. To stabilize your six hidden dimensions, you must wrap them with branes, and then, to force a positive cosmological constant, you again wrap, this time with large numbers of anti-branes, and … hey presto! Mission accomplished!

There were⎯how many epicycles in Ptolemy’s scheme? And, actually, even more in Copernicus’s even more wretched machine. But, in Newton’s, arguably one, the value of G. And, in superstrings; well, brace yourself, 10500. The particular one describing our world has not yet been located. Do not hold your breath!

Lee Smolin emphasizes the simplicity of the great results. Special relativity comes from nothing more than changing a sign from + to – in the Pythagorean theorem applied to four dimensions. Smolin points out that he can summarize General Relativity on a single sheet of paper; well, so can I! This is no accident. Eddington: “There are not many things which can be said about curvature⎯not many of a general character. So that when Einstein felt this urgency to say something about curvature, he almost automatically said the right thing.”

And as for quantum mechanics, there is nothing simpler. That is exactly why I think that in the case of quantum mechanics, we do not have an “effective theory,” but rather, we have the real thing. There is simply no way to make it simpler! I have long been of the opinion that quantum mechanics is not an option, that it flows automatically out of the numerical character of observations. And is therefore not in the least bit mysterious.

Quantum mechanics is just the machinery for discussing observations intelligibly. What we are looking for are the symmetries that give rise to the forces (accelerations) that we observe. My suggestion at the moment is that we will find them in the topology of four-space, not in added dimensions.

But Ed Witten is there, far ahead of me! Seiberg-Witten invariants! Ed has been highly productive in exploring this option, in addition to the superstring path.

It must be difficult for Ed to read the two books I am reviewing (if he has), because really, none of this is his fault. What is he supposed to do, except to try his hardest, which he continues to do? He is smarter than the rest of us, and so, unfortunately, many among us simply look to him for signposts, rather than thinking for ourselves. I am sure that Ed deplores this! But, it is definitely not his fault!

Woit in a nuanced fashion compares Ed with Einstein, pursuing, endlessly, wrong ideas. This is perfectly plausible, given the obtuseness of even a Gauss, as I said! The rest of us do the same in our own smaller spheres.

And where is the answer? Well, maybe, says Smolin, right under your nose! Overlooked! That is something I believe myself, at least as a serious possibility.

Does the next powerful step have to be as simple as special relativity, general relativity, and quantum mechanics? We simply do not know! The superstring people think not; they suspect that truth is a quagmire and that that’s all there is to it: a “landscape” of inconceivably vast numbers of chunks of the universe with random physics, and we are in one that looks intelligently designed because if it weren’t we could not be here. End of story!

My own hope is that I, or someone else, will find an overlooked symmetry that will result, simply and inevitably, in the standard model with all parameters calculable from first principles. That is the holy grail of physics.

So, are there any other things, right under our noses, that we have not recognized? I say yes, big time. Smolin points to five fundamental problems of physics, but emphasizes that the “greatest mystery of all” is the meaning of quantum mechanics. Then surely most of his book is about this most important problem? Well, no. His treatment of this most important problem is superficial in the extreme. He announces that he is a “realist” and dismisses non-realism (mental universe) on grounds that in the early universe there were no minds! That is, he takes a conclusion (that there was an early universe) and deduces his premise from that!

The only thing that we actually know, is that our minds exist; all else is suspect deduction from what we call “observations.” These observations are numbers that occur to us every day and that have patterns in them that we call a world. But, you can test the reality of that world, and it is simply not there: e.g. “Measurements Are the Only Reality, Say Quantum Tests.” (Science Magazine, 1995 December 1, page 1439.)

Ho-hum, turn the page of Science, and go back to simply kicking boulders to refute the pesky mentalists!

Most among us are in denial regarding the obvious. The alternatives are untenable, and counterproductive. I heard Brian Greene talk, fascinating on superstrings, but a look of awe as he indicated his leaning toward “many worlds” quantum mechanics. Why don’t I like many worlds? Not because the number of worlds makes 10500 look like chump change; no, it is because you have introduced your many worlds, with no objective other than to make your electrons real, and yet when you are done … you can’t say one word about what your now-real electrons are. It is simply nonsense!

I highly recommend both of these books; they deserve a wide audience.
Peter Woight professor of physics, Lee Smolin professor of physics proponent of LQG and ex String Voodoo practitioner.

Perhaps this chumps a troll too, perhaps the backlash that is coming against String Theory is a troll?

http://msx4.pha.jhu.edu/woit.html
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Re: Strings 2010 Conference - Webcast

Post by JimC » Fri Mar 19, 2010 7:48 am

Staff position being stated:

This thread is edging closer to exchanging personal insults and accusations of trolling than is necessary. Participants in the thread have opinions on thread theory; state them, do not stray into the personal stuff. Short vacations can be arranged for those who don't play nice...
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Re: Strings 2010 Conference - Webcast

Post by The Dagda » Fri Mar 19, 2010 7:51 am

JimC wrote:Staff position being stated:

This thread is edging closer to exchanging personal insults and accusations of trolling than is necessary. Participants in the thread have opinions on thread theory; state them, do not stray into the personal stuff. Short vacations can be arranged for those who don't play nice...
Indeed.
Until very recently, I was a mainstream advocate of superstrings, glibly mouthing the party line: that superstrings produce quantum gravity; that it is the only game in town; and so on. But, I never spent much time teaching it to students. As I explained to the students, “I do like it, but it might not be right. There are other things that are right, that are so fantastic in their implications that I don’t want to waste a great deal of your time on superstrings: I am here of course referring to Special Relativity, General Relativity, and Quantum Mechanics.” I concentrate on teaching these three glories, as being things that we know are true, and that deeply offend our intuition⎯which must therefore be suppressed as simply wrong. That is enough to keep me, and the young people, busy! Don’t bother me with superstrings and M-theory!
Quote from spoiler.
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Re: String theory is what?

Post by The Dagda » Fri Mar 19, 2010 7:58 am

AshtonBlack wrote:Not yet, but some nice plans for space bourne instrumentation coming on stream in the next few years, plus getting the LHC working at full power might help. But yes, it's just a hypothesis at the moment.
Not at all since the people working there don't think LHC could turn up evidence that would distinguish string theory. So no perhaps in the long distant future but the energy scales that would distinguish string theory are simply enormous and unobtainable. String Theorists disagree but then they would.

There's a documentary where the physicists are asked to give a practical evaluation of the likelihood of CERN confirming strings, I'll try and find it if anyone is interested. It was a Horizon I think with that guy who appears to be on our TVs everywhere with anything to do with physics or astronomy atm, although I forget his name OTTOMH.
JimC wrote:
hackenslash wrote:It's a hypothesis. I would tend to call it something like a 'metatheory' except that I run away from the 'meta' prefix as it makes anything sound like wibble.

I'm neither a supporter nor a detractor, but I do think it has the potential to explain a great deal, and at bottom it's actually quite parsimonious, although the mathematics is quite esoteric. At the moment, I'm happy to wait for the experimental evidence arising from the first predictions.
:tup:

Although you could really call it a speculative model, containing a whole heap of hypotheses and an intricate web of mathematical reasoning that few can grasp in its entirety...

I'm not really against it, just waiting for it to generate experimentally testable predictions, whether via cosmological data, or high energy particle physics.

Neither am I just want some answers to some very valid questions. I'm pro maths and pro science, what I'm not is pro claiming maths as science/theory.
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Re: String theory is what?

Post by The Dagda » Fri Mar 19, 2010 8:04 am

Nautilidae wrote:
Xamonas Chegwé wrote:
hackenslash wrote:
Xamonas Chegwé wrote:I honestly don't understand enough about it to give an opinion on its likelihood of ever being more than an hypothesis. I really need to get my head around QM before I start messing with silly string. :dono:
If you need to get your head around QM first, you're not going to bother. Nobody can get their head around QM.

Brian Greene's The Elegant Universe is an excellent introduction to M-Theory, and covers a good deal of QM and GR as well.
Found it on Amazon for 65p - over £3 with postage but still worth it at that price.

I really do want something of reasonable complexity about QM though. Not pop-sci but well written, starting from the basics and with at least the main parts of the maths intact. Any recommendations?
I suggest "The Quantum World"

http://www.amazon.com/Quantum-World-Phy ... 0674013425

It gives an overview of not just the science, but the history as well. It discusses quantum mechanics and even a bit of quantum field theory. I purchased a copy last year, though all I have done is skim through bits [har har har] and pieces of the book.

I also suggest Leonard Susskind's "The Black Hole War". It discuss the black hole information paradox proposed by Stephen Hawking. It discusses the quantum mechanics of the paradox and even the string theory behind the resolution.
I don't think its hard to resolve at all one merely has to postulate that a physical infinity doesn't exist and that it is an asymptotic limit and there is no need of Strings. I mean we renormalise infinities in wave equations why not do the same when it's fairly clear that mathematical infinities are not universal concerns and are nothing more than concepts, any more than nothing is.
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Re: Strings 2010 Conference - Webcast

Post by lpetrich » Fri Mar 19, 2010 10:41 am

There's another question I'd like addressed. Has there been any progress in coming up with a construction of M-theory that is comparable of existing constructions of string theory?

Here's the state that we are in now:

Low-energy superstrings: yes -- 10-D supergravity (all 5), gauge multiplet (I, HE, HO)
General superstrings: yes
Low-energy M-theory: yes -- 11-D supergravity
General M-theory: ???

The missing piece of the puzzle is the last one, a general theory that reduces to the five superstrings and to 11-D supergravity when one takes appropriate limits.

Has anything happened with it?

SUPERSTRINGS! Supersymmetric Strings
SUPERSTRINGS! M-Theory

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