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January 6th, 2007 at 6:45 pm
I just saw one the other day with a guy standing on the street corner holding a sign that said: “Will explain string theory for beer.”
January 6th, 2007 at 11:05 pm
How about: “Will give away free beer for a good string theory explanation”
January 7th, 2007 at 8:44 am
It’s about time someone stood up for string theory and its wealth of endless predictions over the years.
1. The first string theory predicted in the 60s that if the strong force was due to bits of string holding protons together (against Coulomb repulsion) in the nucleus, the string’s would be like elastic with a tension of 10 tons. It wasn’t a falsifiable theory and was replaced by QCD with gluon Yang-Mills exchange radiation in the 70s.
2. Scherk in 1974 predicted that if strings had a pull of not just 10 tons by 10^39 tons, then they would predict gravity.
3. By 1985, string theory was predicting 10 or 26 dimensions. Supersymmetry was developed, predicting that unification of the three standard model forces conveniently occurs at the uncheckably high energy of the the Planck scale, and requiring merely extra dimensions and one unobserved bosonic superpartner for each observable fermion in the universe.
4. In 1995 M-theory was developed, leading to the dumping of 26-dimensional bosonic string theory and to the new prediction that the 10 dimensional superstring universe is a brane on 11 dimensional supergravity, like a 2-dimensional bubble surface is a brane on 3-dimensional bubble.
5. Now the beautiful fact of the string theory landscape has led to the anthropic prediction that the Standard Model can in principle be reproduced by string. The complexity of the parameters of the 6-dimensional Calabi-Yau manifold which rolls up 6 dimensions is such that there are 10^500 or more sets of solutions, ie 10^500 Standard Models. This landscape of solutions beautifully fits in with the many universes (or multiverse) interpretation. One of these solutions must be our universe, because we exist. (Unless string theory is wrong, of course, but don’t worry because that will always be impossible to prove from the model itself because 10^500 solutions can’t ever be rigorously checked in the time scales available to us. Even at the rate of checking 10^100 solutions per second – which is far beyond anything that can be done – it would take 10^383 times the age of the universe to check each solution rigorously, the universe being merely on the order of 10^17 seconds old.)
January 7th, 2007 at 9:37 am
Whoops. Prediction 2 above should read:
2. Scherk in 1974 predicted that if strings had a pull of not just 10 tons but 10^39 tons, then they would predict gravity.
January 7th, 2007 at 11:25 am
I fail to see what’s funny about this.
January 7th, 2007 at 12:22 pm
B, it’s actually supposed to be sad.
January 7th, 2007 at 12:38 pm
how about funny on one level, sad on another level, difficult for the layman on another level?
January 7th, 2007 at 10:45 pm
Don’t be sad, people. They will see, they will all see.
January 8th, 2007 at 7:40 am
It’s actually closer to 16 tons.
January 8th, 2007 at 8:05 am
Scott on Jan 7th, 2007 at 12:38 pm
how about funny on one level, sad on another level, difficult for the layman on another level?
You still need eight more dimensions.
January 8th, 2007 at 8:21 am
speaking of humour:
http://news.bbc.co.uk/2/hi/americas/6240055.stm
January 8th, 2007 at 8:25 am
Warren, the pion mediated inter-nucleon attractive strong force is usually taken to be 137 times the electromagnetic force strength (Coulomb’s law) between protons (see for example http://hyperphysics.phy-astr.gsu.edu/hbase/forces/funfor.html ), with a range of ~10^{-15} m. This (137 times Coulomb) force between two protons 10^{-15} m apart is easily calculated to be F = 137qq/(4*Pi*Permittivity*[10^{-15}]^2) = 31,600 Newtons ~ 3.22 tons (assuming g = 9.81 ms^-2).
January 8th, 2007 at 8:45 am
Sean,
This is off topic but could you comment on this possible “fifth force” which the Scientific American says was considerd by Glennys Farrar at the the American Astronomical Society meeting ? Thanks.
January 8th, 2007 at 9:57 am
Plutoed?
You know what the Germans voted for as word of the year? ‘Fanmile‘.
… hum … besides the ‘word of the year’, the Germans usually also have an ‘Unwort’ of the year. I couldn’t find the one from 2006, but the Swiss one is apparently ‘Extended Suicide’ (as a synonym for murder with following suicide). Nice, eh?
January 8th, 2007 at 10:59 am
I’m happy to report that after a 3 hour discussion which included a lot
of good jokes at the expense of Woit and Smolin we decided that the
answer is a definite No!
January 8th, 2007 at 12:05 pm
nc, the “16 tons” refers to the hadronic string tension, 1/2πα’, where α’ is the slope of the Regge trajectories, which is roughly the inverse square of 1.05 GeV. Throw in the appropriate powers of c & ħ, and (if you normally use metric units) convert from Newtons to pounds (of force), and you get about 16 tons.
January 8th, 2007 at 12:29 pm
Off-topic, but more interesting (IMO) than the other comments on this post:
First 3D map of the Universe’s Dark Matter scaffolding (NASA/ESA — HST)
January 8th, 2007 at 1:07 pm
The cartoonist must have attended one of those Categorically Not! evenings with Professor Johnson at some point. Maybe a friend or acquaintance of KC Coles; that would make it funny, sad, relevant, and more pointed?
January 8th, 2007 at 1:24 pm
> but the Swiss one is apparently ‘Extended Suicide’ (as a synonym for murder with following suicide). Nice, eh?
Imparts a whole new spin to “The tongue is sharper than the sword”.. can kill in extensions! The power of language
Btw, that’s a great idea. Wish we’d have a vote for the unwordest of them all.
January 8th, 2007 at 3:31 pm
I didn’t know Jeff owns a bar, where everybody knows your name…
January 8th, 2007 at 5:14 pm
Warren, a ‘10 tons’ hadronic string tension figure is quoted on page 126 of Stephen Hawking A Briefer History of Time, Bantam, London, 2005. So if you believe famous experts must never err, he’s the guy to complain to. I’ll leave you and Hawking to resolve it, and until you or someone points out an error in comment 12 above, I’ll continue assuming the attractive strong force between hadrons in nuclei is on the order 3 tons.
January 9th, 2007 at 6:41 pm
“Sean,
This is off topic but could you comment on this possible “fifth force” which the Scientific American says was considerd by Glennys Farrar at the the American Astronomical Society meeting? Thanks.”
I don’t presume to speak for Sean, but I thought the reported result was a bit shaky. It was kind of 2 sigma-ish in terms of significance. There’s nothing that rules out one (or more?) dark force(s) in principle, but any conclusions at this point have to be considered pretty tentative, in my opinion.
January 9th, 2007 at 7:18 pm
Sorry, I missed Joseph’s question in 13. Basically — no, I can’t comment on it, since I don’t know anything about it. Tom’s answer sounds sensible.
January 10th, 2007 at 8:40 am
nc,
Hawking’s figure was just an order-of-magnitude estimate (as indicated by the 2nd figure, for fundamental strings). In any case, Hawking isn’t a “string expert”, except maybe in “cosmic strings”, as you can easily see from his “string” publication list.
The error in your calculation was that the fine structure constant IS 1/137, so 137 times that gives only 1, not the strong coupling, which is by any definition and experimental evidence significantly greater (between hadrons). I assume the one reference you quote (which hardly qualifies as “usually”) was also giving just an order of magnitude; there is no sense in your giving 3 significant digits for your result. There are many ways of defining the strong coupling: E.g., for NNÏ€ coupling, it’s about 13.5 ≫ 1; for Ïππ it’s about 2.6.
Your figure of 10â»Â¹âµ m was obviously also order of magnitude. If you’re considering the range of the Ï€, that’s given by the inverse of its mass, which is 1.4 fm. Again, you give 3 significant digits for your result, while your input has only 1.
The string tension is a more universal quantity, since it doesn’t depend on choice of particle. Unlike your calculation, it also relates directly to the string, since it comes from the Regge trajectories. It thus also includes data from higher-mass hadrons, which are more “stringy” because they are in excited states (i.e., longer strings).
January 10th, 2007 at 9:56 am
Warren, there is plenty of evidence; the nuclei of elements become more weakly bound as the atomic number approaches 137; every element past about 105 only exists from a very brief period due to rapid decay. This is becaus the attractive short range force is being overcome by the long range Coulomb force.
If the strong nuclear force between hadrons was significantly stronger than 137 times the Coulomb force, the stability of havy nuclei would be increased and fission of uranium would no longer be possible with thermal neutrons. You’re theory is just plain wrong by experimental disagreement. See also Glenn T. Seaborg’s article ‘Elements Beyond 100′ in the Annual Review of Nuclear Science v18, 1968, pp53-152.
January 10th, 2007 at 11:31 am
nc,
Your arguments are only qualitative, & give no numerical value for any coupling. You never even stated which coupling you were talking about. Seaborg never even mentions such a coupling constant. So your “plenty of evidence” is so far “just plain” 0.
It’s not my theory. I just quoted known experimental values for the couplings. E.g. Bjorken & Drell, Relativistic Quantum Mechanics, p. 226, give the coupling as 14. Nobody gives “1″ as an actual value, as the coincidence is too improbable. Perl, High Energy Hadron Physics, p. 293, gives the coupling for Ïππ as 2.6, for ppπⰠas 14.9, & for pnπ⻠as twice that.
Furthermore, your method of calculation is worthless, since the force between hadrons is due to an infinite number of different particles: Ï€, Ï, … . This is best represented by a Regge trajectory, which is best interpreted as a string, whose tension follows from just measuring the slope (α’) of their plot of spin vs. (mass)².
Finally, your inputs are all still orders of magnitude, so your result to 3 decimal places is complete garbage.
January 10th, 2007 at 11:32 am
nc: wow! what a day you are having. First you expose the flaws in richard dawkins’ most celebrated contribution to biology and now you generously help warren siegel with his sums.
whatever will you turn to next?
January 11th, 2007 at 3:40 am
Warren, I’ve stated what couping I was referring to above and all assumptions, but I’m not continuing to argue with someone like you. Good day!
January 11th, 2007 at 4:42 am
maximo shark, if you actually read the comments, I quoted an order of magnitude result of string. Warren contradicted me. I then gave sources for my data, including, in comment 21, the approximate nature of the result “is on the order 3 tons.” Warren seems to think this is quoting a result to 3 significant figures: “your inputs are all still orders of magnitude, so your result to 3 decimal places is complete garbage.” Someone reading his comments without actually checking might believe it. For a derivation of a strong force 137.036… times stronger than electromagnetism, see http://nige.wordpress.com/2006/10/20/loop-quantum-gravity-representation-theory-and-particle-physics/
(Note I won’t engage in discussions with stringers any more. There is too big a gap, and it’s better they find someone else to vent their anger on.)
January 11th, 2007 at 1:59 pm
nc,
You said:
My “contradiction”:
So what was the “contradiction”, the fact that I gave 1 more significant digit, or that I made a joke? Then you said that you said:
when what you actually said originally in comment 12 was:
which is 3 digits by my counting. Furthermore, the sources of your data were orders of magnitude, i.e., 1 for the “strong” coupling (which you insist on writing as 137/137), & 1 fm for its range. Then you said,
& refer to a 200+ page blog of yours. How can you derive an experimental result? By the way, an interesting fact that no quacks seem to appreciate: All couplings are “running”, so the number 1/137 for electromagnetism holds only at low energies.
If you actually wrote your comments, you know that all this is true. And then you remark,
on which I may have a comment in the future. And your final remark,
I actually agree with. But if you want to vent your own anger & avoid a response, then a blog is a silly place to attempt it.
January 12th, 2007 at 6:21 am
For the benefit of people interested in physics, here’s an alternative calculation of strong nuclear force strength, for anybody interested in physics, instead of making claims/attacks which aren’t actually backed up by evidence. Helium-4 has two protons and two neutrons. The two protons are on average ~10^{-15} m apart.
The mass of two protons, two electrons and two neutrons is 4.0323 amu, while the measured mass of a helium atom is 4.0026 amu. This mass defect is 0.0063 amu ~ 9.42*10^{-13} Joules of nuclear binding energy (by E=mc^2). Notice that you can quote intermediate results in a calculation to more precision than the final result, to avoid the problem of what are called ‘intermediate rounding errors’ which string theorists haven’t heard about.
The strong nuclear binding energy keeping two protons distance x apart is equivalent to E = {Integral of the force with respect to distance moved in direction of force} = Integral between distance s and infinity of [(q^2)/(4*Pi*Epsilon*x^2)} dx = (q^2)/(4*Pi*Epsilon*s). Putting in the binding energy 9.42*10^{-13} Joules calculated above and the distance of s~10^{-15} m tells us that the effective square of the strong charge q^2 needed is q^2 = 4*Pi*Epsilon*s*E = 1.05*10^{-37}. This is directly proportional to force, and is 4.08 times the square of the charge of the proton.
Hence, by this calculation the strong force needed is not 3 tons (which assumed a force ratio of 137) but only about o.09 tons. Obviously the strong force doesn’t have a sudden cutoff at its range limit, but falls more gradually so the strength of coupling varies with distance. It’s a pity discussions can’t focus on the physics, but result in people calling calculations rubbish without first checking them!
January 12th, 2007 at 7:43 am
For the benefit of nc, who claims not to be talking to “stringers”: You said,
The spins & masses of observed particles aren’t evidence? Your lies are progressively more transparent. Then you said,
…again order of magnitude, and then immediatley contradicted yourself by saying
There is absolutely no advantage to giving one input to more precision (5 decimal places!!), while another input is only an order of magnitude estimate. And now the masterpiece:
by which you reveal that the person you are arguing against is actually yourself!
Well, if you had read Yukawa’s original paper on the subject, or any of the subsequent physics literature, you would have learned that a lot earlier. The fall-off is exponential.
So, why didn’t you check your calculation earlier? And when will you check mine? Have you even read it yet? Do you know what “string tension” means? Do you know what “string” means? How can you claim to give a valid result for the string tension when you claim strings don’t exist? How can you respond to these disproofs of your arguments when you claim to not be talking to “stringers”? These and more humorous absurdities in our next episode…
January 12th, 2007 at 8:42 am
“Well, if you had read Yukawa’s original paper on the subject, or any of the subsequent physics literature, you would have learned that a lot earlier. The fall-off is exponential.”
For the benefit of readers who prefer facts to speculations, my web site has shown the long range fall is an exponential drop in nuclear force at long ranges, for years. For the complete picture, you take a look at the curve here: http://www.nature.com/nature/journal/v445/n7124/fig_tab/445156a_F1.html
There is a short range repulsion from the exchange of pions, and a longer range attraction (a force curve qualitatively like the Van der Waals force between molecules in chemistry).
Frank Wilczek notes: “Our description of how the atomic nucleus holds together has up to now been entirely empirical. Arduous calculations starting from the theory of the strong nuclear force provide a new way into matter’s hard core.”
- http://www.nature.com/nature/journal/v445/n7124/full/445156a.html
January 12th, 2007 at 12:27 pm
That’s a good one. How many years was that? Yukawa found the fall-off in 1935. To beat him you’d have to be at least in your 90’s. From the photo at your web site, you’re very well preserved. But it’s nice to see that Nature has published your results (although unfortunately under pseudonyms). Maybe you should clue Wilczek in on your discovery.
Wrong. The Ï€ has spin 0, & is therefore ALWAYS attractive. It’s also the lightest meson, & therefore responsible for the longest range nuclear force. It’s the Ï, with spin 1, that causes the repulsion. And ALL the nuclear forces mediated by mesons are Van der Waals, residual from the fundamental strong force mediated by gluons between quarks & gluons, whose color charges cancel in hadrons.
If you want to try something useful, here’s a suggestion: Try to redo your calculations including the exponential fall-off factor which you “showed” was there “years ago”, but inexplicably forgot in both of your above calculations (12 & 31) & see if you can get a consistent result, & what new values you get for the “string” tension.
January 12th, 2007 at 1:35 pm
Here’s some more experimental data (what nc calls “speculations”): In the paper
http://arxiv.org/abs/nucl-th/0101056
“The nucleon-nucleon interaction” by R. Machleidt & I. Slaus, the NNÏ€ coupling is given as about 14 (as I said above, but this reference is much more recent). The result is found by fitting the data directly to exchanges of mesons between nucleons. This is the paper cited by
http://arxiv.org/abs/nucl-th/0611096
“The Nuclear Force from Lattice QCD” by N.Ishii, S.Aoki , & T.Hatsuda, the paper that attempts to derive the experimental results from lattice QCD (the article Wilczek was so excited about).
None of the above people are “stringers”, so nc will need to invent a new epithet for them (or at least stop linking to their results).
(Sorry for not putting in the links, but the blog server is fighting me.)
January 13th, 2007 at 6:42 am
I came to this website/blog hoping to learn something. I have. Even highly educated physicists have a hard time being civil on message boards.
Edify me, please.
1. What are “stringers”?
2. Do all of you know who each other are in real life?
3. If the answer to #2 is “yes”, would you be more likely to buy each other shots, or arm-wrestle?
January 13th, 2007 at 1:17 pm
Just for the benefit of readers of comment #35, I don’t call experimental data speculations.
James, a string theorist would be someone who claims a string tension of 16 tons for the strong nuclear force rather than 10 tons, without saying what nucleus is involved, its binding energy (which varies a lot, hence some elements have greater nuclear stability than others). It might also be someone who insists that a 16 tons estimate (without any stated assumptions) is correct but 10 tons isn’t, and then claims that empirical data is speculative.
A “stringer” could be someone who misquotes things deliberately, and holds on to a theory which is doesn’t predict anything.
January 13th, 2007 at 2:02 pm
Okay, nc, I think this has been discussed with sufficient thoroughness. Let’s take anything else to your blog.
January 16th, 2007 at 9:01 am
Maybe a final comment:
The string tension has nothing to do with a nucleus. It is NOT the string coupling, which gives the coupling between different hadrons. It is the tension that binds the quarks inside a single hadron. This is the force that’s stringy, as it’s a constant, independent of separation, whereas the force between hadrons follows the usual Yukawa law.
If you really want to learn this stuff, you’re not going to get it from a blog, especially from a quack like nc. Any standard reference on particle physics will do; there are some written for laymen. The string tension is understood not only by string theorists, but also by field theorists; it’s a standard calculation in lattice QCD.
Please don’t think that nc is a physicist. (He only publishes in “Electronics World”?) Anyone who has had even high-school physics would recognize that nc is a complete fake. I have given references above, which anyone can look up. For those of you who know no physics, I would suggest at least learning what “significant digits” means, to realize that no physicist would ever claim that using a 5-digit input would improve the rounding error in a calculation that also has an order-of-magnitude estimate as input.
Finally, there is nothing uncivil about calling a liar a liar. On the contrary, allowing quacks like nc to repeatedly state lies & self-contradictions would be far more uncivil.
January 16th, 2007 at 3:59 pm
[...] As mentioned here and at Cosmic Variance, the New Yorker recently actually ran a cartoon about the string theory controversy. If that’s not an indication that something has made it into the zeitgeist, I don’t know what is.  Besides the New Yorker, string theory features in Zippy the Pinhead and recent Doonesbury cartoons, as well as one from Rodrigo Alonso entitled Pulling Strings that he sent me recently. [...]