An Exceptionally Simple Theory of Everything?

It’s been unusually long since my last posting, with the main reasons being that

  • Not much has been happening on the math/physics front…
  • I’ve been busy learning more about geometric Langlands, which is a daunting subject. I keep intending to write something about recent work by Witten and others in this area, but saying anything both correct and intelligible seems a rather challenging task that I haven’t been quite up for.
  • Garrett Lisi has a new paper on the arXiv, with the rather over-the-top title of An Exceptionally Simple Theory of Everything. Sabine Hossenfelder has a typically excellent posting about the paper, and Garrett has been discussing his work with people in the comment section there. Lubos Motl, has a typically, how shall I say, Lubosian posting on the topic.

    I’m the first person thanked in the acknowledgment section of the paper, but at Sabine’s blog Garrett explains that this is just because he is using reverse alphabetical order. I’ve corresponded with him in the past about his research in this area, without being able to provide any real help other than a certain amount of encouragement. Two of the ideas he is pursuing are general ones I’m also very fond of. One is well-known, and many people have also tried this, it’s the idea of bringing together the internal gauge symmetry and the symmetry of local frame rotations. The problems with this are also well-known, and some have been brought up by the commenters at Sabine’s blog. I don’t think Garrett has found the answer to this, or that he claims to. I’m still hopeful that this line of thinking will lead somewhere, but think some dramatically different new idea about this is still needed. The other idea he likes is that of trying to interpret the fermionic degrees of freedom of the BRST method for handling gauge invariance as providing the fermions of the Standard Model. I suspect there is something to this, but to get anywhere with it, a much deeper understanding of BRST will be required. I’ve been spending a lot of time trying to understand some of the mathematics related to BRST in recent years, and am in the middle of writing some of this up. It seems to me that there is a lot that is not understood yet about this topic even in much simpler lower-dimensional contexts, so we’re a long way from being able to really see whether something can be done with this idea in a realistic four-dimensional setting.

    One idea Garrett is fond of that has generally left me cold is the idea of unification via a large simple Lie algebra like E8. While there may be some sort of ultimate truth to this, the problem is that, just as for GUTs and for superstring models, all you’re doing when you do this is changing the unification problem into the problem of what breaks the large symmetry. This change in the problem adds some new structure to it, but just doesn’t seem to help very much, with the bottom line being that you get few if any testable predictions out of it (one exception is with the simplest GUTs, where you do get a prediction, proton decay, which turns out to be wrong, falsifying the models).

    Anyway, I’m glad to see someone pursuing these ideas, even if they haven’t come up with solutions to the underlying problems. Garrett is a serious and competent researcher who has pursued a non-traditional career path, and was recently awarded a grant to by the FQXI organization. You can read more about him in an article on their web-site.

    Unfortunately, some of the reaction to Garrett’s article has been depressing. A commenter who sounds well-informed but hides behind anonymity goes on about “this nonsense” (although Garrett’s polite reaction to him/her did lead to a more sensible discussion). Early on in my experience with blogs I believed that no serious professional in particle physics would attack someone and try and carry on a scientific argument anonymously, so any such comments had to be coming from misguided students, or someone not in the profession. Unfortunately I’ve all too often seen evidence that I was wrong about this. Lubos Motl on his blog denounced the fact that Garrett’s paper appeared in the hep-th section of the arXiv, then later wrote in to Sabine’s blog to crow that it had been removed from hep-th. As always with the arXiv, how moderation occurs there is non-transparent, so I don’t know how or why this happened. My own experience with the arXiv over trackbacks to hep-th has been a highly disturbing one. The current hep-th policy seems to be to allow any sort of nonsense to be posted there if it fits into the current string-theory-based ideology (see for example here), while suppressing any criticism of this. A paranoid person might be tempted to wonder whether hep-th is being moderated by someone so ideological and petty that criticism of string theory or including string theory critics in an acknowledgment section would be cause for having ones article removed from hep-th…

    Update: I hear from Garrett that the story of this paper at the arXiv is that it was submitted to gr-qc, not hep-th. Before it was posted, it was re-classified as hep-th, and appeared there. Later on (after the appearance of Lubos’s blog entry denouncing the arXiv for allowing the paper on hep-th I believe), it was re-classified again, this time as general physics (with cross-listing to hep-th).

    Update: Latest news about this is that the paper has now been reclassified again, to the perfectly appropriate hep-th, cross-listed as gr-qc, although no one seems to know why this happened. Another continuing mystery is the trackback situation: there are four trackbacks to the paper, to postings by Lubos, Bee, and to Physics Forums, as well as to an old TWF from John Baez that doesn’t even link to the paper. My postings still seem to be non-trackback worthy on hep-th, not that I can argue with this particular case, since the discussion elsewhere has been more substantive (except for Lubos’s, which is valuable for the way it accurately represents the hysterical reaction to speculation that is not string theory speculation all too common in certain quarters).

    Update: Garrett is making the news here. Whether this is a good thing is yet another question for debate on the next thread, I guess. A lot of the attraction for the media seems to be his personal story. Maybe it’s a good thing for physics for people to see that one can be a theoretical physicist while surfing in Hawaii…

    Update: Lisi-mania spreads. See stories in New Scientist, the Ottawa Citizen, Slashdot, and probably lots of other places I haven’t noticed.

    Update: Steinn Sigurdsson has an excellent posting summarizing the situation. As usual, blogs are the place to get the highest quality information about scientific issues…

    Update: I’ve given up on keeping track of the media stories on this. For some discussion of the representation theory involved, see this posting by Jacques Distler, and comments from Garrett.

    Update: The Angry Physicist examines the Distler critique in some detail.

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    176 Responses to An Exceptionally Simple Theory of Everything?

    1. amused says:

      Garrett,

      “Now please consider that matching the standard model fields and dynamics to parts of the E8 connection and its curvature, with only a handful of exotic fields, is non-trivial.”

      To my mind this has the same status as various remarkable numerical relations and coincidences that people sometimes find among the fundamental constants of nature: interesting to some extent, but, on its own, not real physics.

    2. anon. says:

      Here’s a link to Babelfish’s English translation of the Le Monde article about Garrett’s theory. (It’s not much of a translation, but it’s still helpful if your French is as rusty as mine.)

    3. Fabrizio Nesti says:

      HIGGS boson, Amused:

      I also were quite surprised after understanding that Garrett’s action was not E8 invariant. I think the paper is not so clear about this point. The question is then, which kind of unification is this? Of the three unification steps (find multiplets, give an invariant action and find a breaking mechanism) Garrett only carried out the first one.

      Given that, the result of this first step is really nice and non trivial, since you should appreciate that some Higgs is contained in the E8 connection, as well as _three_ families. This is for the excitement. The rest just calls for much (exciting!) work in the future.

      About Coleman-Mandula, I can clarify: the point is not desitter or noninvariance – because eventually one will look for an invariant theory. The point is that above the unification scale there is probably no metric, because the metric itself is inside the e8 connection. If at high energy there is no metric, there is no time, no standard scatterings and thus no Coleman-Mandula.

      This point made Lubos go berserk even before Garrett’s paper, so I suppose he was prepared – but more robust critics could have been raised than this one..

      best,
      Fabrizio

    4. Aaron Bergman says:

      Given that, the result of this first step is really nice and non trivial, since you should appreciate that some Higgs is contained in the E8 connection, as well as _three_ families.

      But that’s not true even if we accept the identifications made in the paper. The three families are not identical — they live in different representations and do not accord with the standard model.

      The question about C-M is about the low energy effective theory, not so much about the high energy theory. But, given the lack of clarity about what the symmetries of the theory actually are, this may be irrelevant.

    5. Bee says:

      Gag, my visit count is going nuts again, thanks to

      Stuff string theory – try E8 to explain the universe.

    6. Peter Woit says:

      Thanks Bee,

      I’ve given up on trying to keep track of all the articles, thanks to my readers for posting here any they find that haven’t been mentioned and are of interest. On the whole, about the science, many are overhyped and pretty misleading in various ways, a few include an appropriate amount of skepticism.

    7. H-I-G-G-S says:

      Dear Peter,

      Thanks for the link. I suggest you read it. I am not anonymous, I have a pseudonym. As Bee points out, there is a difference. I’ve posted under H-I-G-G-S before and will do so again, unless you block my comments. My actions have consequences, at least in the blogosphere.

      Anyway, let’s get back to the physics. Garrett agrees that as far as the quarks and gluons are concerned G_2 is totally irrelevant. Since he does the same thing with E8, that is combines all the fields into one connection, but then writes down an action piecemeal to agree with the SM, I am tempted to say that the whole E8 is irrelevant. But I think this is not totally fair. After all the SM fields fit into E8 with some room left over, so the model “predicts” these extra particles. Of course I could just as easily invent a theory of everything based on a noncompact form of SU(248) or SO(196884) or an infinite number of other groups which would “unify” everything in the same way. And since the action is whatever he wants it to be and there is no dynamics to break the E8 symmetry, there is no prediction for the masses or couplings of these particles. If they are not found, he can just adjust the mass scale however he wants. I really would have to say that this model is a prime example of a theory that is “not even wrong.” As the old joke goes, this paper contains new and correct results, but what is correct is not new, and what is new is not correct. What part of this do you find interesting and worthy of encouragement?

      Sincerely,
      Not the real P.W.H. FRS

    8. Peter Woit says:

      H-I-G-G-S,

      I suggest you actually read my posting, where I explain precisely what I think about what Garrett is trying to do, and what parts of it I think are worthy of encouragement. You might also notice that I explictly make the point you’re trying to make, explaining why I’m dubious about this kind of “unification” since it doesn’t solve the problem of how to break the larger symmetry in a way that makes the setup predictive. In principle fitting SM symmetries together into a simple exceptional group like E8 could be constraining enough to be predictive, even after symmetry breaking, but lots of people have tried this kind of thing without success. He seems to be trying something different than a standard GUT set-up, one assuming a mixing of space-time and internal symmetries that won’t work in the standard QFT formalism. Maybe he can get something out of this, I certainly encourage him to keep trying.

    9. amused says:

      Fabrizio,

      “About Coleman-Mandula, I can clarify: the point is not desitter or noninvariance – because eventually one will look for an invariant theory. The point is that above the unification scale there is probably no metric, because the metric itself is inside the e8 connection. If at high energy there is no metric, there is no time, no standard scatterings and thus no Coleman-Mandula.”

      If at some point in the future someone comes up with an invariant high energy theory of the kind you describe, which has Lisi’s model as a low energy effective theory, then we can discuss it. But at the moment there is no proposal for such a theory, and no compelling reason for expecting one to exist, so talking about it is just idle speculation.

    10. chris says:

      hi amused,

      if it is only idle speculation, then why do you (and many others) keep poking at this point? is it just motl’s evil spirit haunting :-)

      the lisi lagrangean does fulfill the C-M theorem. just plain simple like that. it does no nontrivial mixing. the hope (and it is just a hope) is, that maybe at higher scales a mechanism will ultimately provide… but he does not even speak about that.

    11. chris says:

      ps:

      oh, and to anticipate the “then it’s all vacous” argument: how much explicit dynamics did the original gell-mann eightfold way provide?

    12. Fabrizio Nesti says:

      Aaron:
      The three families are not identical — they live in different representations and do not accord with the standard model.

      Well, we do know triality. The point (I alrady raised in Bee’s blog) is whether triality is inserted by hand or comes out of the theory itself. For this I think you’ll need a high energy completion… again.

      Peter,
      I happened to re-read your posting and I have a comment that came to me also after reading your book. You wrote that as in GUT programs, you move the problem from symmetry to symmetry breaking, and for this reason you get no predictions, except maybe proton decay in simplest models, that we do not observe. I agree but I just want to point out that simplest models are anyway already ruled out by other aspects (by fermion masses, notably) so there is no point in ruling them out. Realistic nonminimal models, even SU(5), they do _not_ predict a fast proton decay, so they are not ruled out.

      So the situation is probably even worse than how you put it. No new-physics idea can actually be ruled out, they are simply not predictive, alone. Not GUT – not certainly strings or extra dimensions – not even SUSY (if we’ll not see it, one may still raise this and that to make it invisible). And not even these theories unifying Lorentz and internal symmetries.

      Maybe the point is that mathematical ideas, geometry, unifications etc, are just nice frameworks… while one needs a complete detailed theory -scales- to make predictions. Btw this is what the standard model is – a complete theory up to 100GeV :).

      ok, just free thinking,

      best,
      Fabrizio

    13. mitchell porter says:

      It would be funny if Garrett’s theory turned out to be just another limit of string theory – perhaps of some “noncanonical” form of string theory (e.g. see Lubos’s list under “Strong leadership of supersymmetry”, here). There is actually a “single-E8″ string theory, a heterotic tachyon. Only, that’s a compact E8.

      So far as I can see, the situation with respect to Coleman-Mandula is this. Garrett’s action is consistent with the theorem because the full E8 symmetry is broken. However, the hope or presumption is that the symmetry-breaking terms come from somewhere and that the fundamental theory does have full E8 symmetry. At this point the CM problem returns. Fabrizio Nesti in his papers says that CM is evaded because the full symmetry only manifests in a high-temperature topological phase (no metric). If that doesn’t make sense, we will be left with Aaron’s suggestion to use supersymmetry after all – in which case we’d surely end up with some sort of supergravity, and my notion that this is just another superstring limit would look even more plausible.

      What I want to understand now is the part about triality and the three generations. There is definitely handwaving on this point (page 28: “not presently understood well enough to write down”).

    14. mitchell porter says:

      I’ll risk really exposing my ignorance and voice one more thought. One of the basic ideas here is that E8 could provide a nonsupersymmetric way to unite fermions and bosons. Meanwhile, one corner of superstring theory has an E8xE8 symmetry; and the Monster group shows up in certain compactifications, e.g. a Leech lattice orbifold (I think). Now the Leech lattice is rather similar to a copy of three E8 root lattices. So I wonder if there’s a third E8 lurking in string theory, that’s responsible for the supersymmetry.

    15. amused says:

      hi chris,

      It’s hilarious to think that I might be possessed by Lubos’ evil spirit :-) especially considering our previous history in the blogsphere (which includes, among other things, my successful goading of Jacques Distler into denouncing him…although I got the feeling that Jacques quite enjoyed the opportunity to do that). Perhaps Peter W. should be called on to perform an exorcism.

      At any rate, my last two comments above were in reply to comments addressed to me by Garrett and Fabrizio, so I don’t think they qualify as poking. And my first comment above was just a summary of my opinion on the paper after a bit of reflection and recovery from the mammoth discussion over at Bee’s blog.

      Your comment raises an interesting general question though: why were those of us who do physics for a job spending time on reading and discussing this paper? Is it really that interesting compared to all the other physics things we could have been doing? It’s not as if Garrett is the only alternative physicist out there with his own theory. E.g. Tony Smith seems just as well qualified academically (he has a Ph.D. from Princeton), and, for all I know, his theories could be just as deserving (or undeserving) of attention as Garrett’s. (Besides the media hype, it’s kind of ironic that Garrett is getting blog postings devoted to his theory while Tony gets told to shut up every time he mentions his ones.) My own reasons for spending time on this were: (i) The reported opinions of various prominent physicists; e.g. Smolin apparently described it as “fabulous”. (ii) With all the media attention on this, Joe Public wants to know what the consensus opinion of professional physicists is, so probably we have some responsibility to assess the paper and make our opinions known.

      But as far as “alternative theories” go, there are others that are much more worthy of attention than this one. Just to give an example, C. Wetterich has been developing an “alternative” proposal for explaining electroweak symmetry breaking based on chiral coupling of matter to massless antisymmetric tensor field in hep-ph/0607051, arXiv:0709.1102. This looks really interesting and elegant (without having studied it in detail), but seems to have been completely ignored so far. (However, the author is no doubt less colorful: he’s a full professor at one of Europe’s illustrious universities — how boring if progress in physics werre to come from someone like that!) I can’t help getting a feeling that something is fundamentally wrong somewhere when work like this is being ignored while Garrett’s paper is being debated on physics blogs and reported on Fox News. And it is a worry that with this and all the other hype they are subjected to, the public will be too jaded to pay attention and care in the future if and when there really is some major gravity/particle theory breakthrough worth telling them about.

      In reply to the rest of your comments:

      “the lisi lagrangean does fulfill the C-M theorem. just plain simple like that. it does no nontrivial mixing.”

      Indeed. Which is why I wrote in first comment above that C-M is “not relevant” in this case.

      “the hope (and it is just a hope) is, that maybe at higher scales a mechanism will ultimately provide… but he does not even speak about that.”

      No, but Fabrizio did speak about it and my “idle speculation” remark was directed to him.

      “oh, and to anticipate the “then it’s all vacous” argument: how much explicit dynamics did the original gell-mann eightfold way provide?”

      One big difference is that Gell-Mann proposed SU(3) as a genuine (unbroken) symmetry of the strong interactions, so the properties (quantum numbers etc) of the new particles can be inferred from the fact that they are in the same multiplet as other known ones. There is no such information in Garrett’s model since the symmetry is broken. While we’re on this topic, a final poke: It is ridiculous how Garrett has been saying (in statements attributed to him in the press) that the LHC will determine whether his theory is right or not. How does he know whether or not the exotic particles in his theory should show up there? Maybe they should already have shown up in previous experiments, in which case their absence disproves the theory. Or maybe they show up at energies much beyond LHC? Does he have any idea at all at which energies they should show up?

    16. Fabrizio Nesti says:

      …“maybe at higher scales a mechanism will ultimately provide… but he does not even speak about that.”
      No, but Fabrizio did speak about it and my “idle speculation” remark was directed to him.

      Yes, Amused,
      I did’nt reply to you because I agreed with Chris: Garrett does not speak of the full theory in the symmetric phase. (And in any case, he should speak for himself.)

      As far as I am concerned, in our paper (Graviweak Unification) we _do_ provide both the action in the fully symmetric phase and its breaking: above the breaking scale CM does not apply, below it holds, of course. This is why I wrote that clarification.

      In the E8 case, I can only hope that a similar breaking mechanism can be found, but it’s more difficult.

      About the ghosts-as-fermions, I have no idea of how this could work, and if. Lubos says that this can not be done. It should be easy to work out a simple toy model using BRST. Maybe Peter has thought to it.

      I think that blogs (let alone the media) are not the place to demonstrate something right or wrong, and the silence of most scientific community is a good sign. One should just close the browser for some time, sit down and try to see if ideas can be made to work. This is what serious physicists will do, anyway.

      Fabrizio

    17. Aaron Bergman says:

      Well, we do know triality. The point (I alrady raised in Bee’s blog) is whether triality is inserted by hand or comes out of the theory itself. For this I think you’ll need a high energy completion… again.

      Triality at the moment is just a bit of hand-waving hope. There’s no way that I can see that one could insert it by hand to recover the three generation structure of the standard model. Different representations remain different representations no matter how many automorphisms you do.

    18. chris says:

      hi amused,

      thanks for your long, detailed reply. indeed i find it strange too, how the attention of the public and of the theoretical physicists is divided between different approaches and how they influence each other. i think it just serves to show how much our profession is affected by trends and hot topics, too. and also how little every one given individual can actually comprehend of the whole field or how much the judgment is not guided by any higher principle we like to appeal to (like truth or beauty), but just by trust in our or other peoples opinions.

      well. one point i would like to make though is that i think it is not so far out to claim the unobserved particles in the spectrum not to be at too high energies. the natural reason i see is just plain simple again: these are particles that should show up in the effective theory at low energy. they explicitly populate the spots in the broken lagrangean. this is in stark contrast to e.g. the SU(5) X and Y bosons. so while it is still questionable to claim anything will be seen at the LHC it is no more of a misleading statement to me than the TeV scale bulk gravities or anything that tries to bring new particles within lhc reach.

      and finally: you very well know that SU(3) is broken right from the start of the construction. weakly broken i concur, but nonetheless, there never was hope of an unbroken flavor SU(3). all there was were the SU(3) reps and particles of different mass that fitted them.

    19. amused says:

      Hi Fabrizio,

      Thanks for your clarifying comment. I wasn’t aware of your work, and it is interesting to hear that you have a high energy completion of this kind in your case.

    20. amused says:

      hi chris,

      Yes, we are reliant a lot on the opinion of “authorities”, which imo places a lot of responsibility on them to be careful about what they say and what they hype.

      If the TEV scale gravity proponents, string phenomenologists etc make claims that their theories will be tested at the LHC then that is of course just as bad as if Garrett does it. But in the cases I’ve noticed those people always say maybe…

      And yes, I meant of course approximately exact flavour SU(3) symmetry, not 100% exact.

    21. Tony Smith says:

      amused said “… I [amused] can’t help getting a feeling that something is fundamentally wrong somewhere when work like …[that of]… C. Wetterich … hep-ph/0607051 … is being ignored while Garrett’s paper is being debated on physics blogs and reported on Fox News. …”.
      Wetterich says in that paper:
      “… Antisymmetric tensor fields with chiral couplings to quarks and leptons may induce spontaneous electroweak symmetry breaking in a model without a “fundamental” Higgs scalar. … Furthermore a scalar top-antitop condensate forms, giving mass to the weak gauge bosons and fermions. …”.

      Wetterich’s idea of a physical antisymmetric tensor field is interesting both physically and historically, since similar structures were used by Einstein and Schroedinger in some of their models. Maybe Wetterich has found a physical use justifying the basic intuition of Einstein and Schroedinger ? Wouldn’t that be something worthy of popular news commentary ?

      Wetterich’s idea of “a scalar top-antitop condensate” acting effectively as a Higgs mechanism, even if it may not be unique to him, is still a phase of his work that might be explored by experiments at the LHC. Wouldn’t that be worth at least a little pro-LHC publicity ?

      As amused said, Wetterich is “… a full professor at one of Europe’s illustrious universities …”, so lack of professional qualification cannot explain the fact that Wetterich’s work is not as widely publicized and evaluated as that of Garrett Lisi,
      and
      that leads to amused’s statement that
      “… it wouldn’t have happened [for Garrett Lisi] without the backing of some big-name physicist. Smolin was most obliging in this role …”,
      and
      that leads to a question about whether or not approval by a prominent third party is a necessary condition for acceptance of new ideas.

      For example,
      only after Freeman Dyson’s approval was QED of Feynman and Schwinger widely accepted,
      and
      only after Ben Lee’s approval was ‘t Hooft’s proof of electroweak renormalizability widely accepted,
      and
      without such approval-by-prominent-third-party, QED by E. C. G. Stueckelberg was ignored.

      Tony Smith

      PS -amused also said “… Tony Smith … has a Ph.D. from Princeton …”.
      Actually, my Princeton degree is an A.B. in math (1963),
      and I do not have a Ph.D.,
      so I am not “… as well qualified academically …” as Garrett Lisi,
      but
      I appreciate the other kind words from amused.

    22. Coin says:

      C. Wetterich has been developing an “alternative” proposal for explaining electroweak symmetry breaking based on chiral coupling of matter to massless antisymmetric tensor field… I can’t help getting a feeling that something is fundamentally wrong somewhere when work like this is being ignored while Garrett’s paper is being debated on physics blogs and reported on Fox News.

      I don’t think the “people shouldn’t be blogging about X, because blogging about Y would be more important” argument is ever fruitful. If Y is important, okay, blog about that too. If someone wrote a blog post about the Wetterich guy’s thing I’d read it. I’m not sure I’d completely understand it, but I’d try. In the meantime, the energy spent on covering Garrett Lisi is not energy that’s being taken away from covering Prof. Wetterich. If Lisi’s paper had not dropped this month I think the most likely alternative would have been that the physics blogs for the last couple of weeks would have just been quieter.

      And it’s certainly the case that if Lisi hadn’t published this month, Fox News still wouldn’t be talking about Wetterich’s new approach to the EWSB problem– Fox News doesn’t even know what the words “Electroweak Symmetry Breaking” mean. They do know what the words “unifies gravity with particle physics” mean, though, which is why they’ll write stories about that but not Higgsless EWSB models. (If you want to identify something “fundamentally wrong” here, then focus on that– that some of the most objectively important problems in real physics are things that the general public doesn’t even realize are problems that need to be solved! Never mind Wetterich’s “interesting and elegant” new approach for a minute– if the EWSB problem were solved tomorrow, would you know how to express this in a way that a Fox News viewer would care, or clearly realize that something truly important had happened?)

    23. amused says:

      Good grief, I didn’t mean that Wetterich’s papers should be discussed in the popular media instead of Lisi’s. That obviously wouldn’t be appropriate. The point i was trying to make was that it might be interesting to consider how and why those of us who are trained physicists here ended up spending a fair bit of time discussing Lisi’s paper when there are other papers out there that are arguably more deserving of attention but seem to be going unnoticed. The general question of what is it that determines which papers get attention from the physics community seems an interesting one, but perhaps that’s getting off-topic here.

    24. Coin says:

      Amused: Well, alright, sorry I misunderstood you then.

    25. amused says:

      That’s ok, I probably should have made it more clear.
      And apologies to Tony for misremembering his degree.

    26. Pingback: Balderdash– Chatter — Jabberwocky — Prattle — Scat — Twaddle — Yammer

    27. Nic says:

      Distler seems to have purely group-theoretical arguments to exclude the viability of the model:

      http://golem.ph.utexas.edu/~distler/blog/archives/001505.html#more

    28. alex says:

      “Distler seems to have purely group-theoretical arguments to exclude the viability of the model:”

      Good! At last someone put a stop to this absurdity.

      Thanks Jacques!

    29. a.k. says:

      ..I do not think Garrett claimed to have an ‘embedding’ of the direct product of the groups in question into E8 but to have any of these groups embedded as subgroups. As I already mentioned elsewhere, from my point of view, even at high energies, to get predictions, the E8-bundle should reduce to these subgroups which is by standard fibre bundle theory equivalent to having a global section in the bundle associated to E8/H, where H is the subgroup in question. Furthermore, the total connection should reduce to these subbundles, given they exist. Both facts might very well be true without having an embedding of a direct product as Distler discussed.

    30. Tony Smith says:

      According to a recent Telegraph article by Roger Highfield:

      “… a representative of a Hollywood film production company has been in touch with the Telegraph saying that “I loved the article and think it has great potential for a feature film.” And at least one major agent is scrambling to sell publishers a book that will tell the story of Garrett Lisi and his struggles to comprehend the cosmos.

      he has become something of a celebrity and he admitted yesterday that he was finding the attention overwhelming – indeed he has refused to appear on television.
      “I’m currently spending the bulk of my time corresponding with physicists, which I consider to be of prime importance. “…”.

      Garrett’s preference for doing physics over TV etc seems to me to be a very responsible attitude,
      and I hope that he is able to maintain it under the pressure of possibly exploitative offers from Hollywood, book agents, etc.

      Tony Smith

    31. Dany says:

      Tony Smith:” I hope that he is able to maintain it under the pressure of possibly exploitative offers from Hollywood, book agents, etc.”

      Tony,

      I guess it will be great fun to see Hollywood movie and read a book about “his struggles to comprehend the cosmos”. But what about the former American common boy stereotype with the forelock? He is Ockham razor shaven.

      Regards, Dany.

    32. Chris Oakley says:

      According to a friend at UCSD Garrett Lisi already has appeared on TV recently (dressed in once instance as a red indian). They obviously love the idea of him being the rebel who is rocking the foundations of physics.

      Well – good luck to him.

      But I wonder … if the string theory community had not started the trend of trumpeting speculative non-results to the press, would they have taken an interest?

    33. Tony Smith says:

      Chris Oakley said
      “… According to a friend at UCSD Garrett Lisi already has appeared on TV recently (dressed in once instance as a red indian). …”.

      According to a Fox6 (San Diego TV Fox station) web article by Jim Patton:
      “… Lisi is a San Diego native who received his Ph.D. in Physics from U.C.S.D.. He also appears to be a true San Diego son with an obsession for surfing and snow boarding that splits his time between Maui and Nevada.
      My interview with Lisi took place via email. …”.

      In light of that, perhaps Garrett has been true to his “refus[al] to appear on television”, and what appeared on San Diego TV may have been a news story by Jim Patton based on the email interview with background pictures from Garrett’s web site. As to Garrett being “… dressed … as a red indian …”, I suspect that may be a misinterpretation of the cover picture on Garrett’s web site at sifter.org/~aglisi/ which picture shows Garrett at Burning Man standing in front of a colorful exhibit.

      Tony Smith

    34. H-I-G-G-S says:

      Dear Peter,

      While you did not hype the content of this paper, like it or not, once you have a science blog you become part of the science media. Science reporters will look to your blog and others (even though this is in general a dubious method of gathering reliable information) to find out what is new and interesting. Because of this I think you should take some care with the topics you cover, particularly when you say things like you are fond of the ideas he is pursuing or that you are hopeful this line of thinking will lead somewhere. In this case you contributed to the idea that this model has some credibility, which it does not. Sean at Cosmic Variance was an even more egregious example of this, so don’t think I’m singling out your blog.

      I’d also suggest that you be a mensch and replace your latest update concerning Distler’s post on this with something more along the lines of “Distler has found an explicit error in Lisi’s treatment of the representation theory of E8.” You are supposed to be an expert on representation theory, so certainly you should be able to check whether Distler is right or not.

    35. Peter Woit says:

      H-I-G-G-S,

      I see one of the main goals of this blog as being to provide a source of accurate information for anyone interested in the same topics as I am. I think that’s what I’ve done in this posting, and that’s what I’ll continue to do.

      The reference to Jacques’s posting is perfectly accurate and I hope helpful to people. I see no need to editorialize in the way you suggest. For one thing, you might notice that the only comment in my posting about Garrett’s E8 scheme is that it’s the kind of thing that leaves me cold. As you might guess from that, I haven’t worked through the details of the representation theory in Garrett’s paper, nor the details in Jacques’s posting, so I don’t think it’s a good idea for me to do anything other than to refer people to the actual discussion between them, where they can make up their minds for themselves.

      As for the degree of my menschlichkeit, you might notice that I regularly link to and suggest that people look at many things that Jacques posts. In return, his policy towards me is one of absolute refusal to link to or acknowledge the existence of anything I ever write, as well as to make sure that no link appears in any internet source he controls, such as hep-th trackbacks and his Planet Musings blog aggregator.

    36. Arun says:

      The Economist gets Lisi-mania:

      http://www.economist.com/science/displaystory.cfm?story_id=10170958

      This hype is unjustified and IMO, is damaging to particle physics.

      Quoting:

      Yet the theory has several appealing facets. It is elegant. It is expected to make testable predictions. Unlike some of the more complicated efforts to devise a theory of everything, this one should either succeed relatively rapidly or fail spectacularly. And that is more than can be said for three decades of work by other physicists.

      It hasn’t occurred to them that it is not even a theory.

    37. How Can We Turn The Tide? says:

      It is now apparent that the Lisi affair was due largely to “String Theory Envy.”

      But two not even wrongs do not make a right.

      It is understandable that Lee and Peter might have been swayed towards Lisi’s paper by Lubos’s rejection and dismissal of the paper, but it would have been better if Lee and Peter would have judged the paper based on its merits, which would have entailed reading it, and at least attempting to comprehend it, even if being comprehended was not Garrett’s primary incentive for his media campaign, pictures of him surfing, and ultimately meaningless youtube video with the hot, english female voice.

      At least Lubos read the paper, as did Distler.

      Did Lee? And if so, how can he call it “fabulous?”

    38. Bee says:

      Can you turn the tide? : Garrett gave a seminar here at PI about his work in early October, he stayed two weeks during which we had several discussions. New Scientists asked Lee and me for comments on the paper before it was on the arxiv but then extended the deadline (I am not sure why but think Lee complained). I am glad they did, as I find it extremely inappropriate to ask people to comment on a paper they haven’t even seen. If you ask me, they should leave at least several months to think about it. There is a reason why good peer review takes time. The only reason my blog post went out as soon as the paper was on the arxiv was that I had written it previously, since Garrett sent me a copy of the paper (plus it has been on his wiki anyhow). As far as I know NewScientist knew about Garrett’s stuff from a talk he gave earlier during the summer this year. Nothing of that interest in Garrett’s work had anything to do with Lee or Peter. I find it quite astonishing how you (and others above) manage to blame a single person using the word ‘fabulous’, ignoring all the hundreds of people who echoed the same initial articles over and over again, without adding one epsilon of content, gradually polarizing and distorting the little scientific content such an article can have at all. If anybody is to blame for that then its everybody not acting against such a decline of journalism down to cheap entertainment, with no other purpose than collecting links and visitors who click on the advertisement banner.

    39. TonyC says:

      “How Can We Turn The Tide” says “It is now apparent that the Lisi affair was due largely to ‘String Theory Envy”:

      Why is that? Have you found some fatal error in Lisi’s E8 mapping? If so, share it with us. If not, what makes this claim “apparent”? If Lisi maps all known particles to E8 correctly, this puts constraints on possible interactions, and constraints on future discoveries. Why isn’t that a “theory”? Even if he has to work out his symmetry breaks “by hand”, we may gain insight by examining the results and looking for commonalities.

      What evidence do you present that Lisi’s primary incentive was anything other than being comprehended? It seems rather difficult to support your theory of “String Theory Envy” when Lisi’s proposed mapping is at least falsifiable by the LHC and String Theory (also not a theory), to my knowledge, is not. If anything, I think the opposite is true, the string theory community envies Lisi getting any attention whatsoever, probably because the very concept of falsifiability threatens their funding and Lisi is emphasizing the value of that radical concept. As long as we are claiming things are “apparent” with zero evidence to support the claim, I claim my interpretation is even more “apparent” than yours.

    40. alex says:

      Bee, you forgot to add another Lee’s quote: “It is one of the most compelling unification models I’ve seen in many, many years”.
      So, at least Lee has “seen” it and found it “the most compelling”. To make such a conclusion one would presume the Lee must have taken some time (as Jacques did, for example) to check at least some of the details.

    41. H-I-G-G-S says:

      Bee,

      I don’t think you can blame this all on journalists gone bad. It’s amazing that after a seminar and a few discussions neither you nor Lee could understand what Lisi was saying well enough to tell that it was total nonsense. If you had realized that I presume you would not have found it worth blogging about and the reporters would have had one less reason to get worked up over this.

      TonyC,

      Go read Distler’s blog. If you know enough math to understand it you will see that all the elementary particles do not fit into E8. Period, no ifs ands or buts. And the “triality” he proposes as some kind of cure is equally meaningless. This “theory” won’t be tested at the LHC. You can’t make predictions if your starting point is bunch of jumbled up concepts that don’t make sense, a hope and a prayer that someone else will make sense of it, and wrong math.

    42. TonyC says:

      H-I-G-G-S:

      Distler proves you can’t have 3 copies of R in E8. Lisi acknowledges this and anticipated the problem. Later Lisi admits to a mathematical misunderstanding. Distler has NOT proven all the elementary particles do not fit in E8, they just cannot fit in the way Distler thinks they must fit, so he dismisses the entire exercise as futile; while Lisi does not. This academic disagreement over whether Lisi’s mapping has any merit or might lead to something useful seems to me pretty thin evidence for accusing Lisi of String Theory Envy or celebrity mongering.

    43. Arun says:

      H-I-G-G-S: I see nothing wrong in Bee’s no-sharp-elbows approach – she reached the right conclusion.

    44. H-I-G-G-S says:

      TonyC:

      Please tell me what you mean, in mathematical terms, by “Lisi maps all known particles to E8 correctly.” Distler interpreted this in the obvious way and showed it was false. If you have some other mapping of this statement into mathematics please tell me and then we can check if it is true. If you can’t tell me what you mean than I would politely suggest that you should withhold judgement until you learn more.

    45. Bee says:

      H-I-G-G-S: I don’t think you can blame this all on journalists gone bad. It’s amazing that after a seminar and a few discussions neither you nor Lee could understand what Lisi was saying well enough to tell that it was total nonsense. If you had realized that I presume you would not have found it worth blogging about and the reporters would have had one less reason to get worked up over this.

      I don’t blame it all on journalists, certainly not. I blame everybody who blames others, instead of taking responsibility. Journalists who say they just believed the scientists, scientists who say journalists just misrepresent them, bloggers who say it’s all the media’s fault. I blame myself since I possibly contributed to the hype, even though it was my intention to provide a balanced article with pros and cons. I had heard Garrett’s talk, I had read the paper, and I told him (repeatedly) that I think he does not clearly state how much extra assumptions he has to make by hand. I told him that even before he gave the talk at PI. When I wrote my post, I knew the New Scientist article would come out soon, I knew they had asked Lee for his opinion, and I knew Lee’s opinion. I know New Scientist enough to realize they would listen to him. I knew the title of the paper, and I know Lubos enough to predict he’d jump on it, especially thanks to the acknowledgement list. As somebody said so aptly in a comment somewhere (sorry, can’t recall who or where), everybody did exactly what one could have expected.

      How come things like this happen? Because it’s a completely premature reporting on an unclarified issue, a paper that has just been out a couple of days, in a field where peer review takes months, and NO, I don’t think peer review can be ‘replaced’ by discussions on blogs. I don’t appreciate pressure on scientists to put forward opinions, especially when so completely unnecessarily as in this case. I mean, it’s not like there was some phenomenon observed, and expert opinions were needed to explain it. If somebody says he doesn’t want to comment or doesn’t feel qualified one shouldn’t criticise him for knowing what he doesn’t know.
      Regarding what I blogged about: I have repeatedly stated that there are many things about Garrett’s stuff that I don’t understand, and that I don’t like. I have clearly written in my blog post what I find promising about it and what not. I have clearly stated that he does not quantize gravity, what problems he does not address, that he has to write down the action by hand to reproduce the standard model, and that I don’t think it qualifies as a TOE. Neither do I think it is just nonsense. I just think it was, and still is, premature to decide whether it will eventually turn out to describe a part of how nature works.
      If I would write the post today, I would have made the basic statements much clearer and more obvious, but I did not expect the audience I got. Also, I am not a journalist, I am a scientist, and my writing skills are limited. There are several points that only become clear in the comments, and I am afraid little people read more of my posting than the first sentences, and even less actually tried to understand it.
      After all, I am really sorry for Garrett. Though I think he knew exactly what he was doing, the results might eventually not be as expected.

    46. Bee says:

      Hi Arun,
      Thanks. Seems it took me an awfully long time to write the previous comment, so I only just read yours now. In fact, I said this already in the post, but maybe not clearly enough
      “However, for me the question remains which problem he can address at this stage. He neither can say anything about the quantization of gravity, renormalizability, nor about the hierarchy problem. When it comes to the cosmological constant, it seems for his theory to work he needs it to be the size of about the Higgs vev, i.e. roughly 12 orders of magnitude too large. (And this is not the common problem with the too large quantum corrections, but actually the constant appearing in the Lagrangian.) To make predictions with this model, one first needs to find a mechanism for symmetry breaking which is likely to become very involved.”

      Have a nice evening.
      Best,

      B.

    47. Eric says:

      Just curious why noone has brought up the work of Jacob Bourjaily with geometric engineering three-family GUTs from E8? It seems to me to be somewhat higher quality work than that of Lisi.

    48. Arun says:

      Dear Bee,
      Yes you did state it in the post; but then there was the comments thread, which might give the impression that some of your objections were being addressed; that is why the comment is important in my interpretation of the world – you were willing to listen (good!), and when nothing convincing was said, you said so (great!), and wound up the discussion (excellent!).
      Best,
      -Arun

    49. TonyC says:

      >> H-I-G-G-S: If you have some other mapping of this statement into mathematics please tell me and then we can check if it is true.

      I can’t, you are right, I was wrong to say so. I am basing that statement on what Lisi has said, presuming he isn’t lying.

      >> If you can’t tell me what you mean than I would politely suggest that you should withhold judgement until you learn more.

      Good advice. As I have politely suggested it is too soon to pass judgement on Lisi’s mapping, based on Distler’s proving the obvious approach won’t work, when Lisi already anticipated that objection in his paper. I refer you to Lisi’s response on Distler’s blog. And it is also too soon to pass judgement on Lisi as some sort of fame whore, which seemed to be the suggestion of “How Can We Turn The Tide”. Perhaps I am not the only one that needs to withhold judgement until they learn more.

    50. amused says:

      “It is now apparent that the Lisi affair was due largely to “String Theory Envy.” ”

      It’s quite funny how some string theorists (the less enlightened ones) think that any challenge to ST must be driven by “envy”. Envy of what, exactly? Of all your PRL publications?