The most entertaining paper that managed to creep into hep-th today is called



: the preprint was re-classified from the professional hep-th archive to gen-ph, general physics, an archive mostly dedicated to laymen's fantasies. Thanks God. Comment for general readers: this preprint is of course not peer-reviewed and probably won't get published anywhere.

Update II: Roger Highfield whom we know from his article attacking the scientific method and claiming that Einstein may have started the rot has returned. In a new, equally breathtakingly silly article, he suggests that A. Garrett Lisi is a new Einstein. Two months ago, I wrote about bad physicists and populism. You may see that virtually all of the myths I described are realized in this story. Mr Highfield has written at least one more stupidity of the same magnitude - namely that the cosmologists are bringing the Universe closer to the doom by observing it. Sensations are much more important for him than rational thinking or the truth.



Update III: Thousands of blogs and news outlets have copied the utter nonsense from Mr. Highfield and at least tens of thousands of people are Google searching for this "new Einstein". It's called mass hysteria. Isn't it cool if a poor surfer dude (see a snowboarding video) finds a theory of everything? It is surely cool but "cool" is not the same thing as "true". ;-) ArsTechnica, a server dedicated to PC professionals, seems to be one of a limited number of remaining sane sources.



Update IV: Lisi's paper has four citations. The most famous authors referring to him are Ferrara and Bianchi who call Lisi's construction a "(hopeless) attempt to unify" on page 16 of their paper.



Update V: Jacques Distler and Skip Garibaldi wrote a paper for mathematicians, explaining that there can't be any "theory of everything" that embeds gravity and other forces into any form of E8.

My connection of everything = connection for gravity + weak force + strong force + electromagnetism + electron + neutrino + up-quark + down-quark + other-generations

If you want a lecture of a well-known physicist about the Coleman-Mandula theorem, look at MOVIE 13 by Edward Witten at the Sidneyfest.

Its author, A. Garrett Lisi , claims to have found nothing less than a theory of everything. An exceptionally simple one, for that matter. It may sound as a bold statement but from a genius of A. Garrett Lisi's caliber, it shouldn't be surprising. :-)This extraordinary surfer dude managed to collect five citations in the last thirteen years which is only 4 orders of magnitude below leading physicists . Because the work is based on the E8 group that I love, you bet that I have opened the paper.Needless to say, the visually intriguing and colorful paper is a huge joke. The first place where I exploded in laughter was the equation (1.1). It says, using words, the following:That's pretty cute! :-) The author is not constrained by any old "conventions" and simply adds Grassmann fields together with ordinary numbers i.e. bosons with fermions, one-forms with spinors and scalars, neglecting any traces of dimensional analysis, too. He is just so skillful that he can add up not only apples and oranges but also fields of all kinds you could ever think of. Every high school senior excited about physics should be able to see that the paper is just a long sequence of childish misunderstandings. I understood these things when I was 14.Confirming my essay about crackpots' common errors , Garrett Lisi is unable to falsify a wrong hypothesis even in the simplest cases.Concerning the title, I present it as a joke but I agree with Freedom of Science that if the title is viewed seriously by some important readers and if the author allows it, it is a case of scientific fraud.There is not a glimpse of physics in that paper. You won't find anything like a "Lagrangian", "amplitudes", "masses", "cross section", "quantum corrections", "anomalies", "energy", "force", "Hamiltonian", "entropy", "phase transition", "path integral", "renormalization", "temperature", or other words that you expect in a particle physics paper. When he talks about actions, they're always wrong actions from some previous obscure papers that have clearly nothing to do with observable physics either. Of course, the author also seems to have no clue about quantum aspects of gravity - a unification of gravity with quantum mechanics is not even attempted because the author clearly doesn't know what it means. On the other hand, you find a lot of random assignments of particles to vertices of polytopes - something that you know from papers about the octopi It is the same kind of "unification" as if you put stickers with elementary particles on a chessboard and argue that chess is the ultimate theory of everything. Some stickers don't fit so you call them your predictions. Kindergarten stuff, indeed. Or let me give you a better analogy.A. Garrett Lisi and his 222 close personal friends. He needs 18 more to reproduce the roots of E8 and make his theory complete. Click the picture for more details.The role of the E8 group in his picture is therefore completely unphysical. Because different components of the E8 multiplet are assumed to be particles with completely different properties, the E8 symmetry is broken at stage zero. There is no E8 symmetry - and there can't be any E8 symmetry - that would actually relate these different particles.Of course, the comments that this theory may be tested by future experiments are nothing else than journalists' confusions or a politically correct lie (because it is always OK to say an untrue thing about an "anti-establishment" outsider who is moreover a broke). The theory can't reproduce even basic aspects of the observations that have been made decades or centuries ago which is why any talk about even more ambitious tests is rationally unjustifiable.The main mathematical content in these 30+ pages is the decomposition of the fundamental representation of E8 under its F4 x G2 subgroup. It is an elementary fact that e.g. freshmen in Prague who follow my textbook written with Miloš Zahradník know as equation (12.95) . For A. Garrett Lisi, this single line reflecting a simple calculation that has been done a century ago and that a fraction of freshmen learns is a topic for a 30-page paper and an impressive albeit two-dimensional movie Unfortunately, Garrett Lisi, painting himself as an E8 expert, already doesn't know that E8 has a SU(5) x SU(5) subgroup . It's kind of amazing to be ignorant about these elementary facts for a person who is pictured as an expert.Nude Socialist has already created a 2-minute commercial for this nonsense. Don't be intimidated by the animation. It is just a collection of points given by 8 coordinates (being 0, +-1/2, or +-1) projected to a 2-dimensional plane whose direction - i.e. the relevant coefficients - are changing with time. The visual effect has nothing to do with physics. And mathematicians routinely create more sophisticated animations, see e.g. turning sphere inside out Some people might be impressed by some of these formulae about the E8 group - some of which are correct - and/or the pictures. But I assure you that the E8 group is a pretty standard material that students learn in courses of group theory. And there are millions of pictures like that. For example, the picture of the E8 Gossett polytope below is from Wikipedia's article about E8 ; see also string theorist Clifford Johnson's blog from March 2007. E8 is the biggest exceptional animal in the exciting ADE classification and a large portion of string theorists work with it every day.This stuff has been known for a century or so. For example, the E8 group itself was discovered by Wilhelm Killing (click the picture) in 1887. New insights were added by Élie Joseph Cartan (click the picture below) in 1894.The basic facts about the E8 group have nothing to do with problems that physics has been solving in the last 50 years: they are just a part of the mathematical background that high-energy physicists are supposed to know. Garrett Lisi remembered something from math classes he was taking 15-20 years ago but he has forgotten virtually all of his physics classes. Be sure that every physicist who knows basics of his field agrees with me that everything that is nice about the paper has been known for a long time. For example, Le Monde quotes Thibault Damour and Jean Iliopoulos saying exactly the same thing.The way how Antony Garrett Lisi combines his spotty knowledge with ambitious claims mimicks the approach of thousands of other "amateur Einsteins". He was just luckier because a journalist has endorsed him.If you care how the forces and particles are supposed to be embedded into his group, it's like this. You start with a non-compact real form of E8, namely E8(24). You embed a G2 into it. Its centralizer is a non-compact version of F4. Now, you embed the strong SU(3) into the G2 while the non-compact F4 acts as the source of a "graviweak" SO(7,1) group that contains SO(3,1), a "gauge group" that is now fashionable in the circles of amateur physicists to "describe" gravity, and SO(4), their source of cargo cult electroweak symmetry.Of course, the SO(3,1) group mentioned a minute ago plays a different role (in the vielbein formulation of general relativity) than the Yang-Mills groups and the fact that these two kinds of a group cannot be merged is the content of the Coleman-Mandula theorem to be discussed at the end of my text. Moreover, the fermions clearly can't arise from the connection because they have a different spin and statistics and they don't transform in the adjoint representation. For people like A. Garrett Lisi, it is not hard to unify everything with everything else because they don't know any difference between different concepts in physics.Let me repeat the same idea differently. A unification of different forces and matter in physics is difficult because different force and matter particles have different properties, especially spin and statistics (and other features that follow from them, e.g. non-renormalizability of gravity). Garrett Lisi attacks the problem of unification by completely ignoring all these features that actually contain the whole problem. That's why his work is physically vacuous and meaningless.The technical statements that the decomposition etc. can give the right spectrum, e.g. the number of generations, is also wrong. See, for example, Jacques Distler's post . Jacques' group theory looks impressive but his complaints are analogous to telling cargo cult scientists that they should change the shape of their wooden headphones, as Richard Feynman would say.Additionally, you might think that the E8 starting point is analogous to heterotic GUTs - models such as the heterotic MSSM by Bouchard et al. Except that it is completely crucial for physics that E8 in heterotic string theory is compact. Non-compact gauge groups would lead to ghosts and negative probabilities. Moreover, the whole Standard Model is embedded into the same subgroup of the heterotic E8 once it's broken, e.g. to SO(10). Also, everyone knows that the fermions arise as chiral multiplets and not vector multiplets: they are simply not and cannot be a part of the gauge bundle. Most importantly, no sane person has ever claimed that the E8 portion of the heterotic theory already contains gravity. That would be really silly.Also, if you have ever heard about "GUT" (Grand Unified Theory), you should realize that unlike E6 and others, E8 cannot be a grand unified group because it only has real representations which is not good enough to create chiral fermions. In string theory, E8 is only relevant because it is broken to a smaller subgroup by intrinsically stringy effects. Needless to say, Garrett Lisi has no idea what a "chiral fermion" or even "fermion" means so he is not worried about any of these "details".A few years ago, such a paper would almost surely be filtered out from hep-th. Paul Ginsparg has introduced the endorsement system which was circumvented in this case and is likely to become a complete joke in the future. Why? Well, we have seen that a completely continuous spectrum of people between serious physicists and manifest crackpots has been created and the recent fashionable trend is to accept an ever broader set of passionate amateurs and undereducated, intellectually challenged loons into the physics circles.This paper by A. Garrett Lisi had to be endorsed by someone. If you read the acknowledgements, it is not hard to see possible answers. Some of those people such as Lee Smolin may endorse any crackpot paper because they are both endorsers and crackpots at the same moment. Moreover, they have a vested interest to increase the proportion of similar papers on the arXiv because this is where they belong. As Lee Smolin recently pointed out, irrationality has been extremely useful for him in the past.If Ginsparg wants to prevent this possible collapse of his arXiv, he probably has to fine-tune the mechanisms a little bit and make sure that people who are ready to endorse papers like this one are simply not endorsers. Otherwise you can be pretty sure that similar papers will eventually overrun the arXiv. Tony Smith is among the crackpots thanked to in the acknowledgements. Next time, he may also submit his own paper supported by similar endorsers. And maybe A. Garrett Lisi will become an endorser himself. Really entertaining times will start afterwards: the hep-th era of the UFO abductee Jack Sarfatti, Tony Smith, Peter Woit, and their friends.Recently I was stunned that a person who has been a string theorist couldn't understand, despite months or years of working on similar questions and months or years of hearing the right answer, what the Coleman-Mandula theorem actually implies. There seems to be a whole industry of people who are just not getting it.So let me say a few words about the theorem. They asked what symmetries "G" the scattering matrix of a physical theory can have. They assume that it is a group that contains the Poincaré group as a subgroup. If the Poincaré group is not a symmetry, the theory is dead. If the Poincaré symmetry is broken by small effects, a theory may be partially alive or hoping. But if it is broken by effects of order 100 percent, it is the end of the story.Garrett Lisi's statement that the Coleman-Mandula theorem no longer holds because the cosmological constant is nonzero while Coleman and Mandula assumed the Poincaré symmetry instead of SO(4,1) is utterly naive. The cosmological constant is a tiny correction to the flat space, comparable to 10^{-120} in natural units, and the laws associated with the flat space must thus hold with the same accuracy. Moreover, full-fledged generalizations of the theorem exist for spaces with a nonzero cosmological constant.Coleman and Mandula have shown that a theory satisfying the necessary conditions above must contain a spinless excitation and they studied the scattering of several copies of such an excitation. The scattering amplitude is constrained by the Poincaré symmetry and perhaps other symmetries. If you require that there exist Noether conserved charges arising from symmetries that are neither internal (scalar charges) nor the momentum (a vector from the Poincaré symmetry), you can see that it is such a strong constraint that the scattering amplitude is forced to vanish. You can do it with various quantities and prove that a theory with these new kinds of symmetries must be non-interacting, which also means physically unacceptable and uninteresting.The only exception - found a few years later, in the early 1970s - are spin 1/2 conserved charges associated with supersymmetry . They also constrain the S-matrix dramatically but the interactions can nevertheless remain nonzero. The more general theorem that takes supersymmetry into account and excludes other possible symmetries is called the Haag-Sohnius-Lopuszanski theorem.The local Lorentz group in general relativity is sometimes used analogously to other gauge groups - when we write down e.g. anomalies in supergravity-super-Yang-Mills coupled system - but it is essential that physics of gravity is technically different from physics of Yang-Mills forces. Gravitons have spin 2 while gauge bosons have spin 1. It is a technical difference that doesn't spoil certain philosophical analogies between gravity and other forces. Nevertheless, it is a huge technical difference that certainly prevents you from combining the graviton and gauge bosons into the same multiplet (unless you have supersymmetry).It might be a tempting idea to combine fields of a different spin but in field theory, it simply can't work. That's why all of the hundreds (?) of papers that tried to do such a thing have failed and hundreds (?) of similar papers will fail in the future.Some people - see e.g. the recent paper by Nesti and Percacci - think that if they present the vielbein as a Higgs boson that breaks the local Lorentz symmetry (which is of course possible), they achieve a unification of gravity with gauge forces. That's of course a complete nonsense. If we use the vielbein approach to general relativity, the local Lorentz symmetry is an additional symmetry that is needed to make the new unphysical degrees of freedom in the vielbein decouple. Besides this symmetry, there is still the old diffeomorphism symmetry of general relativity that hasn't been moved closer to unification, not even by a millimeter. Diffeomorphisms and Yang-Mills symmetries (and, correspondingly, graviton and gauge bosons) can only be unified if the fundamental "coordinates" in the theory carry a nonzero spin.In string theory, it is true that the string field or the first-quantized wave function combines fields of different spins. But the spin is only generated because the fundamental object, namely the string, is extended: extended objects such as strings simply can spin around their "axes". The expansion in the stringy oscillators - the Fourier modes of the coordinates and fermions over the string - generates internal angular momentum. Alternatively, Kaluza-Klein scenarios also unify these things because the higher-dimensional metric tensor is decomposed into fields of different spins in four dimensions, including a gauge field. See also Why string theory contains gravity . Additionally, gravity may be deduced from spin-two gauge invariance but not spin-one gauge invariance.If you analyze local, four-dimensional field theories which are equivalent to point-like particles, they can't spin. The only way how to add spin to components of a field is to have spacetime coordinates that carry spin themselves. Again, spacetime and superspaces of various kinds (and the space of internal string excitations may be included in this category) are the only known spaces of this kind. Under various assumptions, we can prove that other solutions can't exist.Of course that one has to work a little bit to see that one can't create too many new things analogous to the superspace that would be compatible with observations - or at least with basic consistency and qualitative features of physical theories - but different from the well-known superspaces in an essential way. But Jesus Christ, once you have a pretty well-defined candidate, it is a straightforward homework exercise to show that it can't work.Stephon Alexander and Fabrizio Nesti, just sit down and try to derive the free particles and their leading interactions from whatever bizarre theories with mixed internally external symmeties and with frame-Higgses you consider conceivable. I guarantee that you will fail and mature physicists know why you will fail. Or analyze what global symmetries remain unbroken and try to follow the Coleman-Mandula procedure. What you're doing is just a completely childish and trivial sequence of mistakes and meaningless mathematical masturbation that puts you into the same category as Tony Smith or Garrett Lisi.And that's the memo. (By Luboš Davros-Motl.)