Garrett Lisi has a new paper, “An Exceptionally Simple Theory of Everything.” Many people seem to think that I should have an opinion about it, but I don’t. It’s received a good deal of publicity, in part because of Lisi’s personal story — if you can write an story with lines like “A. Garrett Lisi, a physicist who divides his time between surfing in Maui and teaching snowboarding in Lake Tahoe, has come up with what may be the Grand Unified Theory,” you do it.
The paper seems to involve a novel mix-up between internal symmetries and spacetime symmetries, including adding particles of different spin. This runs against the spirit, if not precisely the letter, of the Coleman-Mandula theorem. Okay, maybe there is a miraculous new way of using loopholes in that theorem to do fun things. But I would be much more likely to invest time trying to understand a paper that was devoted to how we can use such loopholes to mix up bosons and fermions in an unexpected way, and explained clearly why this was possible even though you might initially be skeptical, than in a paper that purports to be a theory of everything and mixes up bosons and fermions so casually.
So I’m sufficiently pessimistic about the prospects for this idea that I’m going to spend my time reading other papers. I could certainly be guessing wrong. But you can’t read every paper, and my own judgment is all I have to go on. Someone who understands this stuff much better than I do will dig into it and report back, and it will all shake out in the end. Science! It works, bitches.
For a discussion that manages to include some physics content, see Bee’s post and the comments at Backreaction.
Well, I can’t explain the comment, as it doesn’t make sense to me, but there are situations in which a particle can “propagate its effects faster than light.” http://en.wikipedia.org/wiki/Quantum_entanglement
I’m not certain if anyone has covered this elsewhere, but I was wondering if this theory explains the relationship between inertial and gravitational mass in any way?
Recently I’ve come to see this relationship as something that must be the litmus test of any TOE. While it may not be absolutely required for a theory to be accurate, it would suggest that any such theory is incomplete if it didn’t address the question in any way.
Similarly, just how front loaded does the theory have to be to produce predicted masses for the standard model particles? I couldn’t find that information in the paper.
Finally, to what extent is this model actually new physics, and to what extent is it simply a new mathematical description of properties of particles, without nescisarilly saying anything new (or indeed anything) about the physics relating those properties? From what I have seen, it would seem possible that the same mathematical structure could be kept even if the physicality of the system is not as it is assumed in the paper. But that could just be the echo chamber getting too loud in String country.
Thomas,
Yes, quantum entanglement does recognize faster than light cause-effect relationships, which is mentioned in the linked article by Halton Arp:
http://www.haltonarp.com/articles/the_observational_impetus_for_le_sage_gravity
Of course, I can’t find the articles from his webpage now, but Halton Arp had posted cosmic observations that pointed to gravitational cause-effect relationships that appeared to occur at speeds of 5, 20 and 300 times the speed of light. Halton believes this is evidence of extremely long wavelength graviton particles that travel faster than light, but given gravity’s position along imaginary vectors of the E8 lattice, I suspect gravity is an apparent “force” resulting from the interactions of the other forces / particles, which would explain “faster than light” cause-effect observations.
It is similar to someone whipping a flashlight beam across the sky, in which the reflected spot appears to be traveling faster than light at great distances, but it is only an illusion (not a great analogy, but sufficient).
How can there be a ToE without directly addressing what 95% of the “missing” universe really is? Just my 2 cents.
I give the medcine for modern theory of gravity:
Gravity is the spacetime background of other interactions.
Einstein was to consider gravity as background. On the other hand, He wanted to unify gravity with others and tried to tranform the theory into field theory. Therefore, curvature is considered to be real matter while reference frames (real background) are no longer the choice of Einstein. General relativity loses connection to real matter.
String and other mainstream relativity do not dare to challenge Einstein and, therefore, dance on the stage of imaginary matter!
Patrick:
I think the most probable explanation for why Lisi’s E8 theory doesn’t explain what dark matter and dark energy are is that they don’t actually exist.
Patrick,
I think there are 18, or so, “roots” of E8 that do not match up to known particles. Some or all of these may be dark matter candidates. I think that a cosmological constant is built in somehow – I have heard the term “DeSitter space” mentioned in describing some aspect of Lisi’s model. I know very little about the theory. I’ve just looked at a few diagrams and heard a few wisps of conversations.
Thanks for the reply Brian, Andy. I didn’t mean to criticise the theory itself because I understand way to less of it, to do that (I’m not even a ‘biker-dude’, even though I love riding my bicycle. Also I don’t have any academical degree, it’s ridiculous to point that even out, because I’m no stereotypical nerd whatsoever *uhh, irony*). I don’t admire Garret’s media-attention for his (maybe) brilliant paper, I even feel sorry for him. That kind of pressure may well be hard to handle. I found his little story here quite nice, especially the parts, in which he didn’t sound he’d have to justify himself. Fame will come, if deserved.
The first thing I did after i read the intro and outro was looking for the phrase “dark” in his theory. Since that is not in there, i searched for any hint of an explanation. Earlier, my point was, that any ToE should at least include solutions for the DM/DE ‘problem’ and not leave room for speculation there. Even it that means, that we’re far from a ToE. But maybe that’s not how theories in phyiscs work. I guess that Einstein wasn’t to eager about explaining every consequence of his theory neither. But for that, there are genious people like Sean, who happen to explain that kind of stuff for a broader but interested audience in a very nice way. Ups, I g2g! Greetings from Germany everyone 🙂
Andy,
I agree, I also suspect that the motions we currently see are the result of known matter that simply relates in ways not yet understood, which may be found in the E8 lattice relationship. In the same way, I don’t believe gravitons exist, and the observed “force” of gravity is just the result of known matter relating in ways we don’t yet understand.
In a sense, I see gravity as a pushing force caused by existing particles / forces that we now know. To me, there is only ONE true unifying force:
entropy
Every other particle / force bows before it.
Quantum entanglement does not involve a faster-than-light causal effect, for the simple reason that there is no operational way of testing this statement. The effect of entanglement is seen in communication protocols (unconditionally secure cryptography) and information processing (quantum computing), and can be acurately described as a correlation between quantum systems that is stronger than any classical correlation. The no-cloning theorem in quantum mechanics ensures that quantum entanglement canot be used to signal faster than light. In particular, simultaneity is still a relative concept (that is, relative to the observer’s intertial frame).
“I got my PhD and looked at my options. I love differential geometry, general relativity, and particle physics. But the only options available then for a postdoc in those combined areas were in string theory, and I thought string theory was overly speculative.”
Before blaming string theory for your lack of opportunities, consider whether your publication record (1 publication, in J.Phys.A) would have made you competitive for postdocs in the absence of string dominance.
String theorists must be loving what they see unfolding here. How will the usual critics ever be able to accuse them of overblown hype and misleading advertising again, given their role in (Smolin&co), or silence during (Woit), the current spectacle.
“String theorists must be loving what they see unfolding here. How will the usual critics ever be able to accuse them of overblown hype and misleading advertising again, given their role in (Smolin&co), or silence during (Woit), the current spectacle.”
Not really. It is simply sad to see how manipulative blog campaigns are semi-successful to switch the public opinion around. First, to discredit string theory and now, to support lousy research. I wonder whether they pay similar attention to the fact that this “theory” has been shown to be wrong.
hi notsoamused,
I should be even less amused than you about this, being on the anti-string (or more precisely, the `let’s curb string theory excesses and give others a fair shot’) side. I’ve always interpreted Peter W.’s blog as being more about provoking a critical debate about ST rather than discrediting it, but he does seem to have made an error of judgement in this case. There are mitigating circumstances though, since a senior professor at PI came out and described the Lisi work as “fabulous” and “one of the most compelling unification models I’ve seen in many, many years”, which signals a green light to physics bloggers and journalists alike to cover it.
I’ve always suspected that Smolin, in his unrestrained drive to make reality conform to his ideological ideas of how things should be, would end up doing much more damage to the “anti-string” cause than Motl’s rantings would ever do to the pro-string side.
Amused, I am not sure what you found so very different in this episode, to my mind everyone behaved exactly as they had numerous times before. Luckily, this includes Jacques, who once again stayed on topic and took the time to provide a thorough analysis of the group theory involved, including where things go wrong. See
http://golem.ph.utexas.edu/~distler/blog/archives/001505.html
Surely it is only hours before we witness lots of retractions…
Moshe, the specifics of this case are way different from anything that has gone before: Smolin&co promoting an unknown person claiming to have a ToE… It is uncharted territory, so I’m not sure if one can say that the people involved are behaving as they had done many times in the past. Depends on the interpretation perhaps… But yes, I agree that Jacques deserves everyone’s thanks for putting the matter to rest.
Please note that Jacques Distler has not pointed out any problems that are not already discussed in the paper. I fully admit that this theory has a problem with the higher two generations that needs work, and have never claimed otherwise. On the contrary, I state and explain this explicitly in the paper.
The simplest theory of everything will be an account that will explain everything in the natural world that cannot be explained as or just as effects caused by the forces.
So that, in particular, this is a cause and effect explnation of how matter as atoms. molecules and liviing organisns can exist despite the forces acting within and upon it. And hence this theory finds that the universe can be and remain the way that it is only because of the universal and constant action of nonlocal and extra-dimensional material form conserving cause.
amused,
This is not a topic I was “silent” on, it’s one I wrote a posting about explaining exactly what I thought, as well as engaging in discussion on the subject in the comment section. That much of the press coverage has been misleading and badly overhyped is something that even Garrett I think agrees with.
But I also think the hysteria over this from some string theorists is unwarranted. The media regularly carries overhyped stories about highly speculative physics papers (do you read New Scientist?), and mostly I think the best policy is to ignore them, because no one in the physics community other than the authors of the papers themselves is paying any attention. The reason I’ve regularly been critical of overhyped articles about string theory is that physicists are paying attention to them. The question of whether string theory has failed as a unification theory is a highly contentious one among people in the field, and ongoing attempts to claim “predictions” of string theory and other successes in the media are part of this story, and something I intend to keep writing about. I also expect to keep mostly ignoring the large amount of nonsense in the media that is not about string theory, unless it shows some sign of actually influencing physics research
Peter,
I see your point, but am worried that next time you (rightly) decry the latest “test of string theory” hype you will get string theorists writing in asking you where was your outrage during the Lisi spectacle when the hype propagated by Smolin&Co was at least as bad. They will point out that, thanks to Smolin’s credentials and status as a senior prof. at PI, this hype had considerable influence on getting the public and quite a few physicists to pay attention.
If you hadn’t covered the Lisi paper in the first place you could deflect this by saying that it is outside the scope of your blog. But since you did cover the paper, it’s less straightforward…
amused,
Remember that string theory fails at every criterion:
(1) It’s not even ad hoc theoretical physics because doesn’t model anything already known successfully (the unobservable values for the moduli of compactified extra spatial dimensions in string theory give that theory a landscape of 10^500 or more models, and it’s not even mathematically possible today to even identify which – if any – of those models encompass Standard Model type physics).
(2) Because there are 100 unknown moduli required in the theory (the parameters of the unobservable Calabi-Yau manifold dimensions), the theory can’t make falfifiable predictions. (Even if it did make falsifiable predictions, so what? Lots of speculative theories make predictions, and nobody gives a damn until they are tested and found correct. Why the premature celebration of string?)
(3) String theory leads to pseudoscientific defenses of the subject by its practitioners, who seek to chuck away the carefully checked scientific method just out of egotism. E.g., they claim that because the theory seems to allow spin-2 gravitons and is (allegedly) self-consistent, it is a theory of quantum gravity, and this make’s it a physical theory.
If string people act this way when there is no physical evidence for their speculations, how will they act if data comes in that is ambiguous, or which isn’t compatible with string? Will they just add some epicycles to the theory and claim to be doing science, like Ptolemy did when the epicycle model of the Earth-centred-universe failed to make accurate predictions?
At what point (if ever) will Professor Witten openly confess that string is just a model for speculations like unobservable Planck scale unification and unobserved spin-2 gravitons, and hasn’t any claim to say anything useful about the Standard Model or gravity? Smolin and Lisi at least are skeptical in case they are wrong. String theory by contrast can’t ever be shown to be wrong.
Professor Richard Dawkin’s should entitle his next book “The String Delusion” (or, at least, he should include a chapter about string theory worship in the next edition of “The God Delusion”).
amused,
It’s not that Gattett’s paper is outside the scope of my blog, just that overhyped descriptions of speculative ideas about physics in the media aren’t all worth paying attention to. This is a very unusual one though in the amount of attention it has gotten (I just noticed that it even made it into the Economist), and unfortunately one reason for that is the overly enthusiastic quotes from Lee Smolin.
In this case I unusually find myself in agreement with Clifford Johnson, see his recent comment on his blog:
http://asymptotia.com/2007/03/19/e8/#comment-90563
Just for reference, here is the Economist article. I particularly like how they manage to bring in the recent computation of the KL polynomials of the split real form.
Here’s the final paragraph:
I’m sure this all the fault of string theorists somehow.
Yeah, any idea should stand or fall on its own, the repeated references to string theory are tacky, and also a pretty good warning sign…
To amused (and others), I am still not sure what one can do in this situation. Suppose you are contacted by a media outlet for your opinion about this story. It was clear from the beginning that there is no TOE there, but there may or may not be an interesting observation somewhere in there. If you are overly harsh you will almost certainly packaged as defending your turf against the new genius, and besides Garrett seems like a nice guy… So, what would you say? (in 10 words or less, of course).
Hi Moshe, I recommend just saying the truth. Actually, what you wrote sounds completely fine:
“It was clear from the beginning that there is no TOE there, but there may or may not be an interesting observation somewhere in there.”
Just say that. They might package you in the way you said, but this media stuff is just a silly game and I don’t think you should degrade yourself by trying to play it and saying something other than the truth.
One unfortunate thing at the moment is that the “establishment” viewpoint is being represented by Lubos; specifically, by his blog posting on the topic. Probably because that’s all that journalists find when they search the internet looking for the “establishment response”. And it plays right into the image of nasty arrogant string theorists trying to squash the new genius who’s set to overthrow their evil empire… So it would be good if you and others talked to the press when you can so that the caricature image has a chance of being replaced with the image of serious scientists expressing their dispassionate opinion. You could also suggest non-string people with expertese in this kind of stuff who journalists can talk to for a “neutral opinion”. (Neuberger is one person who comes to mind, no doubt there are quite a few others.)
For what it’s worth, I am sickened by the things that are being written, e.g. in the quote from the Economist article above. It’s so naive and ridiculous.
Best wishes,
David
the problem are not overly enthusiastic statements. the problem is that people pay attention to them instead caring for the facts. this whole story shows so awfully nicely what the internet does to our opinion making processes. there is one first article (in this case the telegraph) which contains almost no information, and shortly later a longer follow up (NewScientist, which was actually well written and balanced). The whole thing is new, it’s hot, and gets copied and mirrored and echoed by a hundred of other sites with declining degree of content and increasing degree of polarization (Stuff string theory!). Almost none of these add anything, or has something new to say. Even if they wanted to, there is no time for that, who cares about Garrett Lisi in two weeks? (Maybe the Germans, I am surprised they haven’t yet picked it up.) What’s journalism coming to? It’s a nonlinear feedback effect, and it will only become worse the more important people think links and traffic to their website is. The actual content of an article just becomes less and less important, it’s not relevant that people actually read it! It’s completely sufficient if the click on the advertisement banner next to the title. Isn’t it obvious that this kind of financing is a complete disaster?