Garrett's article in SciAm December issue

[marcus]

Does anyone have a link to an online version?

I only get a couple of paragraphs from the SciAm link at Woit's blog:
http://www.math.columbia.edu/~woit/wordpress/?p=3292

Anyone seen it? Know what it covers (besides latest model E8 unification)? It's called *A Geometric Theory of Everything*.

The article is co-authored with someone at UC Irvine. It most likely has merit because pitiful moaning was heard in the comments at Woit's blog: "Oh dear lord, not again!"

The moaner recently bailed out of string theory (after 6 years postdoctoral) and took an attractive science-policy internship in government.
http://www.science.tamu.edu/articles/681

 

[sbrothy]

Dont know if the link was added later but it's there on Woit's page:

http://www.scientificamerican.com/article.cfm?id=a-geometric-theory-of-everything

EDIT: Oops. never mind. You have to pay for it as usual.

 

[MTd2]

Garrett Lisi gave a talk with the same title of this paper last month. The slides are available on his website. Probably, there is nothing new and this is just about his latest paper...

 

[negru]

I know people here get really excited about anything non stringy, but SciAm, Lisi and Weatherall, seriously? Look, many young students come to this forum to learn about physics, and to get an idea of what goes on in research. They are very easily influenced by what they read. I'm fine with the general anti-string bias, but SciAm, Lisi and Weatherall?

I have no problem with those guys working on whatever they want, but seriously Marcus, think of the children!

 

[atyy]

I know people here get really excited about anything non stringy, but SciAm, Lisi and Weatherall, seriously? Look, many young students come to this forum to learn about physics, and to get an idea of what goes on in research. They are very easily influenced by what they read. I'm fine with the general anti-string bias, but SciAm, Lisi and Weatherall?

I have no problem with those guys working on whatever they want, but seriously Marcus, think of the children!

Yeah, unfortunately it's ptrobably not anti-string enough. If it were more anti-string like Smolin's book, more people would see how stupid the anti-string stuff is.

 

[MTd2]

Everyone loves the underdog! But I cannot understand anymore why this thing with Garrett. He is not an underdog anymore thinking proportionally to the level of attention that his theory gets :grumpy:

 

[negru]

It just makes me wonder why these people associate (smolin, lisi and now this Weatherall). I've heard that the enemy of my enemy is my friend, but shouldn't bad physics be everyone's enemy?

 

[MTd2]

I really don't think this is a case of bad physics but of over publicity. His model is OK with 1 generation and it is up to him to fix that and he pointed several ways to try to fix that. He hasn't published on these alternatives. But the problem it is that, despite of being an embryonic state, the theory is still being called by himself a TOE!

 

[negru]

It works for one generation, really? So he has finally learned of the difference between fermions and bosons? And how exactly does renormalization work in his theory?

 

[suprised]

This is as amazing as depressing.

 

[MTd2]

So he has finally learned of the difference between fermions and bosons?

Saying he doesn't know the difference between fermions and bosons is being too dismissive. He always knew. And this is why it looks like being dishonest. He knows that the problem is to implement that within E8 as he wants. To make that work he had always to use an extra group structure, SO(8), which is the only simple lie group with triality, to rotate fermions to mirror fermions to bosons and at the same time rotate between the 3 generations.

There isn't simply enough structure in E8, any kinds, to keep track of all labels of both SO(8). Lately, he has been looking for a geometric set up such that E8 could live, in 4d, and somehow make those trialities appear naturally. But he still didn't say what structure.

The renomalization is supposed to be asymptotic safe, but non renormalizable.

 

[marcus]

Lots of talk about "enemy" and "anti-string" in this thread. I don't recall Garrett ever expressing hostility to string. Always seems modest, undefensive, and diplomatic in references to other people's work. Can anyone point to some exceptions?

To me it seems to have been the other way round. Garrett's work has been attacked by Distler (a string theorist).

To what kind of person is a rival automatically an enemy?

 

[negru]

Garret's work wasn't "attacked" by Distler, it was dismantled by him

 

[marcus]

Whatever: attack, criticize, dismantle.

I haven't commented on Garrett's SciAm article because I haven't seen it. I ASKED about it: does anyone have a link, can anyone say what-all it covers.

(Personally I think it would have great educational value if the SciAm article introduced Garrett's computer-graphic "elementary particle explorer". Call it an educational game or toy. You set up multidimensional visualizations of symmetries and find particles as points in the visualization. There may be other aspects to note: maximal tori in Lie groups, or just a better understanding of Lie groups for wide audience. I'm not a fan or regular reader of SciAm but it does have really good articles on occasion---stuff with long-term usefulness.)

We will just have to see what the ultimate value/usefulness of Garrett's work is, just as with any other unproven physical theory. You can't always tell what will come out of something or what the utility will be. Maybe you mostly can't tell.

One reason I asked about Garrett's SciAm article is that I've recently sensed a slight veering or change of editorial focus at SciAm. The big thing for me was that now, in November 2010, they posted last year's STEVEN WEINBERG VIDEO, which gives his overview of particle physics (with some interesting remarks about string theory at the end, in response to a question.)

It is a wonderful survey of particle physics, by a master, to a conference of SCIENCE WRITERS. The annual conference of the people who do the communicating---the national science writers guild. I remember watching it at the time (October 2009!)--he was feeding them real clarity, with excellent slides, right at the intelligent layman level.

What impressed me is that now, after over a year (!), SciAm is finally making a news item about this Nobelist's superb overview of particle physics. Does anyone else find this interesting. I think it goes along with their publishing Garrett's piece, but you wouldn't know that unless you had watched the Weinberg video all the way through to the end.

 

[negru]

Right, I forgot, criticizing string theory is noble and desirable, but criticizing crackpots is just string theory picking on the little guys.

 

[marcus]

I guess my basic interest is in reporting/analyzing. Current developments in basic physics.
Part of the "news" is what Steven Weinberg says. I think he is fair and gentle in how he puts things---often takes great care to be kind---and has built up wisdom and perspective over the years. You can learn by paying close attention to nuances etc.
Part is also a shift in focus or editorial policy at SciAm, which I'm not sure about, just straws in the wind.
Here is the video at SciAm.

http://www.scientificamerican.com/p...=physics-nobel-laureate-steven-weinb-10-11-15

That science writers' conference happened in October 2009, why is their report dated 15 Nov 2010? Maybe means nothing.

Anyway, if you have read my posts you will realize I have nothing against string theory itself. I don't criticize it. (Last comment I made on the mathematical theory itself was to praise it as mathematics, call it beautiful intriguing whatever. Tom's thread.)
String theory is not an interesting issue for me. However the behavior of string practitioners and their hangers-on is an issue.

Also the historical shift that has been happening since around 2003 or 2005. That is something that I think should be reported as accurately as possible. If it sounds like a criticism, that's tough.

 

[negru]

Yes, there has indeed been a slight veering or change of editorial focus at SciAm, for at least a couple of years now. It is now focusing exclusively on truly retarded physics and science policy articles.

 

[flatcp]

Anyway, if you have read my posts you will realize I have nothing against string theory itself. I don't criticize it.

Dude... You should have been a politician!

 

[marcus]

Dude... You should have been a politician!

Thanks for the compliment, but you quoted me out of context...Dude.

I guess my basic interest is in reporting/analyzing. Current developments in basic physics.
Part of the "news" is what Steven Weinberg says. I think he is fair and gentle in how he puts things---often takes great care to be kind---and has built up wisdom and perspective over the years. You can learn by paying close attention to nuances etc.
Part is also a shift in focus or editorial policy at SciAm, which I'm not sure about, just straws in the wind.
Here is the video at SciAm.

http://www.scientificamerican.com/p...=physics-nobel-laureate-steven-weinb-10-11-15

That science writers' conference happened in October 2009, why is their report dated 15 Nov 2010? Maybe means nothing.

Anyway, if you have read my posts you will realize I have nothing against string theory itself. I don't criticize it. (Last comment I made on the mathematical theory itself was to praise it as mathematics, call it beautiful intriguing whatever. Tom's thread.)
String theory is not an interesting issue for me. However the behavior of string practitioners and their hangers-on is an issue.

Also the historical shift that has been happening since around 2003 or 2005. That is something that I think should be reported as accurately as possible. If it sounds like a criticism, that's tough.

I rarely comment on string theory itself, but my last several comments have been positive. You mustn't confuse the theory with the theorists, and the historical decline of the program.

The decline of the string research program (real people, publications, jobs, careers) is a serious objective fact. Personally I'm interested in other things and rarely mention it, but I think it should be reported. It would be interesting, I guess, to understand better why it's happening. Steven Weinberg's talk to the science-writer's conference actually shed some light on that.

Weinberg BTW is obviously not an "enemy" or "critic" of the theory. He had some very nice appreciative things to say about it. And he has been a major supporter of the program in the past. Used to do string research himself. You should listen to the last 5 or 10 minutes of the video, if you haven't already.

 

[marcus]

I think it's silly that string should enter into the discussion in this thread. It's about Garrett's article in the December 2010 SciAm.
Whoever dragged string into this discussion must have a polarized "for-or-against" mentality. Interpreting everything on a simple level of for or against their pet idea.

Not what science, or mathematics, is about. Garrett's approach to particle symmetries and classification must be interesting to mathematicians and must be seen as having potential for further exploration. I can't think of any other way to interpret the fact of the Banff workshop.

It was organized by some of the world's top mathematicians. Joe Wolf, David Vogan, and others. For people working in the unitary representation of Lie Groups. I don't recall any physicists being invited besides Percacci and Garrett. If anybody remembers others, please correct me on this. I think to a large extent they were taking stock of a recent advance in understanding the structure of E₈.

Banff is the North America version of Oberwolfach. If some development in mathematical physics is seen to have interest and major growth potential they hold a workshop on it. Also significant new developments in other fields of mathematics. Oberwolfach is the number one venue, and Banff comes in second.

 

[atyy]

The article is co-authored with someone at UC Irvine. It most likely has merit because pitiful moaning was heard in the comments at Woit's blog: "Oh dear lord, not again!"

The moaner recently bailed out of string theory (after 6 years postdoctoral) and took an attractive science-policy internship in government.
http://www.science.tamu.edu/articles/681

I think it's silly that string should enter into the discussion in this thread. It's about Garrett's article in the December 2010 SciAm.
Whoever dragged string into this discussion must have a polarized "for-or-against" mentality.

...

 

[suprised]

Look, the mathematicians are interested because E8 is sweet and has been of interest since ever. This does not imply that Lisi's model makes any sense at all physically. Actually everyone in the field knows that this model is wrong on several counts and beyond repair, conceptually and technically. This is not a matter of modifying it a bit here and there until it works. Obviously there hasn't been any progress on this since it came up, and there are good reasons for that (or did the "assigning of particles" exercise discussed here in the past lead to anywhere? A status report would perhaps be useful...)

It is sad if not scandalous that despite of better knowledge, this article has been published in SA. As if things haven't been bad enough, eg when Smolin advertized Lisi as a potential successor of Einstein, next to Hawking and Witten and his own (Ex?-)wife:
http://discovermagazine.com/2008/mar/13-e-nste-n

 

[marcus]

Look, the mathematicians are interested because E8 is sweet and has been of interest since ever...

That's certainly true! Doesn't it go without saying? And their interest certainly does not prove that Lisi's model is physically right. As for "making no sense at all" or putatively leading nowhere, contributing nothing to our understanding, I don't think anyone can say at this point (present company included.)

I doubt the work should be dismissed out of hand. Same way with Roberto Percacci's work, which I think was in part stimulated and motivated by Lisi's.

It is sad if not scandalous that despite of better knowledge, this article has been published in SA.

I see. You are saddened that Lisi got an article in SciAm. I don't know what to say in response. I haven't seen the article and I'm not a regular reader of the magazine. It is hard for me to think of it as doing any harm. It is not as if Lisi was attacking anyone, or that his publishing an article is against anyone's interest, is it? Apparently the editors of the magazine thought the readers would like the article. It's not as if SA were a peer-review journal. I don't see how it can be "sad, if not scandalous". I look on it more as a sign of changes which I want to understand.

However I respect your different point of view and sympathize with your sadness.

 

[Fra]

Look, the mathematicians are interested because E8 is sweet and has been of interest since ever. This does not imply that Lisi's model makes any sense at all physically.

I think string theory is also pretty sweet ;-)

/Fredrik

 

[suprised]

I think string theory is also pretty sweet ;-)

Indeed, as it contains E8 and a million of other things as well. But the relevant difference is that is makes sense physically.

 

[MTd2]

his own (Ex?-)wife

Huh? I didn't see Dina Graser there...

 

[Fra]

Indeed, as it contains E8 and a million of other things as well. But the relevant difference is that is makes sense physically.

I think your last scentence got scambled, but otherwise I think we can agree ;)

/Fredrik

 

[S.Daedalus]

Indeed, as it contains E8 and a million of other things as well. But the relevant difference is that is makes sense physically.

Well, or it can be made to make sense, at least. As you well know, there are any number of difficulties with what one might call 'bare-bones' string theory that have to be gotten rid off using various means -- the introduction of supersymmetry, compactification of extra dimensions and so on -- in order to get the theory to apply to the physical world in any sensible way. This often includes positing new phenomena and then pushing them out of the range of current observation; one could follow a strict philosophy in which such 'trickery' would be frowned upon, a viewpoint from which one would have to discard string theory on the basis on not making any sense physically. Of course, from another viewpoint, these are just the theory's predictions.

The question is, can Lisi's theory perhaps be 'made to make sense' in a similar way? There's a good possibility that it can't, but that doesn't necessarily mean that one should discard the whole direction of research on that possibility alone. Obviously, there are certain people willing to invest time and resources into following what to them at least seem to be promising hints of something that could be connected to physical reality within E₈, just as there once were some people willing to investigate the forbidding structures of strings on the basis of its promise despite its problems, and that's entirely their call to make -- nobody's forcing you to go along with it, or even constrain your criticism in any way.

 

[grosquet]

I stopped subscribing to Scientific American because of the plethora of articles describing multiple universes, clashing branes, extra dimensions & other fantastic notions.

 

[marcus]

I stopped subscribing to Scientific American because of the plethora of articles describing multiple universes, clashing branes, extra dimensions & other fantastic notions.

:rofl:

exactly! Who knows, maybe as the string program loses prestige the editors will reduce SciAm's speculative physics content and move back towards firmer ground.

They still have an occasional article with real educational value, like Charley Lineweaver's Misconceptions about the Big Bang. It's absolutely essential, hard-nose, zero-fantasy, straight dope about cosmology. No Brian Greene literary analogies---just knocks off popular misconceptions one by one.

But over the past ten years there has been rather a glut of articles along the lines you indicated.

 

[garrett]

Hey Kids,
Thanks for making note of this Scientific American article here on Physics Forums. Looking through the comments...

Does anyone have a link to an online version?

Unfortunately, SciAm does not make these articles available for free -- one has to pay five dollars or so to download the pdf, or pick up the magazine. I suppose magazine editors do need to eat. However, Jim and I did negotiate to be able to put our own version of this article on the arxiv in a few months, which we will do.

Garrett Lisi gave a talk with the same title of this paper last month. The slides are available on his website. Probably, there is nothing new and this is just about his latest paper...

This is true of the technical material. But much of the popular material has been updated, especially the weight diagrams for various theories. These diagrams, such as for the electroweak model and for GUTs, are really cool, and I'm excited to see them in SciAm. Also, we've done the best we could describing the geometry of Lie groups, fiber bundles, and unification in a way that's precise but accessible.

Yeah, unfortunately it's ptrobably not anti-string enough.

I tried to avoid string theory -- the point of the article was to lay out an alternative unification effort.

Everyone loves the underdog! But I cannot understand anymore why this thing with Garrett. He is not an underdog anymore thinking proportionally to the level of attention that his theory gets :grumpy:

This is somewhat true. But I was an underdog.

I really don't think this is a case of bad physics but of over publicity. His model is OK with 1 generation and it is up to him to fix that and he pointed several ways to try to fix that. He hasn't published on these alternatives. But the problem it is that, despite of being an embryonic state, the theory is still being called by himself a TOE!

This is also true, and I have personally always tried to make it clear that this is just a prospective and developing ToE, not a completed one. Unfortunately, it's editors that get to choose article titles.

It works for one generation, really? So he has finally learned of the difference between fermions and bosons? And how exactly does renormalization work in his theory?

I will answer this even though it's a troll. Yes, it works for one generation, as described explicitly here: http://arxiv.org/abs/1006.4908
I expect renormalization to work similarly to how it works in Y-M QFT, including asymptotic safety for gravity. I see that MTd2 has answered as well.

Actually everyone in the field knows that this model is wrong on several counts and beyond repair, conceptually and technically.

It is true that most people in the field think this, largely thanks to the effort of Distler and Motl. The "several counts" that I recall were:
1) Impossible mixing of bosons and fermions.
This was agreed on by mathematicians to be possible, such as here: http://golem.ph.utexas.edu/category/2008/05/e8_quillen_superconnection.html
2) Violation of the Coleman-Mandula theorem.
The relevant novel loophole in the theorem was described here: http://arxiv.org/abs/0803.0303
3) Even one generation of fermions does not fit in E8.
This misconception, introduced by Distler and Garibaldi, is directly addressed and cleared up here: http://arxiv.org/abs/1006.4908
It was one of the more enjoyable experiences of my life to see Skip go down in flames over this issue in Banff. What counts remain that say the theory is wrong? That mirror fermions have almost been ruled out by experiment? Is it just me, or does that seem not the same as "E8 Theory can't work"?
4) The theory does not accommodate three generations of fermions.
This issue was identified (by me) as a problem from the beginning, with a potential solution coming from triality. I had lost hope in the theory myself a bit over this issue a year ago, but with some insights gained at Banff I now think triality will indeed work. It's tricky though, and I'm working on that now.

The question is, can Lisi's theory perhaps be 'made to make sense' in a similar way? There's a good possibility that it can't, but that doesn't necessarily mean that one should discard the whole direction of research on that possibility alone. Obviously, there are certain people willing to invest time and resources into following what to them at least seem to be promising hints of something that could be connected to physical reality within E₈, just as there once were some people willing to investigate the forbidding structures of strings on the basis of its promise despite its problems, and that's entirely their call to make -- nobody's forcing you to go along with it, or even constrain your criticism in any way.

This comment from Daedalus is insightful enough that it bares repeating, and I agree completely.
-Garrett

 

[atyy]

Hey Garrett, sorry for my comment. It wasn't aimed at you, though it did come out this way.

 

[marcus]

Congratulations on both the events at Banff and SciAm article!

 

[arivero]

4) The theory does not accommodate three generations of fermions.
This issue was identified (by me) as a problem from the beginning, with a potential solution coming from triality.

If triality fails you, look for some SU(5). It is possible to build three generations into SU(5), the 5x5bar produces a 24, and the 5 x 5 + 5bar x 5bar produces a 15 + 15bar. You fit all the leptons in the 24, and all the quarks of a given colour in the other (yep, that is a 12 + 12 bar; no idea what to do about the other three of the 15.).

 

[Kevin_Axion]

Awesome work garrett! I found it quite odd that Garibaldi and Distler would try to deform your idea since people usually do this when they find that funding isn't being used effectively. Keep on working, E8 is very beautiful and I wouldn't be surprised if your work has something deeper to say about the Universe.