Explicit embedding of gravity+Standard Model in E8 (new Lisi paper)

[MTd2]

Group photo is out.

Garrett = Bruce Willis!

http://temple.birs.ca/gallery/10w5039/groupphoto

 

[marcus]

Garrett and Joe Wolf are the two that happened to be wearing sunglasses. The others are squinting in the bright Canadian Rockies sunlight.
Everybody is grinning like they have been having a good time. (The math must have been good, only thing that would make 30 mathematicians grin like that.)

 

[rhody]

On garrett's twitter (public page):

Oh, and Hopping Fish admitted, grudgingly, that the algebra of gravity and the Standard Model, with one generation of fermions, is in E8.

If this is an inside joke, are we speaking of the now infamous, Showdown at High Noon, Jacques Distiler, or some other as yet under cover conference attendee ?

Rhody...

 

[marcus]

On garrett's twitter (public page):

Oh, and Hopping Fish admitted, grudgingly, that the algebra of gravity and the Standard Model, with one generation of fermions, is in E8.

If this is an inside joke, are we speaking of the now infamous, Showdown at High Noon, Jacques Distiler, or some other as yet under cover conference attendee ?

Rhody...

http://en.wikipedia.org/wiki/Garibaldi_(fish )

 

[MTd2]

Isn't Distler the guy with grey beard at the same row of Garrett?

http://temple.birs.ca/gallery/10w5039/groupphoto

 

[marcus]

Rhody, as far as I know (I haven't kept track of details and have no source of info besides links that you and MTd2 provide) Jacques was not supposed to attend the workshop. There was no "high noon" with Garrett and Jacques. That was only a kind of spin sensation that we got from Distler's blog. Garrett did not mention it or play it up after it was mentioned.

The serious math content is what you could think of as subjecting the Lisi E8 idea to scrutiny and stress-test. This was meant to include an associate of Distler, named Skip, giving a paper. If you look at the schedule of talks you will see the one.

As far as I can tell what they did at the Banff workshop is very much in the age-old tradition of high-level mathematics. After an idea has gotten notice, the experts in that special subject will get together in seminars/workshops and really grill it and probe it and check it out. Sometimes when somebody thinks he has proven a theorem, his colleagues will find a hole or a gap in the proof, and often he takes a few more months and is able to fix it, and maybe finally the theorem may pass muster. That's how they work, oftentimes. You've probably seen examples of this, like, "mathematician's culture" operating. It is really good that Lisi E8 idea is getting this kind of serious traditional reception.

Anyway this is how I interpret the little news I have. I think it is extremely constructive to have workshop with really top people looking carefully at the idea. And who knows the ultimate outcome? There are different degrees of generality and applicability to math models and to theorems. In the end nobody loses. Knowledge is advanced for everybody.

The twitter message was funny!

It sounded like a reference to an Inuit folktale.

 

[marcus]

Isn't Distler the guy with grey beard* at the same row of Garrett?

http://temple.birs.ca/gallery/10w5039/groupphoto

MTd2, I didn't see any mention of Distler being there. Am I missing something? Was he on the list of participants?

I never saw Distler so I wouldn't necessarily be able to recognize him in a group photo. I've just seen random snapshots like this:

http://www.hep.princeton.edu/~mcdonald/nov1702/
http://zippy.ph.utexas.edu/directory.html

In any case Distler is not the important person here. The guy who was supposed to deliver the antithesis is a mathematician called Skip Garibaldi. He is the one we should be looking for in the picture. Distler is just an extraneous string personality with a blog, in this situation. He might not even have been at the workshop.

Here is Skip:
http://www.mathcs.emory.edu/~skip/home/Skip_Garibaldi.html

(young, full professorship in the math department, with a named chair "Winship distinguished professor", looks like a bright happy camper---good person to have doing your constructive crit, from the looks. not a mean-spirited old snark-puss.)

Do you see Skip in the group picture?

Here's my wild guess. If you start at Garrett, in front and to our left is this guy with a yellow shirt, and in front of him and to our left is this young guy in a pale blue work shirt. He is grinning---a big row of front teeth. Draw a straight line from Garrett, through the head of the guy with the yellow shirt, to (who I think is) Skip.

*Actually the guy you mentioned, in the same row as Garrett, with the grey beard, could be David Vogan (MIT math department) co-organizer of the workshop, with Joe Wolf (UC Berkeley math department).
http://www.boston.com/news/globe/he...07/03/26/his_mind_is_on_the_eighth_dimension/
Vogan is one of the giants of Naughties mathematics. His team analyzed the structure of E8 and the computer printout would have covered the Island of Manhattan, maybe even two times over. It was a big computer job. "Naught" means zero and "Naughties" is slang for the 2000s, the decade that we are just barely out of. We are now in the "Tens" or "Teens" decade of this century.

http://www.birs.ca/birspages.php?task=displayevent&event_id=10w5039

To my limited ability to view history, this workshop is something of a landmark. Everybody looks happy to be there, including Skip Garibaldi (whose work putting Lisi-E8 on trial will be a valuable contribution however it goes) and Garrett looks well-satisfied.

 

[rhody]

Thanks Marcus for clearing that up, if you click on the link to the picture of the conference again, it enlarges for a good clean view of everyone. I see Skip Garabaldi as you suggest, blue shirt, second row, big white teeth smile, on the left.

Vogan is one of the giants of Naughties mathematics. His team analyzed the structure of E8 and the computer printout would have covered the Island of Manhattan, maybe even two times over. It was a big computer job. "Naught" means zero and "Naughties" is slang for the 2000s, the decade that we are just barely out of. We are now in the "Tens" or "Teens" decade of this century.

I downloaded the http://www-math.mit.edu/~dav/E8TALK.pdf" a year or two ago. Interesting story. I couldn't help but notice a label that keep my interest about the difficulties in deriving the roots for E8. It read in part: "RTFM (beginning on: page 25 of slide presentation)" -> or Read the blanking Manual ! At least they kept their wits and sense of humor about them after taking on this challenge. Look at page 4 of the slide talk (group pic) and second from left is David Vogan I am guessing, and in the Banff pic he would be in the back row second from the right in light blue shirt, beard and glasses.

They dedicated the work to fellow team member: Fokko du Cloux who passed away, November 10, 2006. 1/8/07 9 A.M. Finished writing to disk the character table of E8.

It was a touching story. I am surprised no one posted it on PF. I apologize in advance if they did and I missed it.

That's my story and I am sticking to it. lol.

Rhody...

 

[marcus]

Garrett says he thoroughly enjoyed today's talk by Skip G. Now since the workshop has the whole Wednesday afternoon off, he's going for a hike in the mountains. http://twitter.com/garrettlisi/
(specifically http://twitter.com/garrettlisi/status/17966854102 )
The talk by Skip, 10:30-11:30 local time, was titled: There is no (interesting) ‘Theory of Everything’ inside E8.
I tend to reserve judgment on such headline claims, but it clearly signals the talk's main direction of effort.
After that there was lunch and then the long break for the rest of the day. Garrett gives his third 90 minute talk tomorrow evening after dinner (Thursday 19:30-21:00) concluding the workshop.

 

[marcus]

Funny mountain climbing story more or less realtime via http://twitter.com/garrettlisi/
Roberto Percacci (Asymptotic Safety approach to joining gravity+standardmodel) proposed climbing Mt. Rundle.

==quote==

Just returned from an amazing climb up Mt Rundle with Roberto Percacci. Fantastic day. I'm totally wiped.Me: "So, how high are we climbing?" Him: "3000" OK, looks pretty steep from here, but I think I can do that. METERS! HE MEANT METERS!Twenty feet from home, with my legs like cement, he tells me "yes, I was in a movie about mountain climbing." Nice. Could have warned me.

====
(about 9 hours ago via web, which I guess would have been around midnight local time)

Percacci is the guy standing next to David Vogan at the end of the back row.

 

[BenTheMan]

Is this facebook or is this a forum where people discuss physics?

Because I can't really tell...

 

[atyy]

In any case Distler is not the important person here. The guy who was supposed to deliver the antithesis is a mathematician called Skip Garibaldi. He is the one we should be looking for in the picture. Distler is just an extraneous string personality with a blog, in this situation. He might not even have been at the workshop.

Garibaldi and Distler are co-authors on http://arxiv.org/abs/0905.2658

 

[unusualname]

Is this facebook or is this a forum where people discuss physics?

Because I can't really tell...

I agree, too much fluff going on in this thread. Lisi proposed an embedding of the Standard Model in E8, media went nuts because they had an angle on a "surfer" guy solving the mystery of particle physics, Distler posted a well-reasoned rebuttal which turned out to be pretty much correct. The positive result was a lot of people got interested in E8 and real embeddings again, this conference enables some of the mathematics to be discussed in a proper environment.

Nothing worthy of so much comment really. I didn't see the media going nuts when Connes' proposed a solution to the standard model based on attaching a discrete structure to spacetime, or when Verlinde proposed his entropic model for gravity earlier this year. (Incidentally, I don't see Distler so quick to comment on those ideas in his blog, maybe he's a little wary after getting an earlier argument on CDTs wrong)

I think Jaques Distler is secretly happy about his high profile resulting from the incident, even though he claims otherwise, but he's not just some "extraneous guy with a blog", you may dislike his personality, but his physics/mathematics ability is extraordinary.

If Lisi didn't keep claiming to have the embedding of the standard model he wouldn't get so much criticism either (I think he mistitled his recent paper, even he agrees), he should be happy that his work has aroused so much interest and some real mathematics has grown from it, and I wish him the best of luck.

Still, if those "mirror fermions" show up we'll all have to hail the "surfer saviour" (Distler's term).

Cvitanovic has a nice quote in the http://www.cns.gatech.edu/GroupTheory/index.html of his Group Theory book (p 242): "to a religious temperament, E8 is the great temptress"

 

[dpackard]

If Lisi's theory is unable to produce the three fermion generations, then Garibaldi is correct and the one generation SM embedded in E8 isn't very interesting. So clearly this should be Lisi's future direction if he wants to stick with the E8 idea. So there isn't much of a controversy or disagreement anymore is there (on the physics itself, nevermind the circus surrounding it)?

 

[marcus]

If Lisi's theory is unable to produce the three fermion generations, then Garibaldi is correct and the one generation SM embedded in E8 isn't very interesting. So clearly this should be Lisi's future direction if he wants to stick with the E8 idea. So there isn't much of a controversy or disagreement anymore is there (on the physics itself, nevermind the circus surrounding it)?

That's basically the right kind of statement, except you have the tenses wrong (which misrepresents the present state of knowledge and interest).

Lisi's theory is not a fixed object. So far Lisi's theory only finds one fermion generation. We cannot say, as you do, "Lisi's theory is unable..." we can only say that it "has so far been unable".
The issue is whether the theory is interesting to work on.
We don't know the future of research in mathematical physics.

The basic fact to focus on, at this point, is that some worldclass people think it is interesting enough to have a select workshop on it. These are potential contributors to the theory.
Given the reputations and track record of the people at the workshop, it would be arrogant for any of us to pretend we can call the outcome.

 

[BenTheMan]

The basic fact to focus on, at this point, is that some worldclass people think it is interesting enough to have a select workshop on it. These are potential contributors to the theory.
Given the reputations and track record of the people at the workshop, it would be arrogant for any of us to pretend we can call the outcome.

This is exactly the type of attitude one should have when doing physics.

Hooray for authority!

 

[marcus]

Heh heh
unusualname, you might want to read again the statement of purpose:
http://www.birs.ca/birspages.php?task=displayevent&event_id=10w5039

I was interested to see that Bertram Kostant is one of the participants.
http://www-math.mit.edu/people/profile?pid=136
MIT math faculty 1962-1993, so way emeritus now. Has shown an interest in Lisi-E8. There seems to be a video of his talk at Banff, somewhere at the Banff workshop's website, but I haven't seen it.
Born 1928. He participated in an Oberwolfach workshop last year, so keeps active.
http://en.wikipedia.org/wiki/Bertram_Kostant
I think if Kostant is in the group photo he might be the white-haired fellow in the second row standing just behind the front-row guy in the bright red shirt. Could be wrong about that being Kostant, but sure about the other two.
http://temple.birs.ca/gallery/10w5039/groupphoto?full=1

Key thing is that Lisi E8 has captured the interest of some really top mathematicians. Significant development.

 

[marcus]

... I didn't see the media going nuts when Connes' proposed a solution to the standard model based on attaching a discrete structure to spacetime, or when Verlinde proposed his entropic model for gravity earlier this year...

Neither did I, but so what? Media hooraw is no indication of the real interest of a development. Media didn't pick up on Asymptotic Safety conference last year either: Steven Weinberg, Roberto Percacci. At least not as far as I know.

Or Horava (if you think that is still interesting.)

Or CDT.

Mass media reaction can in some cases be informative about other things and may be worth watching selectively---but I tend to ignore it most of the time.

Banff workshop now is a different kettle of fish. Far more significant than the media fuss of 2 years back.

 

[unusualname]

Heh heh
unusualname, you might want to read again the statement of purpose:
http://www.birs.ca/birspages.php?task=displayevent&event_id=10w5039

I did it says:

blah blah blah
...
A mathematical study of these questions is interesting for its own sake, and may provide some constraints on the structure of the physical theories that can be built using E8.
...
blah

See, clearly just getting the physics angle in for funding purposes

 

[marcus]

http://garrettlisi.com/albums/MtRundle.mov

unusual, from a certain perspective that is a very intelligent interpretation!

It has to do with how math relates to physics. The way the tools progress cannot always be sharply distinguished from the work done using them. I tend to listen up when people like Joe Wolf say something's interesting or may have potential. I participated in a seminar led by Joe Wolf and George Mackey sometime around 1968 as I recall, based partly on Mackey's current work (Induced Representations of Groups and Quantum Mechanics, 1968). It left me with great respect for Wolf, his integrity, his intuitive sense of what was both mathematically and physically interesting. Mackey too of course (he passed away in 2006).

People like that don't have to promise what they don't know for sure, to get funding. They certainly aren't promising anything here. I would tend to interpret the Banff statement in a straightforward way, without any cynical spin. But it all depends on one's background, how one takes things.

http://www.birs.ca/birspages.php?task=displayevent&event_id=10w5039

 

[marcus]

... (I think he mistitled his recent paper, even he agrees), he should be happy that his work has aroused so much interest and some real mathematics has grown from it, and I wish him the best of luck.
...

I think this strikes a good note! In fact I think it is a win-win situation for everybody whatever happens to the theory. I too am (very) happy the workshop took place and wish Garrett and the rest the best of luck.

Just to keep things in perspective, there has been a proliferation of new approaches to quantum gravity and unification, just since 2006.

LQG put on new footing---both the canonical and covariant versions, and the application to cosmology as well.

Asymptotic safe gravity has emerged as a strong research direction--the first major workshop on it was November 2009--applications to cosmology

Causal dynamical triangulations now much more visible since 2006.

Connes NCG, and also Marcolli's recent NCG+LQG paper (Oberwolfach 2010 workshop)

Hermann Nicolai and Chris Meissner's approach to unification (MaxBornXXV 2009 conference)

Verlinde's entropic force gravity (earlier work by Jacobson, Padmanabhan).

Horava's approach (but interest there may have slacked off.)

It is hard to keep track of all the new gambits that are being pursued. And most of these only started having an impact after 2006 or haven't yet really caught on with researchers.

 

[jal]

Re.: Getting funding

Time is running out!

EROEI (energy returned on energy invested)

If they cannot find something SOON, ... its game over.

Governments are bankrupt and will not be able to dig their way out.

The LHC is the last chance to reveal a path to a new source of energy.
jal

 

[dpackard]

Will the gravitons in E8 theory not be plagued by the non-renormalization problems of other quantum gravity attempts?

 

[marcus]

Will the gravitons in E8 theory not be plagued by the non-renormalization problems of other quantum gravity attempts?

Two of the leading QG attempts are Asymptotic Safety and LQG. They do not have "renormalization problems". What attempts were you thinking of?

Interest seems to have waned in some of the others, but I'm not sure it was because of that, they may have had other problems.

 

[atyy]

Will the gravitons in E8 theory not be plagued by the non-renormalization problems of other quantum gravity attempts?

Lisi's abstract says his construction is consistent with Nesti and Percacci's GraviGUT ideas. Nesti and Percacci do hope that some of their problems will be solved by pure gravity being asymptotically safe, ie. non-perturbatively renormalizable. However, I'm not sure whether Lisi is also assuming asymptotic safety of pure gravity.

 

[dpackard]

atyy basically answered my question, sorry I was vague marcus. I was simply referring to the non-renormalization of straight-forwardly quantizing GR (unless it turns out to be asymptotically safe). I was trying to sort out whether Lisi's approach addressed this problem at all since the renormalizability of stringy gravitons is one of the much publicized advantages of string theory.

I noticed on http://www.science20.com/quantum_diaries_survivor/garrett_lisis_new_e8_paper#comments" a lengthy discussion in the comments between Nesti and Motl. Lubos obviously thinks GraviGUT is "foolish" - do his criticisms have any merit? Nesti seems to have held his own as far as the back and forth goes, but I cannot really evaluate the strengths of the arguments made. Something about mixing diffeomorphisms and Yang-Mills groups.

 

[MTd2]

No, they have no merit. You cannot trust him lately, he was even banned from posting on Jacques Distler's blog for not accepting being wrong, intellectually lazy and impolite.

 

[atyy]

I noticed on http://www.science20.com/quantum_diaries_survivor/garrett_lisis_new_e8_paper#comments" a lengthy discussion in the comments between Nesti and Motl. Lubos obviously thinks GraviGUT is "foolish" - do his criticisms have any merit? Nesti seems to have held his own as far as the back and forth goes, but I cannot really evaluate the strengths of the arguments made. Something about mixing diffeomorphisms and Yang-Mills groups.

There's another interesting discussion between Nesti and Distler and some others here:
http://golem.ph.utexas.edu/~distler/blog/archives/002140.html

 

[JollyJoker]

There's another interesting discussion between Nesti and Distler and some others here:
http://golem.ph.utexas.edu/~distler/blog/archives/002140.html

Lubos lays out his arguments http://motls.blogspot.com/2010/07/why-there-is-no-gravigut-symmetry.html" . If I understand correctly, they're basically the same as Distler's.

 

[MTd2]

No, they are not the same. Distler's calculations are clear and correct. The person you mention built a straw man. This post and thread on another physics problem are enlightening and keep that in your mind, since this is a subject that the person you mention worked on for years:

http://golem.ph.utexas.edu/~distler/blog/archives/002199.html#c032759

 

[MTd2]

I just found someone that claims triality of SO(8) as permutation property, just as I said above:

http://www.7stones.com/Homepage/octotut14.html

And he talks about finding using E8, or something embeded in that, since 1999

http://www.7stones.com/Homepage/AlgebraSite/algebra0.html

DAMN

 

[MTd2]

WORKSHOP SLIDES AND VIDEOS ARE OUT!:

http://www.birs.ca/birspages.php?task=eventvideos&event_id=10w5039

http://temple.birs.ca/~10w5039/

 

[arivero]

Given that the SciAm article will force some revisiting to this paper, let me to add my doubt against spin(11,1) or generically against SO(10) unification models: that it does not fit in maximum supergravity with kaluza klein; SO(10) is the symmetry group of the 9-sphere, and thus it invites to 9 extra dimensions.

Or we can stick with maximum sugra plus SO(10) and a bidimensional space time... after all, bidimensional space times are very in the music of string theory and also of other quantum gravity approaches.

In fact I believe to remember, but I am not sure, that the first appearing of E8 in modern theory was by doing dimensional reduction down to tridimensional or bidimensional space time. For GUT theories, the natural unification was only up to E6.