# An Exceptionally Simple Theory of Everything!

1. Nov 6, 2007

### marcus

http://arxiv.org/abs/0711.0770
An Exceptionally Simple Theory of Everything
A. Garrett Lisi
31 pages, 7 figures
(Submitted on 6 Nov 2007)

"All fields of the standard model and gravity are unified as an E8 principal bundle connection. A non-compact real form of the E8 Lie algebra has G2 and F4 subalgebras which break down to strong su(3), electroweak su(2) x u(1), gravitational so(3,1), the frame-Higgs, and three generations of fermions related by triality. The interactions and dynamics of these 1-form and Grassmann valued parts of an E8 superconnection are described by the curvature and action over a four dimensional base manifold."

This paper is visually a treat.

Too bad i can't print it out in color.

=========UPDATE==============
In post #7 here, Christine tells us that Bee has a discussion of quantum E8 theory at her blog:
http://backreaction.blogspot.com/2007/11/theoretically-simple-exception-of.html

Last edited: Nov 7, 2007
2. Nov 6, 2007

### starkind

Thanks, Marcus. I was hoping to find a link to this paper. Congrats, Garrett

Last edited: Nov 7, 2007
3. Nov 6, 2007

### marcus

first, it is in part understandable.
many people here at PF could read it and get something out of it

second, I get a funny feeling in my gut reading it----it hits me that it could be right.

but most importantly, I gather, it is predictive. there are no free parameters to fudge around. you can unambiguously derive testable quantities. so it is unambiguously right or wrong---clear and forthright either way.

So I am curious to know, is numerical computation at all applicable? And if so, what kind of computing power would it take to derive some new predictions from this ToE?
Dan Christensen at University of Western Ontario has shown an interest in using the supercomputer there to calculate stuff from QG models---spinfoam and other.

what kind of thing might one be able to predict, either by numerical or analytical means, or both, from the ToE?

4. Nov 6, 2007

### garrett

In Morelia I asked Dan Christensen what he thought about the prospect of calculating 10j symbols for an E8 spin network, and he said he found it terrifying. Rightfully so.

This theory is either very right or very wrong -- it could go either way. There are still a few things I don't understand about it, so it's premature to make predications with any confidence yet. But the predictions will come, and make it or break it. It aint over 'till the LHC sings.

5. Nov 7, 2007

### jal

I am remembering the work done by Chris Quigg and The Double Simplex http://arxiv.org/find/hep-ph/1/au:+Quigg_C/0/1/0/all/0/1 and the work done by Tony Smith http://www.valdostamuseum.org/hamsmith/goodnewsbadnews.html [Broken]

Good luck Garrett! With the availabilities of the new computer programs, you should be able to communicate this model better than your predecessors.

Last edited by a moderator: May 3, 2017
6. Nov 7, 2007

### marcus

Garrett, two questions

To derive predictions will it be necessary to do awesome numeric feats like computing E8 10j symbols? (I know you said you had a few more things to understand before discussing this so it probably is not a fair question.) Or will there be some relativity cheap easy predictions and if so what might they look like?

You mentioned a handful of unobserved particles. Where, in the article, are they listed? Can one speculate anything about what they might be like? Could they be candidates for solving any of the outstanding comic puzzles? [sic]

And the third question, of course, is will you be snowboarding in the Sierras this winter?

7. Nov 7, 2007

### ccdantas

Congratulations to Garrett, it's a beautiful paper and it's science. It can be right or wrong.

Bee over at her blog makes some considerations on it.

I wish Garrett all the best with his work!

Christine

8. Nov 7, 2007

### ccdantas

And BTW I would attempt those computer calculations myself with the machinery available here, if I only knew how to do them! I'd need some time to understand Garrett's work in order to build up the programs, etc. I suppose one would need to run the calculations in a high performance computing environment (e.g., a beowulf cluster).

Christine

9. Nov 7, 2007

### garrett

I think burly spin network calculations will only be necessary for figuring out what's going on down at the Planck scale. Standard QFT should be suitable for figuring out how couplings and masses run at lower energies. Predictions... there are twenty or so constants in the standard model I've got my eye on...

This is an "all or nothing" kind of theory -- meaning it's going to end up agreeing with and predicting damn near everything, or it's wrong. At this stage of development, it could go either way.

Sure, I talk about them on pages 21 and 22. They're weakly interacting colored scalar fields. These seem like a decent dark matter candidate. But, as I said, this theory is still under development and I can't currently make predictions with any confidence.

I published the paper because things were beginning to look too good to just keep working on it on my own.

Three times a week, starting as soon as we get some snow. And I brought some kites over from Maui too, so I'm looking forward to trying some kite-snowboarding. :)

10. Nov 7, 2007

### garrett

Thanks, jal. I think Tony has a lot of things right, and I got a lot of good hints from his stuff. I hadn't seen Chris Quigg's work -- it looks interesting and I'll bet it matches up with E8 in a lot of ways.

Last edited by a moderator: May 3, 2017
11. Nov 7, 2007

### garrett

Thanks Christine. Sabine has written a very nice overview.

I use Mathematica a lot, running on my mac. I nearly melted a hole in my dining room table running the calculations to produce this movie:

http://deferentialgeometry.org/anim/e8rotation.mov

High powered computing isn't necessary for playing with the basics.

12. Nov 7, 2007

### marcus

Here's the link to Bee's discussion
http://backreaction.blogspot.com/2007/11/theoretically-simple-exception-of.html

A point that comes out there, as I would interpret it, is that Garrett's "quantum E8 theory" requires a Lambda that is 16 orders of magnitude larger than observed but this could actually be a plus.

Bonanno Reuter's recent paper says Lambda true value, what it is at the UV FIXED POINT, before it runs down with decreasing energy and expanding scale, is in fact much larger than what we observe, and this, Bonanno Reuter say EXPLAINS INFLATION. Heh heh. They could be right!

Several of Reuter's papers say this, but here is the Bonanno and Reuter link, for one:
http://arxiv.org/abs/0706.0174

So assuming that's right, if you have a FUNDAMENTAL theory that determines a value of Lambda, then you want the determined fundamental value to be very large.

Apparently this idea is floating around and is shared by others besides the immediate Asymptotic Safety bunch. So we don't have to pin it on people like Percacci and Reuter if we don't want. But Garrett cites them lightly for some reason in his paper, so perhaps they have his blessing. An associate of Percacci, named Nesti, is mentioned in the acknowledgements.

I think it would be really great if some fundamental theory, like Garrett's, would peg the cosmological constant really high and in agreement with what shows up at the Asymptotic Safety people's fixed point. It would harmonize early inflation with late acceleration and make sense generally of the whole expansion history.

Here is Garrett's comment about the large Lambda, that he made a few minutes ago at Bee's blog:
http://backreaction.blogspot.com/2007/11/theoretically-simple-exception-of.html#c4837564169156800942

At 12:16 PM, November 07, 2007, Garrett said...

bee:

Yes, at first I considered the large value of the cosmological constant in this model to be a worrisome bug. But now this idea is in agreement with current theories of a large cosmological constant at high energy (ultraviolet fixed point) running to the tiny value we experience at low energies. So the bug now looks to be a feature...

Last edited: Nov 7, 2007
13. Nov 7, 2007

### shoehorn

In the interests of balance, we should probably point out that Lubos has savaged the paper.

14. Nov 7, 2007

### garrett

Lubos' post is a hoot!

First he makes two statements that are blatantly wrong, and uses these to justify saying there's no physics in the paper. Then he attacks the physics in the paper. Heh.

His only rational attack is based on the Coleman-Mandula theorem, the abstract of which he kindly provides a link to, but evidently didn't read, since the first assumption of the C-M theorem is stated there in the abstract, and doesn't apply in the case at hand, as stated in the paper. The only other arguments he employs are ad hominem, based on my association with other non-string researchers who I am proud to call colleagues.

I couldn't have asked Lubos to write a more helpful critique, as it fails in its goal of tearing down the paper, while confirming just how different this E8 theory is from string theory.

15. Nov 7, 2007

### jal

Huuummmm!!!...Can I assume that your are saying that the structure (E8) is scale independent?
The scale would come from the inputs?
jal

16. Nov 7, 2007

### Hans de Vries

Hi, Garrett.

related matrix (2.4)

$$\left(\begin{array}{ccc} -\sqrt{1/3},& -\sqrt{1/3}, & -\sqrt{1/3} \\ -\sqrt{1/2},& +\sqrt{1/2}, & 0 \\ -\sqrt{1/6},&-\sqrt{1/6},& \sqrt{2/3} \end{array}\right)$$

and the tribimaximal matrix for neutrino mixing? see here (eq:4)

http://arxiv.org/PS_cache/hep-ph/pdf/0606/0606024v1.pdf

Which can be written as a tetrahedral symmetry:

$$\left(\begin{array}{ccc} z_1,& y_1,& x_1\\ z_2,& y_2,& x_2\\ z_3,& y_3,& x_3 \end{array}\right)\ =\ \left(\begin{array}{ccc} \sqrt{1/3},& \sqrt{2/3},& 0\\ \sqrt{1/3},& -\sqrt{1/6},& +\sqrt{1/2}\\ \sqrt{1/3},& -\sqrt{1/6},& -\sqrt{1/2} \end{array}\right)$$

They are the same except for a transpose, a coordinate swap

Regards, Hans

17. Nov 7, 2007

### garrett

Hi Hans,

Yes, Carl just pointed this out for me earlier today. The transpose and coordinate swap are easy to accommodate -- it's the same matrix, geometrically. This matrix rotates a cube such that two opposing corners line up on an axis. In the paper I'm using it to embed the su(3) root system in a so(6) subalgebra of E8. The fact that this "tribimaximal matrix" may relate neutrino masses is fascinating! It will almost certainly play a role as this E8 theory develops -- this matrix is used in conjunction with a triality rotation between generations.

All along, while working on this stuff, my feeling grew stronger that this theory is much too large for me to work on alone. There are pieces, like this one, that will fit in ways I didn't even know about. I'm very happy now that others are also excited about it and working with these ideas.

18. Nov 7, 2007

### garrett

I'm not sure what you mean by "inputs."

19. Nov 7, 2007

### jal

I should have specified/said "minimum length".

20. Nov 7, 2007

### garrett

Ah, OK. I don't have anything to say about a minimum length.