An Exceptionally Technical Discussion of AESToE

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  • #61
How about SO(9)\oplusSpin(9)? Again, this is just for didactic purposes - for someone who wants to be shown how they can get, say, Feynman rules for a theory like this. So far as I can see, there should be a modified BF F4 theory with SO(9) bosons and Spin(9) fermions in which several of your constructions can be carried out.

One thing that had been troubling me was where the uniqueness (no free parameters) comes from. I couldn't follow it down to the phenomenological level. But I guess it's just that the field couplings are determined by the structure constants, and then the masses are determined by the couplings and the Higgs VEVs.
 
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  • #62
f4 and e8

Mitchell Porter asks about f4 = so(8)+(8+8+8)

Here is how I see that:

f4
=
so(8) 28 gauge bosons of adjoint of so(8)
+
8 vectors of vector of so(8)
+
8 +half-spinors of so(8)
+
8 -half-spinors of so(8) (mirror image of +half-spinors)


Therefore, you can build a natural Lagrangian from f4 as

8 vector = base manifold = 8-dim Kaluza-Klien 4+4 dim spacetime

fermion term using 8 +half-spinors as left-handed first-generation particles
and the 8 -half-spinors as right-handed first-generation antiparticles.

a normal (for 8-dim spacetime) bivector gauge boson curvature term using
the 28 gauge bosons of so(8).

If you let the second and third fermion generations be composites of the first,
i.e., if the 8 first-gen particles/antiparticles are identified with octonion
basis elements denoted by O,
and
you let the second generation be pairs OxO
and the third generation be triples OxOxO
and
if you let the opposite-handed states of fermions not be fundamental,
but come in dynamically when they get mass,
then
f4 looks pretty good IF you can get gravity and the standard model
from the 28 so(8) gauge bosons.

Recall that n=8 supergravity etc had problems because
the 12-dim Standard Model SU(3)xSU(2)xU(1)
does NOT fit inside 28-dim Spin(8) in a nice subgroup way.

If you want to make gravity from 15-dim Conformal group so(2,4) by McD-M
then
you have 28-15 = 13 so(8) generators left over,
which are enough to make the 12-dim SM,
BUT
the 15-dim CG and 12-dim SM are not both-at-the-same-time
either Group-type subroups of Spin(8)
or Algebra-type Lie algebra subalgebras of so(8).

If you try to get both the 15 CG and 12 SM to fit inside the 28 so(8),
you see that they do not fit as Lie Group subgroups
and
you see that they do not fit as Lie algebra subalgebras
so
what I have done is to look at them as root vectors,
where the so(8) root vector polytope has 24 vertices of a 24-cell
and
the CG root vector polytope has 12 vertices of a cuboctahedron
and
the remaining 24-12 = 12 vertices can be projected in a way that
gives the 12-dim SM.

My root vector decomposition (using only one so(8) or D4) is one of
the things that causes Garrett to say that I [Tony]
have "... a lot of really weird ideas which I[Garrett] can't endorse ...".

So,
from a conservative point of view, that you must use group or Lie algebra
decompositions,
f4 will not work because one copy of D4 so(8) is not big enough for
gravity and the SM.

Also,
f4 has another problem for my approach:
f4 has basically real structures,
while
I use complex-bounded-domain geometry ideas of Armand Wyler to calculate
force strengths and particle masses.

So,
although f4 gives you a nice natural idea of how to build a Lagrangian
as integral over vector base manifold
of
curvature gauge boson term from adjoint so(8)
and
spinor fermion terms from half-spinors of so(8)

f4 has two problems:
1 - no complex bounded domain structure for Wyler stuff (a problem for me)
2 - only one D4 (no problem for me, but a problem for more conventional folks).

So,
look at bigger groups:

e6 is nice, and has complex structure for me,
so I can and have constructed an e6 model,
but
it still has only one D4 (which is still a problem from the conventional view),

so

do what Garrett did, and go to e8
and notice that
if you look at EVIII = Spin(16) + half-spinor of Spin(16)
you see two copies of D4 inside the Spin(16)
(Jacques Distler mentioned that)
which are enough to describe gravity and the SM.

I think that Garrett's use of e8 is brilliant,
and have written up a paper about e8 (and a lot of other stuff) at

http://www.valdostamuseum.org/hamsmith/E8GLTSCl8xtnd.html

which has a link to a pdf version
(there is a misprint on page 2 where I said EVII instead of EVIII,
and probably more misprints, but as I said in the paper
"... Any errors in this paper are not Garrett Lisi's fault. ...".

I use a different assignment of root vectors to particles etc
I don't use triality for fermion generations,
since my second and third generations are composites of the first,
as described above in talking about f4.

For an animated rotation using Carl Brannen's root vector java applet from

http://www.measurementalgebra.com/E8.html

see my .mov file at dotMac at

http://web.mac.com/t0ny5m17h/Site/CB4E8snp.mov

In it:

24 yellow points are one D4
24 purple points are the other D4

64 blue points are the 8 vectors times 8 Dirac gammas (of 8-dim spacetime)

They are the 24+24+64 = 112 root vectors of Spin(16)

64 red points are the 8 fermion particles times 8 Dirac gammas

64 green points are the 8 fermion antiparticles time 8 Dirac gammas.

They are the 64+64 = 128 root vectors of a half-spinor of Spin(16).

If you watch them rotate,
you can see how they are related in interesting ways.


Tony Smith
 
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  • #63
Coin said:
Hi Cold Winter, you may want to read the ATLAS group's somewhat tortured narrative of exactly how they went about their calculation. The limiting factor turns out to actually be not CPU power, but RAM. Performing the calculation turns out to involve constructing some tables that grow to hundreds of gigs in size, and they found that they essentially had to store the entire table in RAM, as the calculation requires so many more-or-less-random accesses to this table that access times would have been prohibitive had they allowed swapping to disk.

I've looked at the Atlas code. Yes it seems to be all "C", but with a few modules that seem more GUI related. I am perhaps a bit more jaded when it comes to iron than others. For e.g. I have a supplier pawning DDR2 ram for $9.99/GB... that puts 128GB in the $1278 range. Same source has a 16 way SATA2 controller at around $600 and of course, 250GB SATA2 drives are now in the $120 range ( 16X means $1920 ) Motherboards are now in the $1500 range for 4 socket Opterons... that leaves 4 cpus ( AMD has announced 4 core units for 2009 ? ) typically in the $1200/piece range. I figure I can build one H...! of a monster for around $10,698 in todays terms.

In 18 months that could be under $4000... which I think I can swing at that time.

BTW, that's 2Terabytes of disk mirrored and striped, so getting around the other difficulties ( capacity and I/O speed ) noted in that article isn't a biggy. That SATA2 controller at 300MB/sec will be hitting all disks at about 192Mb/sec... which should translate into a run time guesstimate of 11,000 seconds ( <200 minutes? ).

I'm inclined to go with FP math on this so that conversion will double the bandwidth requirement at a bit higher speed. Although I have to check the SSE capability with the 32 bit integers that the Atlas programmers originally used. That could certainly impact the run times in both directions.

In effect, given some time ( and a budget to fit my limited means ) I should be able to hammer E8 quite nicely. Certainly for much less than what the LieGroup are talking about.
 
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  • #64
mitchell,
I don't want to go too far with tangents like so(9)+9 because the thread will get confusing. But the modified BF setup in the paper is a very adaptable way to take algebras like this and get models with bosons and fermions. What you said about the couplings (from the structure constants) and the masses (from the Higgs VEVs) is correct.

Hi Tony,
Welcome back to PF. I think it's great that you and several other people have taken this E8 idea and run with it. It's good to have people searching in all different directions. In the paper, I tried to use a bare minimum of mathematical structure, but it's possible a little more will be needed in order to solve the generation question. Even if I can't solve it minimally, it will be satisfying to me if others take the mathematical ideas and tools in the paper and use them in their own models.
 
  • #65
kneemo said:
To see this in terms of derivations, take a look at Tits' construction on pg. 49 of Baez's http://xxx.lanl.gov/abs/math/0105155v4". Also, see pg. 41 where another g2 shows up in the f4 decomposition.

Thanks kneemo for the reference. I didn't realize it before but there's
quite a bit on the algebra decompositions in Baez' paper; he just put
towards the end of the paper...long after the octanion setting has worn
me out. The use of quaternions (and octanions, clifford algebras,...)
is probably intersting in its own right and I think it helps if you
have a deep pool of understanding of such things that you can draw
on to clarify things. Unfortunately I don't, so they end up obscurring
rather than clarifying things for me. For the sake of what's in Garrett's
paper, Lie algebras over the complexes (or reals) is enough.

What I was (and am still) looking for is an explicit description of these
decomposition...something I can run explicit calculations with. I have such
a thing for the f4/d4 : f4=28+8+8+8 case (see an earlier post in this thread);
I'm looking for the e8/(d4+d4) and e8/(g2+f4) equivalent. Something like :

(1)a basis for e8; Cartan basis is good, Chevalley even better since that's
what I have already. The structure constants of e8 in either of these
basis are well known and are accessible for my calculations.

(2)another basis of e8 in terms of (1) that exhibits the decomposition.
This could be just a 248x248 matrix where so for example rows 1 to 52
span f4,...

Table 9 in Lisi's paper in principle has the same information for e8/(d4+d4)
so it should be usable if I can work out the mapping between the 8 columns
(1/(2i))w_T^3,(1/2)w_S^3),U^3,V^3,w,x,y,z and an accessible basis of e8.
Altrenatively I can start with the Chevalley basis that I have and mimic
the rotation/projections Gerrett Lisi describes; but each step is susceptible
to misinterpretting conventions (right vs left matrix action for example), typos,...
 
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  • #66
combining quarks

Garrett,

Is it possible to assign the real physical u-quark particle to a combination of the u-L and C-L roots of your table 9 such that its a vector with w-quantum number of zero, just like the t, b quarks? (and the same w=0 for all leptons and quarks). Would this lift the degeneracy of the quark masses due to the higgs fields? Could the neutrino's get their mass from the new x-i.phi fields rotating them to a (+/- one) w quantum number?

berlin
 
  • #67
rntsai,
I think the basis for the roots in Tables 8 and 9 are pretty standard. You may be able to construct or match up a basis of e8 generators from John Baez's paper, but I haven't worked this out explicitly yet.

Hello Berlin,
Yes, these are all ideas worth playing with. There are many ways to take the framework in this paper and develop it in various directions to try and resolve the remaining mysteries.
 
  • #68
rntsai said:
Unfortunately I don't, so they end up obscurring
rather than clarifying things for me. For the sake of what's in Garrett's
paper, Lie algebras over the complexes (or reals) is enough.

What I was (and am still) looking for is an explicit description of these
decomposition...something I can run explicit calculations with. I have such
a thing for the f4/d4 : f4=28+8+8+8 case (see an earlier post in this thread);
I'm looking for the e8/(d4+d4) and e8/(g2+f4) equivalent.

For explicit calculations, Baez's paper isn't the best reference. If you want to see how the F4 and E6 derivations are constructed see pgs. 29-33 of http://arxiv.org/abs/hep-th/0302079" . The E7 and E8 infinitesimal transformations are merely extensions of these.
 
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  • #69
kneemo said:
For explicit calculations, Baez's paper isn't the best reference. If you want to see how the F4 and E6 derivations are constructed see pgs. 29-33 of http://arxiv.org/abs/hep-th/0302079" . The E7 and E8 infinitesimal transformations are merely extensions of these.

I posted a question about this in the GAP forum and a Scott Murray
was kind enough to send me explicit basis for both d4+d4 and g2+f4.

Looking at the last three columns of Table 9, it seems there's a
relationship between the two decompositions. What's the nature
of this relationship?

We have under d4+d4 : e8=(28,1)+(1,28)+(8,8)+(8',8')+(8'',8'');

The table implies for example that 64 dimensional (8',8') breaks up
as 8(l)+8(l')+24(qI)+24(qI') (under g2? or f4?).
 
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  • #70
rntsai said:
I posted a question about this in the GAP forum and a Scott Murray
was kind enough to send me explicit basis for both d4+d4 and g2+f4.

Looking at the last three columns of Table 9, it seems there's a
relationship between the two decompositions. What's the nature
of this relationship?

The first d4 is a subalgebra of f4, and g2 is a subalgebra of the second d4.

We have under d4+d4 : e8=(28,1)+(1,28)+(8,8)+(8',8')+(8'',8'');

The table implies for example that 64 dimensional (8',8') breaks up
as 8(l)+8(l')+24(qI)+24(qI') (under g2? or f4?).

The 8's are acted on by d4 in f4, and the 1's and 3's for l's and q's are acted on by a2 in g2.
 
  • #71
Hello Mr. Garrett!,

I would like you to comment on this. The guy who pointed you some mistakes (Jacques Distler), made several more remarks about your theory, specially after DEC 9TH. He seems to be changing his mind every day, maybe he is confused.

He is still seems to be very hostile to your theory. But if you discuss with him, it would be profitable, as his got some new maths. He is saying you are not even getting the 1st generation right

http://golem.ph.utexas.edu/~distler/blog/archives/001505.html#AlittleU4
***************

Update (11/29/2007):
David Vogan, from MIT, wrote me to point out that I was too fast in saying that G does not embed in F 4×G 2. It is possible to find such an embedding, but it necessarily leads to a completely nonchiral “fermion” representation (and hence contains no copies of R). I simply didn’t bother considering such embeddings, when I was preparing this post. For the record, though
F 4(−20)⊃Spin(8,1)⊃Spin(3,1)×Spin(5)⊃SL(2,ℂ)×SU(2)×U(1)
and
F 4(4)⊃Spin(5,4)⊃Spin(3,1)×Spin(2,3)⊃SL(2,ℂ)×SU(2)×U(1)
In the latter case, one obtains
26=1+9+16 =(1,1) 0+(4,1) 0+(1,3) 0+(1,1) 2+(1,1) −2 +(2,2) 1+(2,2) −1+(2¯,2) 1+(2¯,2) −1 52=36+16 =(Adj,1) 0+(1,3) 0+(1,1) 0+(1,3) 2+(1,3) −2+(4,3) 0+(4,1) 2+(4,1) −2 +(2,2) 1+(2,2) −1+(2¯,2) 1+(2¯,2) −1
In the former case, there are two distinct embeddings of SU(2)×U(1)⊂Spin(5). For the one under which 4=2 1+2 −1, one obtains the same result as above. For the one under which 4=2 0+1 1+1 −1, one obtains
26 =2(1,1) 0+(4,1) 0+(1,2) 1+(1,2) −1 +(2,2) 0+(2,1) 1+(2,1) −1+(2¯,2) 0+(2¯,1) 1+(2¯,1) −1 52 =(Adj,1) 0+(1,3) 0+(1,1) 0+(4,1) 0+(1,1) 2+(1,1) −2+(1,2) 1+(1,2) −1+(4,2) 1+(4,2) −1 +(2,2) 0+(2,1) 1+(2,1) −1+(2¯,2) 0+(2¯,1) 1+(2¯,1) −1
Putting these, together with the embedding of SU(3)⊂G 2,
7 =1+3+3¯ 14 =8+3+3¯
into (3), one obtains a completely nonchiral representation of G.

Update (12/10/2007):
For more, along these lines, see here http://golem.ph.utexas.edu/~distler/blog/archives/001532.html

Correction (12/11/2007):
Above, I asserted that I had found an embedding of G with two generations. To do that, I had optimistically assumed that there is an embedding of SL(2,ℂ) in a suitable noncompact real form of A 4, such that the 5 decomposes as 5=1+2+2. This is incorrect. It is easy to show that only 5=1+2+2¯ arises. Thus, instead of two generations, one obtains a generation and an anti-generation. That is, the spectrum of “fermions” is, again, completely non-chiral. I believe (but haven’t proven) that this is a completely general result: for any embedding of G in either noncompact real form of E 8, the spectrum of “fermions” is always nonchiral. Let’s have a contest, among you, dear readers, to see who can come up with a proof of this statement.I apologize if I’d gotten anyone’s hopes up, with the above example. Not only can one never hope to get 3 generations out of this “Theory of Everything”; it appears that one can’t even get one generation.

*****************

And here is a post apparently claiming a final blow (not his words, but my emotional interpretation). A certain mark refers to Smolin and you almost as crackpots (again, not his words, but my emotional interpretation)

http://golem.ph.utexas.edu/~distler/blog/archives/001532.html#more

******************

There it is Garrett. Would you have some comments about that?
 
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  • #72
Hello MTd2,
This issue of non-compact subalgebras of non-compact real E8 is pretty tricky. Jacques is trying to pass this stuff off as obvious, but having a hard time doing that since he's been making mistakes. I did the calculations using compact real E8, and figured I could change the signature of part of the Killing form to get a non-compact version, by inserting an i in the roots -- but this was probably naive on my part. In the paper, I do use so(7,1)+so(8), and I though this was in E IX, but it isn't. Jacques asserted in a comment to his first post that so(7,1)+so(8) is in split real E8. This was news to me. Then, in his second post, he said so(7,1)+so(8) isn't in split real E8, as if I were the one who initially said it was. Also, in his second post, Jacques asserted that spin(12,4) was in split real E8 -- another mistake -- then he went back this morning and edited that out of the post, without noting his error.

This behavior makes me pretty wary. Despite his hostility and mistakes, I've learned a bit of useful math from the discussion with Jacques, and will see what I can do with it. I may be able to get things to work with so(7,1)+so(1,7), or with so(12,4), or I might have to try something more drastic. I already knew I was going to have to do something significantly different to get the second and third generations to work in this theory, so, really, not much has changed -- there are now just more clues.
 
  • #73
garrett, a question wrt Distler's comments:

My understanding of lie groups is very limited and Distler's blog is very ranty so I've had a great deal of trouble picking out what exactly Distler is trying to say in his posts. However it does seem there is one specific important criticism he has made which I haven't seen addressed yet, which is his claim in his second post (which MTd2 quotes from above) where Distler claims that, even if you only attempt a single-generation embedding, the fermions one gets out of the E8 connection are nonchiral.

Has Distler found an actual problem with the E8 connection idea here? Or is this a problem which is real but which you had already forseen somewhere? Or would you say there is some reason that Distler's claim about E8 producing nonchiral fermions is either incorrect or misapplied?
 
  • #74
Coin,
The Pati-Salam GUT I'm embedding in E8 is a http://en.wikipedia.org/wiki/Left-right_model" standard model -- but ways to do this are well established.
 
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  • #75
OK, thanks for the clarification.
 
  • #76
I want to highlight the effort of embending a link in the words that Garrett used ... ie. chiral ... this is not an exercise needed for the "math kids".
Thanks
 
  • #77
Nice, so your E(8) naturaly has massive and oscilating neutrinos. Maybe it can shed light on the doubts sorrounding the data from LSND and MiniBooNE experiments, that shows the possibility of sterile neutrinos.

http://en.wikipedia.org/wiki/LSND

http://en.wikipedia.org/wiki/MiniBooNE

Notice that are some anomalies detected in the low energy region of neutrinos, showing a high incidence of eneutrinos. That would be a "confirmation" of brane physics, that is, neutrinos "arriving" from other dimensions, the "bulk of the brane", and intersecting our "brane surface". Some string theorists are excited for that ("Bill Louis, of the MiniBooNE project, has emailed the brane theorists saying: "It is indeed startling to see how well your model appears to fit our excess of low energy events!" There remains the possibly that the effect is a spurious statistical or background anomaly and further analysis is underway."). But, maybe your theory can explain that anomaly without appealing to other dimensions.
 
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  • #78
MTd2,
Neutrino oscillation is going to be a large clue for further development of the theory, but right now the second and third generations aren't described well enough in the theory to make any predictions. Also, this is heading into physical speculation, and I'd like to keep this a technical discussion.
 
  • #79
In keeping with this being "a technical discussion",
here is something that I asked in response to a comment by Thomas Larsson over on Cosmic Variance in Sean's post "Garrett Lisi’s Theory of Everything!":

Could Garrett Lisi’s model be understood in terms of a 7-grading of e8 that was described in a sci physics research thread Re: Structures preserved by e8, in which Thomas Larsson said:

“… … e_8 also seems to admit a 7-grading,
g = g_-3 + g_-2 + g_-1 + g_0 + g_1 + g_2 + g_3,
of the form

e_8 = 8 + 28* + 56 + (sl(8) + 1) + 56* + 28 + 8* .

…[in]… the above god-given 7-grading of e_8 … g_-3 is identified with spacetime translations and one would therefore get that spacetime has 8 dimensions rather than 11. …”.

So, if you used g-3 for an 8-dim Kaluza-Klein spacetime,
could you see the 28* and 28 as the two copies of D4 used by Garrett Lisi to get MacDowell-Mansouri gravity from one and the Standard Model gauge bosons from the other
and
see the central sl(8)+1 being related to transformations of the 8-dim spacetime
(actually being a 64-dim thing that is substantially 8×8* ).

The even part of the grading would then be the 112 elements
28* + 8×8* + 28
and
the odd part of the grading would then be the 128 elements
8 + 56 + 56* + 8*
If the 8 and 8* are used for 8-dim Kaluza-Klein spacetime
so
could the 56 + 56* be used for fermion particles and antiparticles ?

Even if the above assignment needs improvement,
my basic question is

could Thomas Larsson’s 7-grading of e8 be useful in making Garrett Lisi’s model a realistic description of physics ?

Tony Smith

PS - My personal favorite interpretation of the e8 7-grading is a bit different from what I described above, but I altered it to fit Thomas Larsson's explicit idea that the 8 should correspond to a spacetime.
 
  • #80
where's the Z?

Some random questions on exchange particles that I hope are not too basic :

- What happens to the Z boson in your (and Pati-Salam) model;
It looks like the W^+ and W^- bosons show up as is, but
the Z is "replaced" by two new bosons : B_1^+,B_1^-;
The photon is burried somehere inside D2_{ew}; is it
W^3 + B_1^3 -sqrt(2/3)B_2 (page 11)

- I think you use circles as a suggestive notation for
"exchange particles". I can identify the purple and yellow
circles (proudly since age 5). I have trouble with the
green ones, do they correspond to anything that might be
more recongnizable?
 
  • #81
Garrett,

it seem Lee Smolin admited he is wrong, and admited that your theory do not include Pati -Salam model:

# Lee Smolin on Dec 15th, 2007 at 8:36 pm

Dear HIGGS

I see, if it is then just a terminological mixup that is of course fine for this issue. I don’t mind making mistakes in public-the time spent studying the Pati-Salam papers was my own and in any case worthwhile-but this shows to me the difficulty of arguing technical issues in the blog environment. Perhaps the experts could find a better way, probably off line, to go through the issues with Lisi point by point and reach a conclusion over the main issues. If so I’d be happy to be involved, so long as everyone involved was patient and professional and no one pretended that the representation theory of non-compact forms of E8 is child’s play.

Thanks,

Lee
# H-I-G-G-S on Dec 15th, 2007 at 10:15 pm

Dear Lee,

I’m glad that we cleared this up, and I appreciate that you admitted error,
in line with your earlier posting on the spirit of science requiring such acknowledgment. I don’t quite agree however that it was a “terminological mixup.” This makes it sounds like there was no real content to the debate, whereas in fact there was. The issue at hand was whether or not Lisi’s embedding contains the Pati-Salam model or not. Jacques showed that it does not. All I did was to provide some helpful clarification. In an earlier post you went on about how “Distler was largely wrong” and so forth, while as far as I can tell, everything he has said has either been correct, or when it was in error, the error was admitted and then clarified. Thus it would be much more appropriate for you to address your admission of error to him than to me. Perhaps if you did so his responses to you would in the future be more temperate.

It is true that blogs are far from the best place to argue technical issues. This discussion was one of the happy exceptions where a point was argued and resolved with all parties in agreement. As for Lisi’s proposal, I believe a conclusion has been reached by the experts.

H
http://cosmicvariance.com/2007/11/16/garrett-lisis-theory-of-everything/
 
  • #82
garrett said:
Quote:
Now it seems clear that the Coleman-Mandula question pertains only to the unbroken theory, or to put it another way, that in the broken theory, although the connection is still E8-valued, the action is no longer E8-symmetric.
That's right.

If your connection would be valued in the algebra, its would be expandable in the generators of E8. But some components of your connection are fermionic and thus anticommute, or? How can these possibly satisfy any E8 commutation relations? And if not, what on Earth has your construction then to do with E8?

As I was writing over at CV, this is completely different to symmetry breaking (where the proper commutation relations are still satisfied, though non-linearly realized).
 
  • #83
Tony,
There are many gradings of E8, most of them interesting. I haven't thought about 7-gradings much. My favorite grading of E8 is a 13 grading corresponding to weak hypercharge -- which currently only works correctly for the first generation.

rntsai,
The Z and the photon fields are (rotated) combinations of W, B_1, and B_2. Specifically, as 1-form coefficients,
\underline{Z} = \sqrt{\frac{5}{8}}\underline{W}^3 - \sqrt{\frac{3}{8}} (\sqrt{\frac{3}{5}} \underline{B}_1^3 + \sqrt{\frac{2}{5}} \underline{B}_2)
and
\underline{\gamma} = \sqrt{\frac{3}{8}}\underline{W}^3 + \sqrt{\frac{3}{8}}\underline{B}_1^3 + \sqrt{\frac{2}{8}}\underline{B}_2
The B_1^\pm, and a leftover
\underline{X} = \sqrt{\frac{2}{5}} \underline{B}_1^3 - \sqrt{\frac{3}{5}} \underline{B}_2
are "new" gauge fields, as in Pati-Salam. (I'm pretty sure I have those right, but I haven't confirmed them.)

The circles are all gauge fields: green for gravitational \omega_{L/R}^{\wedge/\vee}, yellow for weak W^{\pm}, blue for gluons, and white for B_1^\pm. The Z, photon, and X are in the Cartan subalgebra at the origin, and are conventionally not plotted.

MTd2,
H-I-G-G-S was twisting Lee's words, as is clear from his reply (which was visible when you posted).

moveon,
The connection starts out as an E8 valued 1-form. The action (with E8 symmetry broken by hand in my paper, but not in Lee's) introduces dynamical terms for the D4+D4 part of E8, but leaves only the BF term for the rest of E8. These pure gauge degrees of freedom may be replaced by Grassmann fields valued in the non D4+D4 part of E8 -- these are fermions. The resulting generalized connection consists of Lie(E8) valued 1-forms and Grassmann numbers, with the same E8 brackets between Lie algebra elements. This is a fairly standard mathematical construction, used in an unusual way. I'd be happy to expand on it for you or provide references.
 
  • #84
Garrett, exactly what is the 13-grading of e8 that you like to use?

Tony Smith
 
  • #85
Let me make a guess for garrett. The 13 is a weak grading, so it's going to correspond to the weak hypercharge quantum numbers of the standard model, that is, it will use the 13 values: (-1, -5/6, -2/3, -1/2, -1/3, -1/6, 0, +1/6, +1/3, +1/2, +2/3, +5/6, +1). To see the assignment, I would start by looking for the weak hypercharge quantum numbers assignment in his paper. Then you assign a particular root to a blade according to its weak hypercharge quantum number.

My recollection of the standard model is that the +- 5/6 quantum numbers are missing. These blades would be particles that don't appear in the standard model. But my concentration has always been on the fermions -- are there some bosons with weak hypercharge +- 5/6?

The peculiar pattern of the weak hypercharge quantum numbers that are actually used in the standard model, that is, leaving off the +- 5/6, has 11 values. Since I'm a density matrix proponent, (which are bilinear rather than the usual state vector formalism which is linear) I'm going to link in a paper which gives those 11 values, rather than all 13, as a solution to a bilinear equation. See chapter 5: http://www.brannenworks.com/dmfound.pdf
 
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  • #86
Tony,
If we rotate the E8 root system until the vertical axis is weak hypercharge, and rotate out the other axes horizontally to separate the roots a bit, it looks like this:
http://deferentialgeometry.org/blog/hyper.jpg
This makes it visible exactly what is meant by "the charge assignments only work correctly for the first generation," with the other two (smaller triangles) related by triality.
 
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  • #87
When I count the 13-grading from that image I get:

5 + 6 + 15 + 20 + 30 + 30 + 26 + 30 + 30 + 20 + 15 + 6 + 5

which only add to 238, so I must be miscounting two of them somewhere ?

Anyhow, modulo my error of two, the even graded structure would be

5 + 15 + 30 + 26 + 30 + 15 + 5 = 126-dimensional
(if the missing 2 are even, then 128-dimensional)

and the odd graded structure would be

6 + 20 + 30 + 30 + 20 + 6 = 112-dimensional

so

it seems to me that the odd gradings correspond to the 112 root vectors of the adjoint Spin(16) (120 generators - 8 Cartan subalgebra generators = 112)

and

that the even grading probably have the two I miscounted and are the 128 root vectors corresponding to the half-Spinor of Spin(16).

What bothers me about that is that the fermionic spinor-type things are in the even grading and the bosonic vector/bivector adjoint-type things are in the odd grading,

whereas in Thomas Larsson's 7-grading

8 + 28* + 56 + (sl(8) + 1) + 56* + 28 + 8* = 8 + 28 + 56 + 64 + 56 + 28 + 8

the even grade part is
28 + 64 + 28 = 112 dimensional corresponding to the root vectors of adjoint Spin(16) which seems to represent bosonic vector/bivector stuff
while
the odd grade part is
8 + 56 + 56 + 8 = 128-dimensional corresponding to half-spinor of Spin(16) which seems to represent fermionic spinor-type stuff.

Do you have any thoughts about that ?

Tony Smith
 
  • #88
Tony,
Two gluons overlap. There are many such gradings of E8 -- there may be the same kind of 13 grading along a different direction that gives the even/odd 120/128 split you're after.
 
  • #89
no chiral embedding

Hi Garrett,

I would like to have your comments on http://golem.ph.utexas.edu/~distler/blog/archives/001532.html" ).

I personally feel Distler's argument is fundamental, relatively easy to follow, and seems to be correct, at least up to the level of my knowledge (perhaps I'm making a mistake). Lee has been trying to address it on Cosmic Variance, but hasn't succeeded in finding a mistake or a loophole in it yet. Do you have anything to say about it?

Thanks a lot! :-)
 
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  • #90
garrett said:
The resulting generalized connection consists of Lie(E8) valued 1-forms and Grassmann numbers, with the same E8 brackets between Lie algebra elements. This is a fairly standard mathematical construction, used in an unusual way. I'd be happy to expand on it for you or provide references.

Please! To my knowledge the only algebras that contain both bosonic and fermionic generators are superalgebras, and E8 is not one of them. How can the commutation relations close into E8?
 

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