An Exceptionally Simple Theory of Everything

[10st1denTT]

sadly stages one and two do not determine a phase three outcome, right(?)
so your (schopenhauer's) apt observance qualifies better for a a posteriori musing (philosopher style... there is not much Predictive Power in it
The hard work has to be done now!
But not by me :)
The media frenzy garanties that the paper will be scrutenized (and sink to shame(?) or fly to glory). What will not happen is that it simply gathers dust in a dark basement shelf (as has fared to many a fine theory before).
So things are on a deterministic road now anyway.

 

[marcus]

"All truth goes through three stages. First it is ridiculed; then it is violently opposed; finally it is accepted as self-evident." -Schopenhauer

...
The media frenzy garanties that the paper will be scrutenized (and sink to shame(?) or fly to glory). What will not happen is that it simply gathers dust in a dark basement shelf (as has fared to many a fine theory before).
So things are on a deterministic road now anyway.

Lost I,
nice summary.

The issue of the huge wave of public admiration and media attention has come up.
1. is the publicity harmful to the longterm interests of science?
2. is it harmful to the development of E8 theory? (say, by making it less likely that other physicists will want to help Garrett Lisi work out the bugs, derive predictions, and complete the picture)
3. is it harmful to G.L. personally, if not to his theory's prospects?

Does anybody have thoughts about this?

My personal opinion is that the admiration and attention do no harm (aside from possibly provoking anger on part of those with competing demands for science media stature and glamor).

I think it's fine for the public to be exposed to attractive images of scientists. I don't see any harm in a short run of media enthusiasm. Things like this die down after a few weeks and leave no permanent expectations to be disappointed. What actually are we afraid of? What is supposed to be the harmful consequence to science?

I think the several decades of hyping string theory as a Theory of Everything, teaching a generation of adolescents to expect it to provide the final answers---a concerted effort involving public statements by many scientists---has been harmful to science. By debasing standards of empiricism and raising unreasonable expectations. But that is on a different scale.
==================

What I do think has been harmful is what I see as vindictive and relentless hammering of an incipient theory on a handful of science blogs.
I don't completely understand the motivation for all the anger I heard. Some of it came from string theorists, of course, and could have been motivated by jealousy---if they feel that the glamor of aspiring to a ToE, "realizing Einstein's dream", is their turf. If they felt that G.L. was infringing on public attention that was rightfully theirs. Maybe some string theorists feel that any sign of competition is an outrage and should be crushed.

But the outrage I heard in the science blogs didn't just come from envious or defensive string theorists. I think it contained a kind of puritanism and desire of some to control public reaction---a sense that publicity (especially when it gets out of their control) is somehow bad. Somehow G.L.'s infant theory was being given a whipping because it had made a media splash and that was BAD. It was out of control and it was a no-no.

I don't really understand but it seems to me that science blog-owners may think that they should be the gatekeepers and regulators of public attention.
Also the prominent ones are a new type of media personality. A little bit like science "talk show hosts". They have a kind of power. And that means that when things get out of control or where there is an issue of control, then the APPARENT issues (e.g. the degree of incompleteness of a new theory, the prospects for constructive revision, whether inconsistencies are fixable or fatal etc.) may not be what all the animosity is about. It may actually be more about issues of power.

Then there's the issue of conformity. Science is a community function that requires a balance of conformity and individuality. when the chips are down conformity has to win, and the ultimate sanction is ostracism. Ultimately the survival of the community trumps all other considerations. So that instinctive reflex has to be taken into account as well.

All in all, quite a fracas! Even you might call it a kind of minor street-riot.

====EDIT====
I wanted to include this valuable quote from S. Hossenfelder, because I strongly agree with almost everything said here and it is said very well and clearly, for the most part:
==quote Hossenfelder==
The hype of science in the media just reflects a general trend caused by information overflow. In today's world you have to scream really loud to be heard at all, and headlines are the better the fatter. I generally dislike this, as it leads to inaccurate reporting, unnecessary confusion, and bubbles of nothing. All of which obscures sensible discussions and is a huge waste of time.

However, despite this general trend, what worries me specifically about popular science reporting is how much our community seems to pay attention to it. This is a very unhealthy development. The opinion making process in science should not be affected by popular opinions. It should not be relevant whether somebody makes for a good story in the media, or whether he or she neglects advertising himself. What concerns me is not so much the media re-re-repeating fabulous sentences, but how many physicists get upset about it. This clearly indicates that they think this public discussion is relevant, and this should not be the case.

Concerns about the public opinion arise from the fear it might affect the funding of some research areas. But it's not the media who creates fashions and hypes who is to blame. Neither is it the scientists who are not careful enough when talking to journalists who are to blame. To blame is everybody who tolerates that the funding in science is subject to irrelevant factors.
==endquote==

The boldface emphasis is in the original. There is some ambiguity. They should not think that the public discussion is relevant? (Because publicity does not affect the judgement of the agencies.) Or their fears are justified and indeed publicity affects the funding agencies and THIS should not be the case.

the last sentence may require some clarification, is it really true (as some people fear) that irrelevant factors do---and if so what factors. my impression was an oldboygirl network based on prestige and influence entirely within the community and there is some politics sure, but it is not public politics.

But on the whole, apart from some ambiguity, I agree very much with the middle paragraph---and include the rest for context.

 

[10st1denTT]

just want to pay you a compliment on the pithy way you sum things up.
//...//
Hope you keep striving towards conventional understandability, because you have something to say to us((my bold)).

Thanks marcus,
I think that was the kind of welcome on a board that anybody would wish for! In contrast to your last statement, i am somewhat sceptical though. I was mainly lured here by noticing that John Baez and Garrett Lisi had been dialoging here prior to the release of his now famous (read with a neutral tone) paper. My personal expertise on the matter at hand is Not deep. And my presents here is more about receiving than giving! I am well aware that you have been closely involved in the discussions of Lisi's ideas (dating back till 2005!). And i feel honoured to conversing with you now...
My ambition reaches not further than to abstain from disgracing these pages with too much stupidity. (My hope is that the "Lisi-ToE" was a valuable contribution (at least) and that the polemics around it will quiet down.)...

//(a child demands my attention

 

[marcus]

Hi Lost I.

I thought my initial response was immodestly cordial so I toned it down, in edit. But I am glad you saw and copied!

There is something that is more on-topic that concerns me a lot now, and I want to raise.

For several days I have had the suspicion that G.L. project of an E8 theory runs into trouble in part because it is not based on deSitter general relativity.

I have been reading Pereira etal paper 0711.2274 "de Sitter Relativity: a new road..." and trying to understand it.
It has a new form of Einstein's strong equivalence principle (that invokes deS local ambiances rather than the conventional Minkowski ones) and a new form of the Einstein field equation.

I keep struggling to understand the paper, and also why it is not picking up more notice. These guys are not nuts. They are top people by Brazil standards, at the Sao Paolo Institute for Theoretical Physics.
If you are going to unify QM with GR, then what General Relativity do you unify it with?

The conventional Minkowski space doesn't expand. deS space does. In a world with a positive cosmological constant it might be more realistic to work with a form of GR that is locally deS rather than locally Minkowski

So I have been expecting that if Garrett's approach is a good one then at a certain point someone will have a flash of insight and say "Wait! This fits better with deSitter General Relativity!" And then (if the approach is an overall good one) some of the kinks will get worked out, or so I have been imagining.

This is a dim hunch that you don't usually tell people.

 

[10st1denTT]

"subtle is the Lord"

In the end there will be a higher authority than the presently reigning DemiGods, that decides which fundamental theory is simply right and which one is Gloriously FALSE!
Somewhere in the basic foundations of reality there Must be beauty and (a kind of!) simplicity. There Must be logical consistency. And there Must be an answer to the question: Why had Everything to be the way it would?
Every once in a while there Will come an Individual who thinks deeper, abstracts more efficently (the bones from the flesh) and finally goes one step Further (for the mainstream to follow).
It's about time such a "Ferguson" showed up (flying in on a second hand kite or what ever!).
If Nature would be as intricate/convoluted/traversed/outre´/... as the string theoreticians figure, she would trip over her own TOEs at every single instance!
I think, however bad the state of morals in physics, there is enough space under the feet of the bestriding giants for a Ferguson to grow, thrive and bloom. (I think btw that she is sitting in a cold spartan room with a spartan bed and a raw spartan kitchen table and a lot of the Right books - and only a little, shabby computer- Right Now! - talking to herself, the physicists/mathematicians (alive or dead) from her books and to some Imagined/Fancied Higher Being also!)

((ExpectTheUnexpected))

 

[10st1denTT]

(this is going to be a funny game :) , we are seriously out of sync, isntit)
((i accommodate any style bytheby if i have the impression of a likable soul on the other side))
to your last post: I am a trained mathematician and conditioned to talk only things, i understand at least in their basic workings. You are presently talking over my head! I find the Lisi idea promising to think the Einstein world anew (demote the metric, think "connection"). I am just beginning to study MM. As I said, I am here to Learn!

 

[marcus]

Why the fabulous E8 connection could be fabulous.

The basic object in LQG is the SPIN NETWORK. Conceptually the spin network can be thought of as dual to the connection* idea. It only involves a finite (or sometimes countable) number of vertices, while a connection is defined over the whole continuum.
But it does give you information about what happens when you pass from one point to the other. Spin networks and connections are kindred ideas.

In LQG, quantum states of spatial geometry are described by spinnetworks. But so far only geometry is described by them, not matter. Matter fields can be stuck on, but they don't come free as part of the spinnet.

Lee Smolin's research group is embarked on trying to realize the standard particles of matter as TWISTS AND BRAIDS in spin networks. It is a risky and difficult venture. They have to show that patterns of braiding can propagate without getting unravelled, and that their interactions correspond to the known interactions of particles.

Twists and braids (in a network of tubes or wires) could turn out to be dual to a more complicated type of connection----analogous to how ordinary spinnet (without twists and braids) is dual to a simple geometrical connection.

Twists and braids are ALGEBRAIC things in the sense that you can combine them (doing two braids in sequence gives you a new braid) and sometimes one will UN-do another.

I have to go, and don't have time to finish this thought. What I am driving at is that realizing the standar particles as twists and braids in a network as you go from one point to another could be akin to realizing the same particles in the Lie group of a connection. Each could provide helpful guidance for the other. This would be a fabulous duality, especially since the way is difficult on each side.*What is a connection? In ordinary differential geometry a connection specifies a way for tangent directions to change as you travel from one point to a neighboring one---a connection defined on a shapeless continuum can give it geometric shape just as well as defining a distance function (or metric) on it can. If defining the shape of a continuum by specifying a metric on it is the usual way, the practice of defining it with a connection is not far behind.

 

[10st1denTT]

I would simply like to add that i whole heartedly subscribe to your observances in post #152.
BTW, what irritated me in your post #154 was the passus

"it might be more realistic to work with a form of GR that is locally deS rather than locally Minkowski"

i thought i had learned from the (quite excellent) thread on SO(4,1) here on PF that "deS" (meant to be read deesse?) was locally Minkowski Anyway(!) (in perfect accord with what we know about space expansion and what we see in our labs)... Maybe i should have a look on that Pereira paper (ififindthetime

 

[jal]

How will E8 be tested?

3. Dynamics
The dynamics of a connection is specified by the action functional, S[ : A]. Classically, extremizing this action, constrained by boundary data, determines the value of the connection, : A(x), over a region of the base manifold. The value of the connection may also be used to infer topological properties of the base manifold. Quantum mechanically, the action of a connection over the base manifold determines the probability of experiencing that connection.[15] Since quantum mechanics is fundamental to our universe, it may be more direct to describe a set of quantum connections as a spin foam, with states described as a spin network. Under more conventional circumstances, the extensive methods of quantum field theory for a non-abelian gauge field may be employed, with propagators and interactions determined by the action.
In any case, the dynamics depends on the action, and the action depends on the curvature of the connection.
… It should be emphasized that the connection (3.1) comprises all fields over the four
dimensional base manifold. There are no other fields required to match the fields of the
standard model and gravity.
…The theory proposed in this paper represents a comprehensive unification program, describing all fields of the standard model and gravity as parts of a uniquely beautiful mathematical structure. The principal bundle connection and its curvature describe how the E8 manifold twists and turns over spacetime, reproducing all known fields and dynamics through pure geometry.

Everyone has their special model that they are working on and I assume, that is what they will be using to evaluate E8.
They will be looking at E8 to determine if their model is represented and will arrive at one of the following conclusions.

1. Yes, …. My model fits, therefore, E8 could be right.
2. No, …. My model does not fit in, therefore, E8 must be wrong.
3. Maybe, …. My model does not have or need all of the connections shown.
4. Maybe, …. My model needs more connections then what is shown by E8.

Then I expect that the next phase will be,
1. E8 says that it’s there but we cannot locate it in the noise.
2. My model says it’s there but we cannot locate in the noise.
--------
As a concrete example;
What would the following authors conclude?
http://arxiv.org/abs/0711.3910
SU(6), Triquark states, and the pentaquark
----------
jal

 

[cyberiantiger]

I love the theory, though "simple" is perhaps not a word I would choose to describe it.

I confess that my maths probably isn't up to understanding it yet, it seems that I really need to understand octonions and lie groups in order to get a real handle on this theory (I dropped maths 2 years into a university course for reasons I won't go into).

The majority of reviews on science blogs which tear the theory down for one reason or another are mostly flawed and if one reads around you can find alternative reviews which point out the same flaws (except for the one I read which claimed you couldn't add different types of quantity together - where the paper was quite obviously talking about vector maths and not actually adding different types of quantity together) but then added that though there were flaws they could be worked around. I gather that some of these blogs are owned by respected scientists, and I find this quite disturbing.

With regards to the mass media attention, I think it's probably done the theory more good than harm; Alternative theories historically have also initially suffered the same sort of acceptance by mainstream science, it's a shame mainstream science never learned the lesson that theories should be accepted solely on their ability to be proven or disproved.

The best summary I can see is that the paper is an incomplete alternative way of approaching solving some fundamental physics questions which string theory tried to address and mostly failed (Anything which by definition cannot be proven is a religion NOT science).

I will hopefully be spending some of my spare time trying to understand octonions, Lie groups and eventually E8, then I will reread the paper and hopefully understand the finer details and then unfortunately I will have to catch up my physics from a long way behind where it needs to be in order to start trying to apply this theory to anything meaningful.

Meanwhile I'll be sure to be keeping tabs on anything related to this topic, especially this thread.

The theory perhaps strikes a cord with me because what little physics I did led me to believe that there were probably 2 more forces on top of the standard 4 forces I learned about, mainly for reasons of symmetry with the fundamental particles. Well below the level this thread is at, did I mention my physics sucks ?

I suspect the theory will become more beautiful as I understand more about e8 and the Lie Groups, I also suspect the theory will become more flawed as I understand more about the physics side of it though ;)

Sorry for the long post, hopefully I'll have something more useful to contribute if I ever managed to catch up to the level this thread is at.

 

[Count Iblis]

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

What a surprise! http://insti.physics.sunysb.edu/~siegel/parodies/atchoo.html"

 

[Coin]

I love the theory, though "simple" is perhaps not a word I would choose to describe it.

The title was a pun. E8 is an Exceptional Simple Lie Group.

I will give you a few minutes to stop groaning

 

[marcus]

The title was a pun. E8 is an Exceptional Simple Lie Group.

I will give you a few minutes to stop groaning

Yes! and puns aside, this might be a place to cover a few essentials of group theory (counting on Coin's help)

a simple group is sortofanalogous to a prime number in that you can't factor out any subgroup and collapse it down any further.
a simple group is one that contains no subgroup of a type that lends itself to factoring out (called a normal subgroup)
(like a prime number doesn't contain any factor you can divide by to make it smaller)

If the group can't be simplified that way, it is called simple (even if it's highly intricate, because it is already as simple as you can make it without totally trashing it).
=======================

Actually the source of Garrett's beautiful diagrams of E8 is another special kind of subgroup called a maximal abelian subgroup, or Cartan subgroup. A Cartan subgroup for E8 is 8 dimensional. that is the basic reason that all Garrett's E8 diagrams exist in 8D.
The Cartan subgroup is an easy concept to grasp and it's the key to how the larger group's structure is analyzed.

If anyone is curious about it, just ask. Coin, or myself, or half a dozen other people visiting PF Beyond forum these days, could possibly explain.

More difficult ideas, I personally don't make any guarantees or promises. But the Cartan subgroup is a babystep idea---and it's amazing how much structure it unlocks.

 

[dipstik]

please explain the cartan subgroup.

-thanks

 

[marcus]

I'd be happy if some of the others want to take over. But you know what a group is. If you know matrix multiplication you can think of a group of matrices----or pick up a book and think of the different ways to flip it, turn it etc.
Especially if it is square so there are more possible moves (i.e. symmetries. )

You can experiment with groups and find that not all moves commute.

But in any group you can find subgroups (even if it is only the trivial subgroup consisting of the identity) and in any group you can always find one or more commutative subgroups.

Like pick one element, and square it, and keep on multiplying it by itself. At least in a finite group that looks like it would generate a subgroup that is all commutative. Correct me if I'm wrong, or ask questions if you don't follow.

So you can start with one element and its powers (square, cube..) and you can keep picking other elements and trying to see if they commute with what you already have. So you can keep adding more and more and building up the subgroup until you have a maximal commutative subgroup. That means you can't add any more. Any other element you try will not commute with some element you already have.

It's like the maximal bunch of friends you can invite all to the same party at your house. So to sum up:

1. Not all groups are commutative. In some (like even the symmetries of a square) you find a pair of elements that it matters in which order you do them.

2. All groups have subgroups

3. Any group has at least one commutative subgroup.

4. At least under reasonable assumptions, I'd expect a group to have a maximal commutative subgroup.
================

That is basically what a Cartan subgroup is. now you can ask all kinds of questions like is it UNIQUE in some sense.
If you started building a commutative subgroup with different initial choices whould you get something that was at least the same size?
Questions of the sort mathematicians love to ask. don't let these intriguing questions distract us from the basic fact that we are talking about a very simple concept.

And another question is what about INFINITE groups, or what if the group is a continuum. A smooth manifold of a certain dimensionality----like 1, or 2, or 248.
Then what does maximal mean? And you want to know what the DIMENSION of the subgroup is, because you can't count discrete elements any more. And you want to know if maximal commutative subgroups are unique in what sense? At least they should have the same dimension.

Several other people are doubtless more familiar with this and could continue the discussion. my impulse is to consult Wikipedia on Cartan subgroups at this juncture.

But anyway to conclude this intro, E8 has a maximal commutative subgroup of dimension 8.
The whole group is a manifold of dimension 248. And it is not very commutative. But you can find a commutative subgroups of dimension 8.

And that turns out to be cool because you can then study how the small 8d subgroup ACTS on the group at large and...=====but OOPS! at this point we have to say what is a LIE ALGEBRA.
Groups that are manifolds are nice to study because a manifold has a tangent space at every point and if it is a group then it has a tangent space at the identity which the groups own multiplication projects a nice bit of algebra onto, making the tangent vectors at the identity into an algebra.

And then the Cartan subthing is going to act on the thing as a whole and it's linear (vectors, now) so there are going to be eigenvectors and eigenvalues====matrix stuff that you normally get a math package to do, but which is extremely useful.

If want to proceed, ask something. Then maybe somebody else besides me will take a turn.

=========EDIT TO REPLY TO NEXT============

Coin thanks! First of all for not leaving me dangling. Also for clarifying. And what you say is basically right

So the cartan subgroup of E8 would just be the largest subgroup wherein the lie bracket is everywhere 0? Is that right?

Right! (im not an authority but I would say largest subalgebra of e8 wherein the bracket is zero.------or the largest subgroup of E8 wherein ab = ba)

a useful confusion exists between a Lie group and its algebra---as between a diff manifold and its tangent space. one is linear with vectors you can add, and one isn't but they are intuitively much the same thing and should be thot of in the same mental breath :-)

To be circumspect about it, the only added complication here is keeping track of when we are talking about the group E8 and when we are talking about its Lie algebra, the tangentspace at the identity that has the bracket defined. that would normally be called e8. they tend to use caps for the group and lowercase for the algebra. but the two are so closely related that people often don't distinguish carefully and write E8 for the algebra as well as for the underlying group.

 

[Coin]

I'd be happy if some of the others want to take over. But you know what a group is. If you know matrix multiplication you can think of a group of matrices----or pick up a book and think of the different ways to flip it, turn it etc.
Especially if it is square so there are more possible moves (i.e. sym. )

You can experiment with groups and find that not all moves commute.

But in any group you can find subgroups (even if it is only the trivial subgroup consisting of the identity) and in any group you can always find one or more commutative subgroups.

To be clear, "commutative" and "abelian" mean the same thing.

So when marcus says a cartan subgroup is the "maximal abelian subgroup", he just means it is the largest subgroup where a*b=b*a is always true.

(I'm not specifically familiar with what constitutes a "cartan subgroup", though. Does it make any difference that in the case of e8, we're taking the Cartan subgroup of a Lie group? Also, isn't E8 already abelian? Wouldn't that make its maximal abelian subgroup just equal to E8 itself? Or does the subgroup have to be proper? Hm, now I'm confused...)

EDIT: Okay, so I think I've got it: E8 is commutative under the group operation +, but it is NOT commutative under the lie bracket (since of course lie brackets are by definition anticommutative, meaning they must satisfy the [x,y] = -[y,x] property). So the cartan subgroup of E8 would just be the largest subgroup wherein the lie bracket is everywhere 0? Is that right?

 

[william donnelly]

Coin, you're getting closer, but you are confusing E8 (the Lie group) with e8 (its Lie algebra).

E8, the Lie group is a 248 dimensional manifold. It has a multiplication that is NOT always commutative. i.e. a*b != b*a.

e8, the Lie algebra is the 248 dimensional tangent space of E8. It has an addition, and addition is always commutative. It has a Lie bracket that is not necessarily zero, [a,b] != 0.

Sitting inside E8 is the Cartan subgroup, which is 8 dimensional and commutative. It's shaped like an 8-dimensional torus. It's a maximal Abelian subgroup, in the sense that there is no bigger Abelian subgroup that contains the Cartan subgroup.

Sitting inside e8 is the Cartan subalgebra, which is 8 dimensional. The Cartan subalgebra is the tangent space of the Cartan subgroup. It has a Lie bracket that is always zero.

 

[Coin]

William, thanks! While I have your attention, do you think you could maybe offer any help with my questions from page 8?:

From looking at wikipedia and this page (I think from the "atlas" people who "mapped" E8 awhile back?), the impression I get is that E8 consists of those vectors of length 8 that can be formed from adding together integral multiples of the members of a basis of "root" vectors. The group operation appears to be vector addition, and the "root" vectors consist of all 8-member vectors of the form
<±1, ±1, 0, 0, 0, 0, 0, 0>
or
<±0.5, ±0.5, ±0.5, ±0.5, ±0.5, ±0.5, ±0.5, ±0.5>
Because there are 8-vectors which it is not possible to construct by adding together these roots, E8 forms a proper subset of the set of {all 8-member vectors consisting of integer or half-integer values}.

Is all this correct? Okay, so: If so, is this the E8 Lie group or the Lie algebra? In either case, what is the corresponding algebra/group? And in the case of the algebra, what is the lie bracket? (The atlas page says only that the lie bracket for E8 is "very hard to write down". Oh.) And finally, is it "weird" that E8 is a lie group/algebra-- yet has only a countably infinite number of members, and is apparently constructed entirely of discrete structures? I've thus far only encountered lie groups which are continuous, where it makes sense to talk about things like "infinitesimal generators". There doesn't seem to be anything infinitesimal about E8 at all. (Mind you, I'm not complaining-- I have a CS background and I am WAY more comfortable with anything discrete than I am with anything continuous! It just seems jarringly different from the way I understood people to use lie groups/algebras previously, and I'm confused how I missed this.)

Past this, the biggest thing that is confusing me here are the "roots". First off, although this is probably not all that important, how on Earth were they chosen? That is to say, was someone just playing around with addition on different sets of basis vectors, and went "oh hey this particular combination of 248 vectors acts kinda weird, everyone else come look at this"? Or was E8 first discovered as some other kind of structure, and it was later realized that the 8-vectors above are a convenient representation of that structure? Second off and more importantly, I am dreadfully confused by these root "diagrams" such as one finds all over Lisi's paper. As far as I can tell, the idea is that we plot each of the roots as a point in eight-dimensional space. (I take it that we plot them by simply treating each 8-vector as a coordinate?) However, then we for some reason draw lines between some of the roots! Why on Earth do we do this? What do the lines mean?

I'm similarly a little bit confused by this "simple root" thing that wikipedia describes. As far as I can tell, the "simple root"s are an alternate integral basis for E8, consisting of the eight vectors found in the rows of this matrix:

Wow, that's convenient! What's confusing me here though is, why on earth do we bother using the 248 roots described above, when we could just use these 8 simple roots and be done with it? Another thing confusing me: Wikipedia offers a "dynkin diagram" (which I take it is different from the "root diagrams" used with the 248-root system) which looks very deep and beautiful:

http://upload.wikimedia.org/wikipedia/en/d/d3/Dynkin_diagram_E8.png

... but I can't for the life of me figure out what it's supposed to mean. Wikipedia says that this is a graph where vertices represent members of the simple root system, and edges are drawn between any two members of the simple root system (I assume this means a 120 degree angle when we treat the simple roots as coordinates in 8-space.) Okay, that's nice, but why? Why do we care which members of the simple root system are at 120 degree angles to one another?

I have a couple more questions related to what Garrett in specific is doing, but these are just my questions about the E8 [group? algebra?] itself. Any help in figuring these things out would be appreciated. In the meanwhile, something vaguely frustrating me is that there does not seem to be any specific information on E8 in the obvious places. It is clearly a well-researched subject but the best I can find is these very vague wikipedia-style summaries, and John Baez's writeups (which are invariably exhaustive and lucid, but everything I've found which Baez has written covering E8 seems to be primarily about other things, like octonions, and only indirectly concerned with E8). Is there some particular thing, perhaps a book, I would be best served by going and reading if I am curious about the mathematics of E8?

I take it from your comments that the 8-vector w/addition I describe above is the lie algebra. If this is the construction for the lie algebra, how are the members of the lie group constructed? And how do you find the members of the Cartan subgroup of the e8 lie group?

 

[william donnelly]

This 8d space is _a_ Lie algebra, but it's not the e8 Lie algebra, it's the Cartan subalgebra. The set of 240 8-dimensional vectors described in the link is the E8 root system, which lives inside the Cartan subalgebra.

Actually constructing the Lie group E8 is apparently quite complicated, and I have no idea how to do it. John Baez talks about it in TWF 253: http://math.ucr.edu/home/baez/week253.html.

To find the Cartan subgroup, one thing you can prove is that the Cartan subgroup has a single vector, that when you take all multiples of this vector you can recover the whole Cartan subgroup. So if you can find this one vector, you get the whole Cartan subgroup. I'm not sure how you would get this vector though, other than by just trying all of vectors.

 

[rntsai]

root labels

There's a standard way to label the 240 roots in Table 9
of Lisi's paper as weights of the adjoint rep of e8.
The rep is 248 dimensional; it has a weight [0,0,0,0,0,0,0,0]
with multiplicity 8 that corresponds to the cartan subalgebra.
The remaining 240 weights have multiplicty 1 and can be listed as :

[ [ 0, 0, 0, 0, 0, 0, 0, 1 ],
[ 0, 0, 0, 0, 0, 0, 0, -1 ],
[ 0, 0, 0, 0, 0, 0, 1, -1 ],
[ 0, 0, 0, 0, 0, 0, -1, 1 ],
[ 0, 0, 0, 0, 0, 1, -1, 0 ],

... <deleted 230 of 240 nonzero weights>

[ 1, 0, -1, 0, 0, 1, -1, 0 ],
[ -1, 0, 1, 0, 0, 0, -1, 1 ],
[ 1, 0, -1, 0, 0, 0, 1, -1 ],
[ -1, 0, 1, 0, 0, 0, 0, -1 ],
[ 1, 0, -1, 0, 0, 0, 0, 1 ] ]

so each "particle" is represented by 8 integer values.
Actually it looks like only (-2,-1,0,1,2) occur in the list.
This representation is different from the coordinates
of the polytope mentioned in the paper.

Table 9 includes 8 labels :

(1/2i)w_T^3,(1/2)w_S^3,U^3,V^3,w,x,y,z

These are probably more physically meaningful than the
above integral weights. There should be a map between the
two which would be good to have explicitely worked out.

 

[Unbeliever]

Even if Dr. Lisi's model turns out to be other than the long-sought TOE - if it merely points others in fruitful directions - it will have performed its appointed task, and have followed Galileo's Dictum, and contributed to science. And, who knows, maybe we're all in at the ground floor of historic science! I, for one, am happy to be so close to the edge of the envelope of the search for knowledge. I'm not by any means a physicist, only an interested layman, but I enjoy being here. Thanks for having such a fun discussion!

 

[marcus]

Even if Dr. Lisi's model turns out to be other than the long-sought TOE - if it merely points others in fruitful directions - it will have performed its appointed task, and have followed Galileo's Dictum, and contributed to science...

I share your attitude. Win or lose, a testable theory---one that makes new predictions that can be checked---can help advance understanding. especially if it stirs people up and gives them ideas of things to try and not try.

At the moment I can't think what Galileo's dictum might be. Can someone help me out?
I thought the programme of empirical science was laid out by Francis Bacon, early 1600s. A contemporary of Shakespeare and an early martyr to the frozen food business.
(he died after an unfortunate experience with a chicken.)
============================

Online conversation between two science writers: George Johnson and John Horgan
discussing AESTOE among other things
http://bloggingheads.tv/video.php?id=471

the first two minutes is about Horgan's list of the 70 greatest science books, but then they get into a 14 minute discussion of E8 and events surrounding its arrival on the scene. Savvy science journalists, especially George Johnson IMO. They made some astute comment on the academic and media reaction. Then they got on to other (most likely sillier) science stories of the past week.

 

[Unbeliever]

At the moment I can't think what Galileo's dictum might be. Can someone help me out?

I got that from Bertolt Brecht's, The Life of Galileo:

Science knows only one commandment: contribute to science.

I read somewhere else that this is known as Galileo's Dictum.

 

[marcus]

Brecht deserves a lot of respect as a playwright and it is a good dictum.
But there may be two famous Galileo dicta. I googled and found this other saying that the universe is a great book:

"this grand book . . . is written in the language of mathematics, and its characters are triangles, circles, and other geometrical figures."

http://findarticles.com/p/articles/mi_m0425/is_n1_v55/ai_18299591/pg_3

and something like that in Italian
Per Galileo l'universo è un libro, il «grandissimo libro che continuamente ci sta aperto innanzi agli occhi …, ma non si può intendere se prima non s'impara a inteder la lingua, e conoscer i caratteri, ne' quali è scritto. Egli è scritto in lingua matematica, e i caratteri sono triangoli, cerchi, ed altre figure geometriche, senza i quali mezzi è impossibile a intenderne umanamente parola».
http://www.italialibri.net/arretratis/apr00.html
This has the same quote and also a great quote from Johannes Kepler.
http://www.phyast.pitt.edu/~micheles/notabili.html
The Italian Wikipedia begins its Galileo article with this same quote
http://it.wikipedia.org/wiki/Galileo_Galilei

 

[arivero]

A secondary reference is a kind of paperback answer to Horgan's "End of Science" (I guess it because it was contemporary and the editors used the same format and cover colours; it could be reverse, or unrelated)

https://www.amazon.com/dp/0316648280/?tag=pfamazon01-20
https://www.amazon.com/gp/product/0805073493/?tag=pfamazon01-20

The Amazon review of this book contains Brecht's reference. It is taken from the second page of the introduction, and then again from the first quote in first part of the book. So it comes, in some sense, from the editor, Edmund Blair (is he related to Eric Blair, or is it a very common name in England?).

If I were to abstract Brecht to a single quote, it could be
“Of all the days that was the one /
An age of reason could have begun”
But note this is also reductionist; to get an idea of Brecht's arguments, one should at least to read the whole speech of Galileo to Viviani in the last act, if not the whole work with some dense introduction about the text.

 

[jal]

I would like to keep "An Exceptionally Technical Discussion of AESToE" in this forum so that the non-math people (laypeople and amateurs) could ask questions in the adjoining threads.
Maybe we'll get explanations maybe not from Garrett and others.
jal

 

[marcus]

Garrett, here is a not-very-technical somewhat vague question, in case you have time to consider a few of those as well.
BTW thanks for coming around some and helping us understand your work! I wish more researchers did that!

My question is how would you see E8 theory adapting if a deSitter General Relativity emerged and began attracting interest, say along the lines of
http://arxiv.org/abs/0711.2274
?

You may immediately see some reason that Pereira Aldrovandi deS-GR is doomed, flakey or flimsy, in which case the question doesn't matter. Or you may not have time to look at the P&A paper, in which case the question isn't useful and can be ingored. Basically what they do is replace the Poincaré group in the strong equivalence principle by the deS group and get a new version of the Einstein Field Equation with a new term on the RHS. Their equation (27).

This kind of thing could be dime-for-a-dozen or necessarily inconsisitent, but so far I've seen no evidence of that and I find the idea hard to shake.

what if it turned out that the proper local spacetime symmetry group to use was NOT the Poincaré, suppose the right group was SO(4,1)?

If the right group turned out to be SO(4,1), then where would E8 theory be, and how would it adapt? Can you say anything about this, without getting too distracted from your main focus?

 

[garrett]

Hey Marcus,
I can reply with a vague answer. The E8 theory so far includes a so(7,1) symmetry, which breaks up into so(3,1)+so(4) +4 \times 4. The first 4 is the gravitational frame, and the second 4 is the Higgs. When the Higgs gets a VEV, there is sort-of a so(4,1) symmetry because of so(4,1) = so(3,1) + 4. So the theory includes so(4,1) and is compatible with De Sitter gravity this way. But things are more confusing because of the inclusion of the Higgs.

 

[Nuha]

Sorry for poor English.

"An Exceptionally Simple Theory of Everything" is not Theory.
I agree with that that is in its basis. This big achievement!
Respect to the authors.

But.
This is just perfect Mathematical method and modell.

It is a part of the another theory.

"Information fields and their interaction with multivariate coordinate space-time in conformity with the discrete nature of mother"

The discussion is in Russian Phisycs phorum (about 2 month).
(Moscow State University)

The key formula and another information is hear.
Sorry but i'v a problem to translate it in English.

http://forum.dubinushka.ru/index.php?s=&showtopic=12456&view=findpost&p=352715

rot(G*Kg) = n*Kn + rot(H*Kh) + rot(E*Ke)

Metricss of the validity are deduced.
Connecting parities.

 

[Unbeliever]

I hope this question hasn't been covered yet, I don't have time to read this whole thread. I'm curious about the 20 new particles that the theory predicts: must we wait for the LHC to come on-line, or can any of them be gotten at existing facilities, with current energies?

 

[BryanP]

Thanks, just printed it.

 

[polystethylene]

As a fourth year masters student just starting to learn about symmetry groups and unification and the like, this is something of an eye-opener, in that I have no idea what's going on in this paper. From what I can gather from the sections of prose though, it seems like a pretty beautiful and simple theory, congratulations garrett.

 

[Valjean]

Basis rather than theory of everything?

And just maybe...to get to the fundamental condition that everything is based on...attraction exists between everything. Its strength between any two things, in any given circumstances, depends exactly on the amount of mass involved. So exact that the source of that attraction must be a the smallest, indivisible bit of mass there is. To have the same result you have to have the same ingredients. Some of those bits collect, because of the attraction, into units and others orbit around them in regular frequencies and amplitudes. As those motions cause any given two bits to move closer and further relative to each other the attraction between them increases and decreases accordingly. Energy frequencies of attraction that travel outward until they meet another bit causing its orbit to alter ever so slightly but still altered...maybe even a bit inside your eye which passes to the next, etc. So, how might that attraction exist? Consider. Nothing. Starting from the same place as the bang, formation of strings, etc. a separation, a compression of space into one bit of compressed space surrounded by expanded space created by the same action, like a teeter-totter, which then "banged" causing it to shatter into countless bits each still surrounded by the expanded. space. Or maybe there was just a crystalization producing the same thing in one action. Maybe a bad example but...a solid rubber ball. Draw rubber into points of compressed rubber each surrounded by expanded rubber pulling any two compressed points towards each other but can't move them because of the equality of pull between all of them. Move one, however, and a never ending dance starts because of the ineaquality of pull aka attraction. Back to the bits. Some compressed points (energy) our instruments can detect that we view as matter. Others don't. Dark matter? We don't detect it but it still has its attraction basis. We don't detect the expanded space (energy) as such but it is a necessary component for attraction to exist. We detect the results of its being but not it directly. Dark Energy? Or maybe it's all hogwash.

 

[timex]

Where is time in the theory?

 

[rntsai]

Where is time in the theory?

timex,
I think time translation corresponds to one of the generators of one the two
d4 subalgebras; which one I haven't figured out myself yet. The d4 corresponds
to an so(8) (or so(1,7) or so(2,6)); I think somewhere in these so's there's
an so(2,4) related to the poincare algebra; time translation is one of the
15 generators of this so(2,4); x,y,and z translations are another 3,...
My understanding of this at this point is very vague and possible wrong,
but maybe someone can clarify.

 

[Denton]

I really wish I could understand this... its just currently out of reach.

 

[marcus]

On 6 December Smolin posted this paper, and then entered discussion at the blog Cosmic Variance (where content-free insults by anonymous posters are permitted)

http://arxiv.org/abs/0712.0977
The Plebanski action extended to a unification of gravity and Yang-Mills theory
Lee Smolin
13 pages, one figure
(Submitted on 6 Dec 2007)

"We study a unification of gravity with Yang-Mills fields based on a simple extension of the Plebanski action to a Lie group G which contains the local lorentz group. The Coleman-Mandula theorem is avoided because the theory necessarily has a non-zero cosmological constant and the dynamics has no global spacetime symmetry. This may be applied to Lisi's proposal of an E8 unified theory, giving a fully E8 invariant action. The extended form of the Plebanski action suggests a new class of spin foam models."

==================
Two things are especially notable. On one hand, Smolin together with several others (Wan, Hackett, Kauffman, Bilson-Thompson...) is currently working on an entirely different LQG unification program----a scheme for merging matter with geometry that COMPETES with Garrett Lisi's E8 approach. It uses topological features such as twists and braids in the network to represent matter and attempts to realize the standard menu of particles.

On the other hand, in Smolin's paper he offers a second level of competition. Because he proposes to go partway with Lisi but (1) allow for using a different group from E8 should that turn out necessary and (2) realize fermions in a radically different way from how Lisi goes.

So Smolin is offering two competing unification approaches, one which looks somewhat Lisi-like and another (involving more collaborators) which is completely different. I think the aim is to get ideas out there where they can be examined and discussed, presumably in a professional way, and perhaps further modified. The game being not to win arguments or score points but to see if any variations of these ideas could be worth pursuing---maybe even right.

So then that was 6 December and then there was the discussion at CV blog presided over by Sean Carroll. that may have now burnt out and be more or less over. not sure but maybe. have to go, back later

Lee seems to have stated his conclusions from the discussion in the form of a long post, which is an interesting document in itself.
http://cosmicvariance.com/2007/11/16/garrett-lisis-theory-of-everything/#comment-306890
It comments on the blog-context as well as the physics content of the discussion in that CV thread.

One thing that seems very obvious but which no one has remarked on, is that in TRADITIONAL pre-blog scholarly discussion, as soon as Smolin posted his paper (Arxiv 0712.0977) responding to, utilizing, and diverging from Lisi's. Then the obvious thing to do would be for Distler to post a critical response IN THE FORM OF A SCHOLARLY PAPER ALSO ON ARXIV. Traditional scholars do this all the time---they post papers with titles like Comment on "The Plebanski Action Extended to a Unification..."
I have seen dozens of such papers. Sometimes they are published. Sometimes they are replied to with yet another scholarly paper by the original authors!

The advantage is that in an exchange of papers each person assumes responsibility for what they say and has the job of saying it clearly and carefully. Then anyone who is interested can see what each actually said and how they addressed each other's points.
By contrast in a series of BLOG COMMENTS it is very difficult to find and keep track of what people are actually saying because it is mixed in with a lot of anonymous trash and side-discussions. Blog commenters may also use innuendo or careless suggestive language because no one is being held accountable in the way they are with professional journal article format (footnotes, references, point-by-point organization that one can inspect and judge for clarity)

So there really is some merit to the classic way scholarly debate is organized and the classic journal article style. If anybody habitually avoids that format and seems to PREFER the more disorderly, time-consuming, and irresponsible Blog medium----if they have the professional status ensuring ready visibility on arxiv----then to me it seems questionable. I wonder why they insist on Blog-wallow when they could easily and clearly get their message across on HEP-TH.

 

[ccdantas]

I offer a clean, free-of-insults compilation/edition of what is (was) going on over at CV.

http://egregium.wordpress.com/2007/11/10/physics-needs-independent-thinkers/

Scroll down to "disclaimer".

For non-technical ramblings on the episode over at CV, see here

http://egregium.wordpress.com/2007/12/17/competitive-cycle/

and for my concerns on Lisi's theory and Distler's arguments, as well as on how far Smolin's work depends on Lisi's, see here:

http://egregium.wordpress.com/2007/12/11/garrett-and-smolin-to-boldly-go/

For technical discussions on Smolin's paper, I attempt to build a discussion here

http://egregium.wordpress.com/2007/12/07/the-plebanski-action-extended-to-a-unification-of-gravity-and-yang-mills-theory/

To which Smolin has posted a useful comment.

Thanks
Christine

 

[mitchell porter]

I wonder why they insist on Blog-wallow when they could easily and clearly get their message across on HEP-TH.

It may yet happen. But most of the blog discussion is ultimately a reaction to the mass media coverage of Lisi's original paper (except for Lubos Motl's post, which I think was an immediate earnest reaction to what he regarded as an absurd paper). There might have been one or two brief "comments", saying exactly what people have been saying on the blogs. Or it might have been ignored outside of LQG. As someone wrote at Wikipedia, "I don't think anyone here realizes how many wrong papers are posted on that preprint server every day. No researcher has time to debunk them - it would be a completely thankless and Sisyphean exercise. Instead, they just get ignored."

You could compare this case to Joy Christian's paper, earlier in the year, claiming a counterexample to Bell's theorem. That has received about half a dozen rebuttals at the arxiv, and no blogosphere flamefest. But even that paper was in New Scientist, so one cannot tell how much professional attention it would have received in the absence of journalistic attention.

There is actually one advantage to trial-by-blogosphere, and that is that general understanding may progress much more quickly. Look at how many exchanges there have been between Distler and Smolin on that thread at CV, and imagine if that had to take place by exchange of preprints! It would take weeks or months.

 

[marcus]

It may yet happen. But most of the blog discussion is ultimately a reaction to the mass media coverage of Lisi's original paper
...Or it might have been ignored outside of LQG. ...

You could compare this case to Joy Christian's paper, earlier in the year, claiming a counterexample to Bell's theorem. That has received about half a dozen rebuttals at the arxiv, and no blogosphere flamefest. But even that paper was in New Scientist, so one cannot tell how much professional attention it would have received in the absence of journalistic attention.

There is actually one advantage ...

I like the perspective you bring. A calm look at the whole picture.

What I get from you is a picture where even the despised popular media plays a part. Joy Christian posts on arxiv and gets plentiful rebuttals, themselves also on arxiv, partly thanks to agitation by the NewSci weekly hysteria machine.

I understand the advantage of blogs that you point out. The format itself demands rapid response. Comments quickly get covered up and lost in flurry. So quick volleys are exchanged. On the other hand there is something to be said for a slower format and more deliberate exchange. A discussionboard like PF seems to have somewhat longer-lived slower paced threads. As you observe, posting on Arxiv is even slower paced.

Sometimes it helps to say what is your Utopian vision, what you think would be ideal. What would seem ideal to me is if major figures like Smolin and Distler would confine themselves to exchange on Arxiv, in cool orderly style. And then let spectators including ourselves make noise about it. As a member of the mob of bystanders I feel confident that (with or without the help of NewSci and SciAm trombone sections) we could ensure that interesting debates on Arxiv do not go unnoticed.

Courtesy is (I hope) a separate issue. I think MORE courtesy should be required on blog and forum (than in unrecorded head-butting at the blackboard and coffeemachine). I find PF is somewhat unusual in that people actually have to be nice. Nastiness often gets deleted by the mods.

 

[marcus]

I offer a clean, free-of-insults compilation/edition of what is (was) going on over at CV.

http://egregium.wordpress.com/2007/11/10/physics-needs-independent-thinkers/

Scroll down to "disclaimer".

For non-technical ramblings on the episode over at CV, see here

http://egregium.wordpress.com/2007/12/17/competitive-cycle/

and for my concerns on Lisi's theory and Distler's arguments, as well as on how far Smolin's work depends on Lisi's, see here:

http://egregium.wordpress.com/2007/12/11/garrett-and-smolin-to-boldly-go/

For technical discussions on Smolin's paper, I attempt to build a discussion here

http://egregium.wordpress.com/2007/12/07/the-plebanski-action-extended-to-a-unification-of-gravity-and-yang-mills-theory/

To which Smolin has posted a useful comment.

Thanks
Christine

Christine, You have done a remarkable editing job! I like your blog format, where you enable only those comments which meet your standards. The tone is friendly and polite.

With enablement there is a slower pace, which allows your commenters time to have a normal life, and the discussion stays on track.

Your editing the CV script down to serious technical exchange between JD and LS had a surprising effect. there is no rudeness! nobody showing off how funny they can be. I didn't realize how much actual content there was. Your edited script goes up through 19 December. I am not suggesting you continue---you know best.

I was reminded of the folk-saying: "to make a silk purse out of a sow's ear." The CV comment stream was the ear of a pig, and you made a nice scholar's dialog out of it.
the change is almost funny.

Well, I have to go wash the dishes. I hope you and Mitchell think some more about these
blog+arxiv media issues. I will. We are gradually learning by examples what does and doesn't work.

 

[Ivan Seeking]

A note from Nature: Whatever happened to...

E8, that amazing mathematical structure?

E8 (or at least a 2D representation of it).American Institute of Mathematics/Peter McMullenIn March, researchers mapped a bizarre 248-dimensional object, an entity known in mathematics as E8. The map (which can be very prettily rendered in two dimensions) was touted as being useful to physicists interested in fundamental questions of quantum theory and relativity.

Then, in November, E8 surfaced again in reports of something claiming to be an exceptionally simple theory of everything, which basically involves sticking fundamental particles on various points of E8 and then looking at it in different ways to see how the particles relate to each other. The use of symmetrical structures in this way is fascinating and can be very powerful, and the story got lots of press after New Scientist highlighted it — not only because of the grand claim, but also because its source was a lone surfer with a physics degree. But physicists have since cast doubt on whether the idea is really new, really correct, or really able to make testable predictions. We’ll wait for the work to get peer reviewed for a journal, and for those crucial testable predictions to appear, before making a judgement.

http://www.nature.com/news/2007/071221/full/news.2007.390.html

 

[ccdantas]

Christine, You have done a remarkable editing job!

Thanks a lot, Marcus.

The whole CV episode was a complete mess. At the end, I was sad with how things ended.

I think blogs can serve as a serious place for technical or scientific exchanges in a friendly environment, but it is not easy, really. There are much more examples showing that it doesn't work than otherwise... I had to do some off-line moderation work. You must have time, energy and a sense of neutrality. I cannot say I have all these elements, specially the first ones...

Thanks,
Christine

 

[Coin]

We’ll wait for the work to get peer reviewed for a journal, and for those crucial testable predictions to appear, before making a judgement.

Incidentally, has/will Garrett's E8 proposals been submitted for peer review?

 

[Count Iblis]

Incidentally, has/will Garrett's E8 proposals been submitted for peer review?

His paper has already been reviewed by many people. So, he shouldn't bother to submit it to a journal. Submitting papers to a journal is for most papers a redundant exercise as http://users.ecs.soton.ac.uk/harnad/Hypermail/Amsci/1011.html" anyway.

 

[shalayka]

Thanks a lot, Marcus.

The whole CV episode was a complete mess. At the end, I was sad with how things ended.

I think blogs can serve as a serious place for technical or scientific exchanges in a friendly environment, but it is not easy, really. There are much more examples showing that it doesn't work than otherwise... I had to do some off-line moderation work. You must have time, energy and a sense of neutrality. I cannot say I have all these elements, specially the first ones...

Thanks,
Christine

I do agree that it was lugubrious that the conversation had to go the way it did, but it was becoming apparent that Lee Smolin had misstepped by giving unconditional praise to a paper that contained so many fundamental errors, and yet had no interest in describing what remained standing. All of this coming from someone who has such disdain for string theory as an unverified, unscientific meta-theory. The irony is ridiculous. Unfortunately for anyone who behaves in such a two-faced manner, I have a strong feeling that I'll be around for some time to come. I thought it was kind of cute that Sean Carroll doesn't realize that categorizing people as children is in itself an act of childishness. It just goes to show how high up in the clouds these peoples' heads are.

I suppose it's best said as "shut up and calculate". It's plainly obvious who's doing the talking, and who's doing the actual calculating.

 

[Ivan Seeking]

His paper has already been reviewed by many people. So, he shouldn't bother to submit it to a journal. Submitting papers to a journal is for most papers a redundant exercise as http://users.ecs.soton.ac.uk/harnad/Hypermail/Amsci/1011.html" anyway.

The folks at Nature seem to have a different opinion.

 

[Count Iblis]

The folks at Nature seem to have a different opinion.

Well, I don't see why the article would not be accepted in, say, PRD. The referees would perhaps only demand some clarifications on some contentious points. But papers are not usually rejected just because the referee doesn't agree with the author's conclusions.

 

[Electron17]

If Lisi's model turns out to be correct, does that mean all of physics is essentially solved and there will be nothing left to do? Or will the details need to be worked out for many years afterward?

 

[staf9]

If Lisi's model turns out to be correct, does that mean all of physics is essentially solved and there will be nothing left to do? Or will the details need to be worked out for many years afterward?

It means we have a LOT left to do, every question answered raises lots of new questions. In many ways, there may be even more that we don't know about if E8 Theory is correct. Some other people on these forums may be able to enlighten you more on this subject than I could.