attention dr. mmcirvin

[rone]

I seek your opinion on Garrett Lisi's "An Exceptionally Simple Theory of Everything" (other physicists or physics fans are welcome to chime in).  Thanks to venividi for bringing it to my attention.

Comments

[dwenius.livejournal.com]

A cow-orker who actually groks a few of the simple Lie groups (which is a few more than me) says that the paper is less "here is a rigorous argument" and more "look at this fascinating thing I noticed." It mixes several different types of abstraction to place the fundamental particles on the e8 graph (wikipedia it, ooh, pretty, just solved this year), but he leaves out a lot of the hard work to make it obvious/proved. Also, if Lee Smolin likes it, I am immediately skeptical.

On the other hand, it's testable, unlike Strings. So when the LHC comes online, we may know fairly quickly if he's on to something. He ran out of fundamental particles with about 20 empty spots on his read of the E8 graph. By using the E8 like a partially filled out periodic table of fundamental particles, he's created plenty of test cases.

[nothings.livejournal.com]

The thing is, an article I saw on this linked to a March 2007 article about the mapping of the e8 graph... which made frequent reference to the fact that physicists in particular were interested in it, especially re: unification.

So either he's just stating a (semi-)conventional wisdom out loud, or if he actually did some interesting stuff, I imagine there were other physicists working on the same thing as well.

[doctroid.livejournal.com]

Funny, I was going to say "it sounds like crackpottery, but if Smolin says it's a good theory worth investigating, it probably is." Not that I think all of Smolin's ideas are right (indeed, I barely understand any of them) but he's certainly competent to distinguish crackpots from people with good, out-of-the-mainstream ideas.

Strings are not completely untestable.

[dwenius.livejournal.com]

Last I read (Greene's _Fabric of the Cosmos_), even the LHC will fall well short of the energies necessary to observe strings. and the secondary effects/predictions of string theory, which may be observable in the LHC, are not strictly limited to string origin.

Happy to be wrong. This is just a hobby and the math is way beyond me.

[reddragdiva]

Oh yeah. I crapped out on physics maths around first year undergraduate (nineteen years ago). But the paper is beautifully structured - Lisi knows how to tell a story. And he is keenly aware of every hole in this work-in-progress, and will quite readily go "oh well" should it fail to get anywhere.

[eqe.livejournal.com]

Garret has an online workbook at deferentialgeometry.org (http://deferentialgeometry.org/).

His list of blog links seems pretty comprehensive:

• Backreaction (http://backreaction.blogspot.com/2007/11/theoretically-simple-exception-of.html)
• Physics Forums (http://www.physicsforums.com/showthread.php?t=196498)
• The Reference Frame (http://motls.blogspot.com/2007/11/exceptionally-simple-theory-of.html)
• Hidden Variables (http://blog.domenicdenicola.com/post/2007/11/Criteria-for-a-Theory-of-Everything.aspx)
• Not Even Wrong (http://www.math.columbia.edu/%7Ewoit/wordpress/?p=617)
• Arcadian Functor (https://www.blogger.com/comment.g?blogID=28857369&postID=5548882952979522971)
• Freedom of Science (http://globalpioneering.com/wp02/an-exceptionally-simple-theory-of-everything/)
• Theoreman Egregium (http://egregium.wordpress.com/2007/11/10/physics-needs-independent-thinkers/)
• Science Forums (http://www.scienceforums.net/forum/showthread.php?t=29522)

thanks for the leg work!!!

[drieuxster.livejournal.com]

it is a wonder to have a nice consolidated back ground for those of us who have not been following the full on development.

[reddragdiva]

http://uncyclopedia.org/wiki/UnNews:Surfer_dude_stuns_physicists_with_theory_of_everything

Dr Lisi was amused. I wonder if Dr Motl will see it.

[ronebofh.livejournal.com]

Motl sure is a cranky bastard.

[reddragdiva]

Motl is very good, to use the cricketing idiom he has the runs on the board - he is however a completely arrogant arsehole. (I know, arrogant academics, who'da thunk it.)

[mmcirvin.livejournal.com]

Whenever he and Woit get into the same physics forum, you can basically shut down the thread and go home, because it's just going to be the two of them fighting over whether string theory roxx or suxx, and all the other high-energy physicists in the house will take sides and start brawling over it.

Also, when Motl gets into a discussion about race, sex or politics, run.

[mmcirvin.livejournal.com]

My first impression is "maybe promising but needs a lot more work". Grand unified models involving big Lie groups are a dime a dozen, though this one sounds like it has some unusual features. I wouldn't put too much stock in Lubos Motl saying it's obviously stupid.

[mmcirvin.livejournal.com]

Also, unless I'm missing something I don't understand Motl's objection on the basis of the Coleman-Mandula theorem. Surely the symmetry in question is spontaneously broken? If there's no mass gap in the symmetric state, then there's no problem.

The paper seems crackpottier than it is because of the chatty prose style, the profusion of pretty diagrams, and the overdramatic title containing a lame pun.

I think I basically agree with the stuff Peter Woit says about this on his blog (http://www.math.columbia.edu/~woit/wordpress/?p=617).

[mmcirvin.livejournal.com]

Hmm, Lisi's counterargument about Coleman-Mandula is different.

In any event, I wouldn't get too excited about Lisi's claimed unification of gravity with the other forces. There are lots of these papers where somebody says, "lo and behold, I found a spin-2 boson and the action for gravity in my unified foo theory; I have unified gravity and foo." But, as Sabine Hossenfelder says (http://backreaction.blogspot.com/2007/11/theoretically-simple-exception-of.html), that doesn't really address any of the big problems with quantizing gravity, and usually there are a lot of additional questions like how the big symmetry gets broken down.

[reddragdiva]

Lisi does seem to be a down-to-earth fellow, unfailingly polite and helpful in the physics blogosphere posts on the subject, who is keenly aware of every hole in his theory, and happily points out all the bits where it could be dead wrong. But offering actual testability (when he's worked out the particle masses, etc) at least makes it interesting, in that we'll know fairly soon whether he's going somewhere or it's another blind alley.

[dr-memory.livejournal.com]

So-called 'science journalists' at a major newspaper flogging a story because it flatters the preconceptions of their non-technical audience despite it likely being complete hooey? It couldn't be!

[mmcirvin.livejournal.com]

The "outsider surfer dude bests doubledomes, achieves Einstein's dream with revolutionary theory!!! Einstein!" angle of these articles is obnoxious.

[crisper.livejournal.com]

Really, it's just a matter of time before we're doing Science the way we do Politics. FACT-BASED LIBERAL ELITISM IS A RELIC OF THE 20TH CENTURY. WE *WILL* REALITY INTO EXISTENCE NOW! AND WHEN THAT FAILS, FUCK IT, WE OWN THE PRESS ANYWAY!

[eb-oesch.livejournal.com]

I am neither physicist nor "physics fan", but perhaps it is no handicap that I have not mastered the tools with which the physicist oppresses his own imagination.

Why do we expect simple laws of attraction? If we cannot understand human love, how can we expect to understand the relationships of objects whose size and scale are beyond human conception? Yes -- I tell you that atoms and galaxies know love! Nothing could be simpler, yet more complex. Existence without love is not existence, and galaxies exist indeed (though I am not sure about George Bush). But why do we expect physicists, of all people, to understand such things? Newton never married; Einstein was divorced!

"Falsifiability" is held as a great virtue in physics, but why should a tendency towards wrongness be held a virtue? I tell you that my expositions of the natural order are correct now and will remain correct a million years from now, and I defy you to ever prove otherwise! Are not physicists' continued refinements and revisions mere proof of their failure? Picasso did not find it necessary to correct his paintings decades later!

Finally, I read in these comments about such ugliness between this "Lisi" and this "Motl" and this "Woit" -- knowing that truth is beauty, how can these physicists fail to understand that they are on the wrong path?