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A New Theory of Everything?
Posted by
CowboyNeal
on Thu Nov 15, 2007 07:20 PM
from the it's-all-made-of-stars dept.
from the it's-all-made-of-stars dept.
goatherder writes "The Telegraph is running a story about a new Unified Theory of Physics. Garrett Lisi has presented a paper called "An Exceptionally Simple Theory of Everything" which unifies the Standard Model with gravity — without using string theory. The trick was to use E8 geometry which you may remember from an earlier Slashdot article. Lisi's theory predicts 20 new particles which he hopes might turn up in the Large Hadron Collider."
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E8 Structure Decoded 127 comments
arobic writes "A group of mathematicians from US and Europe succeeded in mapping the E8 structure, an example of a Lie group. These were developed by the well-known mathematician Sophus Lie (pronounce Lee) in the last century and are used for many applications, mainly in theoretical physics. This is an important breakthrough as it could help physicists working on Grand Unified Theories (aka GUTs)."
Submission: A New Theory of Everything? by Anonymous Coward
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GUT from a surfer dude! (Score:5, Funny)
Re:GUT from a surfer dude! (Score:5, Informative)
Parent
Go Clifford Algebra (Score:5, Interesting)
I have read of ideas for unifying physics by using these notations for their superior ability to reason with space. (David Hestenes has good examples.) A good physical theory should be like a consistent programmer's interface. If the "code" continues to become unwieldly over time, then a point will be reached where rewrites must be done in order to eliminate special cases and bring out hidden symmetries.
This particular paper may end up failing important tests, but it does seem clear that at some point Clifford Algebras will end up being the thing that ended up simplifying physics.
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5 years isn't bad (Score:5, Interesting)
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Re:GUT from a surfer dude! (Score:5, Funny)
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Re:GUT from a surfer dude! (Score:5, Funny)
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might be on to something (Score:5, Funny)
I'm not sold yet (Score:5, Funny)
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Re:might be on to something (Score:5, Informative)
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Re:might be on to something (Score:5, Informative)
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Re:might be on to something (Score:5, Funny)
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Re:might be on to something (Score:5, Informative)
But note how this theory has made TESTABLE PREDICTIONS - 20 new particles in a specific pattern. That's more than Lubos can claim after years of "research". The theory might be wrong, but at least it's a scientific theory. Lately, in the (rather rarefied) physics community, Lubos really is used as a sort of contrary guide - if Lubos doesn't like it, you might be on the right track.
Parent
I have a horrible feeling... (Score:5, Funny)
Re:I have a horrible feeling... (Score:5, Insightful)
http://lucis.net/stuff/clarke/9billion_clarke.html [lucis.net]
Parent
Best quote from the article (Score:5, Funny)
I smell an XKCD comic approaching....
Re:Best quote from the article (Score:5, Funny)
The author of the paper is claiming
that E8 contains the Standard Model (SU(3)xSU(2)xU(1)),
plus the symmetries belonging to gravity.
/
--- ---
| |
/ \ / \
________________
When I look at you, you make the
patterns in the floor tiles
vanish.
/
--- ---
| \|
/ \ / \
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Re:Best quote from the article (Score:5, Funny)
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Huh? (Score:5, Funny)
Re:Huh? (Score:5, Informative)
It's built upon E8, which is the largest, most complicated (i.e. an exceptional case) finite simple Lie group.
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Huh (Score:5, Funny)
For the non-mathematicians (Score:5, Informative)
A group is a set with an operation (and a couple of extra properties), such as the integers under addition.
The set of a symmetry group is the set of operations that you can perform to an object and have the object remain unchanged. For example, for an equilateral triangle, rotating it by 120 and 240 degrees leaves you with a triangle. So does flipping it around any of its three axes. Add the identity operation, which leaves the triangle untouched and you have the symmetry set for an equilateral triangle. Add an operation and you have a symmetry group.
The U(1) group is the group of all unitary, 1-dimensional operations that leave the inner (dot) product invariant.
The SU(2) group is the group of all unitary, 2-dimensional operations that leave the inner (dot) product invariant and have a determinant of 1.
The SU(3) group is the group of all unitary, 3-dimensional operations that leave the inner (dot) product invariant and have a determinant of 1.
The Standard Model obeys the symmetry found by combining the three above groups: SU(3)xSU(2)xU(1).
E8 is another group with some special properties. The author of the paper is claiming that E8 contains the Standard Model (SU(3)xSU(2)xU(1)), plus the symmetries belonging to gravity.
Re:For the non-mathematicians (Score:5, Funny)
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Re:For the non-mathematicians (Score:5, Funny)
If you swap two cars, that operation with the set of cars forms a group.
Maybe all of your cars are red. Then swapping any two doesn't change the pattern of colors in your garage. You have a color symmetry.
Happy? =)
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Re:For the non-mathematicians (Score:5, Funny)
The U(1) group is the group of all unitary, unicycles that leave the inner (dot) product invariant.
The SU(2) group is the group of all unitary, motorcycles that leave the inner (dot) product invariant and have a determinant of 1.
The SU(3) group is the group of all unitary, 3-wheeled novelty cars that leave the inner (dot) product invariant and have a determinant of 1.
Parent
Understandable Description (Score:5, Informative)
I found this site easier to understand than the wikipedia link. I warned my trig students about higher dimensions - wait till I tell them about 8-d vectors, they'll love it!
PDF (Score:5, Informative)
here's the abstract for those wondering if they should download it:
Although it is chock full of pretty pictures as well. If he's right, somebody is going to do a story about how the Star of David came to be important (Ezekiel's Wheel?) and want to talk to those soldiers who saw the ship in the woods in Britain that was decorated with a complex pattern with triangles in the middle.
OK, enough mindless rambling...
E8's Dimensions (Score:5, Funny)
Re:E8's Dimensions (Score:5, Funny)
Parent
This is most likely BS. Please see here. (Score:5, Informative)
http://motls.blogspot.com/2007/11/exceptionally-simple-theory-of.html [blogspot.com]
'That's pretty cute!
Re:This is most likely BS. Please see here. (Score:5, Informative)
Thats what unifying physics is all about. Coming up with one theory to explain everything that used to take multiple, completely unrelated theories to explain
By your analogy, he is showing that apples and oranges are really just different types of fruits.
The best example I can think of is Maxwell's electro-magnetism equations. It might seem obvious today, but it was an amazing breakthrough to realise that electrical fields, currents and magnetism were really just two sides of the same coin. Most lay people of that time must have thought it was a childish misunderstanding to relate lightning and what makes a compass work
I can't speak for whether the theory is flawed or not, but I think you're a little too quick to dismiss it based on high school seniors knowledge.
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Re:This is most likely BS. Please see here. (Score:5, Informative)
So I wouldn't pay attention to Lubos when he says that someone is a crackpot and their ideas aren't feasible. A lot of physicists just look at his comments as free publicity because if Lubos is criticizing it, it usually means that he feels threatened by it, therefore, it could have some promise if it at least got his attention.
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Re:This is most likely BS. Please see here. (Score:5, Informative)
Here's what he says about Lee Smolin, author of The Trouble with Physics
No true academic speaks that way about any idea, whether he disagrees with it or not. That's not science, that's fanboi-ism.
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Re:This is most likely BS. Please see here. (Score:5, Funny)
It's very clear that if someone dislikes BSD, she or he must dislike most of modern operating systems, too (Lee Smolin certainly does!). It's because BSD is nothing else than the crown, unification, or culmination of modern operating systems and all of its crucial results, insights, methods, principles, and values.
See? Gentoo, Linux, or anything else with fanboys. Try it with "PS3" and "gaming consoles", or any other combo.
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Clear as mud (Score:5, Funny)
Now I know how my wife feels when my friends come over and we talk shop.
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Pure Maths (Score:5, Funny)
"complex simple Lie algebras"?
Mathematics needs some new words, I think. And they need to stop using 'simple' in this kind of context. What about; instead of 'simple' they use 'mindbogglingly complicated' and instead of 'complex', 'totally headfucking' making the statement a more accurate 'totally headfucking mindboggleing complicated Lie algebras'.
Genius? (Score:5, Funny)
What is this new unit? (Score:5, Funny)
Is that more than a LoC(Libraries of congress)?
An attempt at a summary (Score:5, Informative)
Different groups have different symmetries. E8 is a group in Lie algebra. The group is "exceptional" and "simple" which is why the article is entitled tongue-in-cheekishly "Exceptionally Simple". The power and beauty of the E8 group has been known for a long time, and it's featured in many theories of physics that have tried to provide an framework for explaining the bewildered world of particles and forces that make up the universe.
What this author has done is use E8 in a new way to come up with a potential new theory that unifies all the forces and fields. This is not *strictly* a theory of everything, as there's a lot more that has to be answered, but if true it provides a geometric model that can give us insight into the underlying principles that are involved, just the way the Periodic Table does for elements.
The guy is no kook, but his theory leaves a lot to be desired. One problem is that E8 and other lie algebras and their associated symmetries have been well-studied for decades, and most all of them have run into intractable problems or incorrect predictions, so this may just be another beautiful theory that doesn't fit reality. Lisi uses a little-known method called "BRST connections" to make it all seem to work, which most physicists are unfammiliar with. Another is that his theory actually forces something physicists call as "spontaneous symmetry breaking" into the calculations to make it fit what we know to be true in the "standard model". Many people feel this is putting the cart before the horse; they would prefer a theory where the symmetry is broken in a "nautral" way and the "standard model" of the universe just naturally falls out of it. Lisi's theory doesn't really tell us WHY this is the case, it just says it is, but here's the symmetry that underlies it and which you apply it to.
Another problem is that the theory is still new and doesn't have an quantitative predictions as of yet... there's a lot of math that needs to be done, and it's not clear that such calculation *can* be done given the contraints of his theory. At issue is something known as the "Coleman-Mandula" theorem, which basically says a lot of what Lisi does in his theory doesn't work if there are subgroups in the algenbra that are equivalent to what are known as Poincare groups. Lisi says this doesn't apply to his new theory because it posits that the vacuum of spacetime doesn't have Poincare symmetry but instead is deSitter space. Well, the idea of deSitter space is well-known and has been examined in theoretical physics for decades as well, but there are a lot of problems with it. One is that the "Smatrix", which physicists love so much in making calculations in theories with Poincare symmetries, no longer works and simply becomes an approximation.
The theory also predicts a very LARGE cosmological constant, which is contrary to observation, but there are other theories that explain how this is not actually a problem, so that might not be an issue. Perhaps the largest obstacle of the theory, once the calculations can be figured out, is that it pretty much obsoletes all of String Theory in favor of something like Loop Quantum Gravity. This will make a LOT of string physicists very unhappy.
Lisi's theory will probably not be the last work in physics, but it might bring us a step closer to a real "Theory of Everything". The truth is physicists have been toying with similar geometric approaches and arrange particles in tables and trying to tie in gravity for decades now and every new theory looks great but never quite actually works out. The fact that the universe can *almost* be described via these methods probably tells us we're on the right track, but a true
Re:An attempt at a summary (Score:5, Interesting)
-Garrett
(Yes, I'm the author of the paper. Hey look, my server's melting -- must of hit slashdot...)
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Re:Huh? Wat? (Score:5, Funny)
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I think it's some sort of ad. (Score:5, Funny)
Simply put, it's a complex dimensional algebra with lots of non-trivial, commutative degrees of freedom. It features symmetry groups, conjugation and adjoint representation, and comes with a free manifold which displays automorphism - so it can neatly fit into any space. For a small extra fee, we'll throw in some Vogon Polynomials and a Spin(16) (Z/Z2) which, fundamentally, gets your clothes drier, quicker. The best thing about the E8 is it's R8 Root System(TM), which, with the use of Euclidean Space Vectors is guaranteed(*) to make sure you don't get octonions on your breath. And if you order now, we'll send you a bonus 8x6 photo of Jacques Tits.
But honestly, I foud the wikipedia article pretty useless too. I'm not nerd enough.
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Re:I don't understand a thing :( (Score:5, Informative)
Okay, the context is that you've got particles, and they're fundamentally all the same, but they're "turned" in different ways. Think of a ball with 3-color LEDs inside: you can rotate it around three axes, and move it in three directions, and you can also cycle its color and change its blinking pattern. Particles are like that, except that the topology is weird: it's not back to the same orientation until you turn it around 720 degrees, instead of 360 like normal objects. The "gauge group" is the rules for how you can change things. For example, the total color of the universe is white: if you turn something from red to blue, you have to turn something else from blue to red; but you can also create a pair of a green and a purple (anti-green). They write all these rules up in math, and it's tricky because a lot of the features vary continuously (that is, you can rotate something an arbitrarily small amount). And due to the interaction of the rules for one property with the rules for other properties, there are only certain combinations of properties that you can get. They work out all the combinations that you can have and those are what you see as "different" particles that your experiments show. Of course, we don't know what the rules are, and we're trying to figure that out from what combinations of properties we've seen and which ones we're speculating are impossible. And it's hard and takes a lot of calculation to figure out what a candidate set of rules would even mean as far as results. And people are looking at known results and trying to describe them better than "we've done a billion things, and a billion things happened".
Now, the math of rules for how things can interact turns out to be sort of limited; there are basically 4 normal cases, which are boring, and then there are a few exceptional cases, which are interesting. Of these, the hardest to prove stuff about is E8, and it's just now becoming clear what combinations it allows. It's like one of those puzzles where you press a corner and lights change, and you have to turn off all the lights, but it's got dozens of corners and dozens of lights and every time you press a corner a bunch of things change at once, and there are different kinds of corners and it also matters exactly what angle you're holding it at, so there are hundreds of things you can say about each move.
And the mathematicians working on E8 recently said, "well, you can get positions like this and not like that", where "this" and "that" are big complicated lists. And this physicist read that paper and said, "hey, those lists are familiar; I made similar lists of particle interactions". So the proposal is that particles work like E8 in what kind of rules they follow. And it's a really nice theory, because E8 is essentially the most flexible set of rules you can have without it falling apart into just anything being possible (and some rules or properties just not mattering).
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Re:I don't understand a thing :( (Score:5, Funny)
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Re:I don't understand a thing :( (Score:5, Insightful)
I have Bachelor degree in Physics (over 20 years ago) and I had no idea what the hell was being talked about. Your explanation is BRILLIANT. It does not assume readers are morons, does not portray science as magic, explains the subject in a way that even a layman finishes reading it with a better understanding than they started, and even manages to infuse some feeling for what the scientific discovery process is like. Amazing.
As someone who originally got into science because of Carl Sagan's Cosmos I can honestly say that if I had lecturers like you I would still be doing science. (not surprisingly, the subjects that I did best in had lecturers cut from the same cloth).
Thank you.
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Re:I don't understand a thing :( (Score:5, Funny)
Try to picture a spherically inverted multifaceted poly-dimensional plexoid of random size, add in an elemental variable thermal/mass coefficient linking system based on the gravitational and magnetic field enhanced rate of change fluctuations of sub-atomic particles and it all comes together like butter and honey on toast. Well, butter and honey don't really come together on toast but you get the idea...
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Re:Exceptionally simple? (Score:5, Insightful)
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Re:FTFA (Score:5, Informative)
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Re:FTFA (Score:5, Informative)
He's not saying space has 248 dimensions, he's describing the geometry of a polygon. If you read the paper, he's only invoking 3 spatial dimensions and one time dimension to define our universe.
Let's say you've got a cube, and each corner of the cube represents the properties of a subatomic particle. You can have a total of 8 subatomic particles and you can create a direct line between any point on the cube and any other.
E8 is a 248-dimensional set of lines connecting the points of a 57-dimensional imaginary object. What he has done is merge the E8 "object" with the various subatomic particles and used the remaining unassigned points to predict the features of those particles we have yet to detect. In essence, he's created a math representation of a periodic table of subatomic particles.
People with Ph.D's in mathematics aren't expected to understand the theory. People with Ph.D's in particle physics aren't expected to understand the theory.
Quite frankly, there's a serious audience of around one hundred people on the planet that can actually grasp what he's saying, and they seem to be divided about it and its ramifications.
~ J. Barrett
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Think properties, not dimensions. (Score:5, Informative)
Now, there are other valid combinations of properties within E8 beyond the ones that represent the particles in the standard model, and these combinations would represent new particles that we have not seen before, if the model is correct.
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Re:Lubos Motl (Score:5, Insightful)
Would you completely dismiss some new IT products because Steve Balmer speaks out calling it garbage? Probably not.
If lots of other people also spoke out calling it garbage then you might start paying attention. Now I don't know if this guy is the Steve Balmer of the physics community or not, but I know nothing about him so why should I trust his word over some other guy I know nothing about either?
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