E8 Theory of Everything

Og · 11-24-2007, 07:34 AM

http://www.youtube.com/watch?v=-xHw9zcCvRQ&feature=user

So a surfer named Garrett Lisi has a PhD in theoretical physics from UCSD and recently presented the idea that the universe is an expression of the multi-dimensional object "E8". It offers a representation and link between all fundamental forces in nature, requires only 3 dimensions, and makes predictions that can be tested in an upcoming particle accelerator that is being built.

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

That's his wikipedia page. It seems like an elegantly simple way of expressing the universe using geometry of a high dimensional object that we've known for quite some time.

This would unify all of the particles and describe their interactions and forces. It would solve the problem where general relativity meets quantum mechanics and integrate gravity with the electro weak/strong forces and give us a theory of everything.

Thought it was neat and it'll be cool to see if it matches with observation! It's an alternative to String Theory. It's predictions can be tested at the new high energy Large Hadron Collider in switzerland that is currently under construction and will begin operation next year. The problem with string theory is that it doesn't make testable predictions. The E8 Theory seems like an elegant representation of the universe. If new particles discovered in the high energy collider fit with this hypothesis then it will certainly start becoming the focus of much interest of the scientific community.

AB517 · 11-24-2007, 08:17 AM

Cool Og

Thanks

A black hole can do it, why can't we

romansh · 11-24-2007, 11:07 AM

Quote:

Originally Posted by Og

http://www.youtube.com/watch?v=-xHw9zcCvRQ&feature=user

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

Thanks Og .... I'll look forward to reading this when my New Scientist arrives
But it seems like all these theories it has a long way to go before the theory of everything is home and dry:

Quote:

Sabine Hossenfelder of the Perimeter Institute for Theoretical Physics, who recently arranged for Lisi to address an international meeting on loop quantum gravity, and who is thanked in Lisi's paper as having been a useful correspondent, nevertheless stresses the limitations of the work, commenting:

How can I possibly say that clearer: Given today's status,

Garrett's model does *not* naturally lead to a unification of the Standard Model interactions with gravity (he has to choose the action by hand that contains both),
it does *not* allow us to understand quantum gravity (since there's nothing said about quantization);
it does *not* explain the parameters in the SM (since there isn't yet a mechanism for symmetry breaking);
it does *not* explain the cosmological constant or its value (as said above, to claim there has to be one, it would be necessary to show there's no way to do it without one);
it does *not* explain the hierarchy problem (and I see no way to do so);
it does *not* explain why we live in a spacetime with 3 spatial and 1 time-like dimensions.[10]

Overall she is undecided about her feelings towards the theory. She writes that for her, "the attractive and the unattractive features seem to balance each other. To me, the most attractive feature is the way he uses the exceptional Lie-groups to get the fermions together with the bosons. The most unattractive feature are the extra assumptions he needs to write down an action that gives the correct equations of motion".[11]

She also has technical concerns about the lack of coupling constants in the paper, which thus appears to rely on pulling a particular characteristic length scale out of nowhere. However, in the end, she states, "I think Garrett's paper has the potential to become a very important contribution, and his approach is worth further examination."[11]

But I admit it is pretty
all the best

Maximus · 11-24-2007, 12:57 PM

Interesting.

That's all I got to say.

SignMeUp · 12-28-2007, 04:37 PM

I read this not so long ago and i was fascinated by this guys ideas. I think the idea came from a shape that was recently compute, it was highly complex due to the symmetries involved.

My physics and maths are only at A-level, so i will probably not gain a deep understanding of this guys theory, but non-the less i will be watching this space, intently.