New Unified Theories: Current Research

[AlphaT]

Is anyone currently working on new theories unifying matter and fields that differ from string theory?

 

[marcus]

Is anyone currently working on new theories unifying matter and fields that differ from string theory?

Look up the recent papers of Nicolai and Meissner. Their theory is empirically testable---could be falsified (if it is wrong) by the LHC. It is also extremely economical in an Occam Razor sense. Does not require a lot of new machinery. Minimalistic, in a sense.

Do you know how to do an arxiv search, by author's name? If you need coaching on this please ask.
http://arxiv.org/find

There are several unification approaches currently in the works that seem more definite/predictive, and less fantasy-minded than string. Nicolai-Meissner should give you something to start on.

There is also Krasnov's Gravity-YangMills-Higgs unification bid that just came out. I started a thread on it. Krasnov has references to other unification attempts, including a polite salute to string theory, in his bibliography at the end. That's a place you could dig for more, if you want a longer list.

I would suggest if you are at all interested in the currently promising approaches to unification that have appeared since interest in string began to decline, you should watch the video of Nicolai's talk at the July 2009 conference on Planck Scale. It is an introductory level talk. It will give you a concrete idea of something definite that is on the table--not just some second-hand word-of-mouth pablum.

Nicolai is one of Europe's most influential and respected string theorists (yes he as done plenty of stringy research too, but is currently working on this simpler unification alternative) so the direction he has taken is particularly interesting, I think.

I'll get a link to the talk in case you want to watch it. It is number 1.3 on the menu here:
http://www.ift.uni.wroc.pl/~rdurka/planckscale/index-video.php
The slides are also available separately as a PDF if you want to have them handy while you watch the video.

You asked a good question BTW, it is interesting to watch the new bids for unification that are coming up. Nicolai is the director of the quantum gravity and unification arm of the Albert Einstein Institute, which is Germany's main research center involved in this. So the AEI hosts researchers from various parts of the world who are working on various new approaches to unification.

One general strategy you should be aware of is a kind of gradual one where instead of trying to leap directly to unification you first focus on getting the quantum spacetime geometry right (another name for that is quantum gravity since gravity = geometry) and then, once you have a satisfactory quantum version of space time geometry, it might give you a clue how to build matter fields on it. Krasnov is an example of someone who has proceeded along those lines. He started with a new approach to treating gravity/geometry and now he is at the Gravity-YangMills-Higgs stage.

Good question! The new stuff is fascinating to watch develop!

 

[ErnieDouglas]

Believe everyrhing is part of a whole from which all parts can be derived by cause and effect, and it seems like observers describe effects that come from nowhere, and there is no causality. Non professional posted The Ontological Matter. Believe professional can use a basic geometry and implicit forces to account for everything as part of the whole.

 

[humanino]

In this context, I think Alain Connes' ideas deserve to be mentioned. They do realize the standard model + gravitation as we picture it on an ordinary spacetime as only gravitation on a non-commutative generalization thereof. Whether or not those ideas turn out to be relevant at a fundamental level, but in the same context, Kreimer's work on Hopf algebras also put an end to the misconception that the renormalisation program is unsound mathematically.

Which approach we prefer is mostly a matter of taste of course, and it is desirable, even for string proponents !, that several paths are explored. In an ideal world, they would eventually converge.