Petr Horava's quantum Gravity ( without strings)

[MTd2]

Petr Horava attempts to start at this paper a small quantum gravity theory, like Loop Quantum Gravity, except that he, according to his words:

http://arxiv.org/abs/0901.3775v1

"In analogy with Yang-Mills, we are motivated to look for a “small” theory of quantum gravity in 3+1 dimensions, decoupled from strings. One attempt to construct such a “small”
theory is offered by loop quantum gravity. In this paper, we present a new strategy for addressing this problem. Compared to the previous approaches to quantum gravity, the novelty of our approach is that it takes advantage of theoretical concepts developed in recent decades in condensed matter physics, in particular in the theory of quantum critical phenomena."

I haven't yet read the paper, but I am really surprised he didn't use any string theory for that!

Perhaps that can be embended in string theory, but nonetheless, he didn't even adressed that in the conclusion. For those who don't know Petr Horava, he is one of the greatest string theorists.

 

[Sauron]

You have forgoted to put the link...

 

[MTd2]

Ok, I posted the link :)

 

[BenTheMan]

Check out Lubos' review of this idea. Because it was written by a string theorist, he doesn't bash it outright.

http://motls.blogspot.com/2009/01/horava-lifgarbagez-cotton-and-uv-general.html

 

[MTd2]

Hmm, I don't know if you follow my philospophical mumbles in this very subforum, but I think that non diffeoformism in 4 manifolds and lorentz violation causes QM to emerge from gravity and ghosts. It doesn't make sense, and surely sounds insane and crackpot to extreme. But I think if I set up a few things, perhapes related to condensed matter, that makes this something more like natural. I liked that article, because it makes me vaguely remember these ideas...

 

[CarlB]

There's another:

Lorentz symmetry breaking as a quantum field theory regulator
3 Feb 2009
http://arxiv.org/abs/0902.0590

These are going to be big, I think.

 

[MTd2]

This Matt Visser is one of my favorites right now. He is studying Black Hole mimickers, such as fuzzy spheres of string theory or one of the proposals of mimickers from Ashtekar, which I think are the realistic stellar objects, instead of black holes.

This is something I've been thinking because I never considered the usual solutions for GR as the true final state of any matter colapse (although the usual solutions are nearly perfect, almost undistinguishible from mimickers), given that, in the moment in which the even horizon "eats" the star, by considering a star as a continuous object, ignores the fact that particles are still there and they are still discrete objects. And there is the problem, that I see, of the dicotomy between the infinite/finite particle to add itself into a black hole, and which also ignores the fate of the universe (and the black hole), from the point of view of an infalling particle, before it crosses the horizon.

http://arxiv.org/abs/0901.4365
http://arxiv.org/abs/0902.0346

Maybe one of the things Matt has in mind, not cited in the article, by using this new Horava model, would be finding fuzzy spheres without resourting to String Theory.

 

[BenTheMan]

Hmm, I don't know if you follow my philospophical mumbles in this very subforum, but I think that non diffeoformism in 4 manifolds and lorentz violation causes QM to emerge from gravity and ghosts.

You believe it or you've shown it? Because, you know, there's a difference...

 

[MTd2]

You believe it or you've shown it? Because, you know, there's a difference...

I thought it was clear that I believe that...