- #1

MTd2

Gold Member

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## Main Question or Discussion Point

I just heard about Oriti when 3 days ago. But it seems he has interesting ideas. I will try to understand what Oriti is trying to accomplish, helpe please. His last article http://arxiv.org/abs/0710.3276 talks about the realization, or better, the emergence of gravity from fundamental scales.

The novelty here it is that Oriti doesn't merely take the low limit of a parameter, instead, he looks for an phenomenological analogue in the real world. Then, he sugests that the continuum classical limit appears as a Bose Eisntein condensate from Planck scale, in the sameway that we see the lattice of atoms emerging as a a continum condesate in millionth of kelvin.

A similar this point of view is present in a superstring theory, where one can view a brane as a low energy condensate of their energy spectrum, whose geometry is determined by the degrees of freedom of allowed colective motion of the open strings. Brane here, is the classical stuff, where GR can be found somewhere. Note that gravitons can't condensate, just the strings, since there isn't a multi graviton state, at least as they are described by string theory, according to a theorem of Weinberg-Witten., I think

The crucial difference it is that in String theory, you can see explicitly particle that will be part of the gravity in the condensate, the graviton, in the perturbative expansion of the string, whereas in GFT, the graviton is nowhere to be found as a particle, because it will by itself be a fundamental piece of colective motion, that is a multiparticle state. So, in GFT, gravitons may condensate, but I am not sure...

The novelty here it is that Oriti doesn't merely take the low limit of a parameter, instead, he looks for an phenomenological analogue in the real world. Then, he sugests that the continuum classical limit appears as a Bose Eisntein condensate from Planck scale, in the sameway that we see the lattice of atoms emerging as a a continum condesate in millionth of kelvin.

A similar this point of view is present in a superstring theory, where one can view a brane as a low energy condensate of their energy spectrum, whose geometry is determined by the degrees of freedom of allowed colective motion of the open strings. Brane here, is the classical stuff, where GR can be found somewhere. Note that gravitons can't condensate, just the strings, since there isn't a multi graviton state, at least as they are described by string theory, according to a theorem of Weinberg-Witten., I think

The crucial difference it is that in String theory, you can see explicitly particle that will be part of the gravity in the condensate, the graviton, in the perturbative expansion of the string, whereas in GFT, the graviton is nowhere to be found as a particle, because it will by itself be a fundamental piece of colective motion, that is a multiparticle state. So, in GFT, gravitons may condensate, but I am not sure...