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Alejandro recently submitted a post at SPS which engaged the active attention of Lubos Motl. So much so that unless one has sharp eyes one cannot see Alejandro's original post-----there are so many "moderator notes" inserted by Lubos.
this means Alejandro's original post probably has some interesting points, so let us reconstruct it here (without the L.M. comment) so we can see the overall tenor of it----after that we can consider what L.M. interjected, and how Alejandro replied and so forth. Here is the reconstructed original:
----quote from arivero---
Some days ago, in another forum, Urs wondered why some of us are very
positive about the relationship between strings and gauge theory but
we are not excited about the point of strings "knowing gravity".
[1]
Yep, if one thinks about it, it is surprising that I am not surprised.
Perhaps it is because string lessons do not derive, as far as I have
read, Einstein-Hilbert action in some limit.
[2]
Most teachers just show a sort of consistent spin two particle and they
say "see, the graviton here". Some others note that string is about
word-sheet actions, thus it contains a constant having the dimensions
appropiate to measure curvature. But neither spin two nor curvature or
area are definitive signatures of our gravity. It is possible to formulate
a curvature theory for other approximations to Einstein gravity, for
instance for Newtonian gravity.
[3]
Perhaps related to this doubt, note that also Electroweak Theory has a
non-renormalisable, area-like, constant: fermi constant. But it does
not have spin two particles by itself.
[4]
And one could devise some ways
to formulate EW theory, or even electromagnetism, as a worldsheet
action theory, thus sort of strings.
[5]
But I do not see how a elementary spin two field would be forced by using
these formulations.
[6]
Alejandro
--------------end quote--------
I have put numbers as pointers to the "moderator notes", which I will fetch so we can see the general tenor of them as well.
this means Alejandro's original post probably has some interesting points, so let us reconstruct it here (without the L.M. comment) so we can see the overall tenor of it----after that we can consider what L.M. interjected, and how Alejandro replied and so forth. Here is the reconstructed original:
----quote from arivero---
Some days ago, in another forum, Urs wondered why some of us are very
positive about the relationship between strings and gauge theory but
we are not excited about the point of strings "knowing gravity".
[1]
Yep, if one thinks about it, it is surprising that I am not surprised.
Perhaps it is because string lessons do not derive, as far as I have
read, Einstein-Hilbert action in some limit.
[2]
Most teachers just show a sort of consistent spin two particle and they
say "see, the graviton here". Some others note that string is about
word-sheet actions, thus it contains a constant having the dimensions
appropiate to measure curvature. But neither spin two nor curvature or
area are definitive signatures of our gravity. It is possible to formulate
a curvature theory for other approximations to Einstein gravity, for
instance for Newtonian gravity.
[3]
Perhaps related to this doubt, note that also Electroweak Theory has a
non-renormalisable, area-like, constant: fermi constant. But it does
not have spin two particles by itself.
[4]
And one could devise some ways
to formulate EW theory, or even electromagnetism, as a worldsheet
action theory, thus sort of strings.
[5]
But I do not see how a elementary spin two field would be forced by using
these formulations.
[6]
Alejandro
--------------end quote--------
I have put numbers as pointers to the "moderator notes", which I will fetch so we can see the general tenor of them as well.