Recent content by nonunitary

Hi, There are some mistakes in the people that is supposed to be in the photos. -The lady at the photo is not Luisa Doplicher, but K. Giesel. - Jacobson is not with Smolin, but with J. Barret. -That is not Thiemann, but Krasnov -Gikman is not with Magueijo (I don´t know the guy at the photo)

Hi, The guy looking at the camara in the marseille picture is Alejandro Perez.

Hi, DH stands for Dynamical Horizon. There is a nice recent review gr-qc/0407042

Hi, Eqs. (4.54) and (4.55) of the latest Ashtekar-Lewandowski review.

Hi, The paper by Horowitz is gr-qc/0410049. It is written for the volume edited by Pullin and Price. http://www.iop.org/EJ/journal/-page=extra.wypfocus/1367-2630/1

Marcus, Thanks for the comments. I would like to add something to the discussion about diffeos as unitarily implemented in LQG. The Ashtekar-Lewandowski representaion is not only the one that implements diffeos as unitary transformations (according to the standard definition that Selfadjoint...

Marcus, Thanks a lot! please do correct all my mistakes. I think the discussion is sharpening. And that is good.

Hi, I think what Rovelli means is precisely that it really does not make sense to ask for unitary evolution for a theory that has time evolution, classically, as a not unique concept. This is the celebrated problem of time. Rovelli is not carefull in making the distinction between gauge time...

Hi, Do you have the reference of who and why says that LQG is non-unitary?

Hi, There are two upcoming activities related to loop quantum gravity: http://www.perimeterinstitute.ca/activities/scientific/PI-WORK-2/index.php and http://www.nuclecu.unam.mx/~gravit/EscuelaVI/english.html

Marcus, As far as I know the first paper about the invariants was gr-qc/9803018 but you are right about the chunkymorphisms. The are a new invention of Rovelli. I haven't read the paper so I can not comment.

Marcus, If I am correct, the invariants for knots with intersections (I don´t know how many of them) are called Vassiliev invariants, and have been studied by J. Pullin and R. Gambini, even in the context of spin networks. Nonunitary

I think that there are two separate issues regarding the BI parameter. The first one has to do with the inclusion of general type of Isolated Horizons, form the type I, the original ones, to type II. These clasification has to do with the instrinsic geometry of the horizon. Type I means that the...

I am sorry, but I don't see the relation between the "small" paper of Ashtekar and the chapter by Rovelli. They are not even talking about the same thing! The paper by ashtekar is an attempt to show that such "weird" representations can indeed approximate the physics of the standard ones. If...

Marcus, The "shadow states" paper as you call it is certainly very relevant for LQG. The thing is that there are for instance two representation in a field theory, the Fock representation and the "polymer" representation, as Ashtekar has called it lately. LQG is an example of the "polymer"...