[hep-th] naslov i apstrakt

[Branislav Cvetkovic]

Postovane kolege,

U petak 13. oktobra u 11 h na Institutu za fiziku Tijana Radenkovic ce 
odrzati seminar pod naslovom
"Quantum gravity on piecewise-flat manifolds". Apstrakt vam prosledjujem 
u nastavku.

Pozdrav Branislav


Apstrakt:

First, we introduce the Ponzano-Regge model and it is shown that pure
three-dimensional gravity is just the BF theory. Four-dimensional
General Relativity can be formulated as BF theory with an additional
constraint term added to the Lagrangian, so we present here the
quantization procedure of the topological sector for both 3D and 4D
models. We see how General Relativity can be formulated as a gauge
theory for the Poincare 2-group like a constrained topological theory
based on BFCG action. Covariant quantisation of the topological sector
of the spin cube model - BFCG action is implemented the same way as in
BF case. We see how the issues of spinfoam models are successfully
resolved by spin cube model - the edge lengths of a triangulation
become the basic dynamical variables and matter can be consistently
coupled to gravity in this formulation. Additionally, a brief
introduction to the concepts of Regge calculus and 2-groups in higher
category theory is presented.

-- 
Institute of Physics Belgrade
Pregrevica 118, 11080 Belgrade, Serbia
http://www.ipb.ac.rs/