2010/09/02 by Rolando Gaitan Deveras · 1 citation
Physics and Astronomy · #gr-qc #hep-th
paper · pdf · doi:10.1142/s0217751x10050561
published as Int.J.Mod.Phys.A25:4911-4932,2010 · To appear in International Journal of Modern Physics A
arxiv created 2010/09/02 · arxiv updated 2010/11/05
A perturbative regime based on contortion as a dynamical variable and metric as a (classical) fixed background, is performed in the context of a pure Yang-Mills formulation for gravity in a 2+1 dimensional space-time. In the massless case we show that the theory contains three degrees of freedom and only one is a non-unitary mode. Next, we introduce quadratical terms dependent on torsion, which preserve parity and general covariance. The linearized version reproduces an analogue Hilbert-Einstein-Fierz-Pauli unitary massive theory plus three massless modes, two of them represents non-unitary ones. Finally we confirm the existence of a family of unitary Yang-Mills-extended theories which are classically consistent with Einstein's solutions coming from non massive and topologically massive gravity. The unitarity of these YM-extended theories is shown in a perturbative regime. A possible way to perform a non-perturbative study is remarked.