2017/03/31 by Enrique Alvarez, Jesus Anero, Sergio Gonzalez-Martin
Physics and Astronomy · #Black Holes and Theoretical Physics #Conformal gravity #Cosmology and Gravitation Theories #First order #Formalism (music) #Gravitation #Invariant (physics) #Noncommutative and Quantum Gravity Theories #Planck #Planck mass #Quadratic equation #Quantum gravity #Unitary state #hep-th
paper · pdf · doi:10.1088/1475-7516/2017/10/008
50 pages, additions and new section. Version to be published in JCAP; Spotted errata corrected
openalex created_date 2017/04/07 · openalex publication_date 2017/10/06 · arxiv created 2017/12/21 · arxiv updated 2017/12/22 · openalex updated_date 2026/08/05
We consider the most general action for gravity which is quadratic in curvature. In this case first order and second order formalisms are not equivalent. This framework is a good candidate for a unitary and renormalizable theory of the gravitational field; in particular, there are no propagators falling down faster than 1/ p 2 . The drawback is of course that the parameter space of the theory is too big, so that in many cases will be far away from a theory of gravity alone. In order to analyze this issue, the interaction between external sources was examined in some detail. We find that this interaction is conveyed mainly by propagation of the three-index connection field. At any rate the theory as it stands is in the conformal invariant phase; only when Weyl invariance is broken through the coupling to matter can an Einstein-Hilbert term (and its corresponding Planck mass scale) be generated by quantum corrections.