Unifying Einstein and Palatini gravities
We consider a novel class of f(R) gravity theories where the connection is related to the conformally scaled metric ˆgμν=C(R)gμν with a scaling that depends on the scalar curvature R only. We call them C theories and show that the Einstein and Palatini gravities can be obtained as special limits. In...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article (Journal) |
| Language: | English |
| Published: |
8 February 2011
|
| In: |
Physical review. D, Particles, fields, gravitation, and cosmology
Year: 2011, Volume: 83, Issue: 4, Pages: 044016 |
| ISSN: | 1550-2368 |
| DOI: | 10.1103/PhysRevD.83.044016 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1103/PhysRevD.83.044016
|
| Author Notes: | Luca Amendola (Institut für Theoretische Physik, University of Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany), Kari Enqvist (Physics Department, University of Helsinki, and Helsinki Institute of Physics, FIN-00014 University of Helsinki), Tomi Koivisto (Institute for Theoretical Physics and Spinoza Institute, Leuvenlaan 4, 3584 CE Utrecht, The Netherlands) |
| Summary: | We consider a novel class of f(R) gravity theories where the connection is related to the conformally scaled metric ˆgμν=C(R)gμν with a scaling that depends on the scalar curvature R only. We call them C theories and show that the Einstein and Palatini gravities can be obtained as special limits. In addition, C theories include completely new physically distinct gravity theories even when f(R)=R. With nonlinear f(R), C theories interpolate and extrapolate the Einstein and Palatini cases and may avoid some of their conceptual and observational problems. We further show that C theories have a scalar-tensor formulation, which in some special cases reduces to simple Brans-Dicke-type gravity. If matter fields couple to the connection, the conservation laws in C theories are modified. The stability of perturbations about flat space is determined by a simple condition on the Lagrangian. |
|---|---|
| Item Description: | Gesehen am 13.11.2017 |
| Physical Description: | Online Resource |
| ISSN: | 1550-2368 |
| DOI: | 10.1103/PhysRevD.83.044016 |