Unifying Einstein and Palatini gravities

• Verfasst von: Amendola, Luca [VerfasserIn]
• Verfasst von: Enqvist, Kari [VerfasserIn]
• Verfasst von: Koivisto, Tomi [VerfasserIn]
• Titel: Unifying Einstein and Palatini gravities
• Verf.angabe: 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)
• Fussnoten: Gesehen am 13.11.2017
• Titel Quelle: Enthalten in: Physical review / D
• Jahr Quelle: 2011
• Band/Heft Quelle: 83(2011,4) Artikel-Nummer 044016, 14 Seiten
• ISSN Quelle: 1550-2368
• ISSN Quelle: 1089-4918
• DOI: doi:10.1103/PhysRevD.83.044016
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1565268733

Abstract

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.