Authors: Haishan Liu H Lü ZhaoLong Wang
Publish Date: 2012/02/21
Volume: 2012, Issue: 2, Pages: 83-
Abstract
We derive the condition on fR gravities that admit Killing spinor equations and construct explicit such examples The Killing spinor equations can be used to reduce the fourthorder differential equations of motion to the first order for both the domain wall and FLRW cosmological solutions We obtain exact “BPS” domain walls that describe the smooth RandallSundrum II AdS wormholes and the RG flow from IR to UV We also obtain exact smooth cosmological solutions that describe the evolution from an inflationary starting point with a larger cosmological constant to an everexpanding universe with a smaller cosmological constant In addition We find exact smooth solutions of prebig bang models bouncing or crunching universes An important feature is that the scalar curvature R of all these metrics is varying rather than a constant Another intriguing feature is that there are two different fR gravities that give rise to the same “BPS” solution We also study linearized fR gravities in AdS vacua
Keywords: