black hole entropy in scalar-tensor and ？(r) gravity an overview在标量张量和黑洞熵(r)重力概述.pdfVIP

Entropy 2010, 12, 1246-1263; doi:10.3390/ OPEN ACCESS entropy ISSN 1099-4300 /journal/entropy Review Black Hole Entropy in Scalar-Tensor and f R Gravity: An Overview Valerio Faraoni ´ Physics Department, Bishop’s University, 2600 College St., Sherbrooke, Quebec, J1M 1Z7, Canada; E-Mail: vfaraoni@ubishops.ca; Tel.: +1-819-822-9600 ext. 2490; Fax: +1-819-822-9611 Received: 9 April 2010 / Accepted: 13 May 2010 / Published: 14 May 2010 Abstract: A short overview of black hole entropy in alternative gravitational theories is presented. Motivated by the recent attempts to explain the cosmic acceleration without dark energy, we focus on metric and Palatini f (R) gravity and on scalar-tensor theories. Keywords: black hole entropy; alternative gravity; metric and Palatini modified gravity 1. Introduction Alternative theories of gravity have been studied for a long time [ 1–5]. While there is no experimental evidence of deviations from general relativity at Solar System scales, from the theoretical point of view it is well known that corrections to the Einstein-Hilbert action (such as non-linear terms in the Ricci and Riemann tensors, or extra scalar fields coupling explicitly to gravity) always arise from attempts to renormalize general relativity, to build a theory of quantum gravity or at least some effective action (including the low-energy limit of string theories),