Black Hole entropy for two higher derivative theories of gravity

TL;DR

This paper examines the thermodynamic properties of black hole solutions in two higher derivative gravity theories, focusing on entropy, temperature, and challenges in defining mass within these models.

Contribution

It analyzes specific black hole solutions in modified gravity theories, highlighting their thermodynamic characteristics and addressing issues in defining mass.

Findings

Black hole entropy differs from standard theories due to higher derivatives.

Temperature and entropy relations are explored for these solutions.

Challenges in consistent mass definition are discussed.

Abstract

The dark energy issue is focusing the attention of an incresing number of physicists all over the world. Among the possible alternatives in order to explain what as been named the "Mystery of the Millennium" are the so-called Modified Theories of Gravity. A crucial test for such models is represented by the existence and (if this is the case) the properties of their black hole solutions. Nowadays, to our knowledge, only two non-trivial, spherically symmetric, solutions with vanishing cosmological constant are known by Barrow & Clifton (2005) and Deser, Sarioglu & Tekin (2008). Aim of the paper is to discuss some features of such solutions, with emphasis on their thermodynamic properties such as entropy and temperature, little progress being possible along the way which leads to a consistent definition of mass.