A bstract We comment on the recently introduced Gauss-Bonnet gravity in four dimensions.
We argue that it does not make sense to consider this theory to be defined by a set of D→ 4 …

Spherically symmetric solutions of d-dimensional Einstein-Maxwell theory with a Gauss-
Bonnet term are classified. All spherically symmetric solutions of d-dimensional Einstein …

We have recently proposed a special class of scalar-tensor theories known as the Fab Four.
These arose from attempts to analyze the cosmological constant problem within the context …

A bstract We study certain bi-scalar-tensor theories emanating from conformal symmetry
requirements of Horndeski's four-dimensional action. The former scalar is a Galileon with …

abstract In this chapter, we will discuss a particular higher order gravity theory, Lovelock
theory, that generalises in higher dimensions than 4, general relativity. After briefly …

The coupling of the electromagnetic field to gravity is an age-old problem. Presently, there is
a resurgence of interest in it, mainly for two reasons:(i) Experimental investigations are …

We study the Horndeski vector-tensor theory that leads to second order equations of motion
and contains a non-minimally coupled abelian gauge vector field. This theory is remarkably …

A bstract We consider a general Kaluza-Klein reduction of a truncated Lovelock theory. We
find necessary geometric conditions for the reduction to be consistent. The resulting lower …

We study the classical second law of black hole thermodynamics, for Lovelock theories
(other than general relativity), in arbitrary dimensions. Using the standard formula for black …

A bstract We study the renormalization of a particular sector of Horndeski theory. In
particular, we focus on the nonminimal coupling of a scalar field to the Gauss-Bonnet term …