Scalar-tensor theory with EGB term from Einstein Chern-Simons gravity

Abstract

It is shown that the compactification á la Randall-Sundrum of the so-called, five-dimensional Einstein-Chern-Simons action gravity leads to an action for a four-dimensional scalar-tensor gravity that includes a Gauss-Bonnet term, which belongs to a particular case of the action of the Horndeski theory. The five-dimensional action includes new gravitational degrees of freedom that were introduced requiring that the action be invariant under symmetries greater than the usual Poincaré or (A)dS symmetries, namely the so-called generalized Poincare algebras B5.