Holographic renormalization of Horndeski gravity
Nicolás Cáceres (Departamento de Física, Universidad de Concepción, Casilla, 160-C, Concepción, Chile, Facultad de Física, Pontificia Universidad Catolica de Chile, Av. Vicuña Mackenna, Santiago, 4860, Chile); Cristóbal Corral (Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez, Avda. Padre Hurtado 750, Viña del Mar, 2562340, Chile); Felipe Díaz (Departamento de Ciencias Físicas, Universidad Andres Bello, Sazié, Santiago de Chile, 2212, Chile); Rodrigo Olea (Departamento de Ciencias Físicas, Universidad Andres Bello, Sazié, Santiago de Chile, 2212, Chile)
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 and its kinetic coupling to the Einstein tensor. Adopting a power expansion on the scalar function that couples the Gauss-Bonnet term, we find specific conditions on their coefficients such that the action and charges are finite. To accomplish the latter, we add a finite set of intrinsic boundary terms. The contribution of the nonminimal coupling generates an effective scalar mass, allowing us to recover a modified Breitenlohner-Freedman bound. Furthermore, we compute the holographic 1-point functions and Ward identities associated with the scalar field and the metric. We constrain the parameter space of the theory by taking into account the preservation of scaling symmetry at the boundary.