On scalar charges and black-hole thermodynamics

Matteo will present the following paper (https://arxiv.org/abs/2302.11630):

On scalar charges and black-hole thermodynamics, Romina Ballesteros, Carmen Gómez-Fayrén, Tomás Ortín, Matteo Zatti.

Abstract: We revisit the first law of black hole thermodynamics in 4-dimensional theories containing scalar and Abelian vector fields coupled to gravity using Wald's formalism and a new definition of scalar charge as an integral over a 2-surface which satisfies a Gauss law in stationary black-hole spacetimes. We focus on ungauged supergravity-inspired theories with symmetric sigma models whose symmetries generate electric-magnetic dualities leaving invariant their equations of motion. Our manifestly duality-invariant form of the first law is compatible with the one obtained by of Gibbons, Kallosh and Kol. We also obtain the general expression for the scalar charges of a stationary black hole in terms of the other physical parameters of the solution and the position of the horizon, generalizing the expression obtained by Pacilio for dilaton black oles.