Thermodynamics of the Weyl Geometric Gravity Black Holes

TL;DR

This paper explores the thermodynamic properties of a novel black hole solution in Weyl geometric gravity, revealing unique features that distinguish it from black holes in other modified gravity theories.

Contribution

It introduces an exact black hole solution in Weyl geometric gravity and analyzes its thermodynamic properties, highlighting differences from solutions in other theories.

Findings

Black hole solution generalizes Schwarzschild-de Sitter with new radial terms

Distinct thermodynamic behavior compared to other modified gravity black holes

Potential insights into black hole properties in alternative gravity theories

Abstract

We consider the thermodynamic properties of an exact black hole solution obtained in Weyl geometric gravity theory, by considering the simplest conformally invariant action, constructed from the square of the Weyl scalar, and the strength of the Weyl vector only. The action is linearized in the Weyl scalar by introducing an auxiliary scalar field, and thus it can be reformulated as a scalar-vector-tensor theory in a Riemann space, in the presence of a nonminimal coupling between the Ricci scalar and the scalar field. In static spherical symmetry, this theory admits an exact black hole solution, which generalizes the standard Schwarzschild-de Sitter solution through the presence of two new terms in the metric, having a linear and a quadratic dependence on the radial coordinate, respectively. The solution is obtained by assuming that the Weyl vector has only a radial component. After studying the locations of the event and cosmological horizons of the Weyl geometric black hole, we investigate in detail the thermodynamical (quantum properties) of this type of black holes, by considering the Hawking temperature, the entropy, specific heat and the Helmholtz free energy functions on both the event and the cosmological horizons. The Weyl geometric black holes have thermodynamic properties that clearly differentiate them from similar solutions of other modified gravity theories. The obtained results may lead to the possibility of a better understanding of the properties of the black holes in alternative gravity, and of the relevance of the thermodynamic aspects in black hole physics.