No logarithmic corrections to entropy in shift-symmetric Gauss-Bonnet gravity

Abstract

Employing the covariant phase space formalism, we discuss black hole thermodynamics in four-dimensional scalar-tensor Einstein-Gauss-Bonnet gravity. We argue that logarithmic corrections to Wald entropy previously reported in this theory do not appear, due to the symmetry of the theory under constant shifts of the scalar field. Instead, we obtain the standard Bekenstein entropy of general relativity. Then, to satisfy the first law of black hole mechanics, the Hawking temperature must be modified. It has been proposed that such temperature modifications occur generically in scalar-tensor theories, due to different propagation speeds of gravitons and photons. We show that the temperature modifications also emerge in the Euclidean canonical ensemble approach to black hole thermodynamics. Notably, the boundary terms of the type we consider here can be considered in any scalar-tensor gravitational theories. Hence, we illustrate that adding a suitable boundary term to action may drastically affect black hole thermodynamics, changing both the entropy and the temperature.

29 pages, text matches the version published in JHEP. Comments welcome

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Cited by in corpus (6)

• Euclidean and Hamiltonian thermodynamics for regular black holes
• Thermodynamics, Phase Transition and Joule Thomson Expansion of 4-D Gauss-Bonnet AdS Black Hole
• Euclidean methods and phase transitions for the strongest deformations compatible with Schwarzschild asymptotics
• Scaling symmetry, Smarr relation, and the extended first law in lower-dimensional Lovelock gravity
• Non-closed scalar charge in four-dimensional Einstein-scalar-Gauss-Bonnet black hole thermodynamics
• Mergers of hairy black holes: Constraining topological couplings from entropy