Thermodynamics of Hairy Black Holes in Quantum Regimes: Insights from Horndeski Theory

TL;DR

This paper investigates how non-perturbative quantum gravitational corrections influence the thermodynamics and evaporation processes of AdS black holes, revealing new phase transitions and energy behaviors not seen in classical or semi-classical models.

Contribution

It introduces a non-perturbative correction to black hole entropy and analyzes its effects on thermodynamic stability, phase transitions, and quantum work distribution in higher-dimensional AdS black holes.

Findings

Quantum corrections suppress specific heat magnitude at small horizons.

Induces Hawking--Page transition in dimensions n≥4.

Reverses the sign of quantum work during evaporation at small horizons.

Abstract

We study non-perturbative quantum gravitational corrections to the thermodynamics and quantum work distribution of the $n$-dimensional Schwarzschild--Tangherlini--Anti-de Sitter black hole. Starting from the corrected entropy $S = S_0 + \eta\, e^{-S_0}$, where $S_0$ is the Bekenstein--Hawking entropy, we derive the modified specific heat, internal energy, Helmholtz free energy, and Gibbs free energy in closed form. The specific heat retains the classical divergence at $r_h^{*}=l\sqrt{(n-3)/(n-1)}$ for $n\geq 4$, but the quantum correction suppresses its magnitude by up to $78\%$ at small horizon radii. In the extended phase space, the uncharged black hole admits no van der Waals critical point; however, the non-perturbative correction induces a Hawking--Page transition for $n\geq 4$ that is absent in the semi-classical limit. The corrected Gibbs free energy turns negative at small $r_h$, opening a thermodynamic channel with no classical counterpart. Using the Jarzynski equality and Jensen inequality, we obtain the quantum work distribution during evaporation. The free energy difference $\Delta F$ between two black hole states undergoes a sign reversal at small horizon radii for $n\geq 4$ when $\eta=1$, flipping the average quantum work from negative to positive. This sign reversal grows with the spacetime dimension, reaching $\langle W\rangle \approx +4.31$ for $n=10$. These findings demonstrate that non-perturbative quantum gravitational effects qualitatively alter the phase structure and evaporation energetics of AdS black holes, and they cannot be captured by perturbative corrections alone.