Nonsingular black hole chemistry in $4D$ Einstein-Gauss-Bonnet gravity

Abstract

The EGB is an outcome of quadratic curvature corrections to the Einstein-Hilbert gravity action in the form of a Gauss-Bonnet (GB) term in $D>4$ dimensions, and EGB gravity is topologically invariant in $4D$. Several ways have been proposed for regularizing the $D\to 4$ limit of EGB for non-trivial gravitational dynamics in $4D$. Motivated by the importance of AdS/CFT, we obtain an exact static spherically symmetric nonsingular black hole in $4D$ EGB gravity coupled to the nonlinear electrodynamics (NED) in an AdS spacetime. We interpret the negative cosmological constant $\hat{I}›$ as the positive pressure, via $P=-\hat{I}›/8\ddot{I}€$, of the system's thermodynamic properties of the nonsingular black hole with an AdS background. We find that for $P<P_c$, the black holes with $C_P>0$ are stable to thermal fluctuations and unstable otherwise. We also analyzed the Gibbs free energy to find that the small globally unstable black holes undergo a phase transition to the large globally stable black holes. Further, we study the $P-V$ criticality of the system and then calculate the critical exponents to find that our system behaves like Van der Walls fluid.

11 pages, 6 figures, 4 tables