Black Holes in $4D$ AdS Einstein Gauss Bonnet Gravity With Power- Yang Mills Field

Abstract: In this paper we construct an exact spherically symmetric black hole solution with a power Yang-Mills (YM) source in the context of $4D$ Einstein Gauss-Bonnet gravity ($4D$ EGB). We choose our source as $(F_{\mu\nu}^{(a)}F^{\mu\nu(a)})^q$, where $q$ is an arbitrary positive real number. Thereafter we study the horizon structure, thermodynamic issues like thermal stability and black hole phase transition of this black hole solution. Our focus here is to analyse the black hole space-time under the net non-linear effect coming both from the gravitational sector (due to Gauss-Bonnet term) as well as from the gauge fields (the power of Yang-Mills field invariant) in $4$-dimensions. We evaluate some extended thermodynamic quantities such as pressure, temperature, entropy in order to establish the form of the Smarr formula and the first law of thermodynamics. The behaviour of heat capacity as a function of horizon radius is thoroughly studied to understand the thermal stability of the black hole solution. An interesting phenomena of existence/ absence of thermal phase transition occur due to the nonlinearity of YM source. For some values of the parameters, we find that the solution exhibits a first-order phase transition, like a van der Waals fluid. In addition, we also verify Maxwell's equal area law numerically by crucial analysis of Gibbs free energy as a function of temperature. Moreover, the critical exponents are derived and showed the universality class of the scaling behaviour of thermodynamic quantities near criticality.