Some Thermodynamic Aspects of Black Holes and Singularities

We review and correct the classical critical exponents characterizing the transition from negative to positive black hole’s heat capacity at high charge–angular momentum. We discuss the stability properties of black holes as a thermodynamic system in equilibrium with a radiation bath (canonical ensamble) by using the Helmholtz free energy potential. We finally analytically extend the analysis to negative mass holes and study its thermodynamical stability behavior.