We study a solution of the Einstein's equations generated by a selfgravitating, anisotropic, static, non-singular matter fluid. The resulting Schwarzschild like solution is regular and accounts for smearing effects of noncommutative fluctuations of the geometry. We call this solution regular Schwarzschild spacetime. In the presence of an Anti-deSitter cosmological term, the regularized metric offers an extension of the Hawking-Page transition into a van der Waals-like phase diagram. Specifically the regular Schwarzschild-Anti-deSitter geometry undergoes a first order small/large black hole transition similar to the liquid/gas transition of a real fluid. In the present analysis we have considered the cosmological constant as a dynamical quantity and its variation is included in the first law of black hole thermodynamics.
Regular Schwarzschild-anti-deSitter spacetimeThe regular Schwarzschild anti-deSitter (AdS) metric is a static, spherically symmetric solution of the Einstein's equations with negative cosmological constant Λ = −3/b 2 and a Gaussian matter source [1,2,3,4]. To obtain this metric we replace the vacuum with a Gaussian distribution having variance equivalent to the parameter √ θ ρ (r) ≡ M (4πθ ) 3/2 e −r 2 /4θ .