Nonlocal and generalized uncertainty principle black holes
  In this paper we study the issue of the role of nonlocality as a possible ingredient to solve long standing problems in the physics of black holes. To achieve this goal we analytically derive new black hole metrics improved by corrections from nonlocal gravity actions with an entire function of the order 1/2 and lower than 1/2, the latter corresponding to generalized uncertainty principle corrections. This lets us extend our previous findings about noncommutative geometry inspired black holes recently recognized as nonlocal black holes due to an entire function of order higher than 1/2. As a result we show that irrespective of the order of the function, nonlocality leads to the following properties for black hole spacetimes: i) horizon extremization also in the neutral, non rotating case; ii) black hole phase transition from a Schwarzschild phase to a positive heat capacity cooling down phase; iii) zero temperature remnant formation at the end of the evaporation process; iv) negligible quantum back reaction due to the presence of an upper bound for the Hawking temperature. Finally we show that, in agreement with the general theory of cut off functions, a regular deSitter core accounting for the energy density of virtual gravitons replaces the curvature singularity only in the case of entire functions of order 1/2 or higher. 
Piero Nicolini
hep-th gr-qc