Notes on non-singular models of black holes

Understand

We discuss static spherically symmetric metrics which represent non-singular black holes in four- and higher-dimensional spacetime.

• We impose a set of restrictions, such as a regularity of the metric at the center $r=0$ and Schwarzschild asymptotic behavior at large $r$.
• We assume that the metric besides mass $M$ contains an additional parameter $\ell$, which determines the scale where modification of the solution of the Einstein equations becomes significant.
• We require that the modified metric obeys the limiting curvature condition, that is its curvature is uniformly restricted by the value $\sim \ell^{-2}$.