Do regular quantum black holes exist?

Abstract Regular black holes do not exist in any classical theory of gravity including Einstein's general relativity. This unappealing feature is due to the appearance of a singularity in the interior of the black hole described by any classical theory. As Hawking argued, all known laws of physics must break down at the singularity. It is thus an important question whether this singularity can disappear in a quantum mechanical description of spacetime. In this letter, we therefore quantize the black hole interior in a Kantowski-Sachs minisuperspace representation in the presence of spontaneous Klein-Gordon matter field fluctuations. This leads to a Wheeler-DeWitt equation whose solution yields the interior wave function of the black hole. The regular part of this wave function satisfies the DeWitt boundary condition in that it vanishes at the singularity. Moreover, the wave function is regular and well behaved in the region around the singularity. These features of the wave function suggest that regular black holes do exist in quantum gravity.