Brick walls for black holes

Abstract

The authors examine 't Hooft's prescription (1985) for cutting off eigenmodes of particle wavefunctions in the vicinity of black hole event horizons in N dimensions. They find for any N>3 that the cutoff occurs as a consequence of the causal structure of spacetime independently of the strength of the source, in agreement with the four-dimensional case. They separately discuss the special case N=2, showing why in this case the cutoff depends on the strength of the source.