The Hawking cascades of gravitons from higher-dimensional Schwarzschild black holes

摘要

It has recently been shown that the Hawking evaporation process of (3 + 1)-dimensional Schwarzschild black holes is characterized by the dimensionless ratio eta equivalent to iota(gap)/iota(emission) 1, where iota(gap) is the characteristic time gap between the emissions of successive Hawking quanta and iota(emission) is the characteristic timescale required for an individual Hawking quantum to be emitted from the Schwarzschild black hole. This strong inequality implies that the Hawking cascade of gravitons from a (3 + 1)-dimensional Schwarzschild black hole is extremely sparse. In the present paper we explore the semi-classical Hawking evaporation rates of higher-dimensional Schwarzschild black holes. We find that the dimensionless ratio eta(D) equivalent to iota(gap)/iota(emission), which characterizes the Hawking emission of gravitons from the (D + 1)-dimensional Schwarzschild black holes, is a decreasing function of the spacetime dimension. In particular, we show that higher-dimensional Schwarzschild black holes with D greater than or similar to 10 are characterized by the relation eta(D) < 1. Our results thus imply that, contrary to the (3 + 1)-dimensional case, the characteristic Hawking cascades of gravitons from these higher-dimensional black holes have a continuous character. (C) 2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license.