2016/07/08 by Shahar Hod · 2 citations
Physics and Astronomy · #gr-qc #astro-ph.HE #hep-th
paper · pdf · doi:10.1016/j.physletb.2016.03.071
published as Physics Letters B 757, 121 (2016) · 6 pages
arxiv created 2016/07/08 · arxiv updated 2016/07/20
It has recently been suggested [S. B. Giddings, Phys. Lett. B \bf 754, 39 (2016)] that the Hawking black-hole radiation spectrum originates from an effective quantum "atmosphere" which extends well outside the black-hole horizon. In particular, comparing the Hawking radiation power of a (3+1)-dimensional Schwarzschild black hole of horizon radius rH with the familiar Stefan-Boltzmann radiation power of a (3+1)-dimensional flat space perfect blackbody emitter, Giddings concluded that the source of the Hawking semi-classical black-hole radiation is a quantum region outside the Schwarzschild black-hole horizon whose effective radius rA is characterized by the relation Δr≡ rA-rH∼ rH. It is of considerable physical interest to test the general validity of Giddings's intriguing conclusion. To this end, we study the Hawking radiation of (D+1)-dimensional Schwarzschild black holes. We find that the dimensionless radii rA/rH which characterize the black-hole quantum atmospheres, as determined from the Hawking black-hole radiation power and the (D+1)-dimensional Stefan-Boltzmann radiation law, are a decreasing function of the number D+1 of spacetime dimensions. In particular, it is shown that radiating (D+1)-dimensional Schwarzschild black holes are characterized by the relation (rA-rH)/rH≪1 in the large D≫1 regime. Our results therefore suggest that, at least in some physical cases, the Hawking emission spectrum originates from quantum excitations very near the black-hole horizon.