RT Journal Article
T1 Semiclassical gravity effects near horizon formation
A1 Barceló, Carlos
A1 Garay Elizondo, Luis Javier
A1 Boyanov Savov, Valentín
A1 Carballo Rubio, Raúl
AB We study the magnitude of semiclassical gravity effects near the formation of a black-hole horizon in spherically-symmetric spacetimes. As a probe for these effects we use a quantised massless scalar field. Specifically, we calculate two quantities derived from it: the renormalised stress–energy tensor (a measure of how the field vacuum state affects the spacetime) and the effective temperature function (a generalisation of Hawking temperature related to the energy flux of the field vacuum). The subject of our study are spacetimes which contain a spherical distribution of matter and an empty exterior Schwarzschild region, separated by a surface which is moving in proximity to the Schwarzschild radius r_s=2M, with M the total mass. In particular, we analyse the consequences of three types of surface movement: an oscillation just above r_s, a monotonous approach towards r_s in infinite time and a crossing of r_s at different velocities. For a collapsing matter distribution which follows the expected dynamical evolution in general relativity, we recover the standard picture of black-hole formation and its tenuous semiclassical effects. In more general dynamical regimes, allowing deviations from the standard classical evolution, we obtain a variety of different effects: from the emission of Hawking-like radiation without the formation of a horizon, to large values of the renormalised stress–energy tensor, related to the Boulware vacuum divergence in static spacetimes.
PB IOP Publishing
SN 0264-9381
YR 2019
FD 2019
LK https://hdl.handle.net/20.500.14352/88625
UL https://hdl.handle.net/20.500.14352/88625
LA spa
NO C. Barceló, V. Boyanov, R. Carballo-Rubio, and L. J. Garay, Class. Quantum Grav. 36, 165004 (2019).
NO European Commission
NO Ministerio de Economía, Comercio y Empresa (España)
NO Junta de Andalucia
NO Ministerio de Universidades (España)
DS Docta Complutense
RD 17 mar 2026