10,614 research outputs found
Extended black hole cosmologies in de Sitter space
We generalize the superposition principle for time-symmetric initial data of
black hole spacetimes to (anti-)de Sitter cosmologies in terms of an eigenvalue
problem for a conformal scale
applied to a metric with constant three-curvature . Here,
in the Brill-Lindquist and, respectively, Misner construction of
multihole solutions for . For de Sitter and anti-de Sitter
cosmologies, we express the result for in incomplete elliptic
functions. The topology of a black hole in de Sitter space can be extended into
an infinite tower of universes, across the turning points at the black hole and
cosmological event horizons. Superposition introduces binary black holes for
small separations and binary universes for separations large relative to the
cosmological event horizon. The evolution of the metric can be described by a
hyperbolic system of equations with curvature-driven lapse function, of
alternating sign at successive cosmologies. The computational problem of
interacting black hole-universes is conceivably of interest to early cosmology
when was large and black holes were of mass ,
here facilitated by a metric which is singularity-free and smooth everywhere on
real coordinate space.Comment: to appear in Class. Quant. Gra
Vistas in numerical relativity
Upcoming gravitational wave-experiments promise a window for discovering new
physics in astronomy. Detection sensitivity of the broadband laser
interferometric detectors LIGO/VIRGO may be enhanced by matched filtering with
accurate wave-form templates. Where analytic methods break down, we have to
resort to numerical relativity, often in Hamiltonian or various hyperbolic
formulations. Well-posed numerical relativity requires consistency with the
elliptic constraints of energy and momentum conservation. We explore this using
a choice of gauge in the future and a dynamical gauge in the past. Applied to a
polarized Gowdy wave, this enables solving {\em all} ten vacuum Einstein
equations. Evolution of the Schwarzschild metric in 3+1 and, more generally,
sufficient conditions for well-posed numerical relativity continue to be open
challenges.Comment: invited talk, Asian Pacific CTP Winter School on black hole
astrophysics, Pohang, Kore
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