Douglas M. Eardley

Classical black hole production in high-energy collisions

We investigate the classical formation of a D-dimensional black hole in a high-energy collision of two particles. The existence of an apparent horizon is related to the solution of an unusual boundary-value problem for Poissons equation in flat space. For a sufficiently small impact parameter, we construct solutions giving such apparent horizons in

The global existence of Yang-Mills-Higgs fields in

D=4.

4

These supply improved estimates of the classical cross section for black hole production, and of the mass of the resulting black holes. We also argue that a horizon can be found in a region of weak curvature, suggesting that these solutions are valid starting points for a semiclassical analysis of quantum black hole formation.

-dimensional Minkowski space. I. Local existence and smoothness properties

In this paper and its sequel we shall prove the local and then the global existence of solutions of the classical Yang-Mills-Higgs equations in the temporal gauge. This paper proves local existence uniqueness and smoothness properties and improves, by essentially one order of differentiability, previous local existence results. Our results apply to any compact gauge group and to any invariant Higgs self-coupling which is positive and of no higher than quartic degree.

Magnetic viscosity in relativistic accretion disks

We formulate a detailed, self-consistent model of magnetic viscosity in an accretion disk around a rotating, Kerr black hole, in order to help clarify the nature of viscosity in the theory of accretion disks. The magnetic field is amplified by shear and dissipated by reconnection; in steady state a stable balance occurs, leading to a chaotic field configuration consisting of magnetic cells that reconnect with each other about once per orbit. We give detailed models of stationary disks based on the viscosity of this field. The observable properties of these models are similar to those of previous models based on less detailed models of viscosity. We include the relativistic equations governing the time-evolution of an accretion disk around a Kerr black hole, and some criteria for the existence of a radiation-pressure-dominated region or an optically thin region in a stationary disk.

The global existence problem and cosmic censorship in general relativity

We formulate two global existence conjectures for the Einstein equations and discuss their relevance to the cosmic censorship conjecture. We argue that the reformulation of the cosmic censorship conjecture as a global existence problem renders it more amenable to direct analytical attack. To demonstrate the facilty of this approach we prove the cosmological version of our global existence conjecture for the Gowdy spacetimes onT3×R.

Homothetic and Conformal Symmetries of Solutions to Einstein's Equations

We present several results about the nonexistence of solutions of Einsteins equations with homothetic or conformal symmetry. We show that the only spatially compact, globally hyperbolic spacetimes admitting a hypersurface of constant mean extrinsic curvature, and also admitting an infinitesimal proper homothetic symmetry, are everywhere locally flat; this assumes that the matter fields either obey certain energy conditions, or are the Yang-Mills or massless Klein-Gordon fields. We find that the only vacuum solutions admitting an infinitesimal proper conformal symmetry are everywhere locally flat spacetimes and certain plane wave solutions. We show that if the dominant energy condition is assumed, then Minkowski spacetime is the only asymptotically flat solution which has an infinitesimal conformal symmetry that is asymptotic to a dilation. In other words, with the exceptions cited, homothetic or conformal Killing fields are in fact Killing in spatially compact or asymptotically flat spactimes. In the conformal procedure for solving the initial value problem, we show that data with infinitesimal conformal symmetry evolves to a spacetime with full isometry.

Breaking Cosmic Strings without Monopoles

It is shown that topologically stable cosmic strings can, in fact, appear to end or to break, even in theories without monopoles. This can occur whenever the spatial topology of the universe is nontrivial. For the case of Abelian-Higgs strings, we describe the gauge and scalar field configurations necessary for a string to end on a black hole. We give a lower bound for the rate at which a cosmic string will break via black hole pair production, using an instanton calculation based on the Euclidean C-metric.

Nonlinear Wave Equations for Relativity

Gravitational radiation is described by canonical Yang-Mills wave equations on the curved space-time manifold, together with evolution equations for the metric in the tangent bundle. The initial data problem is described in Yang-Mills scalar and vector potentials, resulting in Lie-constraints in addition to the familiar Gauss-Codacci relations

Cygnus x-1: a two-temperature accretion disk model which explains the observed hard X-ray spectrum

We present a model for Cygnus X-1, involving an accretion disk around a black hole, which fits the observed X-ray spectrum from 8 to 500 keV. The hard component of the spectrum (E>8 keV) is produced by an optically thin inner portion of the disk in which the electrons are 10