Nigel T. Bishop,1,2 Roberto Gomez,2 Paulo R. Holvorcem,3,5 Richard A. Matzner,3 Philippos Papadopoulos,2,4 and Jeffrey Winicour2 1Department of Mathematics, Applied Mathematics and Astronomy, University of South Africa, P.O. Box 392, Pretoria 0001, South Africa 2Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 3Center for Relativity, University of Te...

The basic characteristics of the covariant current < Jμ > and the covariant energymomentum tensor < Tμν > in Unruh, Hartle-Hawking and Boulware states are obtained from a chiral effective action. These results are used to justify the covariant boundary condition used in recent approaches [2, 4, 5, 6] of computing the Hawking flux from chiral gauge and gravitational anomalies. We also discuss a ...

The quasi-stationary method for black hole binary inspiral is an approximation for studying strong field effects while suppressing radiation reaction. In this paper we use a nonlinear scalar field toy model (i) to explain the underlying method of approximating binary motion by periodic orbits with radiation; (ii) to show how the fields in such a model are found by the solution of a boundary val...

in this paper, we consider an inverse problem of linear heat equation with nonlinear boundary condition. we identify the temperature and the unknown radiation tern from an overspecified condition on the boundary

Numerical solutions for open-region electromagnetic problems based on differential equations require some means of truncating the computational domain. A number of local Radiation Boundary Conditions (RBCs) for general boundary shapes have been proposed during the past decade. Many are generalizations of the Bayliss-Turkel RBC for circular truncation boundaries. This paper reviews several two-d...

Introduction: Hawking radiation arises upon the quantisation of matter in a background spacetime with an event horizon. It therefore plays an important role in black hole physics. Apart from Hawking’s [4] original derivation, there are other approaches [5, 6], although none is completely clinching or conclusive. This has led researchers to consider alternative derivations providing new insights...

Three-dimensional time-harmonic internal gravity waves are generated by oscillating a bounded object (or by scattering from a fixed object) in a stratified fluid. Energy is found in conical wave beams: the problem is to calculate the wave fields for an object of arbitrary shape. An integral formula for the pressure is derived, using a reciprocal theorem and a Green’s function. The boundary inte...