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We find solutions of the Dirac equation in curved spacetime. In particular, we consider 1+1 dimensional sections of several exotic metrics: the Alcubierre metric, which describes a scenario that allows faster-than-light (FTL) velocity; the…

General Relativity and Quantum Cosmology · Physics 2019-01-16 Javier Faba García , Carlos Sabín

We present the first X-ray reflection model for testing the assumption that the metric of astrophysical black holes is described by the Kerr solution. We employ the formalism of the transfer function proposed by Cunningham. The calculations…

General Relativity and Quantum Cosmology · Physics 2017-06-19 Cosimo Bambi , Alejandro Cardenas-Avendano , Thomas Dauser , Javier A. Garcia , Sourabh Nampalliwar

Beginning with a relativistic action principle for the irrotational flow of collisionless matter, we compute higher order corrections to the Zel'dovich approximation by deriving a nonlinear Hamilton-Jacobi equation for the velocity…

Astrophysics · Physics 2015-06-24 D. S. Salopek , J. M. Stewart , K. M. Croudace

To solve the problem of exact integration of the field equations or equations of motion of matter in curved spacetimes one can use a class of Riemannian metrics for which the simplest equations of motion can be integrated by the complete…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Valery V. Obukhov , Konstantin E. Osetrin

We present a new three-dimensional fully general-relativistic hydrodynamics code using high-resolution shock-capturing techniques and a conformal traceless formulation of the Einstein equations. Besides presenting a thorough set of tests…

General Relativity and Quantum Cosmology · Physics 2011-09-30 L. Baiotti , I. Hawke , P. J. Montero , F. Loeffler , L. Rezzolla , N. Stergioulas , J. A. Font , E. Seidel

We present {\tt radpol} - a numerical scheme for integrating multifrequency polarized radiative transfer equations along rays propagating in a curved spacetime. The scheme includes radiative processes such as synchrotron emission,…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Monika Moscibrodzka

In this paper we return to the subject of Jacobi metrics for timelike and null geodsics in stationary spactimes, correcting some previous misconceptions. We show that not only null geodesics, but also timelike geodesics are governed by a…

General Relativity and Quantum Cosmology · Physics 2020-01-08 Sumanto Chanda , G. W. Gibbons , Partha Guha , Paolo Maraner , Marcus C. Werner

We develop a numerical code to calculate the neutrino transfer with multi-energy and multi-angle in three dimensions (3D) for the study of core-collapse supernovae. The numerical code solves the Boltzmann equations for neutrino…

High Energy Astrophysical Phenomena · Physics 2012-03-26 Kohsuke Sumiyoshi , Shoichi Yamada

In this paper, we proposed a new Monte Carlo radiative transport (MCRT) scheme, which is based completely on the Neumann series solution of Fredholm integral equation. This scheme indicates that the essence of MCRT is the calculation of…

Computational Physics · Physics 2022-11-09 Xiao-lin Yang , Jian-cheng Wang , Chu-yuan Yang

A family of explicit exact solutions of Einstein's equations in four and higher dimensions is studied which describes photon rockets accelerating due to an anisotropic emission of photons. It is possible to prescribe an arbitrary motion, so…

General Relativity and Quantum Cosmology · Physics 2011-04-07 Jiri Podolsky

We discuss the problem of polarized radiative transfer in general relativity. We present a set of equations suitable for solving the problem numerically for the case of an arbitrary space-time metric, and show numerical solutions to example…

Instrumentation and Methods for Astrophysics · Physics 2017-06-28 Pauli Pihajoki , Antti Rantala , Peter H. Johansson

This paper uses the Kerr geodesic equations for massless particles to derive an acceleration vector in both Boyer-Lindquist and Cartesian coordinates. As a special case, the Schwarzschild acceleration due to a non-rotating mass has a…

Astrophysics of Galaxies · Physics 2015-06-22 Steve Walters , Larry Forbes

We present a partial-differential-equation-based optimal path-planning framework for curvature constrained motion, with application to vehicles in 2- and 3-spatial-dimensions. This formulation relies on optimal control theory, dynamic…

Numerical Analysis · Mathematics 2024-04-17 Christian Parkinson , Isabelle Boyle

We demonstrate a systematic method for solving the Hamilton-Jacobi equation for general relativity with the inclusion of matter fields. The generating functional is expanded in a series of spatial gradients. Each term is manifestly…

General Relativity and Quantum Cosmology · Physics 2010-11-01 J. Parry D. S. Salopek , J. M. Stewart

We write down Crofton formulas--expressions that compute lengths of spacelike curves in asymptotically AdS$_3$ geometries as integrals over kinematic space--which apply when the curve and/or the background spacetime is time-dependent.…

High Energy Physics - Theory · Physics 2020-12-30 Bartlomiej Czech , Yaithd D. Olivas , Zi-zhi Wang

We present a general relativistic, ray-tracing radiative transfer code RAIKOU for multi-wavlength studies of spectra and images including the black hole shadows around Kerr black holes. Important radiative processes in hot plasmas around…

High Energy Astrophysical Phenomena · Physics 2023-06-28 Tomohisa Kawashima , Ken Ohsuga , Hiroyuki R. Takahashi

The first globally convergent numerical method for a Coefficient Inverse Problem (CIP) for the Riemannian Radiative Transfer Equation (RRTE) is constructed. This is a version of the so-called \textquotedblleft convexification" method, which…

Numerical Analysis · Mathematics 2023-04-13 Michael V. Klibanov , Jingzhi Li , Loc H. Nguyen , Vladimir G. Romanov , Zhipeng Yang

We develop a numerical code to compute gravitational waves induced by a particle moving on eccentric inclined orbits around a Kerr black hole. For such systems, the black hole perturbation method is applicable. The gravitational waves can…

General Relativity and Quantum Cosmology · Physics 2009-08-05 Ryuichi Fujita , Wataru Hikida , Hideyuki Tagoshi

In this paper we analyze the Kerr geometry in the context of Conformal Gravity, an alternative theory of gravitation, which is a direct extension of General Relativity. Following previous studies in the literature, we introduce an explicit…

General Relativity and Quantum Cosmology · Physics 2014-05-20 Gabriele U. Varieschi

The Hamilton-Jacobi method of constrained systems is discussed. The equations of motion of a singular system with time dependent constraints are obtained as total differential equations in many variables. The integrability conditions for…

Mathematical Physics · Physics 2009-11-07 Sami I. Muslih
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