Author
J. M. Stewart
Bio: J. M. Stewart is an academic researcher from Max Planck Society. The author has contributed to research in topics: General relativity & Theory of relativity. The author has an hindex of 11, co-authored 13 publications receiving 895 citations.
Papers
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TL;DR: In this article, the concept of space-times in general relativity was introduced, and a definition of perturbations of space times was proposed, leading in a natural way to a concept of gauge invariance, and to an extension of a lemma of Sachs (i964).
Abstract: A definition of perturbations of space-times in general relativity is proposed. The definition leads in a natural way to a concept of gauge invariance, and to an extension of a lemma of Sachs (i964). Coupled equations governing linearized perturbations of certain tetrad components of scalar, electromagnetic, and gravitational fields are derived by the use of Geroch, Held & Penrose's (I 973) version of the tetrad formalism of Newman & Penrose (i 962). It is shown that these perturbations are gauge invariant if and only if the unperturbed space-time is vacuum of algebraic type {22} or, equivalently, if and only if the perturbation equations decouple. Finally the maximal subclass of type {22} space-times for which the decoupled perturbation equations can be solved by separation of variables is found. This class comprises all the nonaccelerating type {22} space-times, including that of Kerr, thus elucidating earlier results of Bardeen & Press
385 citations
TL;DR: In this paper, the scalar potentials governing electromagnetic and gravitational perturbations of vacuum space-times are derived for all quantities of physical interest in terms of derivaties of the scalare potential.
Abstract: The problem of deriving scalar potentials governing electromagnetic and gravitational perturbations of vacuum space-times is discussed. For the case of an algebraically special vacuum background space-time, explicit formulae for all quantities of physical interest are given in terms of derivaties of the scalar potential.
82 citations
TL;DR: In this article, the structure of singularities (caustics), self-intersections of wavefronts and wavefront families in arbitrary space-times is discussed in detail and illustrated by explicit examples of stable wavefront singularities in Minkowski space.
Abstract: The structure of singularities (caustics), self-intersections of wavefronts (null hypersurfaces) and wavefront families (null coordinates) in arbitrary space-times is discussed in detail and illustrated by explicit examples of stable wavefront singularities in Minkowski space. It is shown how characteristic initial data determine the caustics and the self-intersections of the characteristics of Einstein’s field equations.
78 citations
TL;DR: In this article, the authors suggest that the singularity is avoided only because of the high symmetry of the model used, which is not the case in the case of intrinsic spin effects.
Abstract: TRAUTMAN has suggested1 that the introduction of intrinsic spin effects into general relativity through the Einstein-Cartan torsion theory may avert a gravitational singularity. In this note we suggest that the singularity is avoided only because of the high symmetry of the model used.
57 citations
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TL;DR: A comprehensive survey of recent work on modified theories of gravity and their cosmological consequences can be found in this article, where the authors provide a reference tool for researchers and students in cosmology and gravitational physics, as well as a selfcontained, comprehensive and up-to-date introduction to the subject as a whole.
3,674 citations
2,084 citations
01 Dec 1982
1,915 citations
TL;DR: Quasinormal modes are eigenmodes of dissipative systems as discussed by the authors, and they serve as an important tool for determining the near-equilibrium properties of strongly coupled quantum field theories, such as viscosity, conductivity and diffusion constants.
Abstract: Quasinormal modes are eigenmodes of dissipative systems. Perturbations of classical gravitational backgrounds involving black holes or branes naturally lead to quasinormal modes. The analysis and classification of the quasinormal spectra require solving non-Hermitian eigenvalue problems for the associated linear differential equations. Within the recently developed gauge-gravity duality, these modes serve as an important tool for determining the near-equilibrium properties of strongly coupled quantum field theories, in particular their transport coefficients, such as viscosity, conductivity and diffusion constants. In astrophysics, the detection of quasinormal modes in gravitational wave experiments would allow precise measurements of the mass and spin of black holes as well as new tests of general relativity. This review is meant as an introduction to the subject, with a focus on the recent developments in the field.
1,592 citations
TL;DR: The successes, as well as the limits, of perturbation theory are presented, and its role in the emerging era of numerical relativity and supercomputers is discussed.
Abstract: Perturbations of stars and black holes have been one of the main topics of relativistic astrophysics for the last few decades. They are of particular importance today, because of their relevance to gravitational wave astronomy. In this review we present the theory of quasi-normal modes of compact objects from both the mathematical and astrophysical points of view. The discussion includes perturbations of black holes (Schwarzschild, Reissner-Nordstrom, Kerr and Kerr-Newman) and relativistic stars (non-rotating and slowly-rotating). The properties of the various families of quasi-normal modes are described, and numerical techniques for calculating quasi-normal modes reviewed. The successes, as well as the limits, of perturbation theory are presented, and its role in the emerging era of numerical relativity and supercomputers is discussed.
1,569 citations