Showing papers on "Stress–energy tensor published in 1983"
TL;DR: An Eulerian variational principle for a spinning fluid in the Einstein-Cartan metric-torsion theory is presented in this article, which yields the complete set of field equations for the system.
Abstract: An Eulerian variational principle for a spinning fluid in the Einstein-Cartan metric-torsion theory is presented. The variational principle yields the complete set of field equations for the system. The symmetric energy-momentum tensor is a sum of a perfect-fluid term and a spin term.
85 citations
TL;DR: The energy-momentum tensor for a conformally invariant scalar field near a Schwarzschild black hole in thermal equilibrium with radiation is found by a combination of analytical and numerical techniques as mentioned in this paper.
Abstract: The energy-momentum tensor for a conformally invariant scalar field near a Schwarzschild black hole in thermal equilibrium with radiation is found by a combination of analytical and numerical techniques Calculations are performed in the Euclidean section of the spacetime, and divergences isolated using the heat kernel expansion It is found that the results agree well with those of Candelas [1], but that there are significant differences from the Gaussian approximation of Page [2]
43 citations
TL;DR: A general form of the metric in a space-time with nonvanishing cosmological constant outside a massive, electrically charged plane of infinite extension is found as a solution of the Einstein-Maxwell field equations as discussed by the authors.
Abstract: A general form of the metric in a space-time with nonvanishing cosmological constant outside a massive, electrically charged plane of infinite extension is found as a solution of the Einstein-Maxwell field equations. The general solution is new, but it includes several well-known solutions corresponding to special physical cases. Also, the general form of our solution makes it possible easily to identify different metrics corresponding to equivalent space-times. Physical properties of the solution are discussed. The plane-symmetric universe analogous to the spherically symmetric de Sitter universe is found separately, since it is not included in the general solution.
38 citations
TL;DR: In this paper, it is shown that for space-times that are radially smooth of order one in the sense of Beig & Schmidt (Communs math. 87, 65 (1982)), with asymptotically electric Weyl curvature, there exists a global concept of a twistor space at spatial infinity.
Abstract: Penrose's 'quasi-local mass and angular momentum' (Penrose, Proc. R. Soc. Lond. A 381, 53 (1982)) is investigated for 2-surfaces near spatial infinity in both linearized theory on Minkowski space and full general relativity. It is shown that for space-times that are radially smooth of order one in the sense of Beig & Schmidt (Communs math. Phys. 87, 65 (1982)), with asymptotically electric Weyl curvature, there exists a global concept of a twistor space at spatial infinity. Global conservation laws for the energy-momentum and angular momentum are obtained, and the ten conserved quantities are shown to be invariant under asymptotic coordinate transformations. The relation to other definitions is discussed briefly.
24 citations
TL;DR: The proper framework for testing Rastall's theory and its generalizations is in the case of non-negligible (i.e. discernible) gravitational effects such as gravity gradients.
Abstract: The proper framework for testing Rastall's theory and its generalizations is in the case of non-negligible (i.e. discernible) gravitational effects such as gravity gradients. These theories have conserved integral four-momentum and angular momentum. The Nordtvedt effect then provides limits on the parameters which arise as the result of the non-zero divergence of the energy-momentum tensor.
20 citations
TL;DR: In this article, the trace-free energy-momentum tensor of conformally invariant scalar field as source is obtained in a spatially homogeneous anisotropic space-time.
Abstract: The solutions of the Einstein equations with the trace-free energy-momentum tensor of conformally invariant scalar field as source are obtained in a spatially homogeneous anisotropic space-time. Some interesting features of the solutions are discussed.
17 citations
TL;DR: In this article, it was shown that a consistent gauging of the Poincar\'e group is capable of including Einstein's general relativity, provided the nontrivial part of the vierbein is taken as the fundamental gravitational field.
Abstract: It is shown that a consistent gauging of the Poincar\'e group is capable of including Einstein's general relativity. This statement holds for matter particles of arbitrary spin, provided the nontrivial part of the vierbein is taken as the fundamental gravitational field, thus giving rise to a known modification of the original theory. Since the gauge approach implies that gravitation is an ordinary field theory over flat space, the standard prescriptions for calculating the asymmetric momentum tensor of both matter and gravitation are available. Applying Belinfante's flat-space symmetrization procedure to the latter, we prove that the symmetrization of the asymmetric matter tensor just gives the dynamically defined symmetric matter tensor, whereas the symmetrization of the asymmetric gravitational momentum tensor leads to another version of the field equations that reveals a deep analogy to the equations of electrodynamics. Furthermore a method is developed that admits an unambiguous calculation of gauge-fixing conditions from a given gauge-breaking term. Besides the harmonic gauge, which can be reproduced by means of this method, new gauge-fixing conditions for local translations and local Lorentz transformations are obtained. These gauge-fixing techniques, as well as the symmetrization procedure, may equally be generalized to the case of nonvanishing torsion.
17 citations
TL;DR: In this paper, the problem of zero-mass scalar fields coupled to the gravitational field in the static plane-symmetric case is completely solved for a traceless energy-momentum tensor.
Abstract: The problem of zero-mass scalar fields coupled to the gravitational field in the static plane-symmetric case is completely solved for a traceless energy-momentum tensor.
12 citations
TL;DR: In this paper, a bimetric formalism is introduced which enables one to replace a gauge-covariant scalar by a geometric quantity, and the resulting theory agrees with the general relativity for phenomena in the solar system.
Abstract: The Weyl theory of gravitation and electromagnetism, as modified by Dirac, contains a gauge-covariant scalar β which has no geometric significance. This is a flaw if one is looking for a geometric description of gravitation and electromagnetism. A bimetric formalism is therefore introduced which enables one to replace β by a geometric quantity. The formalism can be simplified by the use of a gauge-invariant physical metric. The resulting theory agrees with the general relativity for phenomena in the solar system.
9 citations
TL;DR: In this article, two criteria to find the good vacuum in a curved space-time are studied and in a generic Robertson-Walker universe they are not coincident; yielding to the well-known ambiguity in the vacuum definition.
Abstract: Two criteria to find the good vacuum in a curved space-time are studied. In a generic Robertson-Walker universe they are not coincident; yielding to the well-known ambiguity in the vacuum definition. In few cases they coincide and give well-established vacua. An approximate vacuum is introduced in intermediate situations.
8 citations
TL;DR: In this paper, various possible component representations of Kelvin's tensor in orthogonal curvilinear coordinates are examined and discussed in light of the solution being a two-point or double tensor field.
Abstract: Various possible component representations of Kelvin's tensor in orthogonal curvilinear coordinates are examined and discussed in light of Kelvin's solution being a two-point or double tensor field. Next, the most convenient choice of component form for the integrand of Somigliana's integral, with body force derivable from a potential, is obtained from the invariant form of that integral. Throughout, the role played by the double tensor components called “shifters” is emphasized. The explicit ingredients for all quantities of interest pertinent to a circular cylindrical coordinate system are given in the final Section.
Journal Article•
TL;DR: In this article, a particular mechanism for spontaneous compaction in Kaluza-Klein models is analyzed, which results from the quantum vacuum expectation value of the energy-momentum tensor of the matter fields.
Abstract: A particular mechanism for spontaneous compaction in Kaluza--Klein models is analyzed. The compaction in this case results from the quantum vacuum expectation value of the energy-momentum tensor of the matter fields. It is shown that the space M/sup 4/ x S/sup d/ is a solution of the effective Einstein equations.
TL;DR: In this paper, the derivation of an expression of the macroscopic stress tensor in terms of microscopic variables in systems of finite interacting particles is discussed from different points of view.
Abstract: The derivation of an expression of the macroscopic stress tensor in terms of microscopic variables in systems of finite interacting particles is discussed from different points of view.
Journal Article•
TL;DR: In this paper, a homogeneous anisotropic nonsingular space-time metric with a six-parameter symmetry group is found which can be created by the polarization of the vacuum of the quantum fields of matter by a self-consistent gravitational field in the absence of classical matter.
Abstract: A homogeneous anisotropic nonsingular space-time metric with a six-parameter symmetry group is found which can be created by the polarization of the vacuum of the quantum fields of matter by a self-consistent gravitational field in the absence of classical matter. The mean values of the energy-momentum tensors for massless conformally covariant fields and a massive scalar field are computed in this metric. The Green function for a massive scalar field is constructed.
TL;DR: In this article, a covariant approach is proposed for the energy description of matter integrated with gravitation, based on the generalization of the special relativity stress energy tensor up to the fourth tensor rank which introduces the anisotropies of mass, impulse, and their fluxes.
Abstract: The covariant approach is proposed for the energy description of matter integrated with gravitation. The approach is based on the generalization of the special relativity stress-energy tensor up to the fourth tensor rank which introduces the anisotropies of mass, impulse, and their fluxes. The components describing anisotropies form an "energy deviator" which is a traceless fourth-rank tensor corresponding to Weyl's part of gravitation.
TL;DR: This work achieves a realization of a selfdual rank- n antisymmetric tensor gauge field in 2 n -dimensional space-time as an object completely described by lower rank auxilliary tensor fields by introducing mutually dual gauge fixing conditions.
TL;DR: In this paper, the conditions for the existence of a source-free interpretation when a "with source" solution with various types of the source current vector (i.e., timelike, null, or spacelike) is known are investigated.
Abstract: An energy stress tensor satisfying Rainich's algebraic relations along with a specified metric tensor sometimes admits two alternative Maxwell fields-one with a nonvanishing current vector as source and the other without any source. This paper investigates the conditions for the existence of a source-free interpretation when a “with source” solution with various types of the source current vector (i.e., timelike, null, or spacelike) is known and illustrates the results with some examples. It turns out that in the case of timelike currents, a dual interpretation requires this to be a purely convection current, while in other cases a dual interpretation is possible only if the conductivity is infinite and the “conduction” current is in the direction of the magnetic field.
TL;DR: In this article, a theory which makes it possible to classify the points of Riemannian space is used, together with the corresponding associated reference systems for the gravitational field in the classical general theory of relativity, to obtain the expression for the field energy density in the form of a four-dimensional scalar (not a pseudoscalar) and energy-impulse field tensor as an energy-imperceptible tensor of second rank.
Journal Article•
TL;DR: In this paper, the energy momentum tensor is used to predict the momentum density, energy density, momentum flow, and energy flow of a perfect fluid in a magnetic field, rather than starting with differential magnetohydrodynamic equations.
TL;DR: In this article, the authors consider the canonical energy-momentum tensor and angular-momentsum tensors belonging to a second-order Lagrange density for a scalar field.
Abstract: We consider, in the framework of SRT, the canonical energy-momentum tensor and angular-momentum tensor belonging to a second-order Lagrange density for a scalar field. The Lagrange density considered here differs from the usual one by a divergence only. The contribution of this divergence to the angular-momentum tensor is interpreted to be the contribution of a special vector field. In the framework of the gravitation theory, we consider the possibility that the scalar field be not only the source of a Riemannian metric, but a torsion too.
TL;DR: In this paper, the Riemann-Christoffel curvature tensor in general relativity can also acquire such δ-function terms under a certain type of co-ordinate transformations on a certain class of space-times.
Abstract: In a manner quite similar to the Yang-Mills field strength which acquires additional two-dimensional σ-function terms under the singular gauge transformations, the Riemann-Christoffel curvature tensor in general relativity can also acquire such δ-function terms under a certain type of co-ordinate transformations on a certain class of space-times. As an illustration a Curzon metric with the conical-type singularities is adopted and the transformation properties of its energy-momentum tensor under singular co-ordinate transformations are discussed.
TL;DR: In this paper, a description of symmetric second-order spinors is considered and the Lagrange function and the equations of motion are found, as well as the interaction of the gravitational and an arbitrary tensor fields.
Abstract: A description of gauge fields based on symmetric second-order spinors is considered. The Lagrange function and the equations of motion are found. The gravitational field in vacuum and in the presence of matter is studied, as well as the interaction of the gravitational and an arbitrary tensor fields. It is shown that in this approach, the source of the gravitational field is the tensor of the density of the spin part of angular momentum.