|Author||Tangherlini, F. R.|
|Source||United States Department of Energy Office of Scientific and Technical Information|
|Subject Keyword||PHYSICS ♦ ANGULAR MOMENTUM ♦ DENSITY ♦ ENERGY ♦ EQUATIONS ♦ FIELD THEORY ♦ GRAVITATION ♦ LORENTZ TRANSFORMATIONS ♦ MACH PRINCIPLE ♦ MASS ♦ MOMENTUM ♦ TENSORS ♦ VECTORS|
|Abstract||It is suggested that the cosmological term kappa /sup -1/ LAMBDA g/sub i/sub n/i, wi th LAMBDA > 0, fulfills the basic requirements of a generally covariant energy-momentum tensor for the gravitational field. Justification is given for this hypothesis by studying the character of the field equations in the absence of the cosmological term; by a re-interpretation of the line element based on Mach's principle; and by calculating the gravitational proper energy for a de Sitter static universe with and without a Schwarzschild field present, showing that the difference is proportional to the Schwarzschild mass. Finally an attempt is made to define a true tensor for the angular momentum density. It is shown that this line of reasoning leads to a definition of "physical coordinates." These coordinates are determined in such a way that in the weakfield limit they approach the usual Lorentz coordinates. However, it is not possible to arrive at these coordinates by imposing coordinate conditions, since they form the components of a vector. To the extent that the angular momentum of the gravitational field is covariantly conserved, the coordinates may be obtained as the gradient of a world scalar that satisfies an inhomogeneous d'Alembertian equation. (auth)|
|Learning Resource Type||Article|
|Publisher Department||Scuola di Perfezionamento in Fisica Teorica e Nucleare, Naples|
|Organization||Scuola di Perfezionamento in Fisica Teorica e Nucleare, Naples|
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