The Maxwell theory on non-commutative spaces has been considered. The non-linear equations of electromagnetic fields on non-commutative spaces were obtained in the compact spin-tensor (quater-nion) form. We found the symmetric energy-momentum tensor and its non-zero trace. So, the trace anomaly of the energy-momentum tensor was obtained in electrodynamics on non-commutative spaces. It was noted...

By exploiting the mathematical analogy between the propagation of sound in a nonhomogeneous potential flow and the propagation of a scalar field in curved space-time, various wave "energy" and wave "momentum" conservation laws are established in a systematic manner. In particular, the acoustic energy conservation law due to Blokhintsev appears as the result of the conservation of a mixed covari...

Using Ernst's theory of complex potentials, a solution of the coupled Einstein-Maxwell equations in oblate spheroidal coordinates is obtained for a source possessing mass, electric charge, and angular momentum. The density of the electromagnetic energy is evaluated. Explicit expressions are derived for the components of the Ricci tensor Rmunu, and of the electromagnetic energy momentum tensor E...

The Kähler metric which has been constructed by present author in [1] is used in this paper to find an exact solution of Einstein equations with energy-momentum tensor of special type. That type of Tij admits in particular to use it as energy-momentum tensor of charged scalar field and in case of such system the field function is determined.

Starting with a field theoretic approach in Minkowski space, the gravitational energy momentum tensor is derived from the Einstein equations in a straightforward manner. This allows to present them as acceleration tensor = const. × total energy momentum tensor. For flat space cosmology the gravitational energy is negative and cancels the material energy. In the relativistic theory of gravitatio...