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A new method is proposed for calculating the vacuum energy-momentum tensor on bounded manifolds that does not require a cutoff or other artificial devices. The impenetrable boundaries are replaced by a family of localized potentials which depend on a parameter λ, the boundary condition corresponding to impenetrability being obtained in the limit λ → ∞. The Casimir effect in the case of two parallel plates is considered in detail.

The analytic dependences of the vacuum averages of the energy-momentum tensor on geometry and topology are found for scalar, electromagnetic, and massless gluon fields in bounded three-dimensional manifolds. Application of the results obtained to the “bag” model in the theory of hadrons is discussed.

A method is proposed for computing corrections to the Casimir force caused by a broken symmetry of the boundaries. The values of these corrections are obtained for a parallelepiped in the case of scalar and electromagnetic fields.

We consider the topological and geometric relations of the energy-momentum tensor of zero-point vacuum vibrations of a scalar field in two-dimensional manifolds. It is shown that the energy density can change sign under continuous deformation of the region.

Recent experiments have shown that there are discrepancies in Avagadro's number of the order of 10/sup /minus/6/, which are much greater than the errors in deriving the lattice constants in individual experiments (about 10/sup /minus/8/) on Si. This makes it important to examine possible residual systematic errors, in particular the error due to structure imperfection in the Si crystal and surface imperfections in the standard bodies, in addition to specific error sources arising from the methods of experiment. These features together define the limiting-constraint level. This paper considers the limiting-constraint features of residual stresses and strains and crystal response to external pressure as well as solid-solution features for a silicon crystal grown by crucible-free zone melting.

On an example of a two-band system with the electron-phonon interaction we show that a homogeneous stationary spontaneous current may arise when a phase transition in the presence of an external electromagnetic field occurs. The current is proportional to the imaginary part of the vector order parameter. In particular, in an illuminated homogeneous perfect ferroelectric this current appears simultaneously with the spontaneous polarization. The contribution of the spontaneous current into the photogalvanic (photovoltaic) effect is traced.

(1989). An electron beam gun with a metallic rod cathode for welding heat exchanger equipment. Welding International: Vol. 3, No. 1, pp. 9-11.

An expression for the temperature of a spherically symmetric uncharged black hole is found with the help of the general technique proposed in [8] for determining the effective vacuum temperature in external fields, based on investigation of the local properties of the Green function.