Table of contents

The influence of the interaction of the components on the differential probability of pair production is studied.

The properties of a high-temperature plasma in a magnetic field were discussed in a paper by Tamm, in which he demonstrated the possibility of the realization of a magnetic thermonuclear reactor (MTR). In this paper we shall consider other questions concerning the theory of MTRs.

The effective Lagrange function of vacuum polarization is expressed in terms of the spectral density of the eigenvalues of the wave equation and the related five-dimensional Green's function introduced by Fock in his fifth-coordinate method. The method can be used for arbitrarily strong external fields, but the interaction of the vacuum fields is neglected. The vacuum polarization by the gravitational and electromagnetic fields is calculated.

Cosmological models of the universe with reversal of time's arrow are considered. Formulations are given of the hypothesis of Cosmological CPT symmetry suggested earlier by the writer, and of the hypothesis of an open model with many sheets, with negative spatial curvature, and with possible violation of CTT symmetry by an invariant combined charge. The statistical paradox of reversibility is discussed for these models. The small dimensionless parameter δ²/α², which characterizes the mean spatial curvature of the universe, is explained as the result of the evolution of the universe through many successive cycles of expansion and contraction.

Several versions of the pulsating (many-sheeted) model of the Universe are described, in particular, a model with reversal of the arrow of time. It is pointed out that the reversal point may be a singularity or may correspond to maximal cosmological expansion. The smoothing out of inhomogeneities and the growth of entropy produced by baryon decay are discussed, as well as processes involving black holes. It is conjectured that black holes are absent in the cosmological expansion-contraction cycle preceding the present one, and that such exceptional cycles do occur periodically.

It is conjectured that there exist states of the physical continuum which include regions with different signatures of the metric and that the observed Universe and an infinite number of other Universes arose as a result of quantum transitions with a change in the signature of the metric. The Lagrangian in such a theory must satisfy conditions of non-negativity in the regions with even signature. Signature here means the number of time coordinates. The induced gravitational Lagrangian in a conformally invariant theory of Kaluza-Klein type evidently satisfies this requirement and leads to effective equations of the gravitational theory of macroscopic space identical to the equations of the general theory of relativity. It is suggested that in our Universe there exist in addition to the observable (macroscopic) time dimension two or some other even number of compactified time dimensions. It is suggested that the formation of a Euclidean region in the center of a black hole or in the cosmological contraction of the Universe (if it is predetermined by the dynamics) is a possible outcome of gravitational collapse.

The observation of the final stages of the evaporation of black miniholes, if they should be discovered, might provide important information on the physics of high energies, up to the Planck level. Some relevant estimates are offered. It is shown, in particular, that the "shadow world" which has been proposed in certain theories might play a role in the dynamics of the evaporation.

It is proposed to utilize for explosive purposes the nuclear reaction of the transmutation of deuterium into hydrogen and tritium realized by a detonation method.