Table of contents

In 1950, A D Sakharov and I E Tamm put forward the fundamental idea of magnetic thermal confinement of high-temperature plasma, and proposed the magnetic thermonuclear reactor (MTR) concept. Studies in this direction initiated the mammoth 'Tokamak' programme. After many years of persistent scientific and engineering efforts in many countries worldwide, the realisation of the thermonuclear reaction has now become available. The International Thermonuclear Experimental Reactor (ITER) project is currently being developed jointly by the European Community (Euroatom), Russia, USA, and Japan. The aim of the ITER reactor is to demonstrate the scientific and technological feasibility of the peaceful use of nuclear fusion energy. The reactor is based on the Tokamak concept.

This paper examines elements of the general theory of transitions with changing spacetime signature in quantum gravity and cosmology as suggested in a pioneer work of A D Sakharov. Unlike the conventional formal method for functional integration, this approach uses as the starting point the Dirac–Wheeler–de Witt operator quantization and its reduction to quantization in Arnowitt–Deser–Misner variables. It has been demonstrated that motivation to consider Euclidean–Lorentzian transitions consists in global ambiguity of physical reduction on the phase space of the theory (a gravitational analog of the problem of Gribov's copies). This ambiguity in particular results in the indefinite sign of the physical inner product of quantum states and leads to the concept of third quantization. An alternative approach is quantization in the York gauge and in special variables of conformal superspace. This quantization is likely to provide a global solution of the ambiguity problem, but the problems of Euclidean–Lorentzian transitions arise in this formalism in the language of complexification of a conformal space of the Wick-rotation type for the time variable in the Klein–Gordon equation. The problem of origin of the early Universe via gravitational tunneling in Hartle–Hawking and Vilenkin quantum states is considered to illustrate applications of the general theory. The mechanism is described by which loop effects generate the normalizable distribution function for the ensemble of chaotic inflationary universes. In a model with a large non-minimal coupling constant for the scalar inflation, this mechanism gives rise to a sharp probability peak at sub-Planckian values for the Hubble constant which is in good agreement with the contemporary observational status of the cosmological inflation theory.

We review recent progress in the study of the anomalous baryon number non-conservation at high temperatures and in high-energy collisions. Recent results on high temperature phase transitions are described, and applications to the electroweak baryogenesis are considered. The current status of the problem of electroweak instanton-like processes at high energies is outlined.

We present a detailed review of the electroweak radiative corrections to the Z-boson decay, in the framework of the Minimal Standard Model (MSM). After a short historical introduction we describe the optimal parametrization of the MSM, especially of the Born approximation, and derive expressions for the one-loop electroweak corrections. Finally a global fit of all relevant experimental data is performed, resulting in fitted values of the t-quark mass, m_t, and strong coupling constant α_s. Allowed range for the value of the Higgs boson mass, m_H, is discussed. Various details of calculations are described in 16 appendices.

History of creation and schemes of Arzamas-16 explosive laboratory devices for dynamical compressibility measurements at pressures up to 2–2.5 TPa are described, in which a thin, metallic impactor of spherical geometry is accelerated by the explosion products in converging detonation waves. The iron shock adiabat obtained with these devices over the period from 1948 to the early 60s and used as a dynamical standard in megabar and terapascal compressibility studies of other substances, is presented. In deriving its parameters for up to 10 TPa, iron compressibility data from underground nuclear explosions of the 70s, and calculated results from the modified quantum-statistical model have been employed.