Table of contents

Publications devoted to the polarization of the quantum states of ensembles of atomic particles in ionized gases and plasmas are reviewed. A theoretical description of the phenomenon is given and its relationship to anisotropic properties of plasmas is established. Methods of determining the polarization of the states of atomic ensembles from the polarization of the line spectrum of excited particles are described. Experimental studies of gas discharges, beam-plasma systems, and astrophysical objects are summarized. It is shown that the polarization of the quantum states of atoms can be observed over a wide range of plasma conditions.

The physical principles and basic theses of the theory, enabling a unified description of the magnetic properties of all thermodynamically stable domain structures in magnets, are presented. The theory is based on the following proposition proved by the authors: a necessary condition for the formation of all thermodynamically stable domain structures in magnets is the existence of a first-order phase transition induced by an external magnetic field. The approach developed makes it possible to regard the physics of domain structures as a part of thermodynamics, to derive the conditions for the existence of domains with different number of phases, to study the structure of the region of existence of domains, and to formulate for magnets with a domain structure an analogue of Gibbs rule. The general assertions of the theory are amply illustrated with experimental results. The properties of domain structures are analyzed in detail, and an interpretation is given for many experimental results for the most studied spin-reorientational transitions.

The standard quantum limits on several macroscopic quantities and the conditions for attaining these limits are evaluated. Possibilities for exceeding them by means of quantum nondemolition measurements are examined. The best frequency stability in self-excited oscillators, the smallest mechanical displacements, and the highest Q values of mechanical and electromagnetic resonators which have been achieved are reviewed. The outlook for improving the sensitivity in several gravitational experiments is evaluated.

An analysis is made of experimental data from measurements of the specific heat, the resistivity, the critical magnetic fields, the paramagnetic susceptibility above T_c, the Hall effect, and of other properties of the two new types of superconducting materials: lanthanum cuprates and the 1-2-3 compounds. The results of this analysis are discussed from the point of view of applying the Fermi-liquid picture to the description of the normal and superconducting properties of these materials, the role of fluctuations near the critical temperature, and the dimensionality of the superconductivity in them. Estimates of the width of the conduction band and of some other microscopic parameters indicate that there is a rather wide (about 0.7 eV) delocalized band. The fluctuations region near T_c is narrow, but nonetheless wider than that in ordinary superconductors. The superconductivity near T_c is three-dimensional, although sufficiently far from T_c the layered nature of the structure may be important.

The Sagnac experiment can be explained systematically without going beyond the special theory of relativity.

We review a number of the important results of the theory of radiation transport of resonance radiation obtained mainly during the past decade. Situations are stressed in which the traditional hypothesis of complete frequency redistribution of quanta is not fulfilled in the process of reemission. A quite general approach to the problem of radiation transport is presented that assumes small frequency shifts in the scattering event. Results are presented pertaining to the rate of deexcitation in Doppler, Stark, and natural mechanisms of line broadening. The transport of polarized radiation is discussed, including the application to experiments on interference of atomic states (the Hanle effect, etc.). The problem is discussed of transport of high-intensity radiation, in particular as applied to the problem of radiation trapping in lines of hydrogen-like ions. The connection is discussed of the physical mechanisms of radiation transport in spectral lines and in a recombination continuum.