Nonstationary source of resonance radiation at the surface of a stimulated dispersed medium

Upon the sudden connection of a radiation source a reflected wave has two fronts corresponding to scattering by excited and nonexcited atoms of the medium. The former turns out to be leading. It is shaped by collapse of a fur coat of virtual photons, because of the vacuum effect, surrounding the excited atoms.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 33–38, October, 1988.     

Change of quantum statistical properties of resonance radiation during its scattering by excited systems

The effects of a quantized electromagnetic field manifest themselves at the macroscopic level during resonance radiation scattering by excited systems.     

On the propagation of coherent radiation in gases

The propagation of coherent light of high amplitude is governed by the refractive index found herein. Light scattering occurs because of conversion of the coherent into incoherent radiation. Appropriate cross sections are found.Translated from Izvestiya Uchebnykh Zavedenii, Fizika, No. 4, pp. 40–45, April, 1973.     

Point source of polarized resonance radiation in an unbounded medium

The diffusion of polarized resonance radiation is considered. An explicit expression is given for the Green's function of the corresponding equation for an unbounded uniform space.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 53–58, April, 1974.     

Excitation of an atom by a nonmonochromatic electromagnetic field

The time evolution of the process of excitation of an atom in the field of a laser wave is considered. It is shown that there exist three stages of relaxation. The first stage carries the most complete information about the mechanism of the interaction of the field with material inside the laser source.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 23–27, June, 1981.     

Transition radiation in the presence of excited media

The transition radiation in excited dispersing media is determined by the quantum index of refraction found in this paper. In the resonant-frequency region it is not related to the dielectric constant of the medium and cannot be calculated on the basis of the semiclassical radiation theory.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 11–14, November, 1984.The author is grateful to the participants in the seminar conducted by V. L. Bonch-Bruevich for their attention to this paper.     

Change in the electromagnetic field frequency because of stimulated radiation in a medium

The spectrum of a two-photon electromagnetic field in a transparent dispersing medium consists of three branches. Excitation of the secondary branches of the spectrum implies a change in the electromagnetic field frequency during passage through a medium of finite size if excited impurity atoms are present.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 65–69, May, 1982.I am grateful to the participants of the seminar supervised by V. L. Bonch-Bruevich for favorable remarks.     

Vavilov-Cherenkov emission spectrum in an excited isotropic dispersing medium

It is shown that the presence of excited molecules in a medium can involve the appearance of additional branches in the Vavilov-Cherenkov emission spectrum.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 8–11, November, 1984.     

Distribution functions and green's functions

A unitary transformation is indicated which makes it possible when computing a partially traced density matrix to use the method of two-time quantum Green's functions. For systems in strong nonequilibrium, an integral equation is found which describes both the initial and kinetic stages of relaxation of the density matrix of a subsystem from any initial distribution.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 77–81, May, 1978.I am very grateful to V. L. Bonch-Bruevich for his constant attention.     

Thermodynamic fluctuations of an electromagnetic field in dispersing media at finite temperatures

The spatial correlator of vector potentials is calculated for a dispersing absorbing medium. Quantum electrodynamics calculations performed without resorting to the fluctuation_dissipation theorem show that this correlator is determined solely by the refractive index of the medium at low temperatures. In thermally excited media, the correlator is determined by a characteristic which differs from the refractive index entering into the Maxwell equations for classical fields. Moscow Energy Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 17–21, June, 2000.