Black hole uniqueness from a hidden symmetry of Einstein's gravity

A theorem is proven that the only possible exterior solution for a pseudostationary, rotating, electrovacuum black hole with nondegenerate event horizon is the Kerr-Newman solution withM ²-J²/M²-Q²>0. A special role played in the proof of this theorem by the hidden symmetry groupSU(1, 2) of Einstein's equations is established.This essay received the third award from the Gravity Research Foundation for the year 1983 [Ed.].     

Uniqueness and the global Markov property for Euclidean fields: The case of general exponential interaction

The uniqueness and the global Markov property for the regular Gibbs measure corresponding to the interaction $$U_\Lambda (\varphi ): = \lambda \int\limits_\Lambda {d_2 x\int {d\varrho (\alpha ):e^{\alpha \varphi } :_0 (x)} } $$ [forλ>0,d?(α) a probability measure with support in \(( - 2\sqrt {\pi ,} 2\sqrt \pi )\) ] is proved.     

Scattering of electrons by charged dislocations in InSb-type semiconductors

Electron scattering by parallel arrays of charged dislocations in InSb-type semiconductors is considered. In the theoretical approach the nonparabolic structure of the conduction band of the semiconductors considered is taken into account in the approximation of a simplified Kane's band model. The effect of screening by free electrons of the dislocation charge is also included in the theory. The calculated relaxation time of the electrons is used to derive a formula for the dislocation-limited electron mobility in the semiconductors. Some examples of calculations of the charged dislocation-limited mobility as a function of the electron concentration with the dislocation density as a parameter are given for n-InSb at 77 K and 300 K. The ratio of the magnitudes of the charged dislocation-limited mobility to the ionized impurity-limited mobility in n-type material at low temperatures is also discussed.     

Ultrasonic system for accurate distance measurement in the air

This paper presents a system that accurately measures the distance travelled by ultrasound waves through the air. The simple design of the system and its obtained accuracy provide a tool for non-contact distance measurements required in the laser’s optical system that investigates the surface of the eyeball.     

Renormalization group approach to lattice gauge field theories

We study four-dimensional pure gauge field theories by the renormalization group approach. The analysis is restricted to small field approximation. In this region we construct a sequence of localized effective actions by cluster expansions in one step renormalization transformations. We construct also -functions and we define a coupling constant renormalization by a recursive system of renormalization group equations.     

The Monte-Carlo model of a light-emitting diode

The first complete Monte-Carlo model of a surface light-emitting diode is presented in this paper. In the model all important phenomena (including the two-dimensional diffusion of minority carriers before their recombination in the active region and the re-emission of radiation) are taken into account. The influence of various construction parameters on the external quantum efficiency of the homojunction GaAs diode is examined.     

Preparation and semiconducting properties of Th3As4

The resistivity, thermoelectric power and Hall constant in the temperature range of 78–830 K were determined for polycrystalline Th₃As₄ samples obtained by annealing thin thorium slabs in arsenic vapour. The samples examined were n-type semiconductors with a carrier concentration ranging from 1.0 × 10¹⁸cm^?3 to 2.8 × 10¹⁸ cm^?3 for which the effective mass was found to be equal to 0.55–0.76m₀. The Hall mobility, about 450cm²V^?1s^?1 at room temperature, obeys a $\text{T}{}^{\mathrm{<mtext>?3</mtext><mtext>2</mtext>}}$ law at high temperatures. On the basis of the electrical measurements the forbidden gap of Th₃As₄ was found to be equal to 0.43 eV.     

A note on the Percus-Yevick and hypernetted chain theories of adsorption: The second and third virial coefficients for a hard-sphere gas in contact with a wall with a soft surface layer

The first three virial coefficients of a new type in the density expansion of the adsorption isotherm for hard spheres in contact with a wall with a soft surface layer are calculated. The results are compared with those for hard spheres in contact with a hard wall.