Нелинейные явления в сложных системах, 1999, Vol.2, No.4

НЕЛИНЕЙНЫЕ ЯВЛЕНИЯ В СЛОЖНЫХ СИСТЕМАХ Международный научный журнал Издается учреждением "Издательство «Адукацыя і выхаванне»", Минск, Беларусь

Volume 2, Number 4, 1999

СОДЕРЖАНИЕ

Summary: Entropy, information and relative criteria of order for states of open systems are considered. In the theory of communication two definitions of concept "information" are known. One of them coincides in form with the Boltzmann entropy. The second definition of information is defined as the difference between unconditional and conditional entropies. In the present work the latter is used for the definition of information about states of open systems with various meanings of controlling (governing) parameter. Two kinds of open systems are considered. Those systems belong to the first kind that with zero value of controling parameter are in the equilibrium state. The information about the equilibrium state is equal to zero. During self-organization in the process of removal from the equilibrium state the information is increased. For open systems of this class the conservation law for the sum of information and entropy with all values of controlling parameter is proved. In open systems of the second class the equilibrium is impossible. For them the concept ''norm of chaoticity '' is introduced. It allows to consider two kinds of self-organization processes and to give the corresponding definitions of information. The treatment is carried out on a number (classical and quantum) of examples of physical systems. The example of a medico-biological system is also considered.

P.C. Hendry, P.V.E. McClintock
Cosmological experiments in liquid helium. pp. 26--35

Summary: Fast passage through a continuous phase transition is expected to result in the creation of topical defects via the Kibble mechanism. Recent experiments involving the expansion of a small volume of liquid ⁴He through the lambda (superfluid) transition, as a model of the GUT (grand unified theory) symmetry-breaking transition of the early universe, are discussed and set in context. Copious creation of quantized vortices, analogous to cosmic strings, is expected but not observed. The possibility of developing a more sensitive version of the experiment is considered.

A. Cenys, A.Tamasevicius, G. Mykolaitis, A. Namajunas
Hyperchaos with High Metric Entropy. pp. 36--40

Summary: A new design of the hyperchaotic systems with arbitrarily highnumber of positive Lyapunov exponents is suggested. It exploits asa linear subsystem chain of harmonic oscillators corresponding tohigh-pass filter. In the new design characteristic frequency ofthe system is increasing proportionally to the number of identicallinear elements. As a result both number of the positive Lyapunov exponents and metric entropy increase when identical linearelements are added to the system.

K. G. Kyritsi, L. Gallos, A. N. Anagnostopoulos, A. Cenys, G. L. Bleris
Chaotic Photoconductivity. pp. 41--47

Summary: In modern optoelectronics, light sensors are playing a main role. The present work examines the conditions of their performance, concerning photoconductivity. The model of a n-type photosensitive semiconductor containing two localized levels in its energy gap is considered. The semiconductor is illuminated homogeneously with bandgap-light and a constant electric field is applied. Electrons are excited by the illumination from the valence- to the conduction-band and by the electric field from the localized levels to the conduction-band. Electrons are also recombining from the conduction- to the valence-band and from the conduction-band to the localized levels. Depending on the parameters of the system (i.e. generation- and recombination rates, electric field strength, capture- and reemission-coefficients of the levels, ambient temperature, etc) the semiconductor is exhibiting periodic or chaotic conductivity. Different routes to chaos were observed in this system, like period doubling, intermittency and crisis induced intermittency.

Yu. Andreyev, A. Dmitriev, A. Ovsyannikov
Chaotic processors and content-based search of information in unstructured data bases. pp. 48--53

Summary: In this report, we discuss an approach to construction of information searching systems based on dynamic chaos and intended to operate in computer networks, local area or Internet. Also we discuss an application of this technology to the problems of searching for information in unstructured text databases with natural-language requests.

T.A. King, W. Hogervorst, N.S. Kazak, V.A. Tugbaev, V.N.Belyi, N.A.Khilo, A.A.Ryzhevich
Investigation of properties of nonlinear optical frequency-conversion and parametric interactions using Bessel nondiffracting light beams. pp. 54--60

Summary: The fundamental possibility of the formation of higher-order Bessel light beams is confirmed. The transformation of beam order is observed when propagating circularly polarized light along the optical axis of biaxial crystal under conditions of internal conical refraction. Theoretical and experimental investigations were made of the characteristic features of frequency doubling of Bessel light beams by the oe-e interaction in a KTP crystal. All possible vector and scalar interactions of plane-wave components of Bessel beams were observed experimentally. Parametric generation of light by pumping with Bessel light beams is considered. A theory of azimuth-matched nonlinear interaction of Bessel light beams is developed.

A. Antonevich
The Schroedinger operator with d-potential: Finite-dimensional perturbations approach. pp. 61--71