682 research outputs found
Nonintegrability, Chaos, and Complexity
Two-dimensional driven dissipative flows are generally integrable via a
conservation law that is singular at equilibria. Nonintegrable dynamical
systems are confined to n*3 dimensions. Even driven-dissipative deterministic
dynamical systems that are critical, chaotic or complex have n-1 local
time-independent conservation laws that can be used to simplify the geometric
picture of the flow over as many consecutive time intervals as one likes. Those
conserevation laws generally have either branch cuts, phase singularities, or
both. The consequence of the existence of singular conservation laws for
experimental data analysis, and also for the search for scale-invariant
critical states via uncontrolled approximations in deterministic dynamical
systems, is discussed. Finally, the expectation of ubiquity of scaling laws and
universality classes in dynamics is contrasted with the possibility that the
most interesting dynamics in nature may be nonscaling, nonuniversal, and to
some degree computationally complex
The New Science of Complexity
Deterministic chaos, and even maximum computational complexity, have been discovered within Newtonian dynamics. Economists assume that prices and price changes can also obey abstract mathematical laws of motion. Sociologists and other postmodernists advertise that physics and chemistry have outgrown their former limitations, that chaos and complexity provide new holistic paradigms for science, and that the boundaries between the hard and soft sciences, once impenetrable, have disappeared like the Berlin Wall. Three hundred years after the deaths of Galileo, Descartes, and Kepler, and the birth of Newton, reductionism appears to be on the decline, with holistic approaches to science on the upswing. We therefore examine the evidence that dynamical laws of motion may be discovered from empirical studies of chaotic or complex phenomena, and also review the foundation of reductionism in invariance principle
Discrete one-dimensional piecewise chaotic systems without fixed points
Acknowledgements The authors are thankful to the anonymous reviewers for their constructive feedback.Peer reviewe
Properties making a chaotic system a good Pseudo Random Number Generator
We discuss two properties making a deterministic algorithm suitable to
generate a pseudo random sequence of numbers: high value of Kolmogorov-Sinai
entropy and high-dimensionality. We propose the multi dimensional Anosov
symplectic (cat) map as a Pseudo Random Number Generator. We show what chaotic
features of this map are useful for generating Pseudo Random Numbers and
investigate numerically which of them survive in the discrete version of the
map. Testing and comparisons with other generators are performed.Comment: 10 pages, 3 figures, new version, title changed and minor correction
Integrable and Chaotic Systems Associated with Fractal Groups
Fractal groups (also called self-similar groups) is the class of groups
discovered by the first author in the 80-s of the last century with the purpose
to solve some famous problems in mathematics, including the question raising to
von Neumann about non-elementary amenability (in the association with studies
around the Banach-Tarski Paradox) and John Milnor's question on the existence
of groups of intermediate growth between polynomial and exponential. Fractal
groups arise in various fields of mathematics, including the theory of random
walks, holomorphic dynamics, automata theory, operator algebras, etc. They have
relations to the theory of chaos, quasi-crystals, fractals, and random
Schr\"odinger operators. One of important developments is the relation of them
to the multi-dimensional dynamics, theory of joint spectrum of pencil of
operators, and spectral theory of Laplace operator on graphs. The paper gives a
quick access to these topics, provide calculation and analysis of
multi-dimensional rational maps arising via the Schur complement in some
important examples, including the first group of intermediate growth and its
overgroup, contains discussion of the dichotomy "integrable-chaotic" in the
considered model, and suggests a possible probabilistic approach to the study
of discussed problems.Comment: 48 pages, 15 figure
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