Numerical simulations of high Reynolds number ̄ows in the unit driven cavity have been performed. The system is shown to become unsteady at Reˆ 8125 and chaotic at Reˆ 17,000. In between this range the system switches between periodic and quasi-periodic states with step-wise changes in period. A passive concentration ®eld and passive tracer particles are introduced into the ̄ow at its asymptoti...

We investigate the e ect of repeated measurement for quantum dynamics of the suppressed systems which classical counterparts exhibit chaos. The essential feature of such systems is the quantum localization phenomena strongly limiting motion in the energy space. Repeated frequent measurement of suppressed systems results to the delocalization. Time evolution of the observed chaotic systems becom...

We show that the condition for the appearance of quantum chaos (Wigner-Dyson distribution of energy eigenvalues, gaussian-random energy eigenfunctions) in a dilute gas of many hard spheres is λ ≪ l, where λ is the wavelength of a typical particle and l is the mean free path between collisions. For fermions with Fermi wavelength λF ≪ l, this implies that all energy eigenstates, including the gro...

In this paper we introduce and discuss two proprieties related to recurrences in dynamical systems. The rst gives the asymptotic law for the return time in a neighborhood, while the second gives a topological index of fractal type to characterize the system or some regions of the system. Unit e Propre de Recherche 7061 z talk given by Sandro Vaienti at the conference \Disorder and Chaos" (Rome ...

In time series analysis, it has been considered of key importance to determine whether a complex time series measured from the system is regular, deterministically chaotic, or random. Recently, Gottwald and Melbourne have proposed an interesting test for chaos in deterministic systems. Their analyses suggest that the test may be universally applicable to any deterministic dynamical system. In o...

This paper presents a new hyperchaotic system with three positive Lyapunov exponents (called Tri-Chaos). Via linear coupling, Mathieu, and van der Pol systems are coupled with each other and then become a new four order system—Mathieu–van der Pol autonomous system. As we know, two positive Lyapunov exponents confirm hyperchaotic nature of its dynamics and it means that the system can present mo...

This paper summarises an investigation of chaos in a toy potential which mimics much of the behaviour observed for the more realistic triaxial generalisations of the Dehnen potentials, which have been used to model cuspy triaxial galaxies both with and without a supermassive black hole. The potential is the sum of an anisotropic harmonic oscillator potential, Vo = 12 (a 2x2 + b2y2 + c2z2), and ...

Sea clutter is the backscattered returns from a patch of the sea surface illuminated by a radar pulse. The amplitude waveforms of sea clutter and indoor radio propagation are very complicated. Can the apparent randomness of these waveforms be attributed to be generated by low-dimensional chaos? Based on the assumption that a chaotic attractor is characterized by a noninteger fractal dimension a...

Theoretical and experimental investigations of chaos synchronization and its application to chaotic data transmissions in semiconductor lasers with optical feedback are presented. Two schemes of chaos synchronization—complete and generalized synchronization—are discussed in the delay differential systems. The conditions for chaos synchronization in the systems and the robustness for the paramet...

We consider a number of possible roles of complex dynamics and chaos in information processing by neural networks. First, we review the working principles of some well-known neural networks, and then discuss a number of approaches to utilization of chaos in neural networks. Our main goal is to present a novel view of the problem of chaos in information processing. We demonstrate that chaos emer...