Results 1 - 10 of 419
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[en] We investigate the chaotic dynamics of normal mode molecules from the classical point of view using the coupling Morse oscillators. New interesting phenomena of the fractured tori and the cross of tori on the Poincar-section, which go against our traditional understanding, are found and investigated. Also, we find that the phenomenon of tori cross is a signature of the single bond's energy beyond the total vibrational energy. Finally, a method to improve this scarcity is proposed. (authors)
[en] A model is developed for a non-uniform piezoelectric beam suitable for analyzing energy harvesting behavior. System dynamics are projected onto a numerically developed basis to produce energy functions which are used to derive equations of motion for the system. The resulting model reproduces the experimentally observed transition to chaos while providing a conservative estimate of power output and bandwidth. (paper)
[en] Semi-classical dynamics of quantum wave packets spreading is studied for a kicked rotor. Quantum flights are established for a specific, 'magic' value of a chaos control parameter when the classical stickiness of trajectories is most effective. By studying of a survival probability and distribution of the accelerations we identify the presence of quantum Levy-type flights
[en] In two dimensions chaotic level statistics with the Wigner spacing distribution P(S) is expected for massless fermions in the Dirac region. The obtained P(S) for weakly disordered finite graphene samples with zigzag edges turns out, however, to be neither chaotic (Wigner) nor localized (Poisson). It is similar to the intermediate statistics at the critical point of the Anderson metal-insulator transition. The quantum transport of finite graphene for weak disorder, with critical level statistics can occur via edge states as in topological insulators, and for strong disorder, graphene behaves as an ordinary Anderson insulator with Poisson statistics. (papers)
[en] We give a criterion to differentiate between dissipative and diffusive quantum operations. It is based on the classical idea that dissipative processes contract volumes in phase space. We define a quantity that can be regarded as 'quantum phase space contraction rate' and which is related to a fundamental property of quantum channels: nonunitality. We relate it to other properties of the channel and also show a simple example of dissipative noise composed with a chaotic map. The emergence of attractor-like structures is displayed
[en] We investigate the relation between the underlying dynamics of a randomly evolving system and the extrema statistics of such systems. Failure modes, as an exemplar of extreme properties, are considered in independent processes, Fokker-Planck processes and Levy stable processes. Using the diffusional entropy to replace the Kolmogorov-Sinai entropy in the survival probability of a dynamical system, we construct the relation between weak dynamical chaos and the ubiquitous inverse power-law distribution for the survival probability
[en] From Cosmos to Chaos- Peter Coles, 2006, Oxford University Press, 224pp. To confirm or refute a scientific theory you have to make a measurement. Unfortunately, however, measurements are never perfect: the rest is statistics. Indeed, statistics is at the very heart of scientific progress, but it is often poorly taught and badly received; for many, the very word conjures up half-remembered nightmares of 'null hypotheses' and 'student's t-tests'. From Cosmos to Chaos by Peter Coles, a cosmologist at Nottingham University, is an approachable antidote that places statistics in a range of catchy contexts. Using this book you will be able to calculate the probabilities in a game of bridge or in a legal trial based on DNA fingerprinting, impress friends by talking confidently about entropy, and stretch your mind thinking about quantum mechanics. (U.K.)
[en] In intrinsic photoconductors, the photoconduction process can be described with the help of a set of nonlinear differential equations. This paper investigates numerically chaotic behaviors in radiated intrinsic photoconductors under different parameter conditions, and some useful results are presented.
[en] We present experimental data on the development of chaotic oscillations in a nonautonomous magnetoacoustic oscillator based on a hybrid magnetoacoustic resonator of the reflection type. The proposed oscillator exhibits regimes of quasi-periodic and chaotic generation under an external low-frequency periodic force. The chaotic dynamics of the magnetoacoustic oscillator is caused by the presence of delay and bistability in the system.