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JA Holyst

Publications and source records attributed to JA Holyst.

11 recordsLinked to original sources

Influence of stable Floquet exponents on time-delayed feedback control

The performance of time-delayed feedback control is studied by linear stability analysis. Analytical approximations for the resulting eigenvalue spectrum are proposed. Our investigations demonstrate that eigenbranches that develop from the stable Lyapunov exponents of the free system also have a strong influence on the control properties, either by hybridization or by a crossing of branches which interchanges the role of the leading eigenvalue. Our findings are confirmed by numerical analysis of two particular examples, the Toda and the Rossler models. More important is the verification by actual electronic circuit experiments. Here, the observed reduction of control domains can be attributed to these additional eigenvalue branches. The investigations lead to a thorough analytical understanding of the stability properties in time-delayed feedback systems.

Journal Article↗

Stochastic resonance in noisy maps as dynamical threshold-crossing systems

Interplay of noise and periodic modulation of system parameters for the logistic map in the region after the first bifurcation and for the kicked spin model with Ising anisotropy and damping is considered. For both maps two distinct symmetric states are present that correspond to different phases of the period-2 orbit of the logistic map and to disjoint attractors of the spin map. The periodic force modulates the transition probabilities from any state to the opposite one symmetrically. It follows that the maps behave as threshold-crossing systems with internal dynamics, and stochastic resonance (maximum of the signal-to-noise ratio in the signal reflecting the occurrence of jumps between the symmetric states) in both models is observed. Numerical simulations agree qualitatively with analytic results based on the adiabatic theory.

Journal Article↗