TY  - JOUR
A1  - Temirbayev, Amirkhan A.
A1  - Zhanabaev, Zeinulla Zh.
A1  - Tarasov, Stanislav B.
A1  - Ponomarenko, Vladimir I.
A1  - Rosenblum, Michael
T1  - Experiments on oscillator ensembles with global nonlinear coupling
JF  - Physical review : E, Statistical, nonlinear and soft matter physics
N2  - We experimentally analyze collective dynamics of a population of 20 electronic Wien-bridge limit-cycle oscillators with a nonlinear phase-shifting unit in the global feedback loop. With an increase in the coupling strength we first observe formation and then destruction of a synchronous cluster, so that the dependence of the order parameter on the coupling strength is not monotonic. After destruction of the cluster the ensemble remains nevertheless coherent, i.e., it exhibits an oscillatory collective mode (mean field). We show that the system is now in a self-organized quasiperiodic state, predicted in Rosenblum and Pikovsky [Phys. Rev. Lett. 98, 064101 (2007)]. In this state, frequencies of all oscillators are smaller than the frequency of the mean field, so that the oscillators are not locked to the mean field they create and their dynamics is quasiperiodic. Without a nonlinear phase-shifting unit, the system exhibits a standard Kuramoto-like transition to a fully synchronous state. We demonstrate a good correspondence between the experiment and previously developed theory. We also propose a simple measure which characterizes the macroscopic incoherence-coherence transition in a finite-size ensemble.
Y1  - 2012
U6  - https://doi.org/10.1103/PhysRevE.85.015204
SN  - 1539-3755
VL  - 85
IS  - 1
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Schwabedal, Justus T. C.
A1  - Pikovskij, Arkadij
A1  - Kralemann, Björn
A1  - Rosenblum, Michael
T1  - Optimal phase description of chaotic oscillators
JF  - Physical review : E, Statistical, nonlinear and soft matter physics
N2  - We introduce an optimal phase description of chaotic oscillations by generalizing the concept of isochrones. On chaotic attractors possessing a general phase description, we define the optimal isophases as Poincare surfaces showing return times as constant as possible. The dynamics of the resultant optimal phase is maximally decoupled from the amplitude dynamics and provides a proper description of the phase response of chaotic oscillations. The method is illustrated with the Rossler and Lorenz systems.
Y1  - 2012
U6  - https://doi.org/10.1103/PhysRevE.85.026216
SN  - 1539-3755
VL  - 85
IS  - 2
PB  - American Physical Society
CY  - College Park
ER  -