The Unexpected SynchronizationWhen: Wednesday, September 14, 2011 at 3:00 pm
Where: DA 5th fl
Speaker: Professor Zoltán Néda
Organization: Babeş-Bolyai University, Department of Theoretical and Computational Physics, Cluj, Romania
Sponsor: CCNR and Barabási Lab Seminar
Emerging synchronization of a large number of non-identical oscillators coupled through phase-minimizing forces is a fascinating collective behavior. Such phenomena are frequent in biological and social systems. Biological and social systems usually do have a tendency to optimize their evolution, and one might assume that synchronization is not their primary aim. A recently introduced synchronization model assumes that spontaneous synchronization might arise also as a byproduct of simple optimization processes. Therefore, models that aim to describe realistically such systems should take also this possibility into consideration and step over the simple physical models offered by oscillators interacting through phase-minimizing forces. The present research contributes in such sense, considering a system of oscillators coupled through a simple optimization rule. The oscillators are stochastic elements capable of emitting pulses and detecting the pulse emitted by the others. They have several operational modes, characterized by different oscillating periods. Shifting between these modes is induced by a simple optimization rule: the average output intensity of the oscillators is kept around a fixed G threshold. This dynamical rule realizes the coupling of the elements and trigger a complex collective behavior. Computer simulations suggests that for a given interval of the G parameter partial synchronization of the elements can occur. The appearance and disappearance of synchronization as a function of G indicates a phase-transition type behavior. The observed synchronization is highly nontrivial. In contrast with simple synchronization models here no phase-difference minimizing interactions are considered. Another important aspect of the considered system is that the periodicity of the output for the whole ensemble is increased relative to the periodicity level of one element. This suggests interesting practical applications as well. An experimental realization of the system is also discussed.