Introduction to Modern Synchronization Theory

Dr. Nikolai Rulkov and Dr. Mikhail Sushchik

**Institute for Nonlinear Science, CMRR, Room 1J**

**Winter and Spring Quarters**

**Abstract**

Synchronization of periodic oscillations has been known to scientists since the historical observation of this phenomenon by Huygens in pendulum clocks. With the development of radio and electronics in this century, synchronization occupied a very special place in science and technology. As many phenomena studied by nonlinear dynamics, synchronization was observed and shown to play an important role in many problems of a most diverse nature (physical, ecological, physiological, meteorological, to name a few). There is hardly a single communication or data storage application that does not rely on synchronization.

The discovery of deterministic chaos introduced a new kind of an oscillating system, a chaotic generator. Intuitively it would seem that chaos and synchronization are two mutually exclusive terms. Yet it has been shown that synchronization can be observed even in chaotic systems. However, the special features of chaotic systems make it impossible to directly apply the methods developed for synchronization of periodic oscillations. Even defining the notion of synchronization for chaotic systems is difficult without running into a paradox or controversy.

It is the objective of this course to introduce students to the basic
concepts and philosophy of nonlinear dynamics and to apply this philosophy
to the analysis of synchronization problems in physical, electrical and
biological systems. The first part of the course is dedicated to synchronization
of periodic oscillations, including the classical example of synchronization
in Van der Pol generator, synchronization in relaxation oscillators and
phase lock loops. The second part of the course introduces the notion of
chaos and discusses various cases of synchronized chaotic oscillation,
such as identical synchronization, generalized synchronization and phase
synchronization. The examples used here are based on electronic circuits
and biological systems with an emphasis on applications, in particular
on the use of chaos in secure communications. The course will emphasize
the use of analytical and semi-analytical methods in studying synchronization.

Preliminary Course Schedule

Winter Quarter:

Introduction to Nonlinear Dynamics. Synchronization in Periodic Oscillators.

1. Introduction. Synchronization phenomena in nature and technology. Elements of oscillation theory: phase space, classification of equilibrium states on a phase plane.

2. Introduction to bifurcations on a phase plane.

3. Parametric resonance. Discrete maps. Floquet theorem. Floquet multipliers and characteristic exponents.

4. Passive oscillator under the action of an external periodic force:linear and nonlinear resonance.

5-6. Self-sustained oscillations in autonomous dissipative systems. Limit cycles. Synchronization. Arnold tongues.

7. Systems with cylindrical phase space. Dynamics of phase lock loops.

8. Synchronization in large ensembles of periodic oscillations.

9-10. Relaxation oscillators. Synchronization in integrate-and-firesystems.

Spring Quarter:

Introduction to Chaos. Synchronization of Chaotic Oscillators.

1-2. Introduction to chaos. Chaotic oscillations in nature and technology. Transition to chaos: period doubling, quasiperiodicity, intermittency.

3. Chaos in electronic circuits. Experimental methods in chaos studies.

4-6. Synchronization between identical chaotic systems. Synchronization manifold. Stability of synchronization manifolds. Conditional Lyapunov exponents. On-off intermittency. Riddled basins of attraction.

7. Synchronization between non-identical chaotic systems. Generalized synchronization.

8. Phase synchronization of chaotic oscillations.

9-10. Examples and applications of synchronized chaos. Chaos in communications.Synchronization in neurobiology.