arXiv subjects

R. O. Grigoriev

Publications and source records attributed to R. O. Grigoriev.

5 recordsLinked to original sources

arXiv1999

Identification and Control of Symmetric Systems

In a recent paper [Phys. Rev. E 57, p. 1550 (1998)] we demonstrated that the symmetries of the evolution equation and the target state have a profound effect on the selection of the admissible control parameters. In the present paper we extend these results to the case of time-periodic target states and inexact symmetries. We also argue that the problem of phase space reconstruction is affected by the presence of symmetries similarly to the control problem.

chao-dyn↗

arXiv1997

Controlling Physical Systems with Symmetries

Symmetry properties of the evolution equation and the state to be controlled are shown to determine the basic features of the linear control of unstable orbits. In particular, the selection of control parameters and their minimal number are determined by the irreducible representations of the symmetry group of the linearization about the orbit to be controlled. We use the general results to demonstrate the effect of symmetry on the control of two sample physical systems: a coupled map lattice and a particle in a symmetric potential.

chao-dyn↗

arXiv1997

A Solvable Model for Spatiotemporal Chaos

We show that the dynamical behavior of a coupled map lattice where the individual maps are Bernoulli shift maps can be solved analytically for integer couplings. We calculate the invariant density of the system and show that it displays a nontrivial spatial behavior. We also introduce and calculate a generalized spatiotemporal correlation function.

chao-dyn↗

arXiv1997

Pinning Control of Spatiotemporal Chaos

Linear control theory is used to develop an improved localized control scheme for spatially extended chaotic systems, which is applied to a Coupled Map Lattice as an example. The optimal arrangement of the control sites is shown to depend on the symmetry properties of the system, while their minimal density depends on the strength of noise in the system. The method is shown to work in any region of parameter space and requires a significantly smaller number of controllers compared to the method proposed earlier by Qu and Hu. A nonlinear generalization of the method for a 1-d lattice is also presented.

chao-dyn↗

arXiv1997

Dynamics of Coupled Maps with a Conservation Law

A particularly simple model belonging to a wide class of coupled maps which obey a local conservation law is studied. The phase structure of the system and the types of the phase transitions are determined. It is argued that the structure of the phase diagram is robust with respect to mild violations of the conservation law. Critical exponents possibly determining a new universality class are calculated for a set of independent order parameters. Numerical evidence is produced suggesting that the singularity in the density of Lyapunov exponents at $λ=0$ is a reflection of the singularity in the density of Fourier modes (a ``Van Hove'' singularity) and disappears if the conservation law is broken. Applicability of the Lyapunov dimension to the description of spatiotemporal chaos in a system with a conservation law is discussed.

chao-dyn↗