Hole-defect chaos in the one-dimensional complex Ginzburg-Landau equation

We study the spatiotemporally chaotic dynamics of holes and defects in the 1D complex Ginzburg--Landau equation (CGLE). We focus particularly on the self--disordering dynamics of holes and on the variation in defect profiles. By enforcing identical defect profiles and/or smooth plane wave backgrounds, we are able to sensitively probe the causes of the spatiotemporal chaos. We show that the coupling of the holes to a self--disordered background is the dominant mechanism. We analyze a lattice model for the 1D CGLE, incorporating this self--disordering. Despite its simplicity, we show that the model retains the essential spatiotemporally chaotic behavior of the full CGLE.Comment: 8 pages, 10 figures; revised and shortened; extra discussion of self-disordering dynamic

The end of the map?

Martin Smith and Andy Howard* explain why moving away from the printed map to a digital 3D National Geological Model is a ‘coming of age’ for William Smith’s great visio

A model for anomalous directed percolation

We introduce a model for the spreading of epidemics by long-range infections and investigate the critical behaviour at the spreading transition. The model generalizes directed bond percolation and is characterized by a probability distribution for long-range infections which decays in $d$ spatial dimensions as $1/r^{d+\sigma}$. Extensive numerical simulations are performed in order to determine the density exponent $\beta$ and the correlation length exponents $\nu_{||}$ and $\nu_\perp$ for various values of $\sigma$. We observe that these exponents vary continuously with $\sigma$, in agreement with recent field-theoretic predictions. We also study a model for pairwise annihilation of particles with algebraically distributed long-range interactions.Comment: RevTeX, 9 pages, including 6 eps-figure