14 research outputs found
Critical exponents of directed percolation measured in spatiotemporal intermittency
A new experimental system showing a transition to spatiotemporal
intermittency is presented. It consists of a ring of hundred oscillating
ferrofluidic spikes. Four of five of the measured critical exponents of the
system agree with those obtained from a theoretical model of directed
percolation.Comment: 7 pages, 12 figures, submitted to PR
Evidence for directed percolation universality at the onset of spatiotemporal intermittency in coupled circle maps
We consider a lattice of coupled circle maps, a model arising naturally in
descriptions of solid state phenomena such as Josephson junction arrays. We
find that the onset of spatiotemporal intermittency (STI) in this system is
analogous to directed percolation (DP), with the transition being to an unique
absorbing state for low nonlinearities, and to weakly chaotic absorbing states
for high nonlinearities. We find that the complete set of static exponents and
spreading exponents at all critical points match those of DP very convincingly.
Further, hyperscaling relations are fulfilled, leading to independent controls
and consistency checks of the values of all the critical exponents. These
results lend strong support to the conjecture that the onset of STI in
deterministic models belongs to the DP universality class.Comment: Submitted to Physical Review
Breakdown of universality in transitions to spatiotemporal chaos
We show that the transition from laminar to active behavior in extended chaotic systems can vary from a continuous transition in the universality class of directed percolation with infinitely many absorbing states to what appears as a first-order transition. The latter occurs when finite lifetime nonchaotic structures, called "solitons," dominate the dynamics. We illustrate this scenario in an extension of the deterministic Chaté-Manneville coupled map lattice model and in a soliton including variant of the stochastic Domany-Kinzel cellular automaton