PubMed Health⌕ Search

Biomedical subjects

H Riecke

Publications and source records attributed to H Riecke.

17 recordsLinked to original sources

Nonequilibrium defect-unbinding transition: defect trajectories and loop statistics.

In a Ginzburg-Landau model for parametrically driven waves, a transition between a state of ordered and one of disordered spatiotemporal defect chaos is found. To get insight into the breakdown of the order, the defect trajectories are tracked in detail. Since the defects are created and annihilated in pairs, the trajectories form loops in space-time. The probability distribution functions for the size of the loops and the number of defects involved in them undergo a transition from exponential decay in the ordered regime to a power-law decay in the disordered regime. These power laws are also found in a simple lattice model of randomly created defect pairs that diffuse and annihilate upon collision.

Journal Article↗

Defect chaos of oscillating hexagons in rotating convection

Using coupled Ginzburg-Landau equations, the dynamics of hexagonal patterns with broken chiral symmetry are investigated, as they appear in rotating non-Boussinesq or surface-tension-driven convection. We find that close to the secondary Hopf bifurcation to oscillating hexagons the dynamics are well described by a single complex Ginzburg-Landau equation (CGLE) coupled to the phases of the hexagonal pattern. At the band center these equations reduce to the usual CGLE and the system exhibits defect chaos. Away from the band center a transition to a frozen vortex state is found.

Journal Article↗