6,418 research outputs found
Clustered Chimera States in Systems of Type-I Excitability
Chimera is a fascinating phenomenon of coexisting synchronized and
desynchronized behaviour that was discovered in networks of nonlocally coupled
identical phase oscillators over ten years ago. Since then, chimeras were found
in numerous theoretical and experimental studies and more recently in models of
neuronal dynamics as well. In this work, we consider a generic model for a
saddle-node bifurcation on a limit cycle representative for neural excitability
type I. We obtain chimera states with multiple coherent regions (clustered
chimeras/multi-chimeras) depending on the distance from the excitability
threshold, the range of nonlocal coupling as well as the coupling strength. A
detailed stability diagram for these chimera states as well as other
interesting coexisting patterns like traveling waves are presented
Nonlinear transient waves in coupled phase oscillators with inertia
Like the inertia of a physical body describes its tendency to resist changes
of its state of motion, inertia of an oscillator describes its tendency to
resist changes of its frequency. Here we show that finite inertia of individual
oscillators enables nonlinear phase waves in spatially extended coupled
systems. Using a discrete model of coupled phase oscillators with inertia, we
investigate these wave phenomena numerically, complemented by a continuum
approximation that permits the analytical description of the key features of
wave propagation in the long-wavelength limit. The ability to exhibit traveling
waves is a generic feature of systems with finite inertia and is independent of
the details of the coupling function.Comment: 12 pages, 4 figure
Amplitude chimeras and chimera death in dynamical networks
We find chimera states with respect to amplitude dynamics in a network of
Stuart-Landau oscillators. These partially coherent and partially incoherent
spatio-temporal patterns appear due to the interplay of nonlocal network
topology and symmetry-breaking coupling. As the coupling range is increased,
the oscillations are quenched, amplitude chimeras disappear and the network
enters a symmetry-breaking stationary state. This particular regime is a novel
pattern which we call chimera death. It is characterized by the coexistence of
spatially coherent and incoherent inhomogeneous steady states and therefore
combines the features of chimera state and oscillation death. Additionally, we
show two different transition scenarios from amplitude chimera to chimera
death. Moreover, for amplitude chimeras we uncover the mechanism of transition
towards in-phase synchronized regime and discuss the role of initial
conditions
Stochastic Hydrodynamic Synchronization in Rotating Energy Landscapes
Hydrodynamic synchronization provides a general mechanism for the spontaneous
emergence of coherent beating states in independently driven mesoscopic
oscillators. A complete physical picture of those phenomena is of definite
importance to the understanding of biological cooperative motions of cilia and
flagella. Moreover, it can potentially suggest novel routes to exploit
synchronization in technological applications of soft matter. We demonstrate
that driving colloidal particles in rotating energy landscapes results in a
strong tendency towards synchronization, favouring states where all beads
rotate in phase. The resulting dynamics can be described in terms of activated
jumps with transition rates that are strongly affected by hydrodynamics leading
to an increased probability and lifetime of the synchronous states. Using
holographic optical tweezers we quantitatively verify our predictions in a
variety of spatial configurations of rotors.Comment: Copyright (2013) by the American Physical Societ
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