2,462 research outputs found
Swarm-Oscillators
Nonlinear coupling between inter- and intra-element dynamics appears as a
collective behaviour of elements. The elements in this paper denote symptoms
such as a bacterium having an internal network of genes and proteins, a
reactive droplet, a neuron in networks, etc. In order to elucidate the
capability of such systems, a simple and reasonable model is derived. This
model exhibits the rich patterns of systems such as cell membrane, cell fusion,
cell growing, cell division, firework, branch, and clustered clusters
(self-organized hierarchical structure, modular network). This model is
extremely simple yet powerful; therefore, it is expected to impact several
disciplines.Comment: 9 pages, 4 figure
Chimera and globally clustered chimera: Impact of time delay
Following a short report of our preliminary results [Phys. Rev. E 79,
055203(R) (2009)], we present a more detailed study of the effects of coupling
delay in diffusively coupled phase oscillator populations. We find that
coupling delay induces chimera and globally clustered chimera (GCC) states in
delay coupled populations. We show the existence of multi-clustered states that
act as link between the chimera and the GCC states. A stable GCC state goes
through a variety of GCC states, namely periodic, aperiodic, long-- and
short--period breathers and becomes unstable GCC leading to global
synchronization in the system, on increasing time delay. We provide numerical
evidence and theoretical explanations for the above results and discuss
possible applications of the observed phenomena.Comment: 10 pages, 10 figures, Accepted in Phys. Rev.
Synchronous solutions and their stability in nonlocally coupled phase oscillators with propagation delays
We study the existence and stability of synchronous solutions in a continuum
field of non-locally coupled identical phase oscillators with
distance-dependent propagation delays. We present a comprehensive stability
diagram in the parameter space of the system. From the numerical results a
heuristic synchronization condition is suggested, and an analytic relation for
the marginal stability curve is obtained. We also provide an expression in the
form of a scaling relation that closely follows the marginal stability curve
over the complete range of the non-locality parameter.Comment: accepted in Phys. Rev. E (2010
Synchronization Transition in the Kuramoto Model with Colored Noise
We present a linear stability analysis of the incoherent state in a system of
globally coupled, identical phase oscillators subject to colored noise. In that
we succeed to bridge the extreme time scales between the formerly studied and
analytically solvable cases of white noise and quenched random frequencies.Comment: 4 pages, 2 figure
Collective phase synchronization in locally-coupled limit-cycle oscillators
We study collective behavior of locally-coupled limit-cycle oscillators with
scattered intrinsic frequencies on -dimensional lattices. A linear analysis
shows that the system should be always desynchronized up to . On the other
hand, numerical investigation for and 6 reveals the emergence of the
synchronized (ordered) phase via a continuous transition from the fully random
desynchronized phase. This demonstrates that the lower critical dimension for
the phase synchronization in this system is $d_{l}=4
Chimera States for Coupled Oscillators
Arrays of identical oscillators can display a remarkable spatiotemporal
pattern in which phase-locked oscillators coexist with drifting ones.
Discovered two years ago, such "chimera states" are believed to be impossible
for locally or globally coupled systems; they are peculiar to the intermediate
case of nonlocal coupling. Here we present an exact solution for this state,
for a ring of phase oscillators coupled by a cosine kernel. We show that the
stable chimera state bifurcates from a spatially modulated drift state, and
dies in a saddle-node bifurcation with an unstable chimera.Comment: 4 pages, 4 figure
An experimental route to spatiotemporal chaos in an extended 1D oscillators array
We report experimental evidence of the route to spatiotemporal chaos in a
large 1D-array of hotspots in a thermoconvective system. Increasing the driving
force, a stationary cellular pattern becomes unstable towards a mixed pattern
of irregular clusters which consist of time-dependent localized patterns of
variable spatiotemporal coherence. These irregular clusters coexist with the
basic cellular pattern. The Fourier spectra corresponding to this
synchronization transition reveals the weak coupling of a resonant triad. This
pattern saturates with the formation of a unique domain of great spatiotemporal
coherence. As we further increase the driving force, a supercritical
bifurcation to a spatiotemporal beating regime takes place. The new pattern is
characterized by the presence of two stationary clusters with a characteristic
zig-zag geometry. The Fourier analysis reveals a stronger coupling and enables
to find out that this beating phenomena is produced by the splitting of the
fundamental spatiotemporal frequencies in a narrow band. Both secondary
instabilities are phase-like synchronization transitions with global and
absolute character. Far beyond this threshold, a new instability takes place
when the system is not able to sustain the spatial frequency splitting,
although the temporal beating remains inside these domains. These experimental
results may support the understanding of other systems in nature undergoing
similar clustering processes.Comment: 12 pages, 13 figure
Oscillatory phase transition and pulse propagation in noisy integrate-and-fire neurons
We study non-locally coupled noisy integrate-and-fire neurons with the
Fokker-Planck equation. A propagating pulse state and a wavy state appear as a
phase transition from an asynchronous state. We also find a solution in which
traveling pulses are emitted periodically from a pacemaker region.Comment: 9 pages, 4 figure
Globally clustered chimera states in delay--coupled populations
We have identified the existence of globally clustered chimera states in
delay coupled oscillator populations and find that these states can breathe
periodically, aperiodically and become unstable depending upon the value of
coupling delay. We also find that the coupling delay induces frequency
suppression in the desynchronized group. We provide numerical evidence and
theoretical explanations for the above results and discuss possible
applications of the observed phenomena.Comment: Accepted in Phys. Rev. E as a Rapid Communicatio
Dynamics of the Singlet-Triplet System Coupled with Conduction Spins -- Application to Pr Skutterudites
Dynamics of the singlet-triplet crystalline electric field (CEF) system at
finite temperatures is discussed by use of the non-crossing approximation. Even
though the Kondo temperature is smaller than excitation energy to the CEF
triplet, the Kondo effect appears at temperatures higher than the CEF
splitting, and accordingly only quasi-elastic peak is found in the magnetic
spectra. On the other hand, at lower temperatures the CEF splitting suppresses
the Kondo effect and inelastic peak develops. The broad quasi-elastic neutron
scattering spectra observed in PrFe_4P_{12} at temperatures higher than the
quadrupole order correspond to the parameter range where the CEF splittings are
unimportant.Comment: 16 pages, 12 figures, 1 tabl
- …