6,669 research outputs found
Spontaneous structure formation in a network of chaotic units with variable connection strengths
As a model of temporally evolving networks, we consider a globally coupled
logistic map with variable connection weights. The model exhibits
self-organization of network structure, reflected by the collective behavior of
units. Structural order emerges even without any inter-unit synchronization of
dynamics. Within this structure, units spontaneously separate into two groups
whose distinguishing feature is that the first group possesses many
outwardly-directed connections to the second group, while the second group
possesses only few outwardly-directed connections to the first. The relevance
of the results to structure formation in neural networks is briefly discussed.Comment: 4 pages, 3 figures, REVTe
State Differentiation by Transient Truncation in Coupled Threshold Dynamics
Dynamics with a threshold input--output relation commonly exist in gene,
signal-transduction, and neural networks. Coupled dynamical systems of such
threshold elements are investigated, in an effort to find differentiation of
elements induced by the interaction. Through global diffusive coupling, novel
states are found to be generated that are not the original attractor of
single-element threshold dynamics, but are sustained through the interaction
with the elements located at the original attractor. This stabilization of the
novel state(s) is not related to symmetry breaking, but is explained as the
truncation of transient trajectories to the original attractor due to the
coupling. Single-element dynamics with winding transient trajectories located
at a low-dimensional manifold and having turning points are shown to be
essential to the generation of such novel state(s) in a coupled system.
Universality of this mechanism for the novel state generation and its relevance
to biological cell differentiation are briefly discussed.Comment: 8 pages. Phys. Rev. E. in pres
Dynamics of Coupling Functions in Globally Coupled Maps: Size, Periodicity and Stability of Clusters
It is shown how different globally coupled map systems can be analyzed under
a common framework by focusing on the dynamics of their respective global
coupling functions. We investigate how the functional form of the coupling
determines the formation of clusters in a globally coupled map system and the
resulting periodicity of the global interaction. The allowed distributions of
elements among periodic clusters is also found to depend on the functional form
of the coupling. Through the analogy between globally coupled maps and a single
driven map, the clustering behavior of the former systems can be characterized.
By using this analogy, the dynamics of periodic clusters in systems displaying
a constant global coupling are predicted; and for a particular family of
coupling functions, it is shown that the stability condition of these clustered
states can straightforwardly be derived.Comment: 12 pp, 5 figs, to appear in PR
Homogeneous Connectivity of Potential Energy Network in a Solidlike State of Water Cluster
A novel route to the exponential trapping-time distribution within a
solidlike state in water clusters is described. We propose a simple homogeneous
network (SHN) model to investigate dynamics on the potential energy networks of
water clusters. In this model, it is shown that the trapping-time distribution
in a solidlike state follows the exponential distribution, whereas the
trapping-time distribution in local potential minima within the solidlike state
is not exponential. To confirm the exponential trapping-time distribution in a
solidlike state, we investigate water clusters, HO and
HO, by molecular dynamics simulations. These clusters change
dynamically from solidlike to liquidlike state and vice versa. We find that the
probability density functions of trapping times in a solidlike state are
described by the exponential distribution whereas those of interevent times of
large fluctuations in potential energy within the solidlike state follow the
Weibull distributions. The results provide a clear evidence that transition
dynamics between solidlike and liquidlike states in water clusters are well
described by the SHN model, suggesting that the exponential trapping-time
distribution within a solidlike state originates from the homogeneous
connectivity in the potential energy network.Comment: 9 pages, 8 figure
Predictive flavour symmetries of the neutrino mass matrix
Here we propose an flavour symmetry model which implies a lower bound
on the neutrinoless double beta decay rate, corresponding to an effective mass
parameter M_{ee} \gsim 0.03 eV, and a direct correlation between the expected
magnitude of CP violation in neutrino oscillations and the value of
, as well as a nearly maximal CP phase .Comment: 4 pages, 4 figure
Quaternion Family Symmetry of Quarks and Leptons
To a first approximation, the quark mixing matrix has , whereas the lepton mixing matrix has . We show how this structure may be understood if the family symmetry is
, the quaternion group of eight elements. We find three viable scenarios
for the Majorana neutrino mass matrix, each depending on 4 parameters and
predicting a specific mass spectrum. The phenomenology of the two Higgs
doublets which generate the Yukawa sector is analyzed and testable predictions
are derived. We discuss also the closely related model based on , the
symmetry group of the square.Comment: latex, 10 pages, 2 eps figures, notations revised, classification of
models correcte
Periodicity Manifestations in the Turbulent Regime of Globally Coupled Map Lattice
We revisit the globally coupled map lattice (GCML). We show that in the so
called turbulent regime various periodic cluster attractor states are formed
even though the coupling between the maps are very small relative to the
non-linearity in the element maps.
Most outstanding is a maximally symmetric three cluster attractor in period
three motion (MSCA) due to the foliation of the period three window of the
element logistic maps. An analytic approach is proposed which explains
successfully the systematics of various periodicity manifestations in the
turbulent regime. The linear stability of the period three cluster attractors
is investigated.Comment: 34 pages, 8 Postscript figures, all in GCML-MSCA.Zi
Production at Colliders and Anomalous Quartic Coupling
We investigate the constraints on the anomalous quartic
gauge boson coupling through the process .
Considering incoming beam polarizations and the longitudinal and transverse
polarization states of the final W and Z boson we find 95% confidence level
limits on the anomalous coupling parameter with an integrated
luminosity of 500 and =0.5, 1 TeV energies. We show that
initial beam and final state polarizations improve the sensitivity to the
anomalous coupling by up to factors of 2 - 3.5 depending on the energy.Comment: published versio
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