5,934 research outputs found
Condensation in Globally Coupled Populations of Chaotic Dynamical Systems
The condensation transition, leading to complete mutual synchronization in
large populations of globally coupled chaotic Roessler oscillators, is
investigated. Statistical properties of this transition and the cluster
structure of partially condensed states are analyzed.Comment: 11 pages, 4 figures, revte
B_K with two flavors of dynamical overlap fermions
We present a two-flavor QCD calculation of on a
lattice at fm (or equivalently 1.67 GeV). Both valence
and sea quarks are described by the overlap fermion formulation. The matching
factor is calculated non-perturbatively with the so-called RI/MOM scheme. We
find that the lattice data are well described by the next-to-leading order
(NLO) partially quenched chiral perturbation theory (PQChPT) up to around a
half of the strange quark mass (). The data at quark masses
heavier than are fitted including a part of
next-to-next-to-leading order terms. We obtain , where the first error is statistical and the second is an
estimate of systematic uncertainties from finite volume, fixing topology, the
matching factor, and the scale setting.Comment: 36 pages, 14 figures, comments and references added, analysis and
systematic error revised, minor change in the final result. version to appear
in PRD, reference correcte
Vector- and Pseudoscalar-baryon coupled channel systems
In this manuscript, I will report the details of our recent work on the
vector meson-baryon (VB) interaction, which we studied with the motivation of
finding dynamical generation of resonances in the corresponding systems. We
started our study by building a formalism based on the hidden local symmetry
and calculating the leading order contributions to the scattering equations by
summing the diagrams with: (a) a vector meson exchange in the t-channel (b) an
octet baryon exchange in the s-, u-channels and (c) a contact interaction
arising from the part of the vector meson-baryon Lagrangian which is related to
the anomalous magnetic moment of the baryons. We find the contribution from all
these sources, except the s-channel, to be important. The amplitudes obtained
by solving the coupled channel Bethe-Salpeter equations for the systems with
total strangeness zero, show generation of one isospin 3/2, spin 1/2 resonance
and three isospin 1/2 resonances: two with spin 3/2 and one with spin 1/2. We
identify these resonances with (1900) , (2080) ,
(1700) , and (2090) , respectively.
We have further extended our study by including pseudoscalar meson-baryon
(PB) as the coupled channels of VB systems. For this, we obtain the PB
VB amplitudes by using the Kroll-Ruddermann term where,
considering the vector meson dominance phenomena, the photon is replaced by a
vector meson. The calculations done within this formalism reveal a very strong
coupling of the VB channels to the low-lying resonances like (1405)
and (1670), which can have important implications on certain reactions
producing them. In addition to this, we find that the effect of coupling the
higher mass states to the lighter channels is not restricted to increasing the
width of those states, it can be far more strong.Comment: Proceedings of the "DAE-BRNS Workshop on Hadron Physics" held in
Mumbai, India during October 31-November 04, 201
Fractalization of Torus Revisited as a Strange Nonchaotic Attractor
Fractalization of torus and its transition to chaos in a quasi-periodically
forced logistic map is re-investigated in relation with a strange nonchaotic
attractor, with the aid of functional equation for the invariant curve.
Existence of fractal torus in an interval in parameter space is confirmed by
the length and the number of extrema of the torus attractor, as well as the
Fourier mode analysis. Mechanisms of the onset of fractal torus and the
transition to chaos are studied in connection with the intermittency.Comment: Latex file ( figures will be sent electronically upon
request):submitted to Phys.Rev. E (1996
Transitions Induced by the Discreteness of Molecules in a Small Autocatalytic System
Autocatalytic reaction system with a small number of molecules is studied
numerically by stochastic particle simulations. A novel state due to
fluctuation and discreteness in molecular numbers is found, characterized as
extinction of molecule species alternately in the autocatalytic reaction loop.
Phase transition to this state with the change of the system size and flow is
studied, while a single-molecule switch of the molecule distributions is
reported. Relevance of the results to intracellular processes are briefly
discussed.Comment: 5 pages, 4 figure
Spin-Electron-Phonon Excitation in Re-based Half-Metallic Double Perovskites
A remarkable hardening (~ 30 cm-1) of the normal mode of vibration associated
with the symmetric stretching of the oxygen octahedra for the Ba2FeReO6 and
Sr2CrReO6 double perovskites is observed below the corresponding magnetic
ordering temperatures. The very large magnitude of this effect and its absence
for the anti-symmetric stretching mode provide evidence against a conventional
spin-phonon coupling mechanism. Our observations are consistent with a
collective excitation formed by the combination of the vibrational mode with
oscillations of local Fe or Cr 3d and Re 5d occupations and spin magnitudes.Comment: 12 pages, 4 figure
Spectral Properties and Synchronization in Coupled Map Lattices
Spectral properties of Coupled Map Lattices are described. Conditions for the
stability of spatially homogeneous chaotic solutions are derived using linear
stability analysis. Global stability analysis results are also presented. The
analytical results are supplemented with numerical examples. The quadratic map
is used for the site dynamics with different coupling schemes such as global
coupling, nearest neighbor coupling, intermediate range coupling, random
coupling, small world coupling and scale free coupling.Comment: 10 pages with 15 figures (Postscript), REVTEX format. To appear in
PR
Peripheral volume measurements as indices of peripheral circulatory factors in the cardiovascular orthostatic response
Peripheral volume measurements as indices of circulatory factors in cardiovascular orthostatic respons
Evolution Equation of Phenotype Distribution: General Formulation and Application to Error Catastrophe
An equation describing the evolution of phenotypic distribution is derived
using methods developed in statistical physics. The equation is solved by using
the singular perturbation method, and assuming that the number of bases in the
genetic sequence is large. Applying the equation to the mutation-selection
model by Eigen provides the critical mutation rate for the error catastrophe.
Phenotypic fluctuation of clones (individuals sharing the same gene) is
introduced into this evolution equation. With this formalism, it is found that
the critical mutation rate is sometimes increased by the phenotypic
fluctuations, i.e., noise can enhance robustness of a fitted state to mutation.
Our formalism is systematic and general, while approximations to derive more
tractable evolution equations are also discussed.Comment: 22 pages, 2 figure
Dynamics of Multiferroic Domain Wall in Spin-Cycloidal Ferroelectric DyMnO
We report the dielectric dispersion of the giant magnetocapacitance (GMC) in
multiferroic DyMnO over a wide frequency range. The GMC is found to be
attributable not to the softened electromagnon but to the electric-field-driven
motion of multiferroic domain wall (DW). In contrast to conventional
ferroelectric DWs, the present multiferroic DW motion holds extremely high
relaxation rate of s even at low temperatures. This
mobile nature as well as the model simulation suggests that the multiferroic DW
is not atomically thin as in ferroelectrics but thick, reflecting its magnetic
origin.Comment: 4 pages, 4 figure
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