1,210 research outputs found
Damage spreading in the Bak-Sneppen model: Sensitivity to the initial conditions and equilibration dynamics
The short-time and long-time dynamics of the Bak-Sneppen model of biological
evolution are investigated using the damage spreading technique. By defining a
proper Hamming distance measure, we are able to make it exhibits an initial
power-law growth which, for finite size systems, is followed by a decay towards
equilibrium. In this sense, the dynamics of self-organized critical states is
shown to be similar to the one observed at the usual critical point of
continuous phase-transitions and at the onset of chaos of non-linear
low-dimensional dynamical maps. The transient, pre-asymptotic and asymptotic
exponential relaxation of the Hamming distance between two initially
uncorrelated equilibrium configurations is also shown to be fitted within a
single mathematical framework. A connection with nonextensive statistical
mechanics is exhibited.Comment: 6 pages, 4 figs, revised version, accepted for publication in
Int.J.Mod.Phys.C 14 (2003
Effect of the Canting of Local Anisotropy Axes on Ground-State Properties of a Ferrimagnetic Chain with Regularly Alternating Ising and Heisenberg Spins
The effect of the canting of local anisotropy axes on the ground-state phase
diagram and magnetization of a ferrimagnetic chain with regularly alternating
Ising and Heisenberg spins is exactly examined in an arbitrarily oriented
magnetic field. It is shown that individual contributions of Ising and
Heisenberg spins to the total magnetization basically depend on the spatial
orientation of the magnetic field and the canting angle between two different
local anisotropy axes of the Ising spins.Comment: 3 pages, 3 figure
Delocalization and wave-packet dynamics in one-dimensional diluted Anderson models
We study the nature of one-electron eigen-states in a one-dimensional diluted
Anderson model where every Anderson impurity is diluted by a periodic function
. Using renormalization group and transfer matrix techniques, we provide
accurate estimates of the extended states which appear in this model, whose
number depends on the symmetry of the diluting function . The density of
states (DOS) for this model is also numerically obtained and its main features
are related to the symmetries of the diluting function . Further, we show
that the emergence of extended states promotes a sub-diffusive spread of an
initially localized wave-packet.Comment: 6 pages, 6 figures, to appear in EPJ
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