906 research outputs found
Cooperative Parrondo's Games
We introduce a new family of Parrondo's games of alternating losing
strategies in order to get a winning result. In our version of the games we
consider an ensemble of players and use "social" rules in which the
probabilities of the games are defined in terms of the actual state of the
neighbors of a given player.Comment: 4 pages (including 2 figures
Distribution of winners in truel games
In this work we present a detailed analysis using the Markov chain theory of
some versions of the truel game in which three players try to eliminate each
other in a series of one-to-one competitions, using the rules of the game.
Besides reproducing some known expressions for the winning probability of each
player, including the equilibrium points, we give expressions for the actual
distribution of winners in a truel competition.Comment: 14 pages, 10 figures. Conference proceedin
Weakly Nonextensive Thermostatistics and the Ising Model with Long--range Interactions
We introduce a nonextensive entropic measure that grows like
, where is the size of the system under consideration. This kind
of nonextensivity arises in a natural way in some -body systems endowed with
long-range interactions described by interparticle potentials.
The power law (weakly nonextensive) behavior exhibited by is
intermediate between (1) the linear (extensive) regime characterizing the
standard Boltzmann-Gibbs entropy and the (2) the exponential law (strongly
nonextensive) behavior associated with the Tsallis generalized -entropies.
The functional is parametrized by the real number
in such a way that the standard logarithmic entropy is recovered when
>. We study the mathematical properties of the new entropy, showing that the
basic requirements for a well behaved entropy functional are verified, i.e.,
possesses the usual properties of positivity, equiprobability,
concavity and irreversibility and verifies Khinchin axioms except the one
related to additivity since is nonextensive. For , the
entropy becomes superadditive in the thermodynamic limit. The
present formalism is illustrated by a numerical study of the thermodynamic
scaling laws of a ferromagnetic Ising model with long-range interactions.Comment: LaTeX file, 20 pages, 7 figure
Fronts, Domain Growth and Dynamical Scaling in a d=1 non-Potential System
We present a study of dynamical scaling and front motion in a one dimensional
system that describes Rayleigh-Benard convection in a rotating cell. We use a
model of three competing modes proposed by Busse and Heikes to which spatial
dependent terms have been added. As long as the angular velocity is different
from zero, there is no known Lyapunov potential for the dynamics of the system.
As a consequence the system follows a non-relaxational dynamics and the
asymptotic state can not be associated with a final equilibrium state. When the
rotation angular velocity is greater than some critical value, the system
undergoes the Kuppers-Lortz instability leading to a time dependent chaotic
dynamics and there is no coarsening beyond this instability. We have focused on
the transient dynamics below this instability, where the dynamics is still
non-relaxational. In this regime the dynamics is governed by a non-relaxational
motion of fronts separating dynamically equivalent homogeneous states. We
classify the families of fronts that occur in the dynamics, and calculate their
shape and velocity. We have found that a scaling description of the coarsening
process is still valid as in the potential case. The growth law is nearly
logarithmic with time for short times and becomes linear after a crossover,
whose width is determined by the strength of the non-potential terms.Comment: 15 pages, 10 figure
Anticipated synchronization and the predict-prevent control method in the FitzHugh-Nagumo model system
We study the synchronization region of two unidirectionally coupled, in a
master-slave configuration, FitzHugh-Nagumo systems under the influence of
external forcing terms. We observe that anticipated synchronization is robust
to the different types of forcings. We then use the predict-prevent control
method to suppress unwanted pulses in the master system by using the
information of the slave output. We find that this method is more efficient
than the direct control method based on the master. Finally, we observe that a
perfect matching between the parameters of the master and the slave is not
necessary for the control to be efficient. Moreover, this parameter mismatch
can, in some cases, improve the control
Synchronisation Induced by Repulsive Interactions in a System of van der Pol Oscillators
We consider a system of identical van der Pol oscillators, globally coupled
through their velocities, and study how the presence of competitive
interactions affects its synchronisation properties. We will address the
question from two points of view. Firstly, we will investigate the role of
competitive interactions on the synchronisation among identical oscillators.
Then, we will show that the presence of an intermediate fraction of repulsive
links results in the appearance of macroscopic oscillations at that signal's
rhythm, in regions where the individual oscillator is unable to synchronise
with a weak external signal
Stochastic thermodynamics for kinetic equations
Stochastic thermodynamics is formulated for variables that are odd under time
reversal. The invariance under spatial rotation of the collision rates due to
the isotropy of the heat bath is shown to be a crucial ingredient. An
alternative detailed fluctuation theorem is derived, expressed solely in terms
of forward statistics. It is illustrated for a linear kinetic equation with
kangaroo rates
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