27,863 research outputs found
Majority-vote on directed Small-World networks
On directed Small-World networks the
Majority-vote model with noise is now studied through Monte Carlo
simulations. In this model, the order-disorder phase transition of the order
parameter is well defined in this system. We calculate the value of the
critical noise parameter q_c for several values of rewiring probability p of
the directed Small-World network. The critical exponentes beta/nu, gamma/nu and
1/nu were calculated for several values of p.Comment: 16 pages including 9 figures, for Int. J. Mod. Phys.
Ising model spin S=1 on directed Barabasi-Albert networks
On directed Barabasi-Albert networks with two and seven neighbours selected
by each added site, the Ising model with spin S=1/2 was seen not to show a
spontaneous magnetisation. Instead, the decay time for flipping of the
magnetisation followed an Arrhenius law for Metropolis and Glauber algorithms,
but for Wolff cluster flipping the magnetisation decayed exponentially with
time. On these networks the
Ising model spin S=1 is now studied through Monte Carlo simulations.
However, in this model, the order-disorder phase transition is well defined
in this system. We have obtained a first-order phase transition for values of
connectivity m=2 and m=7 of the directed Barabasi-Albert network.Comment: 8 pages for Int. J. Mod. Phys. C; e-mail: [email protected]
Simulation of majority rule disturbed by power-law noise on directed and undirected Barabasi-Albert networks
On directed and undirected Barabasi-Albert networks the Ising model with spin
S=1/2 in the presence of a kind of noise is now studied through Monte Carlo
simulations. The noise spectrum P(n) follows a power law, where P(n) is the
probability of flipping randomly select n spins at each time step. The noise
spectrum P(n) is introduced to mimic the self-organized criticality as a model
influence of a complex environment. In this model, different from the square
lattice, the order-disorder phase transition of the order parameter is not
observed. For directed Barabasi-Albert networks the magnetisation tends to zero
exponentially and for undirected Barabasi-Albert networks, it remains constant.Comment: 6 pages including many figures, for Int. J. Mod. Phys.
Effect of particle polydispersity on the irreversible adsorption of fine particles on patterned substrates
We performed extensive Monte Carlo simulations of the irreversible adsorption
of polydispersed disks inside the cells of a patterned substrate. The model
captures relevant features of the irreversible adsorption of spherical
colloidal particles on patterned substrates. The pattern consists of (equal)
square cells, where adsorption can take place, centered at the vertices of a
square lattice. Two independent, dimensionless parameters are required to
control the geometry of the pattern, namely, the cell size and cell-cell
distance, measured in terms of the average particle diameter. However, to
describe the phase diagram, two additional dimensionless parameters, the
minimum and maximum particle radii are also required. We find that the
transition between any two adjacent regions of the phase diagram solely depends
on the largest and smallest particle sizes, but not on the shape of the
distribution function of the radii. We consider size dispersions up-to 20% of
the average radius using a physically motivated truncated Gaussian-size
distribution, and focus on the regime where adsorbing particles do not interact
with those previously adsorbed on neighboring cells to characterize the jammed
state structure. The study generalizes previous exact relations on monodisperse
particles to account for size dispersion. Due to the presence of the pattern,
the coverage shows a non-monotonic dependence on the cell size. The pattern
also affects the radius of adsorbed particles, where one observes preferential
adsorption of smaller radii particularly at high polydispersity.Comment: 9 pages, 5 figure
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