55 research outputs found
Quenched mean-field theory for the majority-vote model on complex networks
The majority-vote (MV) model is one of the simplest nonequilibrium Ising-like
model that exhibits a continuous order-disorder phase transition at a critical
noise. In this paper, we present a quenched mean-field theory for the dynamics
of the MV model on networks. We analytically derive the critical noise on
arbitrary quenched unweighted networks, which is determined by the largest
eigenvalue of a modified network adjacency matrix. By performing extensive
Monte Carlo simulations on synthetic and real networks, we find that the
performance of the quenched mean-field theory is superior to a heterogeneous
mean-field theory proposed in a previous paper [Chen \emph{et al.}, Phys. Rev.
E 91, 022816 (2015)], especially for directed networks.Comment: 6 pages, 3 figures, and 1 tabl
Heterogeneous nucleation on complex networks with mobile impurities
We study the heterogeneous nucleation of Ising model on complex networks
under a non-equilibrium situation where the impurities perform degree-biased
motion controlled by a parameter \alpha. Through the forward flux sampling and
detailed analysis on the nucleating clusters, we find that the nucleation rate
shows a nonmonotonic dependence on \alpha for small number of impurities, in
which a maximal nucleation rate occurs at \alpha=0 corresponding to the
degree-uncorrelated random motion. Furthermore, we demonstrate the distinct
features of the nucleating clusters along the pathway for different preference
of impurities motion, which may be used to understand the resonance-like
dependence of nucleation rate on the motion bias of impurities. Our theoretical
analysis shows that the nonequilibrium diffusion of impurities can always
induce a positive energy flux that can facilitate the barrier-crossing
nucleation process. The nonmonotonic feature of the average value of the energy
flux with \alpha may be the origin of our simulation results.Comment: 6 pages, 5 figures. arXiv admin note: text overlap with
arXiv:1202.423
Noise-induced vortex reversal of self-propelled particles
We report an interesting phenomenon of noise-induced vortex reversal in a
two-dimensional system of self-propelled particles (SPP) with soft-core
interactions. With the aid of forward flux sampling, we analyze the
configurations along the reversal pathway and thus identify the mechanism of
vortex reversal. We find that statistically the reversal exhibits a
hierarchical process: those particles at the periphery first change their
motion directions, and then more inner layers of particles reverse later on.
Furthermore, we calculate the dependence of the average reversal rate on noise
intensity and the number of SPP. We find that the rate decreases
exponentially with the reciprocal of . Interestingly, the rate varies
nonmonotonically with and a minimal rate exists for an intermediate value
of .Comment: 4 pages, 5 figure
- …