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Krzysztof Malarz

Publications and source records attributed to Krzysztof Malarz.

43 records · Page 3Linked to original sources
arXiv2011

Norm breaking in a queue -- athermal phase transition

Standard order-disorder phase transition in the Ising model is described in terms of rates of processes of spin flips. This formulation allows to extend numerous results on phase transition for sciences other than physics of magnetism. We apply it to the problem of norm breaking. Two strategies: to cooperate or to defect, form an analogy to two spin orientations. An example is a crowd at an exit, where to defect means to push others, and to cooperate is to move slowly together.

physics.soc-ph↗
arXiv2010

Probabilistic spreading of information in a spatial network

Spread of information in crowd is analysed in terms of directed percolation in two-dimensional spatial network. We investigate the case when the information transmitted can be incomplete or damaged. The results indicate that for small or moderate probability of errors, it is only the critical connectivity that varies with this probability, but the shape of the transmission velocity curve remains unchanged in a wide range of the probability. The shape of the boundary between those already informed and those yet uninformed becomes complex when the connectivity of agents is small.

physics.soc-ph↗
arXiv2010

Zaller-Deffuant model of mass opinion

Recent formulation of the Zaller model of mass opinion is generalized to include the interaction between agents. The mechanism of interaction is close to the bounded confidence model. The outcome of the simulation is the probability distribution of opinions on a given issue as dependent on the mental capacity of agents. Former result was that a small capacity leads to a strong belief. Here we show that an intensive interaction between agents also leads to a consensus, accepted without doubts.

physics.soc-ph↗
arXiv2009

Indifferents as an interface between Contra and Pro

In most sociophysical simulations on public opinion, only two opinions are allowed: Pro and Contra. However, in all political elections many people do not vote. Here we analyse two models of dynamics of public opinion, taking into account Indifferent voters: {\it i)} the Sznajd model with symmetry Pro-Contra, {\it ii)} the outflow one move voter model, where Contra's are converted to Indifferent by their Pro neighbours. Our results on the Sznajd model are in an overall agreement with the results of the mean field approach and with those known from the initial model formulation. The simulation on the voter model shows that an amount of Contra's who remain after convertion depends on the network topology.

physics.soc-ph↗
arXiv2007

Clusterization, frustration and collectivity in random networks

We consider the random Erd{\H o}s--Rényi network with enhanced clusterization and Ising spins $s=\pm 1$ at the network nodes. Mutually linked spins interact with energy $J$. Magnetic properties of the system as dependent on the clustering coefficient $C$ are investigated with the Monte Carlo heat bath algorithm. For $J>0$ the Curie temperature $T_c$ increases from 3.9 to 5.5 when $C$ increases from almost zero to 0.18. These results deviate only slightly from the mean field theory. For $J<0$ the spin-glass phase appears below $T_{SG}$; this temperature decreases with $C$, on the contrary to the mean field calculations. The results are interpreted in terms of social systems.

physics.soc-ph↗
arXiv2004

Restoring site percolation on a damaged square lattice

We study how to restore site percolation on a damaged square lattice with nearest neighbor (N$^2$) interactions. Two strategies are suggested for a density $x$ of destroyed sites by a random attack at $p_c$. In the first one, a density $y$ of new sites are created with longer range interactions, either next nearest neighbor (N$^3$) or next next nearest neighbor (N$^4$). In the second one, new longer range interactions N$^3$ or N$^4$ are created for a fraction $v$ of the remaining $(p_c-x)$ sites in addition to their N$^2$ interactions. In both cases, the values of $y$ and $v$ are tuned in order to restore site percolation which then occurs at new percolation thresholds, respectively $π_3$, $π_4$, $π_{23}$ and $π_{24}$. Using Monte Carlo simulations the values of the pairs $\{y, π_3 \}$, $\{y, π_4\}$ and $\{v, π_{23}\}$, $\{v, π_{24}\}$ are calculated for the whole range $0\leq x \leq p_c(\text{N}^2)$. Our schemes are applicable to all regular lattices.

cond-mat.stat-mech↗