1. Collective dynamics of swarmalators with higher-order interactionsMd Sayeed Anwar, Gourab Kumar Sar, Matjaž Perc, Dibakar Ghosh, 2024, original scientific article Abstract: Higher-order interactions shape collective dynamics, but how they affect transitions between different states in swarmalator systems is yet to be determined. To that effect, we here study an analytically tractable swarmalator model that incorporates both pairwise and higher-order interactions, resulting in four distinct collective states: async, phase wave, mixed, and sync states. We show that even a minute fraction of higher-order interactions induces abrupt transitions from the async state to the phase wave and the sync state. We also show that higher-order interactions facilitate an abrupt transition from the phase wave to the sync state bypassing the intermediate mixed state. Moreover, elevated levels of higher-order interactions can sustain the presence of phase wave and sync state, even when pairwise interactions lean towards repulsion. The insights gained from these findings unveil self-organizing processes that hold the potential to explain sudden transitions between various collective states in numerous real-world systems.
Keywords: collective dynamics, nonlinear oscillator, higher-order interactions, complex network, statistical physics
Published in DKUM: 07.05.2025; Views: 0; Downloads: 1
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2. Impact of inter-city interactions on disease scalingNathalia A. Loureiro, Camilo R. Neto, Jack Sutton, Matjaž Perc, Haroldo V. Ribeiro, 2025, original scientific article Abstract: Inter-city interactions are critical for the transmission of infectious diseases, yet their effects on the scaling of disease cases remain largely underexplored. Here, we use the commuting network as a proxy for inter-city interactions, integrating it with a general scaling framework to describe the incidence of seven infectious diseases across Brazilian cities as a function of population size and the number of commuters. Our models significantly outperform traditional urban scaling approaches, revealing that the relationship between disease cases and a combination of population and commuters varies across diseases and is influenced by both factors. Although most cities exhibit a less-than-proportional increase in disease cases with changes in population and commuters, more-than-proportional responses are also observed across all diseases. Notably, in some small and isolated cities, proportional rises in population and commuters correlate with a reduction in disease cases. These findings suggest that such towns may experience improved health outcomes and socioeconomic conditions as they grow and become more connected. However, as growth and connectivity continue, these gains diminish, eventually giving way to challenges typical of larger urban areas - such as socioeconomic inequality and overcrowding - that facilitate the spread of infectious diseases. Our study underscores the interconnected roles of population size and commuter dynamics in disease incidence while highlighting that changes in population size exert a greater influence on disease cases than variations in the number of commuters.
Keywords: complex networks, statistical physics, interactions between cities, disease scaling, social physics
Published in DKUM: 09.01.2025; Views: 0; Downloads: 4
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3. Interpretation of dielectric spectroscopy measurements of ferroelectric nematic liquid crystalsVojko Matko, Ewa Górecka, Damian Pociecha, Joanna Matraszek, Nataša Vaupotič, 2024, original scientific article Abstract: The magnitude of the relative permittivity of the ferroelectric nematic phase (NF ) has been the subject of lively
scientific discussion since the phase was recently discovered. Dielectric spectroscopy measurements (DSMs)
give a huge value of relative permittivity, which depends on the cell thickness, but this is argued to result from
a misinterpretation of the DSM results. We have conducted DSM using a set of cells differing in thickness of
the NF layer, type of electrodes, and presence/absence of nanoscale-thick surface polymer layers. To model the
DSM results, cells are presented by an equivalent electric circuit that includes a capacitor due to the NF layer with
frequency dependent complex relative permittivity, capacitors due to surface layers, and a resistor describing the
limited conductivity of electrodes. DSM results for different cells with the same liquid crystal in the NF phase
are semiquantitatively reproduced by the same set of physical parameters if a huge relative permittivity of the
NF , which is even orders of magnitude larger than the measured apparent values, is assumed. We show that
the capacitance of surface layers should also be considered in cells with no polymer alignment layer on the
electrodes.
Keywords: liquid crystals, statistical physics
Published in DKUM: 27.11.2024; Views: 0; Downloads: 9
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4. Global synchronization in generalized multilayer higher-order networksPalash Kumar Pal, Md Sayeed Anwar, Matjaž Perc, Dibakar Ghosh, 2024, original scientific article Abstract: Networks incorporating higher-order interactions are increasingly recognized for their ability to introduce novel dynamics into various processes, including synchronization. Previous studies on synchronization within multilayer networks have often been limited to specific models, such as the Kuramoto model, or have focused solely on higher-order interactions within individual layers. Here, we present a comprehensive framework for investigating synchronization, particularly global synchronization, in multilayer networks with higher-order interactions. Our framework considers interactions beyond pairwise connections, both within and across layers. We demonstrate the existence of a stable global synchronous state, with a condition resembling the master stability function, contingent on the choice of coupling functions. Our theoretical findings are supported by simulations using Hindmarsh-Rose neuronal and Rössler oscillators. These simulations illustrate how synchronization is facilitated by higher-order interactions, both within and across layers, highlighting the advantages over scenarios involving interactions within single layers.
Keywords: synchronization, network, phase transition, statistical physics
Published in DKUM: 27.11.2024; Views: 0; Downloads: 3
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5. Networks behind the morphology and structural design of living systemsMarko Gosak, Marko Milojević, Maja Duh, Kristijan Skok, Matjaž Perc, 2022, review article Abstract: Technological advances in imaging techniques and biometric data acquisition have enabled us to apply methods of network science to study the morphology and structural design of organelles, organs, and tissues, as well as the coordinated interactions among them that yield a healthy physiology at the level of whole organisms. We here review research dedicated to these advances, in particular focusing on networks between cells, the topology of multicellular structures, neural interactions, fluid transportation networks, and anatomical networks. The percolation of blood vessels, structural connectivity within the brain, the porous structure of bones, and relations between different anatomical parts of the human body are just some of the examples that we explore in detail. We argue and show that the models, methods, and algorithms developed in the realm of network science are ushering in a new era of network-based inquiry into the morphology and structural design of living systems in the broadest possible terms. We also emphasize that the need and applicability of this research is likely to increase significantly in the years to come due to the rapid progress made in the development of bioartificial substitutes and tissue engineering.
Keywords: network, morphology, structural properties, statistical physics
Published in DKUM: 17.09.2024; Views: 0; Downloads: 13
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6. Interplay between particle trapping and heterogeneity in anomalous diffusionHaroldo V. Ribeiro, Angel A. Tateishi, Ervin K. Lenzi, Richard L. Magin, Matjaž Perc, 2023, original scientific article Abstract: Heterogeneous media diffusion is often described using position-dependent diffusion coefficients and estimated indirectly through mean squared displacement in experiments. This approach may overlook other mechanisms and their interaction with position-dependent diffusion, potentially leading to erroneous conclusions. Here, we introduce a hybrid diffusion model that merges a position-dependent diffusion coefficient with the trapping mechanism of the comb model. We derive exact solutions for position distributions and mean squared displacements, validated through simulations of Langevin equations. Our model shows that the trapping mechanism attenuates the impact of media heterogeneity. Superdiffusion occurs when the position-dependent coefficient increases superlinearly, while subdiffusion occurs for sublinear and inverse power-law relations. This nontrivial interplay between heterogeneity and state-independent mechanisms also leads to anomalous yet Brownian, and non-Brownian yet Gaussian regimes. These findings emphasize the need for cautious interpretations of experiments and highlight the limitations of relying solely on mean squared displacements or position distributions for diffusion characterization.
Keywords: particle trapping, heterogeneity, diffusion, statistical physics
Published in DKUM: 11.09.2024; Views: 38; Downloads: 4
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7. Information sharing promotes prosocial behaviourAttila Szolnoki, Matjaž Perc, 2013, original scientific article Abstract: More often than not, bad decisions are bad regardless of where and when they are made. Information sharing might thus be utilized to mitigate them. Here we show that sharing information about strategy choice between players residing on two different networks reinforces the evolution of cooperation. In evolutionary games, the strategy reflects the action of each individual that warrants the highest utility in a competitive setting. We therefore assume that identical strategies on the two networks reinforce themselves by lessening their propensity to change. Besides network reciprocity working in favour of cooperation on each individual network, we observe the spontaneous emergence of correlated behaviour between the two networks, which further deters defection. If information is shared not just between individuals but also between groups, the positive effect is even stronger, and this despite the fact that information sharing is implemented without any assumptions with regard to content.
Keywords: cooperation, information, social dilemma, public goods, interdependent networks, statistical physics of social systems
Published in DKUM: 03.07.2017; Views: 1258; Downloads: 449
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8. Spreading of cooperative behaviour across interdependent groupsLuo-Luo Jiang, Matjaž Perc, 2013, original scientific article Abstract: Recent empirical research has shown that links between groups reinforce individuals within groups to adopt cooperative behaviour. Moreover, links between networks may induce cascading failures, competitive percolation, or contribute to efficient transportation. Here we show that there in fact exists an intermediate fraction of links between groups that is optimal for the evolution of cooperation in the prisoners dilemma game. We consider individual groups with regular, random, and scale-free topology, and study their different combinations to reveal that an intermediate interdependence optimally facilitates the spreading of cooperative behaviour between groups. Excessive between-group links simply unify the two groups and make them act as one, while too rare between-group links preclude a useful information flow between the two groups. Interestingly, we find that between-group links are more likely to connect two cooperators than in-group links, thus supporting the conclusion that they are of paramount importance.
Keywords: social dilemma, cooperation, public goods, biased utility, interdependent networks, statistical physics of social systems
Published in DKUM: 23.06.2017; Views: 1795; Downloads: 427
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9. Self-organization of progress across the century of physicsMatjaž Perc, 2013, original scientific article Abstract: We make use of information provided in the titles and abstracts of over half a million publications that were published by the American Physical Society during the past 119 years. By identifying all unique words and phrases and determining their monthly usage patterns, we obtain quantifiable insights into the trends of physics discovery from the end of the 19th century to today. We show that the magnitudes of upward and downward trends yield heavy-tailed distributions, and that their emergence is due to the Matthew effect. This indicates that both the rise and fall of scientific paradigms is driven by robust principles of self-organization. Data also confirm that periods of war decelerate scientific progress, and that the later is very much subject to globalisation.
Keywords: self-organization, preferential attachment, evolution of progress, history of physics, statistical physics of social systems
Published in DKUM: 23.06.2017; Views: 1163; Downloads: 360
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10. Optimal interdependence between networks for the evolution of cooperationZhen Wang, Attila Szolnoki, Matjaž Perc, 2013, original scientific article Abstract: Recent research has identified interactions between networks as crucial for the outcome of evolutionary games taking place on them. While the consensus is that interdependence does promote cooperation by means of organizational complexity and enhanced reciprocity that is out of reach on isolated networks, we here address the question just how much interdependence there should be. Intuitively, one might assume the more the better. However, we show that in fact only an intermediate density of sufficiently strong interactions between networks warrants an optimal resolution of social dilemmas. This is due to an intricate interplay between the heterogeneity that causes an asymmetric strategy flow because of the additional links between the networks, and the independent formation of cooperative patterns on each individual network. Presented results are robust to variations of the strategy updating rule, the topology of interdependent networks, and the governing social dilemma, thus suggesting a high degree of universality.
Keywords: social dilemma, cooperation, public goods, biased utility, interdependent networks, statistical physics of social systems
Published in DKUM: 23.06.2017; Views: 1213; Downloads: 412
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