EPL

Sun, Gui-Quan; He, Runzi; Hou, Li-Feng; Gao, Shupeng; Luo, Xiaofeng; Liu, Quanhui; Zhang, Yicheng; Chang, Lili

doi: 10.1209/0295-5075/ad5e1bpmid: N/A

In the face of persistent threats posed by infectious diseases, despite remarkable medical advancements, understanding and efficiently controlling their spatial spread through mathematical modeling remain imperative. Networked reaction-diffusion systems offer a promising avenue to effectively delineate population discrete distribution and individual movement heterogeneity. However, the dynamics of spatial diseases within these systems and the formulation of optimal control strategies are currently undergoing vigorous development. In this letter, we illustrate the dynamics of spatial disease spread in networked reaction-diffusion systems through the lens of optimal control, considering various network complexities from pairwise networks to higher-order networks. It then emphasizes their applicability in designing effective spatial disease control strategies across diverse network complexities. Finally, we discuss the existing challenges.

Morisse, M.; Joshi, S.; Mika, J.; Capella, J. C. C.; Kaiser, R.; Bachelard, R.; Slodička, L.; Hugbart, M.

doi: 10.1209/0295-5075/ad5d87pmid: N/A

Light is characterized by its electric field, yet quantum optics has revealed the importance of monitoring photon-photon correlations at all orders. We here present a comparative study of two experimental setups, composed of cold and warm rubidium atoms, respectively, which allow us to probe and compare photon correlations. The former operates in the quantum regime where spontaneous emission dominates, whereas the latter exhibits a temperature-limited coherence time. We demonstrate our capability to measure photon correlations up to the fourth order which could be useful to better characterize light scattered by cold atoms beyond the chaotic statistics.

Chawla, Komal; Sinha, Sudeshna

doi: 10.1209/0295-5075/ad51a2pmid: N/A

We demonstrate that the presence of a single dissimilar chaotic system suppresses chaos in networks of chaotic oscillators, in a diverse set of network topologies, for sufficiently strong coupling. The key property is determined to be the sum of the path lengths between the dissimilar node and all the other nodes (or its maximum, if coupled to unconnected networks), and there exists a linear relation between this quantity and the critical coupling strength for the onset of a spatiotemporal fixed point. This holds true for a chain with the dissimilar node at different locations, a ring and complete network with one embedded dissimilar node, as well as star networks with a dissimilar hub or dissimilar peripheral node. Furthermore, we show that networks with high average degree and high clustering coefficient are more resilient to the influence of an external dissimilar system. These findings will potentially aid in the design of optimally placed dissimilar nodes for controlling chaos in complex networks.

Cheremnykh, Oleg K.; Lashkin, Volodymyr M.

doi: 10.1209/0295-5075/ad54ecpmid: N/A

We present an exact solution to the problem of a self-consistent equilibrium force-free magnetic flux rope. Unlike other approaches, we use magnetostatic equations and assume only a relatively rapid decrease in the axial magnetic field at infinity. For the first time we obtain a new nonlinear equation for the axial current density, the derivation of which does not require any phenomenological assumptions. From the resulting nonlinear equation, we analytically find the radial profiles of the components of the magnetic field strength and current density.

Dubinsky, Alexey

doi: 10.1209/0295-5075/ad51a3pmid: N/A

We examine perturbations of a massive scalar field around spherically symmetric, brane-localized black holes. Although the ringdown and asymptotic tails of various brane-world black holes have been extensively studied, there has been no analysis of the massive late-time tails for the simplest Schwarzschild-like, brane-localized black hole to date. We demonstrate that after the ringdown phase, two stages of oscillatory tails emerge —intermediate and asymptotic. The asymptotic decay law is distinct from those associated with Schwarzschild or Reissner-Nordström solutions. Specifically, during intermediate times, the signal decays as , while the asymptotic decay law is .

Bocaccio, Hernán; Tagliazucchi, Enzo

doi: 10.1209/0295-5075/ad5468pmid: N/A

Criticality can be exactly demonstrated in certain models of brain activity, yet it remains challenging to identify in empirical data. We trained a fully connected deep neural network to learn the phases of an excitable model unfolding on the anatomical connectome of human brain. This network was then applied to brain-wide fMRI data acquired during the descent from wakefulness to deep sleep. We report high correlation between the predicted proximity to the critical point and the exponents of cluster size distributions, indicative of subcritical dynamics. This result demonstrates that conceptual models can be leveraged to identify the dynamical regime of real neural systems.

doi: 10.1209/0295-5075/ad68f2pmid: N/A

Qian, Cheng; Zhao, Dan-Dan; Zhong, Ming; Zhang, Bo; Peng, Hao; Wang, Wei

doi: 10.1209/0295-5075/ad5971pmid: N/A

Network percolation is one of the core topics in network science, especially in understanding and optimizing the robustness of real-world networks. As a powerful tool, the message-passing approach shows unique advantages in characterizing network percolation compared with the mean-field approach. This approach simulates the behavioural response when the network is damaged by transmitting and updating messages between network nodes, thereby accurately assessing the robustness of the network. This paper reviews the progress of message-passing approaches in network percolation on simple networks, multilayer networks and higher-order networks in recent years and discusses the application of this approach in other research fields. Finally, we discuss future research directions around this approach.

Prajapati, Ram Prasad

doi: 10.1209/0295-5075/ad59c0pmid: N/A

The effects of finite Larmor radius (FLR) corrections and heat-flux vector are studied on the pressure anisotropy-driven firehose instability in finitely conducting solar wind plasmas described by the double-adiabatic Chew, Goldberger and Low (CGL) fluid theory. The fluid description of collisionless plasmas is governed through modified adiabatic equations due to the heat-flux vector and finite ion Larmor radius corrections. The analytical dispersion relation of the firehose instability has been derived using the normal mode analysis and discussed in the solar wind plasmas. In the transverse mode, the dispersion relation of the Alfvénic mode is modified due to electrical resistivity and FLR corrections. In the longitudinal mode, the effects of the heat-flux parameter and electrical resistivity are observed separately. The dispersion relation of the firehose mode is modified due to the combined effects of FLR corrections and electrical resistivity. The graphical illustrations show that finite electrical resistivity and ion Larmor frequency destabilize the growth rate of the firehose instability. The results are useful for analyzing the solar mission data to study the firehose instability in the solar wind plasmas.

Ozawa, Misaki; Javerzat, Nina

doi: 10.1209/0295-5075/ad5d89pmid: N/A

Rényi entropy is a one-parameter generalization of Shannon entropy, which has been used in various fields of physics. Despite its wide applicability, the physical interpretations of the Rényi entropy are not widely known. In this paper, we discuss some basic properties of the Rényi entropy relevant to physics, in particular statistical mechanics, and its physical interpretations using free energy, replicas, work, and large deviation.