Suo Gao, Siqi Ding, Herbert Ho-Ching Iu, Uğur Erkan, Abdurrahim Toktas, Cemaleddin Simsek, Rui Wu, Xianying Xu, Yinghong Cao, Jun Mou
{"title":"A three-dimensional memristor-based hyperchaotic map for pseudorandom number generation and multi-image encryption.","authors":"Suo Gao, Siqi Ding, Herbert Ho-Ching Iu, Uğur Erkan, Abdurrahim Toktas, Cemaleddin Simsek, Rui Wu, Xianying Xu, Yinghong Cao, Jun Mou","doi":"10.1063/5.0270220","DOIUrl":"https://doi.org/10.1063/5.0270220","url":null,"abstract":"<p><p>The resistance state of a memristor can be influenced by external stimuli, and these variations can be converted into a pseudorandom sequence through appropriate circuitry and control mechanisms. By leveraging this property, a reliable and complex pseudorandom number generator suitable for encryption can be designed. To enhance the chaotic complexity of memristor-based discrete systems, this paper introduces a three-dimensional hyperchaotic map based on a memristor (3D-HMBM), which integrates a sine-function nonlinearity with a discrete memristor model. Analyzing its dynamical properties via Lyapunov exponents, the 3D-HMBM exhibits evolution from periodicity to chaos and hyperchaos. The complexity of its iterated sequences is verified through metrics such as Spectral Entropy and C0 complexity. Furthermore, the 3D-HMBM displays a unique phenomenon of infinite coexisting attractors. As initial values vary, the system generates attractors at different positions, suggesting that-in theory-an infinite number of attractors exist. Finally, the simulation results are validated via digital-circuit implementation. Building on this foundation, we propose a multi-image encryption algorithm based on the 3D-HMBM, offering a more secure solution for encrypting large volumes of data. Through statistical testing and cryptographic analysis, we confirm the significant potential of the keystream generated by the 3D-HMBM for cryptographic applications.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144539160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Liquid dynamics in a crowded environment: Bond percolation vs site percolation.","authors":"Piotr Polanowski, Andrzej Sikorski","doi":"10.1063/5.0242848","DOIUrl":"https://doi.org/10.1063/5.0242848","url":null,"abstract":"<p><p>The main problem studied is how the diffusion of liquid occurs in the presence of obstacles. In general, this question cannot be reduced to either bond or site percolation, because in real media, the diffusion problem is a complex combination of bond and site percolation. In this work, we make a comparison between site and bond percolation, where the motion of the elements is closely correlated, which is made possible by the unique properties of the dynamic lattice liquid algorithm (no other method allows this). It is clear that even at the two extremes, it is impossible to reduce the problem to just one type of percolation. It should be emphasized that the above comparison has been made within the framework of a single model, which seems very difficult to do with other methods. Extensive and systematic computer simulations have been carried out on a dense (completely filled system) athermal two-dimensional liquid model on a triangular lattice. The behavior of all investigated parameters clearly shows that, for the same obstacle concentration, the liquid molecules in the model with blocked sites are much more mobile, especially as the probability of blocking or the obstacle concentration increases. The research presented here shows that the dynamics of the system is closely related to the morphology of the system. What matters is not only the absolute number of obstacles but the detailed morphology of the local distribution of obstacles and bonds (channels) of the systems.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144539165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Rate-induced phenomena in dynamical systems with attracting limit cycles.","authors":"George Chappelle, Martin Rasmussen","doi":"10.1063/5.0251098","DOIUrl":"https://doi.org/10.1063/5.0251098","url":null,"abstract":"<p><p>We study the behavior of dynamical systems under a time-dependent change of an external parameter. We are interested in phenomena induced by the parameter changing sufficiently quickly, and we refer to these as rate-induced phenomena. We investigate such rate-induced phenomena in continuous-time planar dynamical systems, where the underlying fixed-parameter autonomous dynamics have limit cycles attractors, extending the work of Alkhayuon and Ashwin [Chaos 28(3), 033608 (2018)]. We discover new phenomena of rate-induced phase sensitivity, where the rate at which the parameter changes can trigger finite-time unpredictability in the dynamics. We also find that this new phenomenon interacts in an interesting way with the established notion of rate-induced tipping.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144583190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Physics informed neural networks simulation of fingering instabilities arising during immiscible and miscible multiphase flow in oil recovery processes.","authors":"Pavan Patel, Saroj R Yadav","doi":"10.1063/5.0273935","DOIUrl":"https://doi.org/10.1063/5.0273935","url":null,"abstract":"<p><p>Numerical simulation and experimental techniques are the primary methods for solving fluid dynamics problems. However, while numerical simulation approaches are sensitive when meshing a complex structure, experimental methods have difficulty simulating the physical challenges. Therefore, building an affordable model to solve the fluid dynamics problem is very important. Deep learning (DL) approaches have great abilities to handle strong nonlinearity and high dimensionality that attract much attention for solving fluid dynamics problems. In this paper, we used a deep learning-based framework, physics-informed neural networks (PINNs). The main idea of PINN approaches is to encode the underlying physical law (i.e., the partial differential equation) into the neural network as prior information. In the oil recovery process involving the injection of fluids and multiphase flow in porous media, fingering instability is observed if a fluid with low viscosity displaces a high viscosity fluid. This paper provides a deep learning framework to simulate the instability (fingering) phenomenon during secondary and enhanced oil recovery methods. We have considered two models, namely, the first model on immiscible multiphase flow from the secondary oil recovery method, which is analyzed both with and without deliberating mass flow rate. In the second model, instability arising during the enhanced oil recovery method involving miscible displacement of multiphase is examined, focusing on oil recovery using carbonated water injection. We solve the governing nonlinear partial differential equation using PINNs. Furthermore, we have compared results from PINNs with the semi-analytical solution from the literature. The results show that PINNs are very effective in fluid flow problems and deserve further research.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144599539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Synchronization of spring pendula.","authors":"Dawid Dudkowski, Tomasz Kapitaniak","doi":"10.1063/5.0282572","DOIUrl":"https://doi.org/10.1063/5.0282572","url":null,"abstract":"<p><p>In this paper, we uncover the phenomenon of synchronization of coupled spring pendula. The model is based on two self-excited nodes with varying lengths (elastic elements), suspended on the horizontally oscillating support. We determine the regions of appearance of synchronous states, describing the co-existence scenarios between possible behaviors. The typical examples of solutions are presented and explained, showing different relations between the pendula and the springs oscillations. The properties of synchronous configurations are examined, including the influence of both the characteristics of the elastic elements as well as the damping within the system. The coherent dynamics is compared with desynchronization, showing that both types of responses can co-exist in various scenarios. The results included in this paper uncover new ways of synchronization of mechanical oscillators and contribute to a better understanding of complex dynamical systems in general.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144658578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Switching-induced bifurcation analysis for piecewise nonlinear dynamical systems: A semi-analytical approach.","authors":"Kai Jiang, Jianzhe Huang, Xilin Fu","doi":"10.1063/5.0243774","DOIUrl":"https://doi.org/10.1063/5.0243774","url":null,"abstract":"<p><p>In piecewise nonlinear dynamical systems, the flow is governed by different vector fields across discontinuous boundaries. When switching occurs at these boundaries, the governing vector field changes, inevitably causing the steady-state response to retain transient dynamics from individual subsystems. However, obtaining a complete analytical solution-including the transient component-for each nonlinear subsystem remains an unresolved challenge. This presents significant obstacles to finding unstable hidden bifurcation routes in such systems. The main objective of this paper is to obtain the complete bifurcation trees for piecewise nonlinear dynamical systems, enabling a comprehensive analysis of unconventional bifurcations induced by flow switching. A semi-analytical framework is proposed which integrates generalized mapping structures with local singularity theory to systematically characterize flow-switching dynamics at discontinuous boundaries. A generalized mapping formalism with closed-form constraint conditions at switching points is developed to parameterize periodic motions with higher-order singularities. To demonstrate the effectiveness of the proposed method, we analyze a piecewise nonlinear memristor circuit system exhibiting complex bifurcation and chaotic behaviors. This approach can be readily extended to study other piecewise nonlinear systems.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144697754","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Entanglement-related features of hydrogenic systems and other systems described by bound states of two interacting particles.","authors":"Benny Nogales, Sergio Curilef, Ángel Ricardo Plastino","doi":"10.1063/5.0278593","DOIUrl":"https://doi.org/10.1063/5.0278593","url":null,"abstract":"<p><p>This paper delves into entanglement-related features of one-dimensional and three-dimensional systems comprising two particles interacting through an attractive potential, such as the delta, harmonic, and Coulomb ones. As a quantitative indicator of the amount of entanglement between the particles, we employ the linear entropy of the system's one-particle marginal density matrices. Except in some particular instances involving the harmonic potential, this quantity is not analytically tractable and requires numerical evaluation. Our aim is to elucidate some aspects of entanglement in hydrogenic systems. Hydrogenic systems, consisting of two particles interacting through the Coulomb potential, are of clear importance in physics and chemistry, but their entanglement properties have started to be explored only recently. To better understand entanglement in those systems, we first analyze one-dimensional systems interacting via Dirac delta and harmonic potentials. Insights gained from these one-dimensional cases provide valuable guidelines for studying entanglement in hydrogenic systems. We numerically investigate, for the interaction potentials already mentioned, and for different types of confinement for the center of mass, how the system's entanglement varies with the parameters that determine the size and geometry of the system's quantum state. We find that entanglement depends on a dimensionless quantity given by the quotient of two parameters characterizing the length scales associated with the interaction potential and the center of mass confinement. Entanglement approaches its maximum when the above-mentioned dimensionless quotient tends to its extreme values and adopts its minimum at an intermediate value of the dimensionless quotient. We find that the same general qualitative features of entanglement behavior are observed for different attractive interactions.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144752548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reset induced multimodality in unbounded potential.","authors":"Karol Capała","doi":"10.1063/5.0274016","DOIUrl":"https://doi.org/10.1063/5.0274016","url":null,"abstract":"<p><p>Resetting, as a protocol that restarts the evolution of a system, can significantly influence stochastic dynamics. One notable effect is the emergence of stationary states in unbounded potentials, where such states would otherwise be absent without resetting. In this work, we explore unbounded potentials for which resetting not only induces stationary states but also leads to their multimodality, despite the repulsive nature of the potential. We present examples of potentials that, despite lacking local minima, can generate trimodal and pentamodal states, and we investigate how the modal structure of these states varies with noise intensity and resetting frequency.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144539183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Wavelet-based coarse graining for percolation criticality from a single system size.","authors":"Soo Min Oh, Brani Vidakovic","doi":"10.1063/5.0276783","DOIUrl":"https://doi.org/10.1063/5.0276783","url":null,"abstract":"<p><p>Scaling analysis is a fundamental tool for estimating critical points and exponents of phase transitions in complex systems, typically relying on numerical simulations at multiple system sizes or scales. However, real-world systems often exist at a single system size, making such analysis challenging. Here, we propose a wavelet-based method to extract scaling behavior from a single system size. Considering two-dimensional random and explosive site percolation, we perform wavelet-based coarse graining and compute high-frequency coefficients across multiple effective system sizes, each of which corresponds to the size of the transformed system at a coarser resolution. In these coarser systems, wavelet energy is defined as the squared coefficients that capture cluster boundaries. We finally demonstrate that average wavelet energies follow a scaling law, enabling accurate estimation of the critical points and exponents, which are consistent with those obtained from traditional susceptibility-based scaling analysis. This suggests that average wavelet energy serves as a susceptibility-like observable in percolation systems. Our findings highlight that wavelet-based analysis provides a new perspective on percolation criticality, allowing the identification of scaling properties from a single system size. Furthermore, this approach is potentially applicable to real-world systems such as brain activity patterns, bacterial colonies, or social networks, where collecting data at multiple sizes is impractical or costly.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144583224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A universal route from avalanches in mean-field models with random fields to stochastic Poisson branching events.","authors":"Jordi Baró, Álvaro Corral","doi":"10.1063/5.0268639","DOIUrl":"https://doi.org/10.1063/5.0268639","url":null,"abstract":"<p><p>Avalanches in mean-field models can be mapped to memoryless branching processes defining a universality class. We present a reduced expression mapping a broad family of critical and subcritical avalanches in mean-field models at the thermodynamic limit to rooted trees in a memoryless Poisson branching processes with random occurrence times. We derive the exact mapping for the athermal random field Ising model and the democratic fiber bundle model, where avalanche statistics progress toward criticality, and as an approximation for the self-organized criticality in slip mean-field theory. Avalanche dynamics and statistics in the three models differ only on the evolution of the field density, interaction strength, and the product of both terms determining the branching ratio.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 7","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144539161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}