Chaos最新文献

{"title":"Synchronization phenomenon of temperature oscillation in rotating fluid annulus and optimal waveforms of external forcing.","authors":"Ippei Oshima, Yoji Kawamura","doi":"10.1063/5.0233789","DOIUrl":"10.1063/5.0233789","url":null,"abstract":"<p><p>The synchronization phenomena observed in traveling and oscillating thermal convection within a rotating fluid annulus are investigated using three-dimensional direct numerical simulations. The numerical simulations using the direct method calculate the phase-sensitivity and phase-coupling functions, thereby revealing that the waveforms followed sinusoidal patterns. This finding indicates that a similar synchronization state is achieved from any initial condition, as there are only one local maximum and minimum value. The theoretical synchronization criteria provide accurate predictions of the synchronization region. Furthermore, an individual comparing the period difference between the forcing oscillation period τf and the effective oscillation period τe of the system is found to be insufficient to determine the synchronization state. An accurate assessment requires considering the mean values and magnitude of the standard deviation in the oscillation period of the system. Three optimal waveforms-each optimized with respect to the entrainment range, the entrainment speed, and the duty cycle-are calculated. The waveforms obtained within the entrainment range and the entrainment speed also approximately exhibit a sinusoidal pattern owing to roughly a sinusoidal phase-sensitivity function of the system. Consequently, the synchronization region for both methods exhibits minimal extension. However, the maximum entrainment range is theoretically obtained for an optimal duty cycle of 50%, thereby resulting in an entrainment range that is 12% larger than that for a 100% duty cycle. Numerical experiments confirm that the optimal waveform enlarges the synchronization region.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143802677","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":"Demonstration of chaotic-coherent strength to explore the intrinsic peculiarities of the complex dynamical systems.","authors":"Ghulam Bary, Waqar Ahmed, Riaz Ahmad","doi":"10.1063/5.0244816","DOIUrl":"https://doi.org/10.1063/5.0244816","url":null,"abstract":"<p><p>In this paper, we illustrate the innovative techniques to explore the dynamical properties of the hybrid complex systems by various parameters and demonstrate the clusters under the chaotic-condensation peculiarities to accentuate the different technological challenges in the modern world. The complex dynamic characteristics of the contemplated systems are explored with interferometry techniques, which play key roles in examining the consequences of intricate features to interpreting the dynamics of an assemblage that possesses the ability to traverse along dependable tracks of particles, and thus, the solutions within the framework of quantum perturbation for partially chaotic structures are explored with substantial peculiar outcomes in the expanding active matter systems. Correlation graphs with chaotic parameters illustrate the significance of coherent stochastic generation for quasi-granular systems at finite momenta that possess sufficient fractions of instability fluxes. The distribution of temperature profiles is demonstrated by employing specific techniques to account for the different asymmetries and distinct formulas that characterize the structure of the dynamical system using realistic interference methods. The analytical solution contained distinctive information about the response of chaotic and probabilistic droplets within the multiplicities throughout hot and cold particulates, which are triggered by an influenced time crossover phase that occurs continually under the emissions of various sources that proliferate. Our results indicate that the newly developed phase encompasses the partially coherent collection of active matter with the temperature, which probes the rapidity of its transformation, and such phases exhibit significant mutual relationships. The findings accentuate the significance of contemplating correlations and bestowing extraordinary farsightedness about the meticulous manifestation of complex systems. The current methods are unique in obtaining new forms of solutions that appear beneficial for researchers to further understand nonlinear dynamical problems. The acquired techniques are also applicable to examine the solutions of other types of chaotic systems with mathematical analysis through machine learning.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143967800","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":"Promoting cooperation in the voluntary prisoner's dilemma game via reinforcement learning.","authors":"Yijie Huang, Yanhong Chen","doi":"10.1063/5.0267846","DOIUrl":"https://doi.org/10.1063/5.0267846","url":null,"abstract":"<p><p>Reinforcement learning technology has been empirically demonstrated to facilitate cooperation in game models. However, traditional research has primarily focused on two-strategy frameworks (cooperation and defection), which inadequately captures the complexity of real-world scenarios. To address this limitation, we integrated Q-learning into the prisoner's dilemma game, incorporating three strategies: cooperation, defection, and going it alone. We defined each agent's state based on the number of neighboring agents opting for cooperation and included social payoff in the Q-table update process. Numerical simulations indicate that this framework significantly enhances cooperation and average payoff as the degree of social-attention increases. This phenomenon occurs because social payoff enables individuals to move beyond narrow self-interest and consider broader social benefits. Additionally, we conducted a thorough analysis of the mechanisms underlying this enhancement of cooperation.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143992384","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":"Data-driven nonlinear model reduction to spectral submanifolds via oblique projection.","authors":"Leonardo Bettini, Bálint Kaszás, Bernhard Zybach, Jürg Dual, George Haller","doi":"10.1063/5.0243849","DOIUrl":"https://doi.org/10.1063/5.0243849","url":null,"abstract":"<p><p>The dynamics in a primary spectral submanifold (SSM) constructed over the slowest modes of a dynamical system provide an ideal reduced-order model for nearby trajectories. Modeling the dynamics of trajectories further away from the primary SSM, however, is difficult if the linear part of the system exhibits strong non-normal behavior. Such non-normality implies that simply projecting trajectories onto SSMs along directions normal to the slow linear modes will not pair those trajectories correctly with their reduced counterparts on the SSMs. In principle, a well-defined nonlinear projection along a stable invariant foliation exists and would exactly match the full dynamics to the SSM-reduced dynamics. This foliation, however, cannot realistically be constructed from practically feasible amounts and distributions of experimental data. Here, we develop an oblique projection technique that is able to approximate this foliation efficiently, even from a single experimental trajectory of a significantly non-normal and nonlinear beam.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143955805","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":"Limitations of estimating local dimension and extremal index using exceedances in dynamical systems.","authors":"Ignacio Del Amo, George Datseris, Mark Holland","doi":"10.1063/5.0250492","DOIUrl":"https://doi.org/10.1063/5.0250492","url":null,"abstract":"<p><p>Two dynamical indicators, the local dimension and the extremal index, used to quantify persistence in phase space have been developed and applied to different data across various disciplines. These are computed using the asymptotic limit of exceedances over a threshold, which turns to be a generalized Pareto distribution in many cases. However, the derivation of the asymptotic distribution requires mathematical properties, which are not present even in highly idealized dynamical systems and unlikely to be present in the real data. Here, we examine in detail the issues that arise when estimating these quantities for some known dynamical systems. We focus on how the geometry of an invariant set can affect the regularly varying properties of the invariant measure. We demonstrate that singular measures supported on sets of the non-integer dimension are typically not regularly varying and that the absence of regular variation makes the estimates resolution dependent. We show as well that the most common extremal index estimation method is not well defined for continuous time processes sampled at fixed time steps, which is an underlying assumption in its application to data.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143986612","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":"Beyond nearest-neighbor universality of spectral fluctuations in quantum chaotic and complex many-body systems.","authors":"Debojyoti Kundu, Santosh Kumar, Subhra Sen Gupta","doi":"10.1063/5.0234333","DOIUrl":"https://doi.org/10.1063/5.0234333","url":null,"abstract":"<p><p>Discerning chaos in quantum systems is an important problem as the usual route of Lyapunov exponents in classical systems is not straightforward in quantum systems. A standard route is the comparison of statistics derived from model physical systems to those from random matrix theory (RMT) ensembles, of which the most popular is the nearest-neighbor-spacing distribution, which almost always shows good agreement with chaotic quantum systems. However, even in these cases, the long-range statistics (like number variance and spectral rigidity), which are also more difficult to calculate, often show disagreements with RMT. As such, a more stringent test for chaos in quantum systems, via an analysis of intermediate-range statistics, is needed, which will additionally assess the extent of agreement with RMT universality. In this paper, we deduce the effective level-repulsion parameters and the corresponding Wigner-surmise-like results of the next-nearest-neighbor-spacing distribution (nNNSD) for integrable systems (semi-Poissonian statistics) as well as the three classical quantum chaotic Wigner-Dyson regimes, by stringent comparisons to numerical RMT models and benchmarking against our exact analytical results for 3×3 Gaussian matrix models, along with a semi-analytical form for the nNNSD in the orthogonal-to-unitary symmetry crossover. To illustrate the robustness of these RMT based results, we test these predictions against the nNNSD obtained from quantum chaotic models as well as disordered lattice spin models. This reinforces the Bohigas-Giannoni-Schmit and the Berry-Tabor conjectures, extending the associated universality to longer-range statistics. In passing, we also highlight the equivalence of nNNSD in the apparently distinct orthogonal-to-unitary and diluted-symplectic-to-unitary crossovers.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143983318","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":"Bootstrap percolation on hypergraph.","authors":"Hao Peng, Chenyi Wang, Dandan Zhao, Bo Zhang, Cheng Qian, Ming Zhong, Shenghong Li, Jianmin Han, Wei Wang","doi":"10.1063/5.0245651","DOIUrl":"https://doi.org/10.1063/5.0245651","url":null,"abstract":"<p><p>Bootstrap percolation is a widely studied model to investigate the robustness of a network for cascading failures. Extensive real-world data analysis has revealed the existence of higher-order interactions among elements, i.e., the interactions beyond pairwise, which are usually described by hypergraphs. In this paper, we propose a generalized bootstrap percolation model on hypergraph, which assumes that the activation of an inactive node depends on the number of active neighbors through its hyperedges. Through numerical simulation and theoretical analysis, we found that the bootstrap percolation threshold and the phase transition type are closely related to the infection threshold and the proportion of higher-order edges. When the infection threshold is significant, for any initial activation probability, the size of the giant active component (GAC) shows continuous growth with increasing occupation probability. When the infection threshold is small, with the increase of the initial activation probability, the size of the GAC changes from continuous growth to discontinuous growth. In addition, we found that in the case of a fixed network average degree, increasing the proportion of higher-order edges will reduce the percolation threshold, which is conducive to enhancing the robustness of the network. At the same time, higher-order edges create more opportunities for inactive nodes to be activated, and increasing the proportion of higher-order edges under the same conditions will change the size of the GAC from continuous growth to discontinuous growth.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143969470","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":"Positioned spread models: A mathematical analysis of the topological and random population systems.","authors":"Jung-Chao Ban, Jyy-I Hong, Cheng-Yu Tsai","doi":"10.1063/5.0256337","DOIUrl":"https://doi.org/10.1063/5.0256337","url":null,"abstract":"<p><p>Considering limited environmental resources, this article develops topological and random population systems, as well as positioned spread models that emphasize spatial distribution and growth. It incorporates key factors such as the birth rate and migration rate to analyze the population's spatial dynamics using tools from dynamical systems and probability theory. In addition, numerical examples and simulation results are provided to validate the theory for both topological and random models.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143963537","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":"Non-integer tangential singular beams in the near field: Collinear phase-shifting holography for topological charge determination.","authors":"E Peters, G Funes, E Tajahuerce","doi":"10.1063/5.0258239","DOIUrl":"https://doi.org/10.1063/5.0258239","url":null,"abstract":"<p><p>We introduce tangential singular beams with non-integer or fractional topological charge (TC), which have not yet been studied. These beams are constructed by modulating the spatial phase by a piecewise tangent function. The TC can be controlled by the periodicity parameter and the parameter that limits the range of the function allowing to achieve non-integer phase jumps. We study the effect on their amplitude profiles and TC using numerical simulations. Our results are supported by an experimental implementation using the collinear phase-shifting digital holography technique. By means of experimental phase reconstruction, we calculate the TC of these new beams in the near field.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143762706","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":"Self-organizing network simulation of cardiac electrical dynamics.","authors":"Runsang Liu, Hui Yang","doi":"10.1063/5.0261019","DOIUrl":"10.1063/5.0261019","url":null,"abstract":"<p><p>Network provides a low-dimensional representation of the heart through a sparse adjacency matrix, which ushers in a new opportunity to conduct cardiac simulation. We discovered that a self-organizing network encodes and resembles complex heart geometry. This, in turn, helps characterize the structure-function relationship of the heart through network theory. However, very little has been done to investigate the simulation of electrical activity on a self-organizing network. Thus, this paper presents a new self-organizing network approach for simulating cardiac electrical dynamics. We formulate and solve reaction-diffusion equations on the self-organizing network to simulate the propagation and turbulent behavior of electrical waves. The proposed methodology is evaluated and validated on both 2D cardiac tissues, consisting of healthy and infarcted cells, and the whole heart. Experimental results show that the proposed approach not only yields a compact network representation that resembles the heart geometry but also provides an effective simulation of spatiotemporal dynamics when benchmarking with traditional finite element method simulations.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 4","pages":""},"PeriodicalIF":2.7,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11991855/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143978192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}