IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0271508

Nicolas Thomé, Matthias Wolfrum, Katharina Krischer

引用次数: 0

Lyapunov spectra and fluctuation relations: Insights from the Galerkin-truncated Burgers equation. 李雅普诺夫谱和涨落关系：来自伽辽金截断的Burgers方程的启示。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0261110

Arunava Das, Pinaki Dutta, Kamal L Panigrahi, Vishwanath Shukla

{"title":"Lyapunov spectra and fluctuation relations: Insights from the Galerkin-truncated Burgers equation.","authors":"Arunava Das, Pinaki Dutta, Kamal L Panigrahi, Vishwanath Shukla","doi":"10.1063/5.0261110","DOIUrl":"https://doi.org/10.1063/5.0261110","url":null,"abstract":"The imposition of a global constraint of the conservation of total kinetic energy on a forced-dissipative Burgers equation yields a governing equation that is invariant under the time-reversal symmetry operation, {T:t→-t;u→-u}, where u is the velocity field. Moreover, the dissipation term gets strongly modified, as the viscosity is no longer a constant, but a fluctuating, state dependent quantity, which can even become negative in certain dynamical regimes. Despite these differences, the statistical properties of different dynamical regimes of the time-reversible Burgers equation and the standard forced-dissipative Burgers equation are equivalent, à la Gallavotti's conjecture of equivalence of nonequilibrium ensembles. It is shown that the negative viscosity events occur only in the thermalized regime described by the time-reversible equation. This regime is further examined by calculating the local Lyapunov spectra and fluctuation relations. A pairing symmetry among the spectra is observed, indicating that the dynamics is chaotic, and has an attractor spanning the entire phase space of the system. The negative events are found to satisfy fluctuation relations, namely, the Gallavotti-Cohen relation based on the phase-space contraction rate and the Cohen-Searles fluctuation relation based on the energy injection rate. The results suggest that these events are associated with the effects of the Galerkin-truncation, the latter is responsible for the thermalization.","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144944874","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}

引用次数: 0

Optimization of transport efficiency on bundled networks. 捆绑网络的传输效率优化。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0282648

Zhenhua Yuan, Yuan Zhu, Long Gao, Junhao Peng

引用次数: 0

Overcoming feature scarcity in complex system prediction: An alternative delay embedding. 克服复杂系统预测中的特征稀缺性：一种替代延迟嵌入。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0279303

Tao Wu, Ying Tang, Kazuyuki Aihara

{"title":"Overcoming feature scarcity in complex system prediction: An alternative delay embedding.","authors":"Tao Wu, Ying Tang, Kazuyuki Aihara","doi":"10.1063/5.0279303","DOIUrl":"10.1063/5.0279303","url":null,"abstract":"Predicting the future dynamics of complex systems remains challenging in scientific research. Traditional methods generally approach this issue by approximating the correlations between predictors (features) and target variables, often employing predictors from a pool of target-related variables (system components). However, these approaches are inherently constrained when reliable target-related features are scarce. Here, we introduce a framework, alternative delay embedding (ADE), to effectively integrate the delay embedding technique with a machine learning algorithm based on Gaussian process regression. Rather than relying on the identification of target-related variables, ADE exploits the target's sequential information to generate reconstructions that function as robust predictors. The reliability of the ADE framework is validated across multiple benchmark model systems, e.g., the logistic map, the Mackey-Glass equation, and the Lorenz system, as well as real-world datasets spanning diverse domains, e.g., sea surface temperature, physiological signals, electroencephalography signals, and financial exchange rates. Demonstrations on short input data highlight enhanced robustness of ADE compared to several classic methods. The ADE framework serves as a useful complement to existing predictive approaches, particularly in cases where reliable target-related features are either scarce or elusive.","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144882315","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}

引用次数: 0

Breaking coexistence: Zealotry vs nonlinear social impact. 打破共存：狂热vs非线性社会影响。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0282676

Christopher R Kitching, Lucía S Ramirez, Maxi San Miguel, Tobias Galla

{"title":"Breaking coexistence: Zealotry vs nonlinear social impact.","authors":"Christopher R Kitching, Lucía S Ramirez, Maxi San Miguel, Tobias Galla","doi":"10.1063/5.0282676","DOIUrl":"https://doi.org/10.1063/5.0282676","url":null,"abstract":"We study how zealotry and nonlinear social impact affect consensus formation in the nonlinear voter model, evolutionary games, and the partisan voter model. In all three models, consensus is an absorbing state in finite populations, while coexistence is a possible outcome of the deterministic dynamics. We show that sufficiently strong zealotry, i.e., the presence of agents who never change state, can drive infinite populations to consensus in all three models. However, while evolutionary games and the partisan voter model permit zealotry-induced consensus for all values of their model parameters, the nonlinear voter model does not. Central to this difference is the shape of the social impact function, which quantifies how the influence of a group scales with size, and is, therefore, a measure of majority and minority effects. We derive general conditions relating the slope of this function at small group sizes to the local stability of consensus. Sublinear impact favors minorities and can override zealotry to prevent consensus, whereas superlinear impact promotes majorities and, therefore, facilitates consensus. We extend the analysis to finite populations, exploring the time-to-consensus, and the shape of quasi-stationary distributions.","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144944860","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}

引用次数: 0

Inter-role reciprocity in evolutionary trust game on square lattices. 方格上进化信任博弈中的角色间互惠性。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0285064

Chaoqian Wang, Wei Zhang, Xinwei Wang, Attila Szolnoki

引用次数: 0

High intensity and frequency modulations based on infinite pulse trains and ultrashort pulses in a modified semiconductor laser system. 基于无限脉冲序列和超短脉冲的改进半导体激光系统的高强度和频率调制。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0255044

A D Mengue, J O Nde Naoussi, A M Dikande, B Z Essimbi

{"title":"High intensity and frequency modulations based on infinite pulse trains and ultrashort pulses in a modified semiconductor laser system.","authors":"A D Mengue, J O Nde Naoussi, A M Dikande, B Z Essimbi","doi":"10.1063/5.0255044","DOIUrl":"https://doi.org/10.1063/5.0255044","url":null,"abstract":"We report on high intensity and frequency modulations (IM-FM) through various infinite pulse trains derived from the dynamics of a modified rate equations laser system endowed with an additional control parameter (γ), wherein a direct modulation of the injection current is performed. Analytical and numerical investigations showcase the significant impact of the additional control parameter on the enhancement of the relaxation frequency and a resizing of the modulation bandwidth through a full control of the modulation peak. In this way, linear stability of the new modulated laser system is carried out around the steady-state solutions by using the small-signal analysis method, wherefrom we demonstrate that the stability of equilibria can be governed by γ-variations. A route to a new infinite-scroll vibrational attractor through FM-to-IM conversion is investigated, leading to a linear phase-and-frequency-modulated link. Both scenarios based on the propagation of asymmetric horn-shaped pulse trains lead to high FM and exhibit various amplitude-squeezed states and phase-squeezed states by varying the α-factor and the frequency detuning parameter, respectively. Intricate phenomena such as the nonlinear generation and collapsing of ultrashort pulse trains resulting from the infinite pulse trains, internal crisis appearing as a ground for the amplitude-squeezed state of light, and the modulation instability of large amplitude of laser arising from unstable fixed points are also investigated in this work.","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144944853","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}

引用次数: 0

Signal-noise separation using unsupervised reservoir computing. 基于无监督油藏计算的信噪分离。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0278540

Jaesung Choi, Pilwon Kim

引用次数: 0

2D PT-symmetric nonlinear couplers: Stability and power dynamics in sinusoidal system. 二维pt对称非线性耦合器：正弦系统的稳定性和功率动力学。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0280866

Jaseera Chilappurath, Aysha Muhsina K

{"title":"2D PT-symmetric nonlinear couplers: Stability and power dynamics in sinusoidal system.","authors":"Jaseera Chilappurath, Aysha Muhsina K","doi":"10.1063/5.0280866","DOIUrl":"https://doi.org/10.1063/5.0280866","url":null,"abstract":"This work investigates the stability and power dynamics of a beam in a two-dimensional parity-time (PT)-symmetric cubic nonlinear sinusoidal coupled system under varying imaginary potentials. By analyzing eigenvalues, the phase angle indicating the mode synchronization, eigenfunctions, phase evolution, Poynting vector, and power exchange between coupled channels, we identify stability thresholds and characterize the soliton behavior in both PT-symmetric and broken PT-symmetric phases. Below the threshold potential, solitons remain stable, exhibiting periodic power oscillations and symmetric waveforms. Above the threshold, instabilities emerge, leading to asymmetric eigenfunctions, irregular amplitude fluctuations, and distorted power transfer. The transition is marked by a shift from smooth Gaussian-like waveforms to asymmetric, irregular profiles. The oscillation frequency, which dictates the energy transfer between channels, reflects the influence of the gain/loss balance on soliton dynamics. Our findings highlight the crucial role of nonlinearity, coupling strength, and imaginary potential in dictating soliton stability, providing insights into optical beam propagation and nonlinear wave control in PT-symmetric systems.","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144944844","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}

引用次数: 0

Adaptive normalizing flows for solving Fokker-Planck equation. 求解Fokker-Planck方程的自适应归一化流。

IF 3.2 2区数学

Chaos Pub Date : 2025-08-01 DOI: 10.1063/5.0273776

Wanting Xu, Jinqian Feng, Jin Su, Qin Guo, Youpan Han

{"title":"Adaptive normalizing flows for solving Fokker-Planck equation.","authors":"Wanting Xu, Jinqian Feng, Jin Su, Qin Guo, Youpan Han","doi":"10.1063/5.0273776","DOIUrl":"https://doi.org/10.1063/5.0273776","url":null,"abstract":"The Fokker-Planck (FP) equation governs the probabilistic response of diffusion processes driven by stochastic differential equations (SDEs). Gaussian mixture models and deep learning solvers are two state-of-the-art methods for solving the FP equation. Although mixture models mostly depend on empirical sampling strategies and predefined Gaussian components, deep learning techniques suffer from inherent interpretability deficits and require excessively large training samples. To address these challenges, we propose an adaptive normalizing flow framework for solving FP equations (ANFFP). Normalizing flows are generative models that produce tractable distributions to approximate the complex target distributions. The ANFFP architecture inherently preserves probabilistic interpretability while enabling efficient exact sampling advantages that significantly enhance its applicability to probabilistic response modeling under small sample conditions. Numerical examples involving one-dimensional, two-dimensional, and four-dimensional SDEs demonstrate the effectiveness of the method. In addition, the computational complexity of the ANFFP method is discussed in more detail. This work provides a new paradigm for solving high-dimensional FP equations with theoretical guarantees and practical scalability.","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 8","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144803716","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}

引用次数: 0

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