{"title":"Brownian motion with stochastic energy renewals.","authors":"Ion Santra, Kristian Stølevik Olsen","doi":"10.1063/5.0285588","DOIUrl":"https://doi.org/10.1063/5.0285588","url":null,"abstract":"<p><p>We investigate the impact of intermittent energy injections on a Brownian particle, modeled as stochastic renewals of its kinetic energy to a fixed value. Between renewals, the particle follows standard underdamped Langevin dynamics. For energy renewals occurring at a constant rate, we find non-Boltzmannian energy distributions that undergo a shape transition driven by the competition between the velocity relaxation timescale and the renewal timescale. In the limit of rapid renewals, the dynamics mimics one-dimensional run-and-tumble motion, while at finite renewal rates, the effective diffusion coefficient exhibits non-monotonic behavior. To quantify the system's departure from equilibrium, we derive a modified fluctuation-response relation and demonstrate the absence of a consistent effective temperature. The dissipation is characterized by deviations from equilibrium-like response, captured via the Harada-Sasa relation. Finally, we extend the analysis to non-Poissonian renewal processes and introduce a dimensionless conversion coefficient that quantifies the thermodynamic cost of diffusion.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144999699","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":"Analysis of influencing factors and the most probable transition pathway in the narrow escape problem for molecular systems based on deep learning method.","authors":"Jiangyan Liu, Ming Yi, Ting Gao, Xiaoli Chen","doi":"10.1063/5.0288558","DOIUrl":"https://doi.org/10.1063/5.0288558","url":null,"abstract":"<p><p>This study employs physics-informed neural networks (PINNs) to investigate the narrow escape problem in irregular domains, aiming to understand how key parameters influence molecular escape behavior and to analyze the most probable transition pathway of molecules. We focus on two critical metrics: mean exit time and escape probability, characterizing escape behavior in stochastic systems. Using PINNs, we effectively address the domain's complexities and examine the effects of parameters such as diffusion coefficient, angular velocity, annular area, and absorption domain size on mean exit time and escape probability. Moreover, by computing the most probable transition pathway, we further uncovered the underlying mechanisms that govern molecular motion in complex environments. An interesting observation was that increasing the diffusion coefficient expanded the high-probability escape region but decreased the overall escape probability. The results provide valuable insights for optimizing escape efficiency in practical applications and highlight the potential of PINNs for studying complex diffusion problems.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144999729","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":"Incorporating coupling knowledge into echo state networks for learning spatiotemporally chaotic dynamics.","authors":"Kuei-Jan Chu, Nozomi Akashi, Akihiro Yamamoto","doi":"10.1063/5.0273343","DOIUrl":"https://doi.org/10.1063/5.0273343","url":null,"abstract":"<p><p>Machine learning methods have shown promise in learning chaotic dynamical systems, enabling model-free short-term prediction and attractor reconstruction. However, when applied to large-scale, spatiotemporally chaotic systems, purely data-driven machine learning methods often suffer from inefficiencies, as they require a large learning model size and a massive amount of training data to achieve acceptable performance. To address this challenge, we incorporate the spatial coupling structure of the target system as an inductive bias in the network design. Specifically, we introduce physics-guided clustered echo state networks, leveraging the efficiency of the echo state networks (ESNs) as a base model. Experimental results on benchmark chaotic systems demonstrate that our physics-informed method outperforms existing echo state network models in learning the target chaotic systems. Additionally, we numerically demonstrate that leveraging coupling knowledge into ESN models can enhance their robustness to variations of training and target system conditions. We further show that our proposed model remains effective even when the coupling knowledge is imperfect or extracted directly from time series data. We believe that this approach has the potential to enhance other machine learning methods.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145074291","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}
Elisa Bretón-Fuertes, Clara Clemente-Marcuello, Verónica Sanz-Arqué, Gabriela Tomás-Delgado, Santiago Lamata-Otín, Hugo Pérez-Martínez, Jesús Gómez-Gardeñes
{"title":"Explosive adoption of corrupt behaviors in social systems with higher-order interactions.","authors":"Elisa Bretón-Fuertes, Clara Clemente-Marcuello, Verónica Sanz-Arqué, Gabriela Tomás-Delgado, Santiago Lamata-Otín, Hugo Pérez-Martínez, Jesús Gómez-Gardeñes","doi":"10.1063/5.0292972","DOIUrl":"https://doi.org/10.1063/5.0292972","url":null,"abstract":"<p><p>Human behaviors in social systems are often shaped by group pressure and collective norms, especially since the rise of social media platforms. However, in the context of adopting misbehaviors, most existing contagion models rely on pairwise interactions and thus fail to capture group-level dynamics. To fill this gap, we introduce a higher-order extension of the honesty-corruption-ostracism model to study the emergence of systemic corruption in populations where individuals interact through group structures. The model incorporates contagion-like transitions mediated by hyperedges of arbitrary order, capturing the influence of peer pressure in group settings. Analytical and numerical results show that higher-order interactions induce discontinuous (explosive) transitions between fully honest and fully corrupt regimes, separated by a bistable phase. This abrupt behavior disappears in the pairwise limit, highlighting the destabilizing effect of group interactions. Furthermore, we establish a general correspondence between our model and broader classes of social contagion dynamics with symmetry breaking, recovering previous results as limiting cases. These findings underscore the critical role of a higher-order structure in shaping behavioral adoption processes and the stability of social systems.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144991640","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":"Effects of symmetric and asymmetric habitat loss on species coexistence in cyclic competition.","authors":"Hui Dai, Xiaoyue Wang, Xiaowen Dai, Lei Shi","doi":"10.1063/5.0295840","DOIUrl":"https://doi.org/10.1063/5.0295840","url":null,"abstract":"<p><p>Habitat loss is a critical driver of biodiversity decline; yet, its impact on species coexistence remains complex. We systematically investigated the effects of symmetric and asymmetric habitat loss on both well-mixed and structured populations using the rock-paper-scissors game model. In well-mixed populations, theoretical analysis identified various equilibrium states whose stability is governed by the interplay between habitat-loss intensity, predation, the rates of species mortality, and reproduction. Monte Carlo simulations of structured populations demonstrated that increasing habitat loss significantly disrupts the coexistence of the three species, leading to spatial fragmentation. Notably, asymmetric habitat loss exhibited unique stabilizing effects, promoting the coexistence of two species or the persistence of a single species. Our findings underscore the intricate and nonlinear interactions between habitat loss and species dynamics, highlighting the necessity of incorporating environmental degradation into biodiversity conservation strategies.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145112208","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":"Cluster synchronization via graph Laplacian eigenvectors.","authors":"Tobias Timofeyev, Alice Patania","doi":"10.1063/5.0280142","DOIUrl":"https://doi.org/10.1063/5.0280142","url":null,"abstract":"<p><p>Almost equitable partitions (AEPs) have been linked to cluster synchronization in oscillatory systems, highlighting the importance of structure in collective network dynamics. We provide a general spectral framework that formalizes this connection, showing how eigenvectors associated with AEPs span a subspace of the Laplacian spectrum that governs partition-induced synchronization behavior. This offers a principled reduction of network dynamics, allowing clustered states to be understood in terms of quotient graph projections. Our approach clarifies the conditions under which transient hierarchical clustering and multi-frequency synchronization emerge and connects these dynamical phenomena directly to network symmetry and community structure. In doing so, we bridge a critical gap between static topology and dynamic behavior, namely, the lack of a spectral method for analyzing synchronization in networks that exhibit exact or approximate structural regularity. Perfect AEPs are rare in real-world networks since most have some degree of irregularity or noise. We define relaxation of an AEP we call a quasi-equitable partition at level δ (δ-QEP). δ-QEPs can preserve many of the clustering-relevant properties of AEPs while tolerating structural imperfections and noise. This extension enables us to describe synchronization behavior in more realistic scenarios, where ideal symmetries are rarely present. Our findings have important implications for understanding synchronization patterns in real-world networks, from neural circuits to power grids.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144999721","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":"Particle model of creation and annihilation captures termination dynamics of spiral defect chaos.","authors":"Timothy J Tyree, Michael Reiss, Wouter-Jan Rappel","doi":"10.1063/5.0277113","DOIUrl":"https://doi.org/10.1063/5.0277113","url":null,"abstract":"<p><p>Excitable media, including a cardiac tissue, can exhibit spiral defect chaos (SDC), during which spiral waves are continuously created and annihilated. Simulating this behavior typically requires solving large-scale reaction-diffusion systems, limiting computational feasibility especially for larger model domains. To address this, we have previously developed a particle model that was capable of replicating spiral-wave annihilation via short-range attraction and diffusion. In this study, we extend that model to capture spiral-wave creation by introducing a short-lived repulsive interaction between newly formed particle pairs. Our extended model accurately reproduces the termination statistics of SDC in cardiac simulations, including mean termination time, offering a simplified yet faithful description of SDC dynamics at much lesser computational cost.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145074348","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}
Antonio Palacios, Samir Sahoo, Madeline Parker, Aradhana Singh, Sheksha Dudekula
{"title":"Forced symmetry-breaking in networks with dihedral symmetry.","authors":"Antonio Palacios, Samir Sahoo, Madeline Parker, Aradhana Singh, Sheksha Dudekula","doi":"10.1063/5.0288584","DOIUrl":"https://doi.org/10.1063/5.0288584","url":null,"abstract":"<p><p>Adaptation in complex systems implies a natural ability to change. In networks, adaptation may include a change in structural connectivity, which can lead to a change in collective behavior. When dihedral symmetry is present, i.e., rotations and reflections of a regular polygon, it is well-known that traveling and standing waves occur, generically, via spontaneous symmetry-breaking Hopf bifurcations. While synchronization appears via standard, symmetry-preserving, Hopf bifurcations. In these cases, the symmetries of the network equations do not change even though the bifurcating solutions may lose symmetry as parameters are varied. But when they do, possibly due to adaptation, there is, however, little knowledge of what happens to those patterns. Here, we choose to investigate the effects of forced-breaking the rotation symmetry of a network with (unperturbed) dihedral symmetry. We study, in particular, the changes in the region of existence and stability of the unperturbed patterns-traveling and standing waves and synchronization.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145022932","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}
Aleksey Ryabov, Elena Rybalova, Andrei Bukh, Tatiana E Vadivasova, Vladimir V Semenov
{"title":"Nonlocal-coupling-based control of coherence resonance.","authors":"Aleksey Ryabov, Elena Rybalova, Andrei Bukh, Tatiana E Vadivasova, Vladimir V Semenov","doi":"10.1063/5.0288025","DOIUrl":"https://doi.org/10.1063/5.0288025","url":null,"abstract":"<p><p>We demonstrate that nonlocal coupling enables control of the collective stochastic dynamics in the regime of coherence resonance. The control scheme based on the nonlocal interaction properties is presented by means of numerical simulation on an example of coupled FitzHugh-Nagumo oscillators. In particular, increasing the coupling radius is shown to enhance or to suppress the effect of coherence resonance, which is reflected in the evolution of the dependence of the correlation time and the deviation of interspike intervals on the noise intensity. Nonlocal coupling is considered an intermediate option between local and global coupling topologies, which are also discussed in the context of the coherence resonance control.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144999737","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":"Energy of quasi-zero stiffness energy harvester under strange non-chaotic attractor.","authors":"Prakash Duraisamy, Dianavinnarasi Joseph, Suresh Kumarasamy, Balamurali Ramakrishnan","doi":"10.1063/5.0281427","DOIUrl":"https://doi.org/10.1063/5.0281427","url":null,"abstract":"<p><p>This study investigates the Quasi-Zero Stiffness Energy Harvester (QZEH), a nonlinear, multi-stable system designed for enhanced energy extraction from vibrating mechanical devices. Nonlinear harvesters, like QZEH and bistable systems, operate over a wider frequency range, effectively capturing energy from broadband or irregular inputs, but can lead to complex behaviors. Maintaining a quasi-periodically forced QZEH in a periodic state is challenging due to the intricate interaction between the system's nonlinear dynamics and the input's incommensurate frequencies. While periodic solutions are typically associated with higher energy yields than chaotic ones, we report a novel dynamical domain under quasi-periodic excitation. Surprisingly, this regime, characterized by a strange non-chaotic attractor, demonstrates a significantly higher energy harvesting efficiency than chaotic motion. This finding challenges conventional expectations and opens new avenues for optimizing energy harvesters. We examine robustness under practical conditions by analyzing the effects of additive white noise on the QZEH system. The results show that increasing noise intensity progressively erodes the basin of strange nonchaotic attractors, while energy harvesting performance remains stable in the single-attractor regime. This discovery represents a significant advancement in energy harvesting technologies, offering a pathway to achieve higher energy extraction by utilizing nontraditional dynamical behaviors.</p>","PeriodicalId":9974,"journal":{"name":"Chaos","volume":"35 9","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145112231","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}