Physica D: Nonlinear Phenomena最新文献_第8页

Three-dimensional time-dependent water flows with constant non-vanishing vorticity and depth dependent density

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2025.134523

Anna Geyer , Calin I. Martin

引用次数: 0

Improved detection of chaos with Lagrangian descriptors using differential algebra

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2024.134506

Alexandru Căliman, Jérôme Daquin, Anne-Sophie Libert

{"title":"Improved detection of chaos with Lagrangian descriptors using differential algebra","authors":"Alexandru Căliman, Jérôme Daquin, Anne-Sophie Libert","doi":"10.1016/j.physd.2024.134506","DOIUrl":"10.1016/j.physd.2024.134506","url":null,"abstract":"<div><div>Lagrangian descriptors (LDs) based on the arc length of orbits previously demonstrated their utility in delineating structures governing the dynamics. Recently, a chaos indicator based on the second derivatives of the LDs, referred to as <span><math><mfenced><mrow><mi>Δ</mi><mi>LD</mi></mrow></mfenced></math></span>, has been introduced to distinguish regular and chaotic trajectories. Thus far, the derivatives are numerically approximated using finite differences on fine meshes of initial conditions. In this paper, we instead use the differential algebra (DA) framework as a form of automatic differentiation to introduce and compute <span><math><mfenced><mrow><mi>Δ</mi><mi>LD</mi></mrow></mfenced></math></span> up to machine precision. We discuss and exemplify benefits of this framework, such as the determination of reliable thresholds to distinguish ordered from chaotic trajectories. Our extensive parametric study quantitatively assesses the accuracy and sensitivity of both the finite differences and differential arithmetic approaches by focusing on paradigmatic discrete models of Hamiltonian chaos, namely the Chirikov’s standard map and coupled 4-dimensional variants. Our results demonstrate that finite difference techniques for <span><math><mfenced><mrow><mi>Δ</mi><mi>LD</mi></mrow></mfenced></math></span> might lead to significant misclassification rate, up to 20% when the phase space supports thin resonant webs, due to the difficulty to determine appropriate thresholds. On the contrary, <span><math><mfenced><mrow><mi>Δ</mi><mi>LD</mi></mrow></mfenced></math></span> computed through DA arithmetic leads to clear bimodal distributions which in turn lead to robust thresholds. As a consequence, the DA framework reveals as sensitive as established first order tangent map based indicators, independently of the underlying dynamical regime. Finally, the benefits of the DA framework are also highlighted for non-uniform depleted meshes of initial conditions.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"472 ","pages":"Article 134506"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143163342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Inverse scattering transform for the discrete nonlocal PT symmetric nonlinear Schrödinger equation with nonzero boundary conditions

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2025.134528

Ya-Hui Liu, Rui Guo, Jian-Wen Zhang

引用次数: 0

Minimal model for investigation of noise-induced bubbling

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2024.134475

Viktor Avrutin , Zhanybai T. Zhusubaliyev , Kuntal Mandal , Frank Bastian , Abdelali El Aroudi

引用次数: 0

Controlled fluid transport by the collective motion of microrotors

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2025.134536

Jake Buzhardt , Phanindra Tallapragada

{"title":"Controlled fluid transport by the collective motion of microrotors","authors":"Jake Buzhardt , Phanindra Tallapragada","doi":"10.1016/j.physd.2025.134536","DOIUrl":"10.1016/j.physd.2025.134536","url":null,"abstract":"<div><div>Torque-driven microscale swimming robots, or microrotors, hold significant potential in biomedical applications such as targeted drug delivery, minimally invasive surgery, and micromanipulation. This paper addresses the challenge of controlling the transport of fluid volumes using the flow fields generated by interacting groups of microrotors. Our approach uses polynomial chaos expansions to model the time evolution of fluid particle distributions and formulate an optimal control problem, which we solve numerically. We implement this framework in simulation to achieve the controlled transport of an initial fluid particle distribution to a target destination while minimizing undesirable effects such as stretching and mixing. We consider the case where translational velocities of the rotors are directly controlled, as well as the case where only torques are controlled and the rotors move in response to the collective flow fields they generate. We analyze the solution of this optimal control problem by computing the Lagrangian coherent structures of the associated flow field, which reveal the formation of transport barriers that efficiently guide particles toward their target. This analysis provides insights into the underlying mechanisms of controlled transport.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"472 ","pages":"Article 134536"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143162922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Integrating physics of the problem into data-driven methods to enhance elastic full-waveform inversion with uncertainty quantification

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2024.134518

Vahid Negahdari, Seyed Reza Moghadasi, Mohammad Reza Razvan

{"title":"Integrating physics of the problem into data-driven methods to enhance elastic full-waveform inversion with uncertainty quantification","authors":"Vahid Negahdari, Seyed Reza Moghadasi, Mohammad Reza Razvan","doi":"10.1016/j.physd.2024.134518","DOIUrl":"10.1016/j.physd.2024.134518","url":null,"abstract":"<div><div>Full-Waveform Inversion (FWI) is a nonlinear iterative seismic imaging technique that, by reducing the misfit between recorded and predicted seismic waveforms, can produce detailed estimates of subsurface geophysical properties. Nevertheless, the strong nonlinearity of FWI can trap the optimization in local minima. This issue arises due to factors such as improper initial values, the absence of low frequencies in the measurements, noise, and other related considerations. To address this challenge and with the advent of advanced machine-learning techniques, data-driven methods, such as deep learning, have attracted significantly increasing attention in the geophysical community. Furthermore, the elastic wave equation should be included in FWI to represent elastic effects accurately. The intersection of data-driven techniques and elastic scattering theories presents opportunities and challenges. In this paper, by using the knowledge of elastic scattering (physics of the problem) and integrating it with machine learning techniques, we propose methods for the solution of time-harmonic FWI to enhance accuracy compared to pure data-driven and physics-based approaches. Moreover, to address uncertainty quantification, by modifying the structure of the Variational Autoencoder, we introduce a probabilistic deep learning method based on the physics of the problem that enables us to explore the uncertainties of the solution. According to the limited availability of datasets in this field and to assess the performance and accuracy of the proposed methods, we create a comprehensive dataset close to reality and conduct a comparative analysis of the presented approaches to it.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"472 ","pages":"Article 134518"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143162932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Spatiotemporal dynamics of immune responses to viral infection and re-infection

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2024.134519

Peng Wu , Xiunan Wang , Hao Wang

{"title":"Spatiotemporal dynamics of immune responses to viral infection and re-infection","authors":"Peng Wu , Xiunan Wang , Hao Wang","doi":"10.1016/j.physd.2024.134519","DOIUrl":"10.1016/j.physd.2024.134519","url":null,"abstract":"<div><div>To test the hypothesis that the chemotactic movement of immune cells is pivotal in controlling within-host viral infection and re-infection, we formulate a chemotaxis model with multiple chemokines and spatial heterogeneity to investigate spatiotemporal dynamics of immune responses. The system admits globally bounded classical solutions in one-dimensional space, and the global classical solvability is derived in a high-dimensional space. We discuss the existence and local stability of four equilibria in the homogeneous case. By constructing Lyapunov functionals, we prove the global stability and the convergence rates of equilibria. Numerical simulations verify the theoretical results and provide additional insights. With stronger chemotaxis, the fluctuation of viral load in the early stage of viral infection is significantly reduced and enters a stable state faster, which indicates that chemotaxis can inhibit viral infection. During re-infection, the chemotactic movement of memory CTLs is more important than that of effector CTLs, and vice versa in initial infection. Furthermore, spatial heterogeneity, due to different patients or organs, should inevitably be considered to guarantee the success of clinical treatments.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"472 ","pages":"Article 134519"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143163344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Reductions on B-type universal character hierarchy

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2024.134514

Shuxian Wang, Chuanzhong Li

引用次数: 0

Corrigendum to “An elapsed time model for strongly coupled inhibitory and excitatory neural networks” [Physica D: Nonlinear Phenomena, 2021, vol. 425, p. 132977]

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2025.134544

Nicolás Torres , María J Cáceres , Benoît Perthame , Delphine Salort

引用次数: 0

Boundedness of bouncing balls in quadratic potentials

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-02-01 DOI: 10.1016/j.physd.2024.134465

Zhichao Ma , Jinhao Liang , Junxiang Xu

{"title":"Boundedness of bouncing balls in quadratic potentials","authors":"Zhichao Ma , Jinhao Liang , Junxiang Xu","doi":"10.1016/j.physd.2024.134465","DOIUrl":"10.1016/j.physd.2024.134465","url":null,"abstract":"<div><div>In this paper, we consider the dynamics of a ball elastically bouncing off an infinitely heavy plate. Suppose the plate periodically moves in vertical direction and the ball between impacts is only subjected to the force with quadratic potential <span><math><mrow><mi>U</mi><mrow><mo>(</mo><mi>z</mi><mo>)</mo></mrow><mo>=</mo><mfrac><mrow><mi>α</mi></mrow><mrow><mn>2</mn></mrow></mfrac><msup><mrow><mi>z</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></math></span>, where <span><math><msup><mrow><mrow><mo>(</mo><mn>4</mn><mi>α</mi><mo>)</mo></mrow></mrow><mrow><mo>−</mo><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math></span> is Diophantine. Without imposing any assumption on the motion of plate besides smoothness, we prove that the ball never goes to infinity. Comparing to previous works, we drop certain assumptions which are usually imposed on the motion of the plate to guarantee twist conditions. This result depends on the famed Herman’s Last Geometric Theorem, which is given by Herman no later than 1995 in his “Seminaire de Systemes Dynamiques” at the Universite Paris VII and also in his 1998 ICM address (Herman, 1998 <span><span>[1]</span></span>). Its proof is also provided by Fayad and Krikorian (Fayad and Krikorian, 2009 <span><span>[2]</span></span>) in 2009 and recently we obtained a slightly different version (Ma and Xu, 2023 <span><span>[3]</span></span>), which is more convenient for this physical model.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"472 ","pages":"Article 134465"},"PeriodicalIF":2.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143162907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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