Pub Date : 2025-12-20DOI: 10.1016/j.physd.2025.135084
N. Balabanova , J.A. Montaldi
We investigate the motion of point vortices on the Möbius band and Klein bottle. Since these are non-orientable surfaces, the standard Hamiltonian approach does not apply. We therefore begin by establishing a modified Hamiltonian approach which works for arbitrary non-orientable surfaces, through describing the phase space, the Hamiltonian and the local equations of motion. We use a combination of twisted functions and oriented double covers to adapt some of the known notions of vortex dynamics to non-orientable surfaces. For both of the surfaces of interest, we write Hamiltonian-type equations of vortex motion explicitly and follow that by the description of relative equilibria and an investigation of the motion of one and two vortices.
{"title":"A Hamiltonian approach for point vortices on non-orientable surfaces","authors":"N. Balabanova , J.A. Montaldi","doi":"10.1016/j.physd.2025.135084","DOIUrl":"10.1016/j.physd.2025.135084","url":null,"abstract":"<div><div>We investigate the motion of point vortices on the Möbius band and Klein bottle. Since these are non-orientable surfaces, the standard Hamiltonian approach does not apply. We therefore begin by establishing a modified Hamiltonian approach which works for arbitrary non-orientable surfaces, through describing the phase space, the Hamiltonian and the local equations of motion. We use a combination of twisted functions and oriented double covers to adapt some of the known notions of vortex dynamics to non-orientable surfaces. For both of the surfaces of interest, we write Hamiltonian-type equations of vortex motion explicitly and follow that by the description of relative equilibria and an investigation of the motion of one and two vortices.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"488 ","pages":"Article 135084"},"PeriodicalIF":2.9,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145870484","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}
Pub Date : 2025-12-20DOI: 10.1016/j.physd.2025.135056
Bradley Pascoe , Michael Groom , Ben Thornber
Recent engineering models of turbulent mixing layers under strain imply that there may be a permanent modification of important mixing layer physics following a temporary application of strain. This paper presents a set of Implicit Large-Eddy Simulations of a canonical Richtmyer-Meshkov instability to explore the validity of this model result. The well-characterised θ-group quarter scale case is modified to include a strain rate which halves domain widths in approximately five eddy turnover times. Following the removal of strain, the observed value of the growth rate exponent which is a 2.5 times reduction compared with the unstrained case. Whilst θ is slowly rising at late time, the actual change in θ is qualitatively in good agreement with the engineering model but is quantitatively a much greater change than expected. Mixedness also increases significantly, from for the unstrained to following the application of strain. Turbulent kinetic energy substantially rises during strain, but then dissipates more rapidly following the removal of strain due to the decreased turbulent length-scales. Overall these results demonstrate that modifications to engineering models, such as those proposed by Pascoe et al. (Phys. Rev. Fluids 10 (6), 064609, 2025) are needed to capture these significant variations in flow physics which persist even following the removal of strain. The engineering model further predicts more substantial impacts at high overall compression or expansion as expected in typical applications in inertial confinement fusion, supernovae or explosions.
{"title":"Late-time growth of an inhomogeneous, turbulent mixing layer subjected to transient compression","authors":"Bradley Pascoe , Michael Groom , Ben Thornber","doi":"10.1016/j.physd.2025.135056","DOIUrl":"10.1016/j.physd.2025.135056","url":null,"abstract":"<div><div>Recent engineering models of turbulent mixing layers under strain imply that there may be a permanent modification of important mixing layer physics following a temporary application of strain. This paper presents a set of Implicit Large-Eddy Simulations of a canonical Richtmyer-Meshkov instability to explore the validity of this model result. The well-characterised <em>θ</em>-group quarter scale case is modified to include a strain rate which halves domain widths in approximately five eddy turnover times. Following the removal of strain, the observed value of the growth rate exponent <span><math><mrow><mi>θ</mi><mo>=</mo><mn>0.112</mn></mrow></math></span> which is a 2.5 times reduction compared with the unstrained case. Whilst <em>θ</em> is slowly rising at late time, the actual change in <em>θ</em> is qualitatively in good agreement with the engineering model but is quantitatively a much greater change than expected. Mixedness also increases significantly, from <span><math><mrow><mstyle><mi>Θ</mi></mstyle><mo>=</mo><mn>0.8</mn></mrow></math></span> for the unstrained to <span><math><mrow><mstyle><mi>Θ</mi></mstyle><mo>=</mo><mn>0.9</mn></mrow></math></span> following the application of strain. Turbulent kinetic energy substantially rises during strain, but then dissipates more rapidly following the removal of strain due to the decreased turbulent length-scales. Overall these results demonstrate that modifications to engineering models, such as those proposed by Pascoe et al. (Phys. Rev. Fluids 10 (6), 064609, 2025) are needed to capture these significant variations in flow physics which persist even following the removal of strain. The engineering model further predicts more substantial impacts at high overall compression or expansion as expected in typical applications in inertial confinement fusion, supernovae or explosions.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"488 ","pages":"Article 135056"},"PeriodicalIF":2.9,"publicationDate":"2025-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928013","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}
Pub Date : 2025-12-17DOI: 10.1016/j.physd.2025.135082
A. Bandera , S. Fernández-García , M. Gómez-Mármol , A. Vidal
We present a novel methodology that combines machine learning techniques with dynamical analysis to classify and interpret the behavior distribution of network models of coupled dynamical systems. Our methodology determines the optimal number of distinct behaviors and classifies them based on time-series features, allowing for an interpretable and automated partition of the parameter space. Applying this approach to a homogeneous two-clusters model of intracellular calcium concentration dynamics, we identify nine different long-term behaviors, including complex and chaotic regimes, mapping experimental data available in the literature. The results highlight the complementarity between data-driven classification and classical dynamical analysis in capturing rich synchronization patterns and detecting subtle transitions in multiple timescale biological systems.
{"title":"Machine learning techniques to identify synchronization patterns in multiple timescale dynamical systems networks","authors":"A. Bandera , S. Fernández-García , M. Gómez-Mármol , A. Vidal","doi":"10.1016/j.physd.2025.135082","DOIUrl":"10.1016/j.physd.2025.135082","url":null,"abstract":"<div><div>We present a novel methodology that combines machine learning techniques with dynamical analysis to classify and interpret the behavior distribution of network models of coupled dynamical systems. Our methodology determines the optimal number of distinct behaviors and classifies them based on time-series features, allowing for an interpretable and automated partition of the parameter space. Applying this approach to a homogeneous two-clusters model of intracellular calcium concentration dynamics, we identify nine different long-term behaviors, including complex and chaotic regimes, mapping experimental data available in the literature. The results highlight the complementarity between data-driven classification and classical dynamical analysis in capturing rich synchronization patterns and detecting subtle transitions in multiple timescale biological systems.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"487 ","pages":"Article 135082"},"PeriodicalIF":2.9,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841956","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}
Pub Date : 2025-12-16DOI: 10.1016/j.physd.2025.135073
Zhengwu Miao , Yong Chen
The Schrödinger spectral problem is a central topic in mathematical physics. In numerical inverse scattering transform (NIST), the reflection coefficient R(k) contained in the scattering data must be repeatedly computed by solving the spectral problem at discrete wave number k. We propose a novel neural operator framework, the Jost operator network (JostONet), for fast inference of the Jost solution and its associated R(k), offering a promising alternative for computing R(k) in the NIST. JostONet is composed of three specialized modules: (i) High-energy region : inspired by the asymptotic behavior of the Jost solution, a novel amplitude decomposition is derived, based on which a variable amplitude operator network is constructed. Normalization conditions and conservation property are embedded in the loss function, and hard boundary constraints are imposed. (ii) Intermediate-energy region : The wave number k is treated as a degenerate functional variable, and a wave function operator network is constructed based on the multi-input operator network. (iii) Low-energy region : a perturbation-wave function operator network is introduced, which exploits the perturbation expansion of the Jost solution with respect to k and is composed of a sequence of Deep Operator Networks. During training, a novel function space is constructed based on Hermite polynomials to generate potential functions with Gaussian decay, which serve as inputs to the neural operators. JostONet achieves satisfactory predictive accuracy across all energy regions, with an inference speed at least an order of magnitude faster than traditional methods, and it is capable of generalizing to higher-order potentials in the space . In addition, we provide theoretical support and extensive numerical validation for the partitioning of k, along with detailed numerical analysis of each module.
{"title":"JostONet: A neural operator architecture for solving the Jost solution and scattering coefficients of the Schrödinger spectral problem","authors":"Zhengwu Miao , Yong Chen","doi":"10.1016/j.physd.2025.135073","DOIUrl":"10.1016/j.physd.2025.135073","url":null,"abstract":"<div><div>The Schrödinger spectral problem is a central topic in mathematical physics. In numerical inverse scattering transform (NIST), the reflection coefficient <em>R</em>(<em>k</em>) contained in the scattering data <span><math><mi>S</mi></math></span> must be repeatedly computed by solving the spectral problem at discrete wave number <em>k</em>. We propose a novel neural operator framework, the Jost operator network (JostONet), for fast inference of the Jost solution and its associated <em>R</em>(<em>k</em>), offering a promising alternative for computing <em>R</em>(<em>k</em>) in the NIST. JostONet is composed of three specialized modules: (i) High-energy region <span><math><msub><mi>R</mi><mi>h</mi></msub></math></span>: inspired by the asymptotic behavior of the Jost solution, a novel amplitude decomposition is derived, based on which a variable amplitude operator network is constructed. Normalization conditions and conservation property are embedded in the loss function, and hard boundary constraints are imposed. (ii) Intermediate-energy region <span><math><msub><mi>R</mi><mi>m</mi></msub></math></span>: The wave number <em>k</em> is treated as a degenerate functional variable, and a wave function operator network is constructed based on the multi-input operator network. (iii) Low-energy region <span><math><msub><mi>R</mi><mi>l</mi></msub></math></span>: a perturbation-wave function operator network is introduced, which exploits the perturbation expansion of the Jost solution with respect to <em>k</em> and is composed of a sequence of Deep Operator Networks. During training, a novel function space <span><math><mrow><msup><mover><mrow><mi>H</mi></mrow><mo>˜</mo></mover><mrow><mi>κ</mi><mo>,</mo><mi>η</mi></mrow></msup><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span> is constructed based on Hermite polynomials to generate potential functions with Gaussian decay, which serve as inputs to the neural operators. JostONet achieves satisfactory predictive accuracy across all energy regions, with an inference speed at least an order of magnitude faster than traditional methods, and it is capable of generalizing to higher-order potentials in the space <span><math><mrow><msup><mover><mrow><mi>H</mi></mrow><mo>˜</mo></mover><mrow><mi>κ</mi><mo>,</mo><mi>η</mi></mrow></msup><mrow><mo>(</mo><mi>R</mi><mo>)</mo></mrow></mrow></math></span>. In addition, we provide theoretical support and extensive numerical validation for the partitioning of <em>k</em>, along with detailed numerical analysis of each module.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"486 ","pages":"Article 135073"},"PeriodicalIF":2.9,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840767","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}
Pub Date : 2025-12-14DOI: 10.1016/j.physd.2025.135083
M.A. Rehman , M.J. Iqbal , Zeeshan Iqbal , H.A. Shah
The effect of adiabatic trapping in electron-positron-ion (epi) plasmas plays a crucial role in the formation and evolution of drift double-layer (DL) structures, with significant implications for both space and laboratory plasmas. In this study, we investigate the influence of adiabatic trapping, a microscopic phenomenon, on the evolution of drift DLs in epi plasma. Using the Sagdeev potential method, we investigate the conditions necessary to form electrostatic drift DL solutions in epitaxial plasma. Our analysis reveals that key parameters, such as positron concentration, ion drift speed, and the electron-to-positron temperature ratio, significantly influence the formation of drift DLs and their nonlinear characteristics. Notably, only compressive drift DLs are observed, with their amplitude varying based on changes in plasma parameters. Furthermore, the nonlinear dynamical response of the system to external periodic forcing exhibits a rich spectrum of behaviors, including periodic (e.g., period-2 and period-3), quasiperiodic, and chaotic regimes. To the best of our knowledge, this is the first study to conduct a nonlinear dynamical analysis of drift double layers in epi plasmas under external periodic forcing while incorporating adiabatic trapping effects. This work provides new insights into the interplay of microphysical trapping and external drivers in shaping nonlinear plasma structures, thereby advancing the understanding of DL dynamics in space, astrophysical, and laboratory environments.
{"title":"Chaos and order in drift double layers: Nonlinear dynamics in epi plasmas with adiabatic trapping","authors":"M.A. Rehman , M.J. Iqbal , Zeeshan Iqbal , H.A. Shah","doi":"10.1016/j.physd.2025.135083","DOIUrl":"10.1016/j.physd.2025.135083","url":null,"abstract":"<div><div>The effect of adiabatic trapping in electron-positron-ion (<em>epi</em>) plasmas plays a crucial role in the formation and evolution of drift double-layer (<em>DL</em>) structures, with significant implications for both space and laboratory plasmas. In this study, we investigate the influence of adiabatic trapping, a microscopic phenomenon, on the evolution of drift <em>DLs</em> in <em>epi</em> plasma. Using the Sagdeev potential method, we investigate the conditions necessary to form electrostatic drift DL solutions in epitaxial plasma. Our analysis reveals that key parameters, such as positron concentration, ion drift speed, and the electron-to-positron temperature ratio, significantly influence the formation of drift <em>DLs</em> and their nonlinear characteristics. Notably, only compressive drift <em>DLs</em> are observed, with their amplitude varying based on changes in plasma parameters. Furthermore, the nonlinear dynamical response of the system to external periodic forcing exhibits a rich spectrum of behaviors, including periodic (e.g., period-2 and period-3), quasiperiodic, and chaotic regimes. To the best of our knowledge, this is the first study to conduct a nonlinear dynamical analysis of drift double layers in <em>epi</em> plasmas under external periodic forcing while incorporating adiabatic trapping effects. This work provides new insights into the interplay of microphysical trapping and external drivers in shaping nonlinear plasma structures, thereby advancing the understanding of <em>DL</em> dynamics in space, astrophysical, and laboratory environments.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"487 ","pages":"Article 135083"},"PeriodicalIF":2.9,"publicationDate":"2025-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145766054","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}
Pub Date : 2025-12-13DOI: 10.1016/j.physd.2025.135081
Yi Ding , Chun Yan , Wei Liu , Jiahui Liu
Risk contagion in financial systems presents spatially hierarchical patterns and temporally nonlinear accumulation. To explore this dynamic contagion process, this paper constructs a multilayer dynamic financial network incorporating three types of interbank interactions: interbank lending, cross-holding, and overlapping investment portfolios. We extend the classical Eisenberg-NOE clearing model to a multiplex and sequential dynamic setting, characterizing the propagation of risk through nonlinear clearing dynamics. Bank defaults are classified into illiquidity and insolvency, with temporal evolution achieved through deferred debt. Next, we model the government control as a Markov decision process and introduce fairness constraints to balance systemic stability and equity. Finally, we use Monte Carlo simulations to analyze the numerical results obtained with different control strategies and provide robustness tests.
{"title":"Sequential clearing dynamics and systemic risk control for multilayer financial system","authors":"Yi Ding , Chun Yan , Wei Liu , Jiahui Liu","doi":"10.1016/j.physd.2025.135081","DOIUrl":"10.1016/j.physd.2025.135081","url":null,"abstract":"<div><div>Risk contagion in financial systems presents spatially hierarchical patterns and temporally nonlinear accumulation. To explore this dynamic contagion process, this paper constructs a multilayer dynamic financial network incorporating three types of interbank interactions: interbank lending, cross-holding, and overlapping investment portfolios. We extend the classical Eisenberg-NOE clearing model to a multiplex and sequential dynamic setting, characterizing the propagation of risk through nonlinear clearing dynamics. Bank defaults are classified into illiquidity and insolvency, with temporal evolution achieved through deferred debt. Next, we model the government control as a Markov decision process and introduce fairness constraints to balance systemic stability and equity. Finally, we use Monte Carlo simulations to analyze the numerical results obtained with different control strategies and provide robustness tests.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"487 ","pages":"Article 135081"},"PeriodicalIF":2.9,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799685","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}
Pub Date : 2025-12-13DOI: 10.1016/j.physd.2025.135055
Chris Budd , Rachel Kuske
We study critical relationships between the smoothness parameter for the underlying fold bifurcation and the noise level in the context of B-tipping near smooth and non-smooth dynamic fold bifurcations. The motivation is the Stommel 2-box model, a piecewise-smooth continuous dynamical system modeling thermohaline circulation in the North Atlantic, and related climate models. These contain non-smooth fold bifurcations which arise when a saddle-point and a stable focus meet at a border collision bifurcation. An asymptotic analysis of the corresponding Fokker-Planck Equation (FPE) for the stochastic system provides insight into critical noise levels, depending on the relative rate of parameter variation and a measure of smoothness of the underlying bifurcation. Critical scales are obtained from different reductions of the FPE, identifying cases where noise may advance tipping relative to deterministic behavior. Applying this approach for B-tipping near both smooth and non-smooth folds shows that the non-smooth case has greater sensitivity to smaller noise levels, with a smaller critical scale for noise-advanced tipping in the non-smooth case. Since these results do not depend on obtaining a solution of the FPE, the approach can be adapted to multi-degree-of-freedom models and in other applications.
{"title":"Critical noise for advanced dynamic B-tipping in nearly non-smooth Stommel-type models","authors":"Chris Budd , Rachel Kuske","doi":"10.1016/j.physd.2025.135055","DOIUrl":"10.1016/j.physd.2025.135055","url":null,"abstract":"<div><div>We study critical relationships between the smoothness parameter for the underlying fold bifurcation and the noise level in the context of B-tipping near smooth and non-smooth dynamic fold bifurcations. The motivation is the Stommel 2-box model, a piecewise-smooth continuous dynamical system modeling thermohaline circulation in the North Atlantic, and related climate models. These contain non-smooth fold bifurcations which arise when a saddle-point and a stable focus meet at a border collision bifurcation. An asymptotic analysis of the corresponding Fokker-Planck Equation (FPE) for the stochastic system provides insight into critical noise levels, depending on the relative rate of parameter variation and a measure of smoothness of the underlying bifurcation. Critical scales are obtained from different reductions of the FPE, identifying cases where noise may advance tipping relative to deterministic behavior. Applying this approach for B-tipping near both smooth and non-smooth folds shows that the non-smooth case has greater sensitivity to smaller noise levels, with a smaller critical scale for noise-advanced tipping in the non-smooth case. Since these results do not depend on obtaining a solution of the FPE, the approach can be adapted to multi-degree-of-freedom models and in other applications.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"488 ","pages":"Article 135055"},"PeriodicalIF":2.9,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145928012","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}
Switching power conversion circuits are of great importance within a wide variety of applications, including automotive, wearable device, and so on. Their widespread use is largely due to their high efficiency and small size. However, when such circuits are subject to capacitor degradation, undesired turbulence and a degradation in the overall performance of the converter circuit can be observed. This paper investigates the effect of capacitor degradation on the occurrence of chattering in high-side gate driver circuits within power conversion systems. We introduce a simple mathematical model of a high-side gate driver circuit, which incorporates a hysteresis characteristic as a result of the under-voltage lockout (UVLO) function. We analytically derived the conditions in which chattering events occur and how the number of switching events changes. These analytical expressions were achieved by analyzing the period of the return map and identifying the thresholds that can be used to characterize the different behaviors that the system exhibits. In this work, we obtain a relationship between capacitor degradation and the chattering events.
{"title":"Chattering phenomenon in high-side gate driver circuits with degraded capacitors","authors":"Daisuke Ito , Yusuke Goto , Kaito Kato , Hiroyuki Asahara , Takuji Kousaka","doi":"10.1016/j.physd.2025.135076","DOIUrl":"10.1016/j.physd.2025.135076","url":null,"abstract":"<div><div>Switching power conversion circuits are of great importance within a wide variety of applications, including automotive, wearable device, and so on. Their widespread use is largely due to their high efficiency and small size. However, when such circuits are subject to capacitor degradation, undesired turbulence and a degradation in the overall performance of the converter circuit can be observed. This paper investigates the effect of capacitor degradation on the occurrence of chattering in high-side gate driver circuits within power conversion systems. We introduce a simple mathematical model of a high-side gate driver circuit, which incorporates a hysteresis characteristic as a result of the under-voltage lockout (UVLO) function. We analytically derived the conditions in which chattering events occur and how the number of switching events changes. These analytical expressions were achieved by analyzing the period of the return map and identifying the thresholds that can be used to characterize the different behaviors that the system exhibits. In this work, we obtain a relationship between capacitor degradation and the chattering events.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"486 ","pages":"Article 135076"},"PeriodicalIF":2.9,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840824","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}
Pub Date : 2025-12-12DOI: 10.1016/j.physd.2025.135074
Uday Chand De , Füsun ÖZEN ZENGİN , Sezgin ALTAY DEMIRBAG , Krishnendu De
In the present paper, we investigate the classification of a spacetime admitting gradient Ricci-Yamabe solitons in special conditions. We acquire that such a spacetime obeying divergence-free Weyl tensor becomes a generalized Robertson-Walker spacetime as well as a static spacetime and the spacetime represents dark matter era. Also, we show that such a spacetime is a Robertson-Walker spacetime and it is of Petrov type “O”. Moreover, it has also been investigated under what conditions this spacetime turns into a stiff matter era. In the last section of this paper, we examine the effect of this spacetime under f(R)-gravity scenario and derive several energy conditions graphically using two different models.
{"title":"Characterizations of a spacetime admitting gradient Ricci-Yamabe solitons and f(R)-gravity","authors":"Uday Chand De , Füsun ÖZEN ZENGİN , Sezgin ALTAY DEMIRBAG , Krishnendu De","doi":"10.1016/j.physd.2025.135074","DOIUrl":"10.1016/j.physd.2025.135074","url":null,"abstract":"<div><div>In the present paper, we investigate the classification of a spacetime admitting gradient Ricci-Yamabe solitons in special conditions. We acquire that such a spacetime obeying divergence-free Weyl tensor becomes a generalized Robertson-Walker spacetime as well as a static spacetime and the spacetime represents dark matter era. Also, we show that such a spacetime is a Robertson-Walker spacetime and it is of Petrov type “O”. Moreover, it has also been investigated under what conditions this spacetime turns into a stiff matter era. In the last section of this paper, we examine the effect of this spacetime under <em>f</em>(<em>R</em>)-gravity scenario and derive several energy conditions graphically using two different models.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"487 ","pages":"Article 135074"},"PeriodicalIF":2.9,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799701","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}
Pub Date : 2025-12-12DOI: 10.1016/j.physd.2025.135080
Pedro Gatón-Pérez , Enrique Rodríguez-Fernández , Rodolfo Cuerno
The occurrence of strong coupling or nonlinear scaling behavior for kinetically rough interfaces whose dynamics are conserved, but not necessarily variational, remains to be fully understood. Here we formulate and study a family of conserved stochastic evolution equations for one-dimensional interfaces, whose nonlinearity depends on a parameter n, thus generalizing that of the stochastic Burgers equation, whose behavior is retrieved for . This family of equations includes as particular instances a stochastic porous medium equation and other continuum models relevant to various hard and soft condensed matter systems. We perform a one-loop dynamical renormalization group analysis of the equations, which contemplates strong coupling scaling exponents that depend on the value of n and may or may not imply vertex renormalization. These analytical expectations are contrasted with explicit numerical simulations of the equations with and 3. For odd n, numerical stability issues have required us to generalize the scheme originally proposed for by T. Sasamoto and H. Spohn [J. Stat. Phys. 137, 917 (2009)]. Precisely for and 3, and at variance with the and 2 cases (whose numerical exponents are consistent with non-renormalization of the vertex), numerical strong coupling exponent values are obtained which suggest vertex renormalization, akin to that reported for the celebrated conserved Kardar-Parisi-Zhang (cKPZ) equation. We also study numerically the statistics of height fluctuations, whose probability distribution function turns out (at variance with cKPZ) to have zero skewness for long times and at saturation, irrespective of the value of n. However, the kurtosis is non-Gaussian, further supporting the conclusion on strong coupling asymptotic behavior. The zero skewness seems related with space symmetries of the and 2 equations, and with an emergent symmetry at the strong coupling fixed point for odd values of n.
对于动力学守恒但不一定变分的动力学粗糙界面，其强耦合或非线性标度行为的发生仍有待充分理解。本文建立并研究了一类非线性依赖于参数n的一维界面的守恒随机演化方程，从而推广了n=0时可获取其行为的随机Burgers方程。这一系列方程包括随机多孔介质方程和其他与各种硬、软凝聚态系统相关的连续介质模型。我们对方程进行了一个单环动态重整化群分析，该分析考虑了依赖于n值的强耦合缩放指数，并且可能或可能不意味着顶点重整化。这些分析期望与n= 1,2,3的方程的显式数值模拟进行了对比。对于奇数n，数值稳定性问题要求我们推广最初由T. Sasamoto和H. Spohn在n=0时提出的方案[J]。[j].物理学报，2003,17(5)。精确地说，对于n=1和3，并与n=0和2的情况（其数值指数与顶点的非重整化一致）不同，得到了数值强耦合指数值，表明顶点重整化，类似于著名的保守kardar - paris - zhang （cKPZ）方程的报告。我们还研究了高度波动的数值统计，其概率分布函数（与cKPZ不同）在长时间和饱和时，无论n的值如何，都具有零偏度。然而，峰度是非高斯的，进一步支持了强耦合渐近行为的结论。零偏度似乎与n=0和n= 2方程的空间对称性有关，并且与奇数n值的强耦合不动点的突现对称性有关。
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