{"title":"参数为 $$L^p$$ 的线性均质微分方程的简单 Lyapunov 谱","authors":"Dinis Amaro, Mário Bessa, Helder Vilarinho","doi":"10.1007/s00030-024-00931-w","DOIUrl":null,"url":null,"abstract":"<p>In the present paper we prove that densely, with respect to an <span>\\(L^p\\)</span>-like topology, the Lyapunov exponents associated to linear continuous-time cocycles <span>\\(\\Phi :\\mathbb {R}\\times M\\rightarrow {{\\,\\textrm{GL}\\,}}(2,\\mathbb {R})\\)</span> induced by second order linear homogeneous differential equations <span>\\(\\ddot{x}+\\alpha (\\varphi ^t(\\omega ))\\dot{x}+\\beta (\\varphi ^t(\\omega ))x=0\\)</span> are almost everywhere distinct. The coefficients <span>\\(\\alpha ,\\beta \\)</span> evolve along the <span>\\(\\varphi ^t\\)</span>-orbit for <span>\\(\\omega \\in M\\)</span> and <span>\\(\\varphi ^t: M\\rightarrow M\\)</span> is an ergodic flow defined on a probability space. We also obtain the corresponding version for the frictionless equation <span>\\(\\ddot{x}+\\beta (\\varphi ^t(\\omega ))x=0\\)</span> and for a Schrödinger equation <span>\\(\\ddot{x}+(E-Q(\\varphi ^t(\\omega )))x=0\\)</span>, inducing a cocycle <span>\\(\\Phi :\\mathbb {R}\\times M\\rightarrow {{\\,\\textrm{SL}\\,}}(2,\\mathbb {R})\\)</span>.\n</p>","PeriodicalId":501665,"journal":{"name":"Nonlinear Differential Equations and Applications (NoDEA)","volume":"32 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2024-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Simple Lyapunov spectrum for linear homogeneous differential equations with $$L^p$$ parameters\",\"authors\":\"Dinis Amaro, Mário Bessa, Helder Vilarinho\",\"doi\":\"10.1007/s00030-024-00931-w\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>In the present paper we prove that densely, with respect to an <span>\\\\(L^p\\\\)</span>-like topology, the Lyapunov exponents associated to linear continuous-time cocycles <span>\\\\(\\\\Phi :\\\\mathbb {R}\\\\times M\\\\rightarrow {{\\\\,\\\\textrm{GL}\\\\,}}(2,\\\\mathbb {R})\\\\)</span> induced by second order linear homogeneous differential equations <span>\\\\(\\\\ddot{x}+\\\\alpha (\\\\varphi ^t(\\\\omega ))\\\\dot{x}+\\\\beta (\\\\varphi ^t(\\\\omega ))x=0\\\\)</span> are almost everywhere distinct. The coefficients <span>\\\\(\\\\alpha ,\\\\beta \\\\)</span> evolve along the <span>\\\\(\\\\varphi ^t\\\\)</span>-orbit for <span>\\\\(\\\\omega \\\\in M\\\\)</span> and <span>\\\\(\\\\varphi ^t: M\\\\rightarrow M\\\\)</span> is an ergodic flow defined on a probability space. We also obtain the corresponding version for the frictionless equation <span>\\\\(\\\\ddot{x}+\\\\beta (\\\\varphi ^t(\\\\omega ))x=0\\\\)</span> and for a Schrödinger equation <span>\\\\(\\\\ddot{x}+(E-Q(\\\\varphi ^t(\\\\omega )))x=0\\\\)</span>, inducing a cocycle <span>\\\\(\\\\Phi :\\\\mathbb {R}\\\\times M\\\\rightarrow {{\\\\,\\\\textrm{SL}\\\\,}}(2,\\\\mathbb {R})\\\\)</span>.\\n</p>\",\"PeriodicalId\":501665,\"journal\":{\"name\":\"Nonlinear Differential Equations and Applications (NoDEA)\",\"volume\":\"32 1\",\"pages\":\"\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-03-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Nonlinear Differential Equations and Applications (NoDEA)\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1007/s00030-024-00931-w\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nonlinear Differential Equations and Applications (NoDEA)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1007/s00030-024-00931-w","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Simple Lyapunov spectrum for linear homogeneous differential equations with $$L^p$$ parameters
In the present paper we prove that densely, with respect to an \(L^p\)-like topology, the Lyapunov exponents associated to linear continuous-time cocycles \(\Phi :\mathbb {R}\times M\rightarrow {{\,\textrm{GL}\,}}(2,\mathbb {R})\) induced by second order linear homogeneous differential equations \(\ddot{x}+\alpha (\varphi ^t(\omega ))\dot{x}+\beta (\varphi ^t(\omega ))x=0\) are almost everywhere distinct. The coefficients \(\alpha ,\beta \) evolve along the \(\varphi ^t\)-orbit for \(\omega \in M\) and \(\varphi ^t: M\rightarrow M\) is an ergodic flow defined on a probability space. We also obtain the corresponding version for the frictionless equation \(\ddot{x}+\beta (\varphi ^t(\omega ))x=0\) and for a Schrödinger equation \(\ddot{x}+(E-Q(\varphi ^t(\omega )))x=0\), inducing a cocycle \(\Phi :\mathbb {R}\times M\rightarrow {{\,\textrm{SL}\,}}(2,\mathbb {R})\).