English

Simple Lyapunov spectrum for linear homogeneous differential equations with Lp parameters

Dynamical Systems 2023-01-13 v1 Classical Analysis and ODEs

Abstract

In the present paper we prove that densely, with respect to an LpL^p-like topology, the Lyapunov exponents associated to linear continuous-time cocycles Φ:R×MGL(2,R)\Phi:\mathbb{R}\times M\to \text{GL}(2,\mathbb{R}) induced by second order linear homogeneous differential equations x¨+α(φt(ω))x˙+β(φt(ω))x=0\ddot x+\alpha(\varphi^t(\omega))\dot x+\beta(\varphi^t(\omega))x=0 are almost everywhere distinct. The coefficients α,β\alpha,\beta evolve along the φt\varphi^t-orbit for ωM\omega\in M and φt:MM\varphi^t: M\to M is an ergodic flow defined on a probability space. We also obtain the corresponding version for the frictionless equation x¨+β(φt(ω))x=0\ddot x+\beta(\varphi^t(\omega))x=0 and for a Schr\"odinger equation x¨+(EQ(φt(ω)))x=0\ddot x+(E-Q(\varphi^t(\omega)))x=0, inducing a cocycle Φ:R×MSL(2,R)\Phi:\mathbb{R}\times M\to \text{SL}(2,\mathbb{R}).

Keywords

Cite

@article{arxiv.2301.04909,
  title  = {Simple Lyapunov spectrum for linear homogeneous differential equations with Lp parameters},
  author = {Dinis Amaro and Mario Bessa and Helder Vilarinho},
  journal= {arXiv preprint arXiv:2301.04909},
  year   = {2023}
}
R2 v1 2026-06-28T08:10:05.123Z