Lyapunov exponents of the Schrödinger equation with quasi-periodic potential on a strip
The authors prove that all the non-negative Lyapunov exponents of the difference Schrödinger equation \(-y_{n+1}+Q_ ny_ n-y_{n-1}=0\) \(-\infty<n<+\infty\) are strictly positive. Here \(y_ n\in R^ m\) and \(Q_ n\) is a symmetric \(m\times m\) matrix whose off-diagonal elements do not depend on \(n\), and the diagonal elements are quasiperiodic functions.
scientific article; zbMATH DE number 61986