A note on reflectionless Jacobi matrices

TL;DR

This paper introduces a new characterization of reflectionless Jacobi matrices using stationary scattering theory, proving its equivalence to existing definitions and connecting it to non-equilibrium statistical mechanics.

Contribution

It provides a novel characterization of reflectionless Jacobi matrices via scattering theory, linking it to dynamical reflectionlessness and applications in statistical mechanics.

Findings

New characterization in terms of scattering theory

Equivalence to classical Weyl and resolvent conditions

Application to non-equilibrium statistical mechanics

Abstract

The property that a Jacobi matrix is reflectionless is usually characterized either in terms of Weyl m-functions or the vanishing of the real part of the boundary values of the diagonal matrix elements of the resolvent. We introduce a characterization in terms of stationary scattering theory (the vanishing of the reflection coefficients) and prove that this characterization is equivalent to the usual ones. We also show that the new characterization is equivalent to the notion of being dynamically reflectionless, thus providing a short proof of an important result of [Breuer-Ryckman-Simon]. The motivation for the new characterization comes from recent studies of the non-equilibrium statistical mechanics of the electronic black box model and we elaborate on this connection. To appear in Commun. Math. Phys.