English

Reflectionless operators and automorphic Herglotz functions

Spectral Theory 2024-12-17 v1 Mathematical Physics math.MP

Abstract

I am interested in canonical systems and Dirac operators that are reflectionless on an open set. In this situation, the half line mm functions are holomorphic continuations of each other and may be combined into a single function. By passing to the universal cover of its domain, we then obtain a one-to-one correspondence of these operators with Herglotz functions that are automorphic with respect to the Fuchsian group of covering transformations. I investigate the properties of this formalism, with particular emphasis given to the measures that are automorphic in a corresponding sense. This will shed light on the reflectionless operators as a topological space, on their extreme points, and on how the heavily studied smaller space of finite gap operators sits inside the (much) larger space.

Keywords

Cite

@article{arxiv.2412.10992,
  title  = {Reflectionless operators and automorphic Herglotz functions},
  author = {Christian Remling},
  journal= {arXiv preprint arXiv:2412.10992},
  year   = {2024}
}
R2 v1 2026-06-28T20:35:31.656Z