English

The original Weyl-Titchmarsh functions and sectorial Shr\"odinger L-systems

Spectral Theory 2023-06-14 v2 Mathematical Physics math.MP

Abstract

In this paper we study the L-system realizations generated by the original Weyl-Titchmarsh functions mα(z)m_\alpha(z) in the case when the minimal symmetric Shr\"o\-dinger operator in L2[,+)L_2[\ell,+\infty) is non-negative. We realize functions (mα(z))(-m_\alpha(z)) as impe\-dance functions of Shr\"odinger L-systems and derive necessary and sufficient conditions for (mα(z))(-m_\alpha(z)) to fall into sectorial classes Sβ1,β2S^{\beta_1,\beta_2} of Stieltjes functions. Moreover, it is shown that the knowledge of the value m(0)m_\infty(-0) and parameter α\alpha allows us to describe the geometric structure of the L-system that realizes (mα(z))(-m_\alpha(z)). Conditions when the main and state space operators of the L-system realizing (mα(z))(-m_\alpha(z)) have the same or not angle of sectoriality are presented in terms of the parameter α\alpha. Example that illustrates the obtained results is presented in the end of the paper.

Cite

@article{arxiv.2012.08069,
  title  = {The original Weyl-Titchmarsh functions and sectorial Shr\"odinger L-systems},
  author = {Sergey Belyi and Eduard Tsekanovskii},
  journal= {arXiv preprint arXiv:2012.08069},
  year   = {2023}
}

Comments

16 pages, 2 figures. arXiv admin note: substantial text overlap with arXiv:2006.13045, arXiv:1709.07370

R2 v1 2026-06-23T20:58:36.806Z