English

Operator E-norms and their use

Functional Analysis 2021-09-28 v6 Mathematical Physics math.MP Operator Algebras Quantum Physics

Abstract

We consider a family of norms (called operator E-norms) on the algebra B(H)B(H) of all bounded operators on a separable Hilbert space HH induced by a positive densely defined operator GG on HH. Each norm of this family produces the same topology on B(H)B(H) depending on GG. By choosing different generating operator GG one can obtain operator E-norms producing different topologies, in particular, the strong operator topology on bounded subsets of B(H)B(H). We obtain a generalised version of the Kretschmann-Schlingemann-Werner theorem, which shows continuity of the Stinespring representation of CP linear maps w.r.t. the energy-constrained cbcb-norm (diamond norm) on the set of CP linear maps and the operator E-norm on the set of Stinespring operators. The operator E-norms induced by a positive operator GG are well defined for linear operators relatively bounded w.r.t. the operator G\sqrt{G} and the linear space of such operators equipped with any of these norms is a Banach space. We obtain explicit relations between the operator E-norms and the standard characteristics of G\sqrt{G}-bounded operators. The operator E-norms allow to obtain simple upper bounds and continuity bounds for some functions depending on G\sqrt{G}-bounded operators used in applications.

Keywords

Cite

@article{arxiv.1806.05668,
  title  = {Operator E-norms and their use},
  author = {M. E. Shirokov},
  journal= {arXiv preprint arXiv:1806.05668},
  year   = {2021}
}

Comments

31 pages, in v.5 essential improvements and simplifications have been made by using the coincidence of two definitions of the operator E-norms proved in arXiv:2002.03969

R2 v1 2026-06-23T02:30:29.344Z