The spectrum of free Schrödinger operators at the half space with boundary condition ( being the normal derivative, a self-adjoint operator at the boundary) is investigated and a connection between its negative part and the spectrum of a family of Klein–Gordon type operators is stated.
Cite this article
Manfred Schröder, On the Spectrum of Schrödinger Operators at the Half Space with a Certain Class of Boundary Conditions. Z. Anal. Anwend. 7 (1988), no. 3, pp. 233–239