Potential Theory for Schrödinger operators on finite networks

Autores: Angeles Carmona Mejías, Enrique Bendito Pérez , A. M. Encinas
Localización: Revista matemática iberoamericana, ISSN 0213-2230, Vol. 21, Nº 3, 2005, págs. 771-818
Idioma: inglés
DOI: 10.4171/rmi/435
Títulos paralelos:
- Teoría del potencial para operadores de Schrödinger en redes finitas.
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Resumen
- We aim here at analyzing the fundamental properties of positive semidefinite Schrödinger operators on networks. We show that such operators correspond to perturbations of the combinatorial Laplacian through 0-order terms that can be totally negative on a proper subset of the network. In addition, we prove that these discrete operators have analogous properties to the ones of elliptic second order operators on Riemannian manifolds, namely the monotonicity, the minimum principle, the variational treatment of Dirichlet problems and the condenser principle. Unlike the continuous case, a discrete Schrödinger operator can be interpreted as an integral operator and therefore a discrete Potential Theory with respect to its associated kernel can be built. We prove that the Schrödinger kernel satisfies enough principles to assure the existence of equilibrium measures for any proper subset. These measures are used to obtain systematic expressions of the Green and Poisson kernels associated with Dirichlet problems.