Spectrum preserves on unbounded operators

SEMINARIO DE ANÁLISIS FUNCIONAL

Conferenciante: Prof. Bojan Kuzma (University of Primorska, Eslovenia)

Abstract: Unbounded, densely defined, closed operators are encountered in quantum physics when solving linear second-order partial differential equation with the method of variable separation (Sturm-Liouville problem) and as generators of strongly continuous one-parameter semigroups. Particularly important is their spectrum. We will present a recent result that classifies additive bijections preserving the spectrum of such operators and compare it to the classification of spectrum-preserving maps whose domain consists of all unbounded operators.