Search for dissertations about: "pseudospectrum"

Found 2 swedish dissertations containing the word pseudospectrum.

  1. 1. Non-selfadjoint operator functions

    University dissertation from Umeå : Umeå universitet

    Author : Axel Torshage; Christian Engström; Marco Marletta; [2017]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Non-linear spectral problem; numerical range; pseudospectrum; resolvent estimate; equivalence after extension; block operator matrices; operator functions; operator pencil; spectral divisor; joint numerical range; Mathematics; matematik;

    Abstract : Spectral properties of linear operators and operator functions can be used to analyze models in nature. When dispersion and damping are taken into account, the dependence of the spectral parameter is in general non-linear and the operators are not selfadjoint. READ MORE

  2. 2. Reliable hp finite element computations of scattering resonances in nano optics

    University dissertation from Umeå : Umeå Universitet

    Author : Juan Carlos Araujo-Cabarcas; Christian Engström; David Cohen; Mats G. Larson; Jeffrey Ovall; [2019]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Scattering resonances; Helmholtz problems; pseudospectrum; Lippmann-Schwinger equation; finite element methods; nonlinear eigenvalue problems; spurious solutions;

    Abstract : Eigenfrequencies are commonly studied in wave propagation problems, as they are important in the analysis of closed cavities such as a microwave oven. For open systems, energy leaks into infinity and therefore scattering resonances are used instead of eigenfrequencies. READ MORE