Sökning: "Spectral estimates"

Visar resultat 6 - 10 av 81 avhandlingar innehållade orden Spectral estimates.

  1. 6. Spectral estimates for the magnetic Schrödinger operator and the Heisenberg Laplacian

    Författare :Anders Hansson; Ari Laptev; B Malcolm Brown; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; spectral theory; Schrödinger operator; magnetic field; Aharonov-Bohm; Lieb-Thirring; diamagnetic inequality; Heisenberg group; Heisenberg Laplacian; hypoelliptic; spektralteori; Schrödingeroperator; magnetfält; Aharonov-Bohm; Lieb-Thirring; diamagnetisk olikhet; Heisenberggrupp; Heisenberg-Laplace-operator; hypoelliptisk; MATHEMATICS; MATEMATIK;

    Sammanfattning : I denna avhandling, som omfattar fyra forskningsartiklar, betraktas två operatorer inom den matematiska fysiken. De båda tidigare artiklarna innehåller resultat för Schrödingeroperatorn med Aharonov-Bohm-magnetfält. LÄS MER

  3. 7. Resolvent Estimates and Bounds on Eigenvalues for Schrödinger and Dirac Operators

    Författare :Alexandra Enblom; Vladimir Kozlov; Ari Laptev; David Krejcirik; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Spectral theory; Schrödinger operators; polyharmonic operators; Dirac operators; non-self-adjoint perturbations; complex potential; estimation of eigenvalues; Carleman inequalities; Hardy inequalities;

    Sammanfattning : This thesis concerns the spectral theory of Schrödinger and Dirac operators. The main results relate to the problems of estimating perturbed eigenvalues. The thesis is based on four papers.The first paper focuses on the problem of localization of perturbed eigenvalues for multidimensional Schrödinger operators. LÄS MER

  4. 8. Inverse Problems in Analytic Interpolation for Robust Control and Spectral Estimation

    Författare :Johan Karlsson; Anders Lindquist; Alberto Isidori; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nevanlinna-Pick Interpolation; Approximation; Model Reduction; Robust Control; Gap-robustness; Sensitivity Shaping; Entropy functional; Spectral Estimation; Weak*-topology; Monge-Kantorovic Transportation; Optimization; systems theory; Optimeringslära; systemteori;

    Sammanfattning : This thesis is divided into two parts. The first part deals with theNevanlinna-Pick interpolation problem, a problem which occursnaturally in several applications such as robust control, signalprocessing and circuit theory. We consider the problem of shaping andapproximating solutions to the Nevanlinna-Pick problem in a systematicway. LÄS MER

  5. 9. Group-Sparse Regression : With Applications in Spectral Analysis and Audio Signal Processing

    Författare :Ted Kronvall; Statistical Signal Processing Group; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; sparse regression; group-sparsity; statistical modeling; regularization; hyperparameter-selection; spectral analysis; audio signal processing; classification; localization; multi-pitch estimation; chroma; convex optimization; ADMM; cyclic coordinate descent; proximal gradient;

    Sammanfattning : This doctorate thesis focuses on sparse regression, a statistical modeling tool for selecting valuable predictors in underdetermined linear models. By imposing different constraints on the structure of the variable vector in the regression problem, one obtains estimates which have sparse supports, i.e. LÄS MER

  7. 10. Some Resolvent Estimates in Harmonic Analysis

    Författare :Anders Dahlner; Matematik (naturvetenskapliga fakulteten); []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; field theory; Number Theory; algebra; algebraic geometry; Talteori; group theory; Tauberian theorem. Quantitative inversion. Cesaro operator. Bishops property beta.; algebraisk geometri; fältteori; gruppteori;

    Sammanfattning : This thesis contains three papers about three different estimates of resolvents in harmonic analysis. These papers are: Paper 1. ``A Wiener tauberian theorem for weighted convolution algebras of zonal functions on the automorphism group of the unit disc'' Paper 2. ``Uniform spectral radius and compact Gelfand transform'' Paper 3. LÄS MER