Sökning: "Spectral measure"

Visar resultat 1 - 5 av 102 avhandlingar innehållade orden Spectral measure.

  1. 1. Asymptotic and universal spectral estimates with applications in many-body quantum mechanics and spectral shape optimization

    Författare :Simon Larson; Ari Laptev; Stefan Steinerberger; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Spectral theory; shape optimization; semiclassical asymptotics; spectral inequalities; quantum mechanics; Mathematics; Matematik;

    Sammanfattning : This thesis consists of eight papers primarily concerned with the quantitative study of the spectrum of certain differential operators. The majority of the results split into two categories. LÄS MER

  3. 2. Titchmarsh-Weyl M-function asymptotics and some results in the inverse spectral theory for vector-valued Sturm-Liouville equations and a certain higher order ordinary differential equation

    Författare :Erik Andersson; Matematik (naturvetenskapliga fakulteten); []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Functions; differential equations; Funktioner; differentialekvationer; Paley-Wiener.; The generalized Fourier transform; A certain higher order ordinary differential equation; Borg-Marchenko theorems; Vector-valued Sturm-Liouville equations; Inverse spectral theory; Titchmarsh-Weyl M-function asymptotics; Asymptotics of solutions; Spectral measure;

    Sammanfattning : This discourse is constituted by two separate reprots, where the first one offers an elementary deduction of the leading order term asymptotics for the Titchmarsh-Weyl M-function corresponding to a vector-valued Sturm-Liouville equation of the form -(PU')'+QU=zu, xin[0,b), with P^{-1},W,Q being hermitean with locally integrable entries; and under some additional conditions on P^{-1} and W. In the special case of P=W=I, we give some further asymptotic results for the same M-function. LÄS MER

  4. 3. On the Military Utility of Spectral Design in Signature Management : a Systems Approach

    Författare :Kent Andersson; Jouko Vankka; Gunnar Hult; Hans Kariis; Hans Liwång; Harold Lawson; Jari Hartikainen; Försvarshögskolan; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; military utility; survivability; signature management; systems engineering; camouflage; Low Observable Technology; spectral design; multi-spectral; Försvarssystem; Military Technology;

    Sammanfattning : There is an ongoing duel between military sensor development and developments in signature management. The last decade, with warfare characterized by joint expeditionary operations and asymmetry, has favored sensors. LÄS MER

  5. 4. The Dirac Operator; From Numerics to the Theory of G-convergence

    Författare :Hasan Almanasreh; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Dirac operator; spuriousity; cubic Hermitian; stability parameter; G-convergence; ¡-convergence; spectral measure; quadratic form; stability parameter;

    Sammanfattning : We consider two main issues concerning the Dirac operator, the first is widely known as the appearance of spurious eigenvalues within the spectrum. The second is the study of the asymptotic behavior of the eigenvalues for a family of Dirac operators with oscillatory potential added to the Coulomb-Dirac Hamiltonian. LÄS MER

  7. 5. 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