Sökning: "Spectral stability"

Visar resultat 1 - 5 av 74 avhandlingar innehållade orden Spectral stability.

  1. 1. Spectral Inequalities and Their Applications in Quantum Mechanics

    Författare :Fabian Portmann; Ari Laptev; Robert Seiringer; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Spectral inequalities; quantum mechanics; Hardy inequalities; Sobolev inequalities; Lieb-Thirring inequalities; stability of matter; Bose gases; Bose-Einstein condensation; Matematik; Mathematics; Physics; Fysik;

    Sammanfattning : The work presented in this thesis revolves around spectral inequalities and their applications in quantum mechanics.In Paper A, the ground state energy of an atom confined to two dimensions is analyzed in the limit when the charge of the nucleus Z becomes very large. LÄS MER

  2. 2. Stability results for viscous shock waves and plane Couette flow

    Författare :Mattias Liefvendahl; KTH; []
    Nyckelord :nonlinear stability; shock waves; Couette flow; Chebyshev spectral method; resolvent estimates; threshold amplitudes;

    Sammanfattning : .... LÄS MER

  3. 3. The Effect of Different Perturbations on the Stability Analysis of Light Water Reactors

    Författare :Victor Dykin; Chalmers University of Technology; []
    Nyckelord :NATURVETENSKAP; TEKNIK OCH TEKNOLOGIER; NATURAL SCIENCES; ENGINEERING AND TECHNOLOGY; BWR and PWR stability; stability indicators; propagating density perturbation; autocorrelation function; density wave oscillations; decay ratio; non-white driving force; damped harmonic oscillator; reduced order models; Green s function technique;

    Sammanfattning : Neutron noise analysis techniques are studied and developed, with primary useof determining the stability of Boiling Water Reactors (BWRs). In particular, the role ofa specific perturbation prevailing in Light Water Reactors, the propagating densityperturbation, in the stability of BWRs and on the noise field of LWRs in general, isinvestigated by considering three topics. LÄS MER

  4. 4. Global stability analysis of three-dimensional boundary layer flows

    Författare :Mattias Brynjell-Rahkola; Dan Henningson; Philipp Schlatter; Ardeshir Hanifi; Spencer Sherwin; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hydrodynamic stability; transition to turbulence; global analysis; boundary layers; roughness; laminar flow control; Stokes Laplace preconditioner; optimal forcing; crossflow vortices; Ginzburg-Landau; Falkner-Skan-Cooke; Blasius; lid-driven cavity;

    Sammanfattning : This thesis considers the stability and transition of incompressible boundary layers. In particular, the Falkner–Skan–Cooke boundary layer subject to a cylindrical surface roughness, and the Blasius boundary layer with applied localized suction are investigated. LÄS MER

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

    Författare :Hasan Almanasreh; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Nyckelord :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