Sökning: "scattering poles"

Hittade 5 avhandlingar innehållade orden scattering poles.

  1. 1. Inverse scattering and distribution of resonances on the real line

    Författare :Michael Hitrik; Matematik LTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; scattering poles; reflection coefficient; Schrödinger operator; inverse scattering; Matematik;

    Sammanfattning : We study aspects of scattering theory for the Schrödinger operator on the real line. In the first part of the thesis we consider potentials supported by a half-line, and we are interested in the inverse problem of reconstruction of the potential from the knowledge of values of the reflection coefficient at equidistributed points on the positive imaginary axis. LÄS MER

  2. 2. Ways of determining and characterising resonances in scattering processes

    Författare :Ksenia Shilyaeva; Nils Elander; Dage Sundholm; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum scattering theory; complex scaling; resonances; Molecular physics; Molekylfysik; fysik; Physics;

    Sammanfattning : Scattering cross sections very often display structures. To clarify if these structures correspond to resonances one has to check if they are poles of the scattering matrix (S-matrix) in the fourth quadrant of the complex momentum plane. Furthermore, the states corresponding to these poles also need to have an appropriate scattering amplitude. LÄS MER

  3. 3. Elastic Wave Scattering by Closed Cracks and Thin Flaws - Multiple Scattering and Resonances

    Författare :Arne S. Eriksson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; SH-wave; evaluation of materials; direct integral equation; singularity expansion; ultrasonic testing;

    Sammanfattning : In this thesis we study elastic wave scattering by thin flaws and closed cracks, which finds applications in ultrasonic testing and evaluation of materials. First we consider the scattering of an SH-wave by a thin finite elastic layer between two elastic half-spaces. LÄS MER

  4. 4. Effective Field Theory for QCD-like Theories and Constraints on the Two Higgs Doublet Model

    Författare :Jie Lu; Teoretisk partikelfysik - Geonomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; QCD-like; effective field theory; symmetry breaking; renormalization group; two Higgs doublet model;

    Sammanfattning : This thesis includes two topics.The first three papers is the major part of this thesis, which is about higher order calculations in the effective field theories of three QCD-like theories. These three QCD-like theories are distinguished by having quarks in a complex, real or pseudo-real representation of gauge group. LÄS MER

  5. 5. Analysis of Planar and Circular Cylindrical Multilayer Structures with Application to Soft and Hard Surfaces

    Författare :Zvonimir Sipus; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; antennas; periodic surfaces; integral equations; approximate boundary conditions; soft and hard surfaces; Green s functions; corrugated surfaces; moment method; periodic metal strips; multilayer structures; EFIE; microstrip antennas; spectral domain analysis; group representation theory; strip scatterers;

    Sammanfattning : This thesis deals with the analysis of planar and circular cylindrical multilayer structures, such as strip-loaded dielectric layers, corrugated surfaces and microstrip antennas. In particular, we study corrugations and strip-loaded grounded dielectric slabs when they are used to realize soft and hard surfaces. LÄS MER