Sökning: "perturbation-theory"

Visar resultat 6 - 10 av 97 avhandlingar innehållade ordet perturbation-theory.

  1. 6. Multi-Meson Dynamics in Chiral Perturbation Theory

    Författare :Mattias Sjö; Partikel- och kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Spridningsamplituder; Effektiv Fältteori; Spontant symmetribrott; Ickelinjära sigmamodellen; Kirala Lagrangianer; Hadronspektroskopi; Strukturer och Interaktioner; Gitter-QCD; Scattering amplitudes; Effective Field Theories; Spontaneous Symmetry Breaking; Nonlinear sigma model; Chiral Lagrangians; Hadronic Spectroscopy; Structure and Interactions; Lattice QCD;

    Sammanfattning : This thesis concerns scattering of light mesons in the case where the number of external particles exceeds four (that is, three or more particles in the initial or final state), calculated using chiral perturbation theory.This is both of theoretical interest in the study of scattering amplitudes, and relevant for systems of three or more pions simulated using lattice quantum chromodynamics. LÄS MER

  3. 7. Soft and Hard Mesons in Chiral Perturbation Theory

    Författare :Ilaria Jemos; Teoretisk partikelfysik - Geonomgår omorganisation; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis deals with Chiral Perturbation Theory (ChPT), an effective field theory for the strong force used to describe meson interactions. The work done can be split in two parts. The first one is on ChPT in its standard formulation. This theory has been very successful so far in describing low energetic processes. LÄS MER

  4. 8. Towards a relativistically covariant many-body perturbation theory - With numerical implementation to helium-like ions

    Författare :Daniel Hedendahl; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; many-body perturbation theory; bound state QED; helium-like ions; Green s operator; covariant evolution operator; combined effects of QED and correlation; atomic structure calculations;

    Sammanfattning : The experimental results for simple atomic systems have become more and more accurate and in order to keep up with the experimental achievements the theoretical procedures have to be refined. Recent accurate experimental results obtained for helium-like ions in the low- and moderate-Z regions proclaim the importance of theoretical calculations that combines relativistic, QED and electron correlation effects. LÄS MER

  5. 9. Modeling of intra- and intermolecular potentials

    Författare :Stevica Brdarski; Beräkningskemi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Theoretical chemistry; N-formylglycinamide; formamide; water dimer; quantum chemistry; molecular dynamics simulations; repulsion modeling; perturbation theory; NEMO; molecular interactions; Teoretisk kemi; kvantkemi;

    Sammanfattning : Modeling of interactions between molecules is investigated by theoretical means within the NEMO model. The model is based on a partitioning of the interaction energy at the Hartree-Fock level into first- and second-order perturbation theory. The interaction energy is given as a sum of electrostatic, induction, repulsion, and dispersion energies. LÄS MER

  7. 10. Simulation of Irregular Waves and Wave Induced Loads on Wind Power Plants in Shallow Water

    Författare :Jenny Trumars; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wave load; Non-linear wave models; ocean engineering; wind energy converter; perturbation theory; shallow water;

    Sammanfattning : The essay gives a short introduction to waves and discusses the problem with non-linear waves in shallow water and how they effect an offshore wind energy converter. The focus is on the realisation of non-linear waves in the time domain from short-term statistics in the form of a variance density spectrum of the wave elevation. LÄS MER