Search for dissertations about: "symmetry breaking"

Showing result 11 - 15 of 65 swedish dissertations containing the words symmetry breaking.

  2. 11. Ultrafast spin dynamics at the nanoscale : using coherent X-ray and terahertz radiation

    Author : Nanna Zhou Hagström; Stefano Bonetti; Stefan Eisebitt; Ferran Macià Bros; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; XFEL; small-angle X-ray scattering; X-ray holography; ultrafast magnetism; symmetry-breaking; magnetic domains; terahertz; magnetic field enhancement; metamaterial; time-resolved magneto-optical microscope; Physics; fysik;

    Abstract : The field of ultrafast magnetism is driven by the growing need for faster and more efficient magnetic data storage, which comprises the vast majority of the digital information worldwide. However, after more than two decades of intense research, the understanding of the fundamental physical processes governing the transfer of angular momentum necessary for magnetic switching, is still lacking, partially hampered by the appropriate experimental tools. READ MORE

  4. 12. Dissociation dynamics of highly excited molecules: Theory and Experiment

    Author : Shabnam Oghbaie; Synkrotronljusfysik; []
    Keywords : Molecular dissociation; core-electron excitation; double ionization; femtoseconds molecular dynamics; Isomerization; symmetry breaking; momentum imaging; site-selective dissociation; butadiene; cyclopropane; nuclear dynamics; Auger decay;

    Abstract : This thesis presents studies on dissociation of two model molecules: Butadiene and Cyclopropane. Tunable synchrotron radiation was used to ionize or excite the molecules in the gas phase, and the momentum correlation of the resulting fragment ions were measured using a 3D momenta coincident ion spectroscopy. READ MORE

  5. 13. Multi-Meson Dynamics in Chiral Perturbation Theory

    Author : Mattias Sjö; Partikel- och kärnfysik; []
    Keywords : 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;

    Abstract : 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. READ MORE

  6. 14. Breaking the symmetry: creation and transfer of optical activity via total spontaneous resolution and stereoselective reactions

    Author : Susanne Olsson; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; absolute asymmetric synthesis; enantioselective reactions; chirality; spontaneous resolution; conglomerate; organometallic chemistry; coordination compounds; attritionenhanced deracemisation; polymorphism; organolithium compounds; single-crystal X-ray crystallography;

    Abstract : The generation of optical activity from achiral or racemic precursors – absolute asymmetric synthesis – is discussed in relation to the origin of biomolecular homochirality but is also often (incorrectly) regarded as being impossible. One approach to absolute asymmetric synthesis is the use of compounds that form chiral crystals. READ MORE

  7. 15. Quantum electronic transport in low-dimensional semiconductors

    Author : Heiner Linke; Fasta tillståndets fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; quantum transport; two-dimensional electron gas; contact-free characterisation; ballistic transport; mesoscopic; electron billiard; quantum dot; electron-electron interaction; non-linear; phase breaking; Halvledarfysik; Fysicumarkivet A:1997:Linke; non-symmetric conductio; Semiconductory physics; low-dimensional structures;

    Abstract : Electronic transport is studied at low temperatures in two-dimensional electron gases (2DEGs) and in mesoscopic semiconductor microstructures. The method of microwave-detection of the Shubnikov-de Haas effect for the contact-free characterisation of transport properties of 2DEGs is explored using both magnetic-field modulation and light-induced carrier modulation. READ MORE