Search for dissertations about: "Quantum Chromodynamics"

Showing result 6 - 10 of 20 swedish dissertations containing the words Quantum Chromodynamics.

  2. 6. Maximal Unitarity at Two Loops : A New Method for Computing Two-Loop Scattering Amplitudes

    Author : Kasper J. Larsen; Lisa Freyhult; David Kosower; Joseph Minahan; Paul Heslop; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Amplitudes; NNLO calculations; Quantum Chromodynamics; Unitarity; Fysik med inriktning mot elementarpartikelfysik; Physics with specialization in Elementary Particle Physics;

    Abstract : The study of scattering amplitudes beyond one loop is necessary for precision phenomenology for the Large Hadron Collider and may also provide deeper insights into the theoretical foundations of quantum field theory. In this thesis we develop a new method for computing two-loop amplitudes, based on unitarity rather than Feynman diagrams. READ MORE

  4. 7. Defects, renormalization and conformal field theory

    Author : Alexander Söderberg Rousu; Agnese Bissi; Pedro Liendo; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; defects; boundaries; replica twist defect; conformal field theory; quantum field theory; Coleman-Weinberg mechanism; renormalization group flows; Theoretical Physics; Teoretisk fysik;

    Abstract : Defects in quantum field theories appear in many different contexts and are of great physical interest. Among other things, defects are used to describe the Kondō effect in condensed matter, confinement in quantum chromodynamics, Rényi entropy in quantum information and cosmic strings in string theory. READ MORE

  5. 8. 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. 9. Shout at the eta

    Author : Mårten Stenmark; Göran Fäldt; Colin Wilkin; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Nuclear physics; Theoretical physics; Meson production; Noncommutative geometry; Kärnfysik; Nuclear physics; Kärnfysik;

    Abstract : Quantum chromodynamics has interesting limits both in the low and the high-energy region. In the low energy region one has phenomenology of meson interactions which are still not clearly understood. READ MORE

  7. 10. Hot and Dense Gauge Theories with External Fields

    Author : David Persson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In the introductory part of this thesis, I briefly review quantum statistichal mechanics; quantum field theory with external fields; the real and imaginary time formalisms in thermal field theory; and the hard thermal loop resummation. In the second part, consisting of here reprinted research articles, we apply this to quantum electrodynamics and quantum chromodynamics with a background (chromo-) magnetic field in the presence of a heat and charge reservoir. READ MORE