Search for dissertations about: "non-perturbative theory"

Showing result 1 - 5 of 28 swedish dissertations containing the words non-perturbative theory.

  2. 1. Automorphic forms and string theory: Small automorphic representations and non-perturbative effects

    Author : Henrik Gustafsson; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; instantons; automorphic forms; automorphic representations; Eisenstein series; U-duality; non-perturbative effects; string theory;

    Abstract : This compilation thesis stems from a project with the purpose of determining non-perturbative contributions to scattering amplitudes in string theory carrying important information about instantons, black hole quantum states and M-theory. The scattering amplitudes are functions on the moduli space invariant under the discrete U-duality group and this invariance is one of the defining properties of an automorphic form. READ MORE

  4. 2. Some Aspects of Non-Perturbative Quantum Field Theory

    Author : Joakim Hallin; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Yang-Mills; QED; pair production; density matrix; external field; Schwinger model; gauge invariant; functional representation;

    Abstract : The aim of this thesis is to describe some different ways in which non-perturbative methods enter in quantum field theory. In the thesis such methods enter in 1+1-dimensional theories: various Yang-Mills theories and electrodynamics. It also enters when treating charged bosons or fermions interacting with an external, classical field. READ MORE

  5. 3. Non-Perturbative Quantum Field Theory in Extreme Environments

    Author : Per Liljenberg; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; pair production; Bose-Einstein condensation; functional representation; Schwinger model; external field; boson stars; temperature; magnetisation;

    Abstract : The aim of this thesis is to describe some physical systems which can be treated by non-perturbative methods in quantum field theory. In the thesis we study systems described by quadratic Hamiltonians, possibly extended with an external electromagnetic field and/or with a thermal heat bath. READ MORE

  6. 4. A study of finite-size and non-perturbative effects on the van der Waals and the Casimir-Polder forces

    Author : Thiyam Priyadarshini; Clas Persson; Mathias Boström; Thomas Ederth; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; finite-size effects; non-perturbative theory; van der Waals and Casimir Polder forces; Teknisk materialvetenskap; Materials Science and Engineering;

    Abstract : This licentiate thesis addresses two important aspects of the van der Waals and the Casimir-Polder ground-state and excited-state (resonance) interactions between two atoms or molecules. The first is the finite-size effect and the second is the non-perturbative effect. READ MORE

  7. 5. Aspects of Yang-Mills Theory : Solitons, Dualities and Spin Chains

    Author : Lisa Freyhult; Antti Niemi; Poul Damgaard; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Theoretical physics; Theoretical Physics; Field theory; String theory; Yang-Mills; Effective models; Supersymmetry; Solitons; Fermion number; Duality; AdS CFT correspondence; Bethe ansatz; Teoretisk fysik; Physics; Fysik;

    Abstract : One of the still big problems in the Standard Model of particle physics is the problem of confinement. Quarks or other coloured particles have never been observed in isolation. Quarks are only observed in colour neutral bound states. The strong interactions are described using a Yang-Mills theory. READ MORE