Search for dissertations about: "quantum field theory"

Showing result 11 - 15 of 234 swedish dissertations containing the words quantum field theory.

  2. 11. 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

  4. 12. 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. 13. Quantum Transport Theory in Graphene

    Author : Anders Bergvall; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; quantum coherent electron transport; nanoribbons; FT-LDOS; grain boundaries; tight-binding; graphene;

    Abstract : In this thesis, we focus on different aspects of electron transport in nanostructured graphene (such as graphene nanoribbons). Wedevelop and implement numerical methods to study quantum coherent electron transport on an atomistic level, complemented by analytical calculations based on the Dirac approximation valid close to the points $\vec{K}$ and $\vec{K}^\prime$ in the graphene Brillouin zone. READ MORE

  6. 14. Quantum Chemical Interpretation of Protein Crystal Structure

    Author : Kristina Nilsson; Beräkningskemi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; structure; Theoretical chemistry; quantum chemistry; Teoretisk kemi; kvantkemi; protein; ComQum-X; Hess2FF; QM MM; hetero-compound; metal; oxidation state; protonation; force field; quantum refinement; refinement;

    Abstract : An initial model in the crystallographic structure determination process, usually contains many errors. To produce an accurate model, one must carry out several cycles of crystallographic refinement. READ MORE

  7. 15. Holographic Wilson Loops : Quantum String Corrections

    Author : Daniel Ricardo Medina Rincon; Konstantin Zarembo; Gianluca Grignani​; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Gauge-string correspondence; AdS CFT; Wilson loops; String theory; Theoretical Physics; Teoretisk fysik;

    Abstract : The gauge-string duality has been one of the most exciting areas in theoretical physics as it connects strongly coupled field theories with weakly interacting strings. The present thesis concerns the study of Wilson loops in this correspondence. READ MORE