Sökning: "Schwinger model"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Schwinger model.

  1. 1. Two-dimensional antiferromagnetism : from Schwinger bosons to spin waves

    Författare :Ann Mattsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; honeycomb lattice; antiferromagnet; Heisenberg model;

    Sammanfattning : .... LÄS MER

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

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

    Sammanfattning : 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. LÄS MER

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

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

    Sammanfattning : 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. LÄS MER

  5. 4. Reliable hp finite element computations of scattering resonances in nano optics

    Författare :Juan Carlos Araujo-Cabarcas; Christian Engström; David Cohen; Mats G. Larson; Jeffrey Ovall; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Scattering resonances; Helmholtz problems; pseudospectrum; Lippmann-Schwinger equation; finite element methods; nonlinear eigenvalue problems; spurious solutions;

    Sammanfattning : Eigenfrequencies are commonly studied in wave propagation problems, as they are important in the analysis of closed cavities such as a microwave oven. For open systems, energy leaks into infinity and therefore scattering resonances are used instead of eigenfrequencies. LÄS MER

  7. 5. Modelling and analyzing strong-field effects in quantum plasma

    Författare :Haidar Al-Naseri; Gert Brodin; Jens Zamanian; J. Tito Mendonca; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Plasma physics; Strong-field physics; Kinetic theory; Quantum plasma; fysik; Physics;

    Sammanfattning : Under the extreme conditions that can be found around dense stars and in the accretion discs of black holes, several strong-field quantum phenomena dominate the dynamics of the plasma. This includes the creation of matter and anti-matter from the vacuum (Schwinger mechanism), radiation reaction and Landau quantization. LÄS MER