Sökning: "Fawad Hassan"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Fawad Hassan.

  1. 1. Computation of constraints in bimetric theory

    Författare :Anders Lundkvist; Fawad Hassan; Edwin Langmann; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; teoretisk fysik; Theoretical Physics;

    Sammanfattning : The Hassan-Rosen bimetric theory describes two interacting spin-2 fields, one massless and one massive. In this thesis, a complete canonical analysis of this theory is performed in the metric formulation and all constraints are computed. LÄS MER

  3. 2. Constraints and symmetries in theories of interacting spin-2 fields

    Författare :Anders Lundkvist; Fawad Hassan; Edvard Mörtsell; Antonio Padilla; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; modified gravity; bimetric theory; spin-2 fields; classical field theory; partially massless symmetry; teoretisk fysik; Theoretical Physics;

    Sammanfattning : The Hassan-Rosen bimetric theory describes two interacting spin-2 fields, one massless and one massive. In this thesis, a complete canonical analysis of this theory is performed in the metric formulation and all constraints are computed. LÄS MER

  4. 3. Beyond Bimetric Theory: Consistent Theories of Multiple Spin-2 Fields

    Författare :Joakim Flinckman; Fawad Hassan; Florian Niedermann; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Theoretical Physics; teoretisk fysik;

    Sammanfattning : The mathematical formulations of the fundamental interactions in nature are all expressed in terms of fields classified by their mass and spin. Two of the most successful theories in physics, general relativity and the standard model, can both, in principle, be derived uniquely from fields with fixed mass and spin, guided by theoretical considerations such as consistency. LÄS MER

  5. 4. Geometry of interactions in ghost-free bimetric theory

    Författare :Mikica Kocic; Sayed Fawad Hassan; Tomi Koivisto; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Modified gravity; Interacting spin-2 fields; Bimetric theory; Massive gravity; teoretisk fysik; Theoretical Physics;

    Sammanfattning : The ghost-free bimetric theory is an extension to general relativity where two metric tensors are used instead of one. A priori, the two metrics may not have compatible notions of space and time, which makes the formulation of the initial-value problem problematic. LÄS MER

  7. 5. Interpretation of gamma-ray burst X-ray and optical afterglow emission : From the central engine to the circumburst interaction

    Författare :Liang Li; Felix Ryde; Fawad Hassan; Kim Page; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; gamma-ray bursts; central engine; afterglow; teoretisk fysik; Theoretical Physics;

    Sammanfattning : Gamma-ray bursts are the largest electromagnetic explosions known to happen in the Universe and are associated with the collapse of stellar progenitors into blackholes. After an energetic prompt emission phase, lasting typically less than a minute and emitted in the gamma-rays, a long-lived afterglow phase starts. LÄS MER