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Showing result 1 - 5 of 8 swedish dissertations matching the above criteria.

  2. 1. Gravitational collapse in bimetric gravity

    Author : Marcus Högås; Edvard Mörtsell; Tomi Koivisto; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Bimetric gravity; bigravity; modified gravity; gravitational collapse; Bimetrisk gravitation; modifierad gravitation; gravitationskollaps; teoretisk fysik; Theoretical Physics;

    Abstract : Einstein’s theory of general relativity has been the prevailing theory of classical gravity for over a century. Its observational consistency is unparalleled. There are however a few (arguably) serious short-comings. READ MORE

  4. 2. Was Einstein Wrong? : Theoretical and observational constraints on massive gravity

    Author : Marcus Högås; Edvard Mörtsell; David Mota; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Gravity; Massive gravity; Bimetric gravity; Cosmology; Gravitational collapse; Gravitational waves; Observational constraints; Theoretical Physics; teoretisk fysik;

    Abstract : For more than a century, Einstein's theory of general relativity has described gravitational phenomena with astonishing precision. However, for the theory to fit observations we need to add two elusive substances: dark energy and dark matter. Together they add up to 95% of the energy budget of the Universe. READ MORE

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

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

    Abstract : 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. READ MORE

  6. 4. Strings, Gravitons, and Effective Field Theories

    Author : Igor Buchberger; Marcus Berg; Joseph A. Minahan; Karlstads universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; string theory; amplitudes; supersymmetry; particle phenomenology; BMSSM; modified gravity; bimetric; massive gravity; Lie algebras; ribbon categories; Physics; Fysik;

    Abstract : This thesis concerns a range of aspects of theoretical physics. It is composed of two parts. In the first part we motivate our line of research, and introduce and discuss the relevant concepts. In the second part, four research papers are collected. READ MORE

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

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

    Abstract : 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. READ MORE