Search for dissertations about: "string compactifications"

Showing result 1 - 5 of 13 swedish dissertations containing the words string compactifications.

  2. 1. Vacua in String Theory : de Sitter Space and Stability in Flux Compactifications

    Author : Sergio C. Vargas; Ulf Danielsson; Alessandro Tomasiello; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; String theory; Cosmology; Flux Compactifications; Landscape; Swampland;

    Abstract : Our understanding of cosmology has evolved radically in the last decades. Current models demand the presence of dark energy in our universe and the most favored candidate behind this component is a small positive cosmological constant that characterizes a de Sitter (dS) spacetime. READ MORE

  4. 2. Cosmoparticle Physics and String Theory

    Author : Stefan Sjörs; Marcus Berg; Joseph Conlon; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Supersymmetry; dark matter; cosmology; inflation; modifications of gravity; string theory; flux compactifications; perturbative string theory; teoretisk fysik; Theoretical Physics;

    Abstract : This thesis deals with phenomenological and theoretical aspects of cosmoparticle physics and string theory. There are many open questions in these topics. In connection with cosmology we would like to understand the detailed properties of dark matter, dark energy, generation of primordial perturbations, etc. READ MORE

  5. 3. Automorphic string amplitudes

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

    Abstract : This thesis explores the non-perturbative properties of higher derivative interactions appearing in the low-energy expansion of four-graviton scattering amplitudes in toroidal compactifications of type IIB string theory. We summarise the arguments for finding such higher derivative corrections in terms of automorphic forms using U-duality, supersymmetry and string perturbation theory. READ MORE

  6. 4. Pierced, Wrapped and Torn : Aspects of String Theory Compactifications

    Author : Magdalena Larfors; Ulf Danielsson; Gary Shiu; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematical physics; Matematisk fysik; Theoretical Physics; teoretisk fysik;

    Abstract : An outstanding problem in physics is to find a unified framework for quantum mechanics and general relativity. This is required for a better understanding of black holes and the early cosmology of the universe. String theory provides such a unification. In this thesis, we study aspects of compactifications of type IIB string theory. READ MORE

  7. 5. Aspects of vacuum moduli in string theory

    Author : Matthew Magill; Magdalena Larfors; James Sparks; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; string compactifications; g structures; homological algebra; Theoretical Physics; Teoretisk fysik;

    Abstract : In this thesis we explore geometric aspects of the space of vacua in supersymmetric string compactifications. More specifically, we will look at heterotic strings compactified on Calabi-Yau manifolds and, separately, G2 structure manifolds. READ MORE