Search for dissertations about: "string backgrounds"
Showing result 1  5 of 10 swedish dissertations containing the words string backgrounds.

1. String Theory at the Horizon Quantum Aspects of Black Holes and Cosmology
University dissertation from Uppsala : Institutionen för teoretisk fysikAbstract : String theory is a unified framework for general relativity and quantum mechanics, thus being a theory of quantum gravity. In this thesis we discuss various aspects of quantum gravity for particular systems, having in common the existence of horizons. READ MORE

2. Vacua in String Theory de Sitter Space and Stability in Flux Compactifications
University dissertation from Uppsala : Acta Universitatis UpsaliensisAbstract : 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

3. Tensionless Strings and Supersymmetric Sigma Models Aspects of the Target Space Geometry
University dissertation from Uppsala : Acta Universitatis UpsaliensisAbstract : In this thesis, two aspects of string theory are discussed, tensionless strings and supersymmetric sigma models.The equivalent to a massless particle in string theory is a tensionless string. Even almost 30 years after it was first mentioned, it is still quite poorly understood. READ MORE

4. Strings as Sigma Models and in the Tensionless Limit
University dissertation from Uppsala : Acta Universitatis UpsaliensisAbstract : This thesis considers two different aspects of string theory, the tensionless limit of the string and supersymmetric sigma models with extended supersymmetry. First, the tensionless limit is used to find a IIB supergravity background generated by a tensionless string. The background has the characteristics of a gravitational shockwave. READ MORE

5. Strings, Branes and Nontrivial Spacetimes
University dissertation from Karlstad : Karlstad UniversityAbstract : This thesis deals with different aspects of string and /p/brane theories. One of the motivations for string theory is to unify the forces in nature and produce a quantum theory of gravity. /p/branes and related objects arise in string theory and are related to a nonperturbative definition of the theory. READ MORE