Sökning: "Supergravity Backgrounds"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Supergravity Backgrounds.

1. 1. Supersymmetric Geometries in Type IIA Supergravity

   Författare :Christian von Schultz; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Flux compactifications; Supergravity; Supersymmetry; Superstring vacua;

   Sammanfattning : Supergravity theory is any supersymmetric theory with a local supersymmetry parameter. This thesis undertakes the study of type IIA supergravity, a supergravity theory in ten dimensions associated with type IIA string theory. LÄS MER

3. 2. Tensionless Strings and Supersymmetric Sigma Models : Aspects of the Target Space Geometry

   Författare :Andreas Bredthauer; Ulf G. Lindström; Bengt E.W. Nilsson; Uppsala universitet; []
   Nyckelord :Theoretical physics; Theoretical Physics; String Theory; Tensionless Strings; Supergravity Backgrounds; Plane Wave; Supersymmetry; Non-linear Sigma Models; Generalized Complex Geometry; Teoretisk fysik;

   Sammanfattning : 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. LÄS MER

4. 3. Strings as Sigma Models and in the Tensionless Limit

   Författare :Jonas Persson; Ulf Lindström; Joseph Minahan; Fawad Hassan; Uppsala universitet; []
   Nyckelord :Theoretical physics; Theoretical Physics; String Theory; Tensionless Strings; Supergravity Backgrounds; Plane Wave; Extended Supersymmetry; Non-Linear Sigma Models; Generalized Complex Geometry; T-duality; Teoretisk fysik;

   Sammanfattning : 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 shock-wave. LÄS MER

5. 4. Aspects of vacuum moduli in string theory

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

   Sammanfattning : 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. LÄS MER

7. 5. Vacua in String Theory : de Sitter Space and Stability in Flux Compactifications

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

   Sammanfattning : 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. LÄS MER