Sökning: "Non-Linear Sigma Models"
Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Non-Linear Sigma Models.
1. Tensionless Strings and Supersymmetric Sigma Models : Aspects of the Target Space Geometry
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
2. The Complex World of Superstrings : On Semichiral Sigma Models and N=(4,4) Supersymmetry
Sammanfattning : Non-linear sigma models with extended supersymmetry have constrained target space geometries, and can serve as effective tools for investigating and constructing new geometries. Analyzing the geometrical and topological properties of sigma models is necessary to understand the underlying structures of string theory. LÄS MER
3. Strings as Sigma Models and in the Tensionless Limit
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
4. Going Round in Circles : From Sigma Models to Vertex Algebras and Back
Sammanfattning : In this thesis, we investigate sigma models and algebraic structures emerging from a Hamiltonian description of their dynamics, both in a classical and in a quantum setup. More specifically, we derive the phase space structures together with the Hamiltonians for the bosonic two-dimensional non-linear sigma model, and also for the N=1 and N=2 supersymmetric models. LÄS MER
5. Factors Shaping Process and Representation in Multiple-Cue Judgment
Sammanfattning : This thesis investigates the cognitive processes and representations underlying human judgment in a multiple-cue judgment task. Several recent models as-sume that people have several qualitatively distinct and competing levels of knowledge representations (Ashby, Alfonso-Reese, Turken, & Waldron, 1998; Erickson & Kruschke, 1998; Nosofsky, Palmeri, & McKinley, 1994; Sloman, 1996). LÄS MER