Sökning: "non-perturbative effects"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden non-perturbative effects.

1. 1. Automorphic forms and string theory: Small automorphic representations and non-perturbative effects

   Författare :Henrik Gustafsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; instantons; automorphic forms; automorphic representations; Eisenstein series; U-duality; non-perturbative effects; string theory;

   Sammanfattning : This compilation thesis stems from a project with the purpose of determining non-perturbative contributions to scattering amplitudes in string theory carrying important information about instantons, black hole quantum states and M-theory. The scattering amplitudes are functions on the moduli space invariant under the discrete U-duality group and this invariance is one of the defining properties of an automorphic form. LÄS MER

3. 2. A study of finite-size and non-perturbative effects on the van der Waals and the Casimir-Polder forces

   Författare :Thiyam Priyadarshini; Clas Persson; Mathias Boström; Thomas Ederth; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite-size effects; non-perturbative theory; van der Waals and Casimir Polder forces; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : This licentiate thesis addresses two important aspects of the van der Waals and the Casimir-Polder ground-state and excited-state (resonance) interactions between two atoms or molecules. The first is the finite-size effect and the second is the non-perturbative effect. LÄS MER

4. 3. Automorphic string amplitudes

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

   Sammanfattning : 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. LÄS MER

5. 4. A study of finite-size, non-perturbative and anisotropic effects on the Lifshitz-van der Waals forces and torque with material dielectric responses from first-principles calculations

   Författare :Priyadarshini Thiyam; Clas Persson; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Lifshitz-van der Waals forces; Casimir torque; optical calculations with density functional theory; phosphorus; phosphorene;

   Sammanfattning : The van der Waals and the Casimir-Lifshitz forces are forces of attraction that exist between neutral polarizable bodies due to quantum fluctuations. They can be repulsive depending on the material properties and the geometry of the system. LÄS MER

7. 5. D-instantons and Dualities in String Theory

   Författare :Christoffer Petersson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : In this thesis we study non-perturbative aspects of string theory. We focus our analysis on D-instanton effects which play key roles in the context of dualities, moduli stabilization and phenomenology. LÄS MER