Visar resultat 1 - 5 av 11 avhandlingar innehållade ordet instantons.
1. Automorphic forms and string theory: Small automorphic representations and non-perturbative effects
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
Sammanfattning : This thesis consists of an introductory text followed by two separate parts which may be read independently of each other. In Part I we analyze certain hyperbolic structures arising when studying gravity in the vicinity of spacelike singularities (the BKL-limit). LÄS MER
Sammanfattning : This thesis consists of an introductory text together with five appended research papers. The Ariadne's thread through the whole thesis is various effects coming from high-dimensional p-branes in various subsectors of string and M-theory. LÄS MER
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
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