Sökning: "geometry effects"
Visar resultat 1 - 5 av 410 avhandlingar innehållade orden geometry effects.
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
2. Geometry, Topology and Emergence in Moiré Systems
Sammanfattning : The experimental discovery of correlated insulators and superconductivity in highly tunable Van der Waals heterostructures, such as twisted bilayer graphene, has highlighted the role of moiré patterns, resulting from tiny relative twists or lattice constant mismatches, in realizing strongly correlated physics. A key ingredient is the existence of very narrow flat bands where interaction effects are dominant. LÄS MER
3. Fatigue strength of welds in 800 MPa yield strength steels : Effects of weld toe geometry and residual stress
Sammanfattning : Nowadays there is a strong demand for lighter vehicles in order to increase the pay load. Through this the specific fuel consumption is decreased, the amount of greenhouse gases is lowered and the transport economy improved. One possibility to optimize the weight is to make the components from high strength steels and join them by welding. LÄS MER
4. Drift waves in non-circular tokamak geometry
Sammanfattning : One of the main concerns in fusion research is to understand the anomalously high transport in magnetically confined plasmas. In recent years, substantial progress in the understanding of transport in terms of drift waves in tokamaks has been achieved. LÄS MER
5. Quantum effects in nanoscale Josephson junction circuits
Sammanfattning : This thesis presents the results of an experimental study on single-charge effects in nanoscale Josephson junctions and Cooper pair transistors (CPTs). In nanoscale Josephson junctions the charging energy EC becomes significant at sub-Kelvin temperatures and single-charge effects, such as the Coulomb blockade of Cooper pair tunneling, influence the transport properties. LÄS MER