UC Berkeley

One of the most striking and surprising aspects of string theory is the vast web of string dualities which relates many seemingly distinct string backgrounds. In this dissertation, I explore several novel dualities between systems of D-branes and closed string flux compactifications. I use geometric transitions to analyze a variety of supersymmetry-breaking D-brane constructions. I additionally present an explanation of the Calabi-Yau fourfold geometries which appear in the computation of superpotentials for D-branes on compact Calabi-Yau threefolds.