Warped throat solutions in string theory and their cosmological applications

This thesis is devoted to a study of certain examples of gauge/string duality related to warped throat backgrounds in string theory. Namely, we consider a family of IIB SUGRA solutions dual to a moduli space of certain cascading N = 1 gauge theory. This theory exhibits rich low-energy behavior, including chiral symmetry breaking and confinement. The first part of this thesis is focused on the gravity dual description of these phenomena. In particular, we discuss string theory description of the continuous gauge theory moduli space, evaluate the tension of BPS domain wall, and calculate baryonic condensates. The second part of the thesis is devoted to the embedding of the warped throat backgrounds into flux compactifications. To this end we calculate the nonperturbative superpotential of the D3-D7 system on warped conic geometries. This superpotential plays an important role in fixing Kahler moduli and is an important ingredient in constructing consistent compactification scenarios. In the last part of the thesis we apply this superpotential to a particular cosmological inflation scenario based on the dynamics of a D3-brane moving along the throat. We conclude that the realization of stringy inflation within this scenario is possible only around an inflection point of the potential and requires a fine tuning of the parameters.