The geometry and physics of F-theory compactifications

In this PhD thesis we study the structure of gauge and gravitational anomalies in effective theories obtained by compactfication of F-theory on Calabi-Yau manifolds. In particular, we study the continuous local anomalies in 2D N = (0, 2) effective theories from elliptically fibered Calabi-Yau five-fold compactifications and discrete gauge anomalies in 6D N = (1, 0) theories from F-theory on genus-one fibrations of Calabi-Yau three-folds. Certain anomalies associated with these symmetries, induced at 1-loop in perturbative theories, can be cancelled by a corresponding generalized Green-Schwarz mechanism operating at the level of chiral fields in the effective theories. We derive closed expressions for types Green-Schwarz mechanisms in F-theory compactifications, as well as the gravitational and gauge anomalies. These expressions in both cases involve topological invariants of the underlying fibrations of Calabi-Yau manifolds. Cancellation of these anomalies in the effective theories predicts intricate topological identities which must hold on every corresponding Calabi-Yau manifold. Some of the identities we find on elliptic 5-folds are related in an intriguing way to previously studied topological identities governing the structure of local anomalies for continuous symmetry in 6D N = (1, 0) and 4D N = 1 theories obtained from F-theory.