Hitchin's equations are a system of gauge theoretic equations on a Riemann surface that are of interest in many areas including representation theory, Teichmu ̈ller theory, and the geometric Langlands correspondence. In this talk, I'll describe what solutions of SL(n, C)-Hitchin's equations “near the ends” of the moduli space look like, and the resulting compactification of the Hitchin moduli space. Wild Hitchin moduli spaces are an important ingredient in this construction. This construction generalizes Mazzeo-Swoboda-Weiss-Witt's construction of SL(2, C)-solutions of Hitchin's equations where the Higgs field is “simple.”[-]

The so-called BPS states in a conformal field theory with extended supersymmetry are key when assigning a geometric interpretation to the theory. Standard invariants for such theories arise from a net count of BPS, half or quarter BPS states, according to the Z2 grading into ‘bosons' and ‘fermions'. This allows for boson-fermion pairs of states to cease being BPS under deformation of the theory. The talk will give a review of this phenomenon, arguing that it is ubiquitous in theories with geometric interpretation by a K3 surface. For a particular type of deformations, we propose that the process is channelled by the action of SU(2) on an appropriate subspace of the space of states.
This is joint work with Anne Taormina.[-]