Speaker
Description
While the general structure of the partition function for 4d N=2 gauge theories is by now understood using localisation, the detailed form of its various ingredients has not been worked out in full generality yet. One main difficulty is to obtain flux contributions from the localisation procedure. We solve this problem for a large class of four-manifolds B by starting with a 5d N=1theory on Sasakian S1-principal bundles over B. Here, the partition function can be expressed as a product over slices of the toric cone. Taking a Z_h-quotient along the S1 adds flat connections to the BPS locus which, in the limit of large h, become the desired flux-contributions in the 4d theory on B. Depending on how we slice the cone, the 4d theory will contain different numbers of point-like instantons and anti-instantons in the full partition function.
