Greg Moore

Title: Four-dimensional wall-crossing via three-dimensional field theory

Abstract: We give a physical explanation of the Kontsevich-Soibelman  
wall-crossing formula for the BPS spectrum in Seiberg-Witten theories.  
In the process we give an exact description of the BPS instanton  
corrections to the hyperk¨ahler metric of the moduli space of the  
theory on R3 × S1. The wall-crossing formula reduces to the statement  
that this metric is continuous. Our construction of the metric uses a  
four-dimensional analogue of the two-dimensional tt∗ equations.

Joint work with Davide Gaiotto and Andy Neitzke.