Sommaire:

The insertion of defect operators of various types can change the Hilbert space of a quantum field theory. Surface defects in 4d N=2 theories introduce a class of ”2d-4d” BPS states which the original 4d theory does not possess. For theories of class S spectral networks count 2d-4d BPS states, and through the 2d-4d wall-crossing phenomenon the 4d BPS spectrum can be obtained. In this talk I will give a brief introduction to spectral networks, with an emphasis on their physical interpretation. Some of their applications and extensions will then be illustrated.

Pour plus d'informations, merci de contacter Alexandrov S.