String Theory Seminar  

11/05/2009, 16:30 — 17:30 — Room P3.10, Mathematics Building
Paolo Aschieri, Alessandria

Abelian Gerbes, Nonabelian Gerbes, and Global Anomalies

Gauge theories with gauge potential that is an abelian 2-form or  3-form are relatively well understood and are relevant in supergravity and in string theory. We study the nonabelian version of  these gauge theories, in particular  their underlying geometry. We see that a relaxed version of  the notion of connection one form on a principal bundle is  necessary in the context of nonabelian gerbes. We then give evidence that such nonabelian gerbes are relevant for the description of a stack of M5-branes in M-theory.