### Talk at IIASS: Nonabelian Strings

#### Posted by Urs Schreiber

Next week the Istituto Internazionale per gli alti Studi Scientifici hosts the conference Problemi Attuali di Fisica Teorica in Vietri sul Mare (Italy). As I have mentioned before, I’ll give a talk on ‘nonabelian strings’ concerned with

2-bundles, 2-connections and 2-holonomy and the relation to nonabelian gerbes.

Here are the slides: `VietriTalk.ps`.

(Special thanks go once again to Eric Forgy for having provided the picture that I display on the title slide.)

Here is the abstract:

Posted at March 16, 2005 3:29 PM UTCIntersections of membranes with stacks of M5-branes are expected to give rise to a dimensional generalization of nonabelian gauge theory from point particles to strings. This can be described in the language of nonabelian gerbes. A gerbe is a generalization of the concept of a sheaf of sections of a fiber bundle obtained by a method known as categorification. Applying the same method to the more direct description of bundles in terms of projection maps and local trivializations yields the concept of a 2-bundle. We describe the theory of 2-bundles in general, how gerbes are obtained from 2-bundles and how global nonabelian surface holonomy can be defined using 2-bundles. This should play a role both for action principles of nonabelian strings as well as for elliptic cohomology.

## Re: Talk at IIASS: Nonabelian Strings

Nice :) Speaking of the cover figure, there seems to be an extraneous “X” in there next to one of the arrows that is not part of the original figure and is not in the same figure on a later slide.

Artists are sensitive about these kinds of things ;)