Cihan Okay Title: Commutative bundles and their applications Abstract: Principal bundles with commutativity structure on their transition functions are introduced by Adem and Gomez. These objects are classified by the classifying space for commutativity which is a variant of the ordinary classifying space of a topological group assembled from pairwise commuting group elements. In this talk, based on joint work with Pal Zsamboki, I will describe how to carry over such constructions to the category of simplicial groups. This leads to interesting variants of Kan's loop group functor and the bar construction for simplicial groups. Moreover the geometric realization functor relates the simplicial version to the topological version. This way many interesting examples studied earlier can be carried over to the simplicial category. Time permitting I will tell a bit about applications to problems arising in quantum information theory.