**Venue**: PovoZero, via Sommarive, 14 - Povo - Sala Seminari "-1"**Ore**: 14:30

**Speaker:**

**Jochen Zahn**(Università di Lipsia)

**Abstract**:

In Quantum Field Theory one frequently splits the fields into a classical (background) part, and a perturbation, which is quantised. It is thus a natural question in which sense the theory is independent of this split. We define background independent observables in a geometrical formulation as flat sections of the observable algebra bundle over the manifold of background configurations, with respect to a flat connection which implements background variations. A theory is then called background independent if such a flat (Fedosov) connection exists. We analyze the obstructions to preserve background independence at the quantum level for pure Yang-Mills theory and find that all potential obstructions can be removed by finite renormalization. Based on joint work with M. Taslimi Tehrani.

**Contact person: **Valter Moretti