Locality and beyond: from algebraic quantum field theory to effective quantum gravity

Local Quantum Physics and beyond - In memoriam Rudolf Haag
Katarzyna Rejzner on September 26, 2016

The paradigm of algebraic quantum field theory, developed by Haag, Kastler and Araki, has proven to be successful in studying foundations of QFT and turned out to be very effective in constructing QFT models on curved spacetimes. The main advantage of this approach is that it allows to separate the local features of the theory (observables) form the global features (states). Recently, this framework has been pushed even further and has been applied to effective quantum gravity. While doing so, one needs to weaken the notion of locality to obtain a suitable class of gauge invariant observables. In this talk I will review the recent results obtained in this program, including applications to cosmological perturbation theory.