We wish to thank E. Seiler for a critical reading of the manuscript and for suggesting various improvements on the field theoretical parts. M.N. would like to thank C. Bervellier, D. Litim, R. Loll, and A. Niemi for comments and correspondence. M.R. wishes to thank A. Bonnano, O. Lauscher, F. Saueressig, J. Schwindt and H. Weyer for fruitful collaborations on the work summarized here, and R. Percacci and C. Wetterich for many discussions.
© Max Planck Society and the author(s)