Dr Dario Benedetti
9/28/18, 9:00 AM
The large-N limit of quantum field theories with fields in the fundamental or adjoint representation of a compact Lie group, such as O(N) or U(N), has been extensively studied over the years as a tool for accessing non-perturbative physics by analytic means. Not much has been done instead until recent years for the large-N limit of theories in tensor product representations, or in the...
Dr Omar Zanusso
9/28/18, 9:45 AM
We discuss the low-energy gravitational effective action induced by quantum fluctuations of two- and four-dimensional massive matter fields. We show that the effective action agrees with expectations based on the Appelquist-Carazzone theorem and provide a renormalization group interpretation of the results which is rather scheme-independent in that it does not depend explicitly on a cutoff...
Prof. Bianca Dittrich
9/28/18, 11:00 AM
A quantum gravity theory should yield a prescription of how to assign quantum amplitudes to arbitrary boundary geometries. I will describe a renormalization program for background independent theories, where the coarseness of the boundary data is used to define a notion of scale and truncations for the renormalization flow. This allows to bootstrap the amplitudes from coarse to finer and finer...
Prof. Roberto Percacci
9/28/18, 11:45 AM
I will discuss various definitions of Wick rotation in a gravitational context and argue in favor of a definition where it is viewed as an analytic continuation of the metric. I will then show that also this definition has severe shortcomings. In particular, it may not always be possible to preserve the field Equations and the symmetries at global level.