ITP|
|
SS26 – Abstract
Renata Ferrero
(Friedrich-Alexander-Universität Erlangen-Nürnberg)
11.6.2026
How do we measure anything in Quantum Gravity? From relational observables to the RG
In quantum field theory, we describe physics at points in spacetime and at energy scales set by external rulers. In quantum gravity neither is available: there is no fixed background and no external scale. Physical quantities must instead be defined relationally, using fields within the theory as clocks and rods. In the first part of the talk I will introduce the relational formalism and show how it leads to gauge-invariant observables. I will then explain how this framework changes perspective on the renormalization group: the coarse-graining scale is no longer an external ruler, but is tied to the resolution provided by the physical clocks and rods. This approach connects naturally to methods from quantum information and to the problem of defining observables in cosmology.
