Aspects of low-energy quantum gravity

Speaker: Prof. Federico Piazza (Aix Marseille University)
Date/Time: Wednesday 28 January 2026, 15:00
Room: Theresienstr. 37, A318

Title: Aspects of low-energy quantum gravity

Abstract:

Quantum gravitational effects are commonly associated to UV physics. However, deviations from classical General Relativity could be at play also within the low energy theory, if the wavefunction of the metric presents features (typically, a large width) that cannot be captured by a classical solution. These macroscopic deviations from classicality impact measurements and observations made inside the spacetime, e.g. by a set of free falling observers. The latter can effectively be used to define a frame. I will show that the average distances between the events in this frame are not the geodesic distances of any metric and portray an interesting ''average causal structure” that has no classical analogue. At the same time, coordinate transformations between frames become probabilistic in the presence of these metric fluctuations. As an example I will consider the 1+1 dimensional model of JT gravity and discuss different localization in that framework. Finally, I will show how low-energy quantum gravitational effects can help resolving spacetime singularities.