Speaker
Description
I’ll describe recent work with Laurent Freidel in which we quantize the perturbative gravitational data on a null ray in a gauge-invariant manner. The main technical difficulty is due to anomalies in quantum diffeomorphism invariance. I'll explain how these originate in the use of a background time dependent renormalization procedure, and I’ll describe how to eliminate the anomalies by replacing the background time with a dynamical time (the dressing time), thus invoking a quantum reference frame (QRF) dependent renormalization prescription. The fluctuations of the QRF have implications for QG observables. The algebra of non-anomalous gauge invariant operators obtained in this way has the structure of a Virasoro crossed product.
Based on:
https://arxiv.org/abs/2510.26589
https://arxiv.org/abs/2604.02228