Topic: Null geometry

Null Musings

One of the main achievements of my last four years at Perimeter has been the development and formulation of intrinsic null geometry. This framework has served as a common denominator for the study of the (algebraic) quantization of gravity on null hypersurfaces; connections to quantum-gravity phenomenology for causal diamonds and the derivation of the Verlinde-Zurek fluctuation identity; a complete characterization of the null gravitational phase space; links to asymptotic null infinity; and the related classification of eBMS anomalies. After introducing the basic toolkit of null geometry, I will digress on Carrollian connections and on how the intrinsic geometry is related to an ambient manifold. I will then introduce the null Brown-York stress tensor, which allows the intrinsic gravitational constraints to be recast as conservation laws. Finally, I will briefly retrace the path through the aforementioned applications, with particular emphasis on new and ongoing results.