Την Πέμπτη 30 Οκτωβρίου στις 17:00 μ.μ. (παρακαλώ προσέξτε την ασυνήθιστη μέρα και ώρα) ο Luca Ciambelli (Perimeter Institute) θα δώσει ένα διαδικτυακό σεμινάριο.

Η ομιλία θα αναμεταδοθεί μέσω Zoom στον ακόλουθο σύνδεσμο:
https://authgr.zoom.us/j/95087591277?pwd=CS4PPaGSkA9og9910lQVJqqVGDBqaE.1

Meeting ID: 950 8759 1277
Passcode: 595871

Ακολουθούν ο τίτλος και η περίληψη της ομιλίας.

Τίτλος: Radiation, Holography, and Quantum Null Physics

Περίληψη: This seminar is divided into two parts. The first explores gravitational radiation in spacetimes with a cosmological constant. For negative values, we relate it to the fluid/gravity correspondence and to dissipative processes in the dual boundary fluid. By then taking the flat limit using classic techniques developed together with the Thessaloniki group, we show how specific aspects of Carrollian boundary physics are sourced by bulk radiation, providing a first step toward understanding dissipative phenomena in Carrollian frameworks.
The second part, connected to the first through the physics of null hypersurfaces, turns to quantum physics and the recently developed framework of quantum null geometry. I will describe the canonical quantization of gravity on null hypersurfaces, offering a potential resolution to the problem of time in QG. Finally, I will connect this to recent bottom-up approaches to defining the entropy of generic subregions in QG and to the study of quantum area fluctuations. This involves the use of geometric modular flows to implement the crossed-product construction in semiclassical gravity, the generalization of entanglement wedges beyond AdS/CFT, and connections to QG tabletop experiments probing quantum fluctuations of the area of a causal diamond.