Counting out the geometry
Speaker:
Fay Dowker, Imperial College London
Date and Time:
Friday, October 7, 2022 - 4:10pm to 5:00pm
Location:
Fields Institute, Room 230
Abstract:
I will give examples of geometric quantities in the approximating continuum that can be read off the causal order of the underlying causal set. Ricci scalar curvature in approximately flat spacetimes is one example and to explain its origins I will tell the story of the D'Alembertian operator for a scalar field on a causal set and how the Ricci scalar fell out of it. I will explain the ``long skinny interval'' problem, which illustrates just how different Lorentzian geometry is from Riemannian geometry and which has prevented us from extending our results away from the approximately flat regime. If there is time I will show that we can count the area of the horizon of a black hole.