Program: a "flat space holography" special edition

13h30: Tea & Coffee

14h00: Speaker 1: Cindy Keeler  (ASU), “(Directed) Graphs for (Quantum) Spacetime Entropies''

15h15: Coffee break

15h45: Speaker 2: Upamanyu Moitra (UvA) “Extremal Black Holes in AdS/CFT: from Weak Gravity to Photon Rings” 

17h00: Borrel (drinks and snacks)

Information on the talks:

Speaker 1: Cindy Keeler 

Title: "(Directed) Graphs for (Quantum) Spacetime Entropies"

Abstract:

After reviewing how the Ryu-Takayanagi relation allows us to rebuild spacetime shapes from boundary entanglement entropies, we will review the discrete undirected graphs whose max flow/min cut reproduces the entropies for a any given set of AdS boundary regions.  We will then discuss a new protocol for *directed* graphs, whose max flow then reproduces the entropies of a larger class of quantum states, perhaps allowing a graph-theoretic method of discretizing quantum spacetime.

Speaker 2: Upamanyu Moitra 

Title: “Extremal Black Holes in AdS/CFT: from Weak Gravity to Photon Rings” 

Abstract:

In this talk, I will summarize some remarkable lessons one can learn by studying massive and massless charged particle trajectories in a charged black hole background in AdS spacetime. The interplay between Newtonian and Coulomb interactions for a charged particle, when translated into the boundary CFT language, allows one to naturally formulate the WGC for AdS black holes. There turns out to be an interesting connection between the WGC and ISCO. A consideration of massless particles, on the other hand,  leads to some novel features – including the emergence of a new time-scale of relaxation of perturbations. I will discuss a relatively simple iε prescription for the JWKB approximation and its utility in this set-up.

About

This event is part of a regular series of meetings sponsored by Delta ITP with the objective of bringing together the theoretical physics communities in Amsterdam, Leiden, Utrecht and our sister nodes Groningen, Brussels (ULB and VUB) and Leuven. The topic of this meeting is holography and its applications to different physical systems. We encourage researchers from different areas in theoretical physics to participate!

Organisers

Diego Hofman Uv Amsterdam
Umut Gursoy Utrecht Un.
Koenraad Schalm Leiden Un.