Near Extremal de Sitter Black Holes and JT Gravity

Watch a physics seminar where Harvard researcher Chiara Toldo delves into the thermodynamic properties of charged black holes in four-dimensional Einstein-Maxwell theory with positive cosmological constant. Explore three distinct extremal limits of these black holes - cold, Nariai, and ultracold configurations - and understand their unique near-horizon geometries. Learn about the dimensional reduction process used to construct effective two-dimensional theories for each case, with special attention given to the ultracold configuration's distinctive relationship between entropy and charge variations, which demonstrates novel symmetry breaking patterns compared to other near-extremal limits.