BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20250709T181746EDT-2368mcJK7v@132.216.98.100 DTSTAMP:20250709T221746Z DESCRIPTION:Title: The spectral gap of a random hyperbolic surface\n Abstrac t: On a compact hyperbolic surface\, the Laplacian has a spectral gap betw een 0 and the next smallest eigenvalue if and only if the surface is conne cted. The size of the spectral gap measures both how highly connected the surface is\, and the rate of exponential mixing of the geodesic flow on th e surface. There is an analogous concept of spectral gap for graphs\, with analogous connections to connectivity and dynamics. Motivated by theorems about the spectral gap of random regular graphs\, we proved that for any $\epsilon > 0$\, a random cover of a fixed compact connected hyperbolic su rface has no new eigenvalues below 3/16 - $\epsilon$\, with probability te nding to 1 as the covering degree tends to infinity. The number 3/16 is\, mysteriously\, the same spectral gap that Selberg obtained for congruence modular curves. The talk is intended to be accessible to graduate students and is based on joint works with Frédéric Naud and Doron Puder.\n\n \n\nF or zoom link for the meeting please contact dmitry.jakobson [at] mcgill.ca \n DTSTART:20200715T150000Z DTEND:20200715T160000Z SUMMARY:Michael Magee (Durham University) URL:/mathstat/channels/event/michael-magee-durham-univ ersity-323238 END:VEVENT END:VCALENDAR