Suppose MM is a closed Riemannian manifold with an orthonormal basis BB of L2(M)L2(M) consisting of Laplace eigenfunctions. A classical result of Shnirelman and others proves that if the geodesic flow on the cotangent bundle of MM is ergodic, then MM is quantum ergodic, in particular, on average, the probability measures defined by the functions ff in BB on MM tends on average towards the Riemannian measure on MM in the high energy limit (i.e, as the Laplace eigenvalues of f→∞f→∞).

We now want to look at a level aspect of this property, namely, instead of taking a fixed manifold and high energy eigenfunctions, we take a sequence of Benjamini-Schramm convergent compact Riemannian manifolds MjMj together with Laplace eigenfunctions ff whose eigenvalue varies in short intervals. This perspective has been recently studied in the context of graphs by Anantharaman and Le Masson, and for hyperbolic surfaces and manifolds by Abert, Bergeron, Le Masson, and Sahlsten. In my talk I want to discuss joint work with F. Brumley in which we study this question in higher rank, namely sequences of compact quotients of


This talk is part of the online Number Theory Web Seminar, and will be streamed live on Zoom.

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Mike Bennett (University of British Columbia)

Philipp Habegger (University of Basel)

Alina Ostafe (UNSW Sydney)


Jasmin Matz

Research Area

Number Theory Seminar


University of Copenhagen


Tue, 24/11/2020 - 9:00pm


RC-4082, The Red Centre, UNSW