Polyakov's formula expresses a difference of zeta-regularized determinants of Laplace operators, an anomaly of global quantities, in terms of simple local quantities. Such a formula is well known in the case of closed surfaces (Osgood, Philips, & Sarnak 1988) and surfaces with smooth boundary (Alvarez 1983). Due to the abstract nature of the definition of the zeta-regularized determinant of the Laplacian, it is typically impossible to compute an explicit formula. Nonetheless, Kokotov (genus one Kokotov & Klochko 2007, arbitrary genus Kokotov 2013) demonstrated such a formula for polyhedral surfaces ! I will discuss joint work with Clara Aldana concerning the zeta regularized determinant of the Laplacian on Euclidean domains with corners. We determine a Polyakov formula which expresses the dependence of the determinant on the opening angle at a corner. Our ultimate goal is to determine an explicit formula, in the spirit of Kokotov's results, for the determinant on polygonal domains.[-]

A pair consisting of a K3 surface and a non-symplectic automorphism of order three is called an Eisenstein K3 surface. We introduce an invariant of Eisenstein K3 surfaces, which we obtain using the equivariant analytic torsion of an Eisenstein K3 surface and the analytic torsion of its fixed locus. Then this invariant gives rise to a function on the moduli space of Eisenstein K3 surfaces, which consists of 24 connected components and each of which is a complex ball quotient depending on the topological type of the automorphism of order three. Our main result is that, for each topological type, the invariant is expressed as the product of the Petersson norms of two kinds of automorphic forms, one is an automorphic form on the complex ball and the other is a Siegel modular form. In many cases, the automorphic form on the complex ball obtained in this way is a so-called reflective modular form. In some cases, this automorphic form is obtained as the restriction of an explicit Borcherds product to the complex ball. This is a joint work with Shu Kawaguchi.[-]

This is joint work with Jasmin Matz. The goal is to introduce a regularized version of the analytic torsion for locally symmetric spaces of finite volume and higher rank. Currently we are able to treat quotients of the symmetric space $SL(n,\mathbb{R})/SO(n)$ by congruence subgroups of $SL(n,\mathbb{Z})$. The definition of the analytic torsion is based on the study of the renormalized trace of the corresponding heat operators. The main tool is the Arthur trace formula. I will also discuss problems related to potential applications to the cohomology of arithmetic groups.[-]

Reidemeister torsion was the first topological invariant that could distinguish between spaces which were homotopy equivalent but not homeomorphic. The Cheeger-Müller theorem established that the Reidemeister torsion of a closed manifold can be computed analytically. I will report on joint work with Frédéric Rochon and David Sher on finding a topological expression for the analytic torsion of a manifold with fibered cusp ends. Examples of these manifolds include most locally symmetric spaces of rank one. We establish our theorem by controlling the behavior of analytic torsion as a space degenerates to form hyperbolic cusp ends.[-]