Geometry-Topology Archives for Fall 2021 to Spring 2022


A Weyl law for PFH spectral invariants

When: Sun, February 14, 2021 - 3:00pm
Where: Kirwan Hall 3206
Speaker: Rohil Prasad (Princeton ) -
Abstract: Hutchings' periodic Floer homology (PFH) is a Floer-theoretic invariant associated to an area-preserving diffeomorphism of a closed, oriented surface. It has a set of associated quantitative invariants, called "PFH spectral invariants", which encode information about periodic orbits of this diffeomorphism. The main topic of this talk is a "Weyl law" for PFH spectral invariants, which relates the asymptotics of PFH spectral invariants to the Calabi invariant of Hamiltonian surface diffeomorphisms. We will state the Weyl law and discuss a bit of its proof, which relies on a quantitative analysis of the Lee-Taubes isomorphism of PFH and monopole Floer homology. Time permitting, we will discuss some applications to the dynamics of area-preserving surface diffeomorphisms. This talk is based on joint work with Dan Cristofaro-Gardiner and Boyu Zhang.