# Klaus Kröncke: A Volume-Renormalized Mass for Asymptotically Hyperbolic Manifolds

**Time: **
Thu 2023-10-12 10.30 - 11.30

**Location: **
3418, Lindstedtsvägen 25

**Language: **
English

**Participating: **
Klaus Kröncke, KTH

We define a geometric quantity for asymptotically hyperbolic manifolds, which we call the volume-renormalized mass. It is essentially a linear combination of a renormalization of the volume and the standard ADM mass integral.

We show that the volume-renormalized mass is well-defined and diffeomorphism invariant under weaker fall-off conditions than required to ensure the renormalized volume and ADM mass integral are well-defined separately. We prove several positivity results for this mass, and we use it to define a renormalized Einstein--Hilbert action and an expander entropy in the context of Ricci flow on asymptotically hyperbolic manifolds. Furthermore, we show that the expander entropy is monotonically nondecreasing under the Ricci flow, critical points are Poincaré--Einstein metrics, and local maximizers of the entropy are local minimizers of the volume-renormalized mass. This is joint work with Mattias Dahl and Stephen McCormick.

(Please note the unusual starting time.)