# On the volume of Anti-de Sitter maximal globally hyperbolic three-manifolds

## TL;DR

This paper investigates the volume of maximal globally hyperbolic Anti-de Sitter 3-manifolds with a closed surface, relating it to geometric invariants from Teichmüller space and establishing bounds involving Thurston's distances and Weil-Petersson metric.

## Contribution

It establishes a coarse relationship between the volume and the minima of L^1-energy of maps, linking it to Thurston's Lipschitz and Weil-Petersson distances, and provides bounds and examples illustrating this behavior.

## Key findings

- Volume is coarsely equivalent to the length of measured geodesic laminations.
- Volume is bounded above by the exponential of Thurston's Lipschitz distance.
- Volume is bounded below by the exponential of the Weil-Petersson distance.

## Abstract

We study the volume of maximal globally hyperbolic Anti-de Sitter manifolds containing a closed orientable Cauchy surface $S$, in relation to some geometric invariants depending only on the two points in Teichm\"uller space of $S$ provided by Mess' parameterization - namely on two isotopy classes of hyperbolic metrics $h$ and $h'$ on $S$. The main result of the paper is that the volume coarsely behaves like the minima of the $L^1$-energy of maps from $(S,h)$ to $(S,h')$. The study of $L^p$-type energies had been suggested by Thurston, in contrast with the well-studied Lipschitz distance. A corollary of our result shows that the volume of maximal globally hyperbolic Anti-de Sitter manifolds is bounded from above by the exponential of (any of the two) Thurston's Lipschitz asymmetric distances, up to some explicit constants. Although there is no such bound from below, we provide examples in which this behavior is actually realized. We prove instead that the volume is bounded from below by the exponential of the Weil-Petersson distance. The proof of the main result uses more precise estimates on the behavior of the volume, which is proved to be coarsely equivalent to the length of the (left or right) measured geodesic lamination of earthquake from $(S,h)$ to $(S,h')$, and to the minima of the holomorphic 1-energy.