Spacetime foam: a review

S Carlip - Reports on Progress in Physics, 2023 - iopscience.iop.org
More than 65 years ago, John Wheeler suggested that quantum uncertainties of the metric
would be of order one at the Planck scale, leading to large fluctuations in spacetime …

Arithmeticity, superrigidity, and totally geodesic submanifolds

U Bader, D Fisher, N Miller, M Stover - Annals of mathematics, 2021 - projecteuclid.org
Let Γ be a lattice in SO_0(n,1). We prove that if the associated locally symmetric space
contains infinitely many maximal totally geodesic subspaces of dimension at least 2, then Γ …

Arithmeticity, superrigidity and totally geodesic submanifolds of complex hyperbolic manifolds

U Bader, D Fisher, N Miller, M Stover - Inventiones mathematicae, 2023 - Springer
For n≥ 2, we prove that a finite volume complex hyperbolic n-manifold containing infinitely
many maximal properly immersed totally geodesic submanifolds of real dimension at least …

Homology and homotopy complexity in negative curvature

U Bader, T Gelander, R Sauer - Journal of the European Mathematical …, 2020 - ems.press
Homology and homotopy complexity in negative curvature Page 1 DOI 10.4171/JEMS/971 J.
Eur. Math. Soc. 22, 2537–2571 c European Mathematical Society 2020 Uri Bader · Tsachik …

Systoles of hyperbolic hybrids

S Douba - arXiv preprint arXiv:2309.16051, 2023 - arxiv.org
We exhibit closed hyperbolic manifolds with arbitrarily small systole in each dimension that
are not quasi-arithmetic in the sense of Vinberg, and are thus not commensurable to those …

Finiteness of maximal geodesic submanifolds in hyperbolic hybrids.

D Fisher, JF Lafont, N Miller, M Stover - Journal of the European …, 2021 - ems.press
We show that large classes of non-arithmetic hyperbolic n-manifolds, including the hybrids
introduced by Gromov and Piatetski-Shapiro and many of their generalizations, have only …

Hyperbolic four-manifolds

B Martelli - arXiv preprint arXiv:1512.03661, 2015 - arxiv.org
arXiv:1512.03661v2 [math.GT] 30 Dec 2015 Page 1 HYPERBOLIC FOUR-MANIFOLDS
BRUNO MARTELLI Abstract. This is a short survey on finite-volume hyperbolic four-manifolds …

On the Growth of L2-Invariants of Locally Symmetric Spaces, II: Exotic Invariant Random Subgroups in Rank One

M Abert, N Bergeron, I Biringer… - International …, 2020 - academic.oup.com
In the 1st paper of this series we studied the asymptotic behavior of Betti numbers, twisted
torsion, and other spectral invariants for sequences of lattices in Lie groups G. A key element …

Counting and effective rigidity in algebra and geometry

B Linowitz, DB McReynolds, P Pollack… - Inventiones …, 2018 - Springer
The purpose of this article is to produce effective versions of some rigidity results in algebra
and geometry. On the geometric side, we focus on the spectrum of primitive geodesic …

Superrigidity, arithmeticity, normal subgroups: results, ramifications and directions

D Fisher - arXiv preprint arXiv:2003.02956, 2020 - arxiv.org
This essay points to many of the interesting ramifications of Margulis' arithmeticity theorem,
the superrigidity theorem, and normal subgroup theorem. We provide some history and …