Frieder Jackel

activity

20222026

collaborators

5 papers

math.AP2026

Constant potentials do not minimize the fundamental gap on convex domains in negatively curved Hadamard manifolds

Frieder Jäckel

We show that for every negatively curved Hadamard manifold $X$ and every $D > 0$ there exists a convex domain $Ω \subseteq X$ with diameter $D$ and a convex potential $V$ on $Ω$ suc…

math.AP2025

Constant potentials do not minimise the fundamental gap on convex domains in hyperbolic space

Julie Clutterbuck, Frieder Jäckel, Xuan Hien Nguyen

We show that for every $n \geq 2$ and $D > 0$ there exist a convex domain $Ω \subseteq H^{n}$ with diameter $D$ and a convex potential $V$ on $Ω$ such that the fundamental gap…

math.DG2024

Negatively curved Einstein metrics on Gromov-Thurston manifolds

Ursula Hamenstädt, Frieder Jäckel

For every $n \geq 4$ we construct infinitely many mutually not homotopic closed manifolds of dimension $n$ which admit a negatively curved Einstein metric but no locally symmetric m…

math.DG2023

Improved decay rate in a stability theorem for hyperbolic metrics

Frieder Jäckel

Recently, Ursula Hamenstädt and the author proved a stability result for finite volume hyperbolic metrics in dimension three that does not assume any upper volume bounds, but that…

math.DG2022

Stability of Einstein metrics and effective hyperbolization in large Hempel distance

Ursula Hamenstädt, Frieder Jäckel

Extending earlier work of Tian, we show that if a manifold admits a metric that is almost hyperbolic in a suitable sense, then there exists an Einstein metric that is close to the…