We consider an $n$-dimensional spherically symmetric, asymptotically
Euclidean manifold with two ends and a codimension 1 trapped set which is
degenerately hyperbolic. By separating variables and constructing a
semiclassical parametrix for a time scale polynomially beyond Ehrenfest time,
we show that solutions to the linear Schr\"odiner equation with initial
conditions localized on a spherical harmonic satisfy Strichartz estimates with
a loss depending only on the dimension $n$ and independent of the degeneracy.
The Strichartz estimates are sharp up to an arbitrary $\beta>0$ loss.
We consider the operator associated to a random walk on finite volume
surfaces with hyperbolic cusps. We study the spectral gap (upper and lower
bound) associated to this operator and deduce some rate of convergence of the
iterated kernel towards its stationary distribution.
We study dispersive properties of one-dimensional surface water-waves under
surface tension, based on the formulation of the problem as a nonlinear
dispersive equation coupled with a transport-type equation. We establish a
dispersion estimate on time scales depending on the size of the frequencies. We
infer that, if $s$ is large enough, then a solution $u$ of the dispersive
equation satisfies local-in-time weighted Strichartz estimates with loss in the
admissibility condition: