On Asymptotic Weil-Petersson Geometry of Teichm\"{u}ller Space of Riemann Surfaces

In this paper, we study the asymptotic geometry of Teichmuller space of Riemann surfaces and give bounds on the Weil-Petersson sectional curvature of Teichmuller space, in terms of the length of the shortest geodesic on the surface. This will also imply that the sectional curvature is not pinched from above or below by any negative constant.Comment: 38 pages, minor revisio

Asymptotic flatness of the Weil-Petersson metric on Teichmuller space

The sectional curvature of the Weil-Petersson metric on Teichmuller space is known to be negative. We show that this Weil-Petersson sectional curvature is not pinched from above by any negative constants, i.e., there is no negative upper bound.Comment: 26 pages, to appear on Geometriae Dedicat

The Weil-Petersson Geometry On the Thick Part of the Moduli Space of Riemann Surfaces

On the thick part of the moduli space of Riemann surfaces, where there is a positive lower bound of the systole of the surface, we show that all Weil-Petersson Riemannian curvatures are bounded, independent of the genus of the surface.Comment: 11 pages, a missing reference is adde

Do W_L and H form a p-wave bound state?

We examine the possibility of bound state formation in the W_L H --> W_L H channel. The dynamical calculation using the N/D method indicates that when the interactions among the Goldstone and Higgs bosons become sufficiently strong, a p-wave state [I^G(J^P)=1^-(1^+)] may emerge.Comment: 3 pages, one separate uuencoded figure. Talk presented at Beyond the Standard Model IV, 13-18 December 1994, Lake Tahoe

Asymptotics of the Gaussian Curvatures of the Canonical Metric on the Surface

We study the canonical metric on a compact Riemann surface of genus at least two. While it is known that the canonical metric is of nonpositive curvature, we show that its Gaussian curvatures are not bounded away from zero nor negative infinity when the surface is close to the compactification divisor of Riemann's moduli space.Comment: 11 pages. A previous post "The Canonical Metric on a Riemann Surface and Its Induced Metric on Teichm\"{u}ller Space" has been rewritten to two separate papers. This is the one focusing on the canonical metric on a compact Riemann surfac

The Weil-Petersson curvature operator on the universal Teichm\"uller space

The universal Teichm\"uller space is an infinitely dimensional generalization of the classical Teichm\"uller space of Riemann surfaces. It carries a natural Hilbert structure, on which one can define a natural Riemannian metric, the Weil-Petersson metric. In this paper we investigate the Weil-Petersson Riemannian curvature operator $\tilde{Q}$ of the universal Teichm\"uller space with the Hilbert structure, and prove the following: (i) $\tilde{Q}$ is non-positive definite. (ii) $\tilde{Q}$ is a bounded operator. (iii) $\tilde{Q}$ is not compact; the set of the spectra of $\tilde{Q}$ is not discrete. As an application, we show that neither the Quaternionic hyperbolic space nor the Cayley plane can be totally geodesically immersed in the universal Teichm\"uller space endowed with the Weil-Petersson metric.Comment: Math. Ann, to appea

Mean Curvature Flows in Almost Fuchsian Manifolds

An almost Fuchsian manifold is a quasi-Fuchsian hyperbolic three-manifold that contains a closed incompressible minimal surface with principal curvatures everywhere in the range of (-1,1). In such a hyperbolic three-manifold, the minimal surface is unique and embedded, hence one can parametrize these three-manifolds by their minimal surfaces. We prove that any closed surface which is a graph over any fixed surface of small principal curvatures can be deformed into the minimal surface via the mean curvature flow. We also obtain an upper bound for the hyperbolic volume of the convex core of M, as well as estimates of the Hausdorff dimension of the limit set for $M$.Comment: 22 pages. Sections are re-organized to clarify some arguments, a subsection is added and some typos are fixed

Complex length of short curves and Minimal Fibration in hyperbolic 33-Manifolds fibering over the circle

We investigate the maximal solid tubes around short simple geodesics in hyperbolic three-manifolds and how complex length of curves relate to closed, incompressible, least area minimal surfaces. As applications, we prove, there are some closed hyperbolic three-manifolds fibering over the circle which are not foliated by closed incompressible minimal surfaces diffeomorphic to the fiber. We also show, the existence of quasi-Fuchsian manifolds containing arbitrarily many embedded closed incompressible minimal surfaces. Our strategy is to prove main theorems under natural geometric conditions on the complex length of closed curves on a fibered hyperbolic three-manifold, then we find explicit examples where these conditions are satisfied via computer programs.Comment: final version, to appear at the Proceeding of the London Math. So

Closed Minimal Surfaces in Cusped Hyperbolic Three-manifolds

Motivated by classical theorems on minimal surface theory in compact hyperbolic three-manifolds, we investigate the questions of existence and deformations for least area minimal surfaces in complete noncompact hyperbolic three-manifold of finite volume. We prove any closed immersed incompressible surface can be deformed to a closed immersed least area surface within its homotopy class in any cusped hyperbolic three-manifold. Our techniques highlight how special structures of these cusped hyperbolic three-manifolds prevent any least area minimal surface going too deep into the cusped region.Comment: 23 pages, 2 figures: Final version, to appear in Geometriae Dedicat

Counting Minimal Surfaces in Quasi-Fuchsian three-Manifolds

It is well known that every quasi-Fuchsian manifold admits at least one closed incompressible minimal surface, and at most finitely many of them. In this paper, for any prescribed integer $N>0$, we construct a quasi-Fuchsian manifold which contains at least $2^N$ such minimal surfaces. As a consequence, there exists some simple close Jordan curve on $S^2_\infty$ such that there are at least $2^N$ disk-type complete minimal surface in $\mathbb{H}^3$ sharing this Jordan curve as the asymptotic boundary.Comment: 22 pages, 9 figures, changes made following referee's many corrections and suggestions. Accepted by the Transactions of the AM