Planar minimal surfaces with polynomial growth in the $\mathrm{Sp}(4, \mathbb{R})$-symmetric space
Andrea Tamburelli, Michael Wolf
TL;DR
The paper studies planar minimal surfaces in the symmetric space $ ext{Sp}(4,\mathbb{R})/ ext{U}(2)$ that arise from Higgs bundles with polynomial quartic data, establishing a bridge between polynomial quartic differentials on $\mathbb{C}$ and geometric boundary data in Ein^{1,2}. It constructs a conformal harmonic map $f:\mathbb{C} o ext{Sp}(4,\mathbb{R})/ ext{U}(2)$ from a meromorphic irregular Higgs bundle, solves Hitchin’s equations with a diagonal metric, and analyzes the asymptotics of the associated minimal surface. The authors show that these planar maximal surfaces are asymptotic to a discrete collection of flats and exhibit a Stokes-type transition across half-planes, with precise error control. They also realize a convex immersion into the Grassmannian Gr_2(𝔈_ℝ), relate it to maximal surfaces in $ ext{H}^{2,2}$ via the $ ext{Sp}(4,\mathbb{R}) o ext{SO}_0(2,3)$ isomorphism, and describe a boundary correspondence sending polynomial quartics to future-directed negative light-like polygons in Ein^{1,2}. Finally, they prove that the moduli space of polynomial quartic differentials of degree $n$ is homeomorphic to a connected component of the moduli space of such light-like polygons, and establish localization results along rays that connect the analytic PDE analysis to geometric boundary data.
Abstract
We study the asymptotic geometry of a family of conformally planar minimal surfaces with polynomial growth in the $\mathrm{Sp}(4,\mathbb{R})$-symmetric space. We describe a homeomomorphism between the "Hitchin component" of wild $\mathrm{Sp}(4,\mathbb{R})$-Higgs bundles over $\mathbb{CP}^1$ with a single pole at infinity and a component of maximal surfaces with light-like polygonal boundary in $\mathbb{H}^{2,2}$. Moreover, we identify those surfaces with convex embeddings into the Grassmannian of symplectic planes of $\mathbb{R}^{4}$. We show, in addition, that our planar maximal surfaces are the local limits of equivariant maximal surfaces in $\mathbb{H}^{2,2}$ associated to $\mathrm{Sp}(4,\mathbb{R})$-Hitchin representations along rays of holomorphic quartic differentials.
