Minimal submanifolds in spheres and complex-valued eigenfunctions
Aleksei Kislitsyn
TL;DR
The paper links minimal submanifolds of spheres to complex-valued $(\lambda,\mu)$-eigenfunctions, proposing a construction of codimension-1 minimal submanifolds in $\mathbb{S}^n$ via level sets associated with real lines under a complex eigenfunction. It proves a concise classification (Theorem $\text{['Sn_class']}$) that any $(\lambda,\mu)$-eigenfunction on $\mathbb{S}^n$ comes from a homogeneous $(0,0)$-eigenfunction, and demonstrates how this yields explicit Clifford torus and Lawson $\tau_{n,m}$-surface immersions on $\mathbb{S}^3$. The work analyzes $\mathbb{S}^4$ examples showing many low-degree polynomial cases yield trivial minimal submanifolds, while outlining a general Hessian-based criterion for minimality of $f^{-1}(l_\alpha)$ and its consequences in $\mathbb{S}^3$. Overall, the paper strengthens the connection between spectral geometry and minimal submanifold theory on spheres and provides concrete constructions via $f^{-1}(l_\alpha)$ and polynomial $(0,0)$-eigenfunctions.
Abstract
A new approach for constructing minimal submanifolds of codimension 1 in the round spheres is proposed. In the case of $\mathbb{S}^3$ two immersions of the Clifford torus and all Lawson $τ_{n, m}$ surfaces are described in terms of $(λ, μ)$-eigenfunctions. Also, a new proof of a theorem that describes $(λ, μ)$-eigenfunctions on sphere is obtained. This proof is based on a statement that a function $f$ is a $(λ, μ)$-eigenfunction if and only if $f$ and $f^2$ are eigenfunctions for the Laplace-Beltrami operator.
