Real hypersurfaces in $Q^m$ with commuting structure Jacobi operator

TL;DR

This paper classifies real hypersurfaces in complex quadrics with commuting structure Jacobi operators, revealing conditions for Reeb curvature and characterizing Reeb flat hypersurfaces with specific geometric properties.

Contribution

It establishes the constancy of Reeb curvature for such hypersurfaces and characterizes Reeb flat hypersurfaces with commuting Ricci tensor or shape operator.

Findings

Reeb curvature is constant for hypersurfaces with commuting structure Jacobi operator.

The tube around $ ext{CP}^k$ with radius $rac{ extpi}{4}$ is unique as a Reeb flat Hopf hypersurface with commuting Ricci tensor.

No Reeb flat Hopf hypersurfaces have non-parallel Killing Ricci tensor or Killing shape operator.

Abstract

In this paper we study real hypersurfaces in the complex quadric space $Q^m$ whose structure Jacobi operator commutes with their structure tensor field. We show that the Reeb curvature $\alpha$ of such hypersurfaces is constant and if $\alpha$ is non-zero then the hypersurface is a tube around a totally geodesic submanifold $\mathbb{C} P^k \subset Q^m$, where $m=2k$. We also consider Reeb flat hypersurfaces, namely, when the Reeb curvature is zero. We show that the tube around $\mathbb{C} P^k \subset Q^m$ ($m=2k$), with radius $\frac{\pi}{4}$ is the only Reeb flat Hopf hypersurface with commuting Ricci tensor and also the only one with commuting shape operator. Finally, we prove that there does not exist any Reeb flat Hopf hypersurfaces with non-parallel Killing Ricci tensor or with Killing shape operator.