The stability of Yang-Mills connections on $δ$-pinched manifolds
Xiaoli Han, Yang Wen
TL;DR
This work addresses rigidity of weakly stable Yang-Mills connections on compact, δ-pinched manifolds. It introduces a dimension-dependent pinching constant δ(n) by constructing specialized variation fields $V_y$ and applying the Bochner–Weitzenböck framework to estimate the second variation along $i_{V_y}R^\nabla$, reducing the problem to the sign of a radial integral involving a function $\Phi_\delta$ with weight $v_\delta$. By optimizing over δ via volume comparison and injectivity radius considerations, the authors prove that in the δ-pinched regime, all weakly stable Yang-Mills connections are flat, and they provide computed δ(n) values for dimensions $n=5$–$20$; the approach also yields a generalized δ(n,R) for varying injectivity radius. The results extend rigidity phenomena for YM fields in pinched geometries and offer concrete geometric constants for classification of YM connections on such manifolds.
Abstract
In this article, we establish pinching conditions under which all weakly stable Yang-Mills connections on compact manifolds are flat. As a corollary, we provide a dimension-dependent constant $δ(n)$ and prove that there exist no non-flat weakly stable Yang-Mills connections on $δ(n)$-pinched compact simply-connected Riemannian manifolds.
