Bergman Kernel Asymptotics for Semipositive Line Bundles near Curvature-Degenerate Points

Yueh-Lin Chiang

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arXiv · 2609.24869

Bergman Kernel Asymptotics for Semipositive Line Bundles near Curvature-Degenerate Points

Yueh-Lin Chiang

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Abstract

We study the asymptotic behavior of Bergman kernels for high tensor powers of semipositive line bundles over Hermitian manifolds. At points where the curvature degenerates, the classical asymptotic expansion may fail. In this paper, we establish a full local asymptotic expansion and rapid off-diagonal decay near degenerate points at which the metric admits a local decoupled model. More generally, we make the following two spectral hypotheses: a localized mild spectral gap for the Kodaira Laplacian and a spectral gap for the rescaled local model. Under these assumptions, we prove a localization property and the rapid off-diagonal decay for the Bergman kernel. Furthermore, if the metric has a local quasi-homogeneous structure, we obtain a full local asymptotic expansion in the $C^\infty$-topology. As an application, we study pull-backs of positive line bundles under branched coverings. Near a smooth ramification hypersurface, the resulting asymptotic expansion reflects the branching order. Finally, for certain non-quasi-homogeneous models, we still obtain localization and leading-order asymptotics.

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BibTeX RIS

Yueh-Lin Chiang. 2026-09-21. Bergman Kernel Asymptotics for Semipositive Line Bundles near Curvature-Degenerate Points. https://arxiv.org/abs/2609.24869

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