The index of Dirac operators on manifolds with fibered boundaries

Low energy limit for the resolvent of some fibered boundary operators

For certain Dirac operators $ð_ϕ$ associated to a fibered boundary metric $g_ϕ$, we provide a pseudodifferential characterization of the limiting behavior of $(ð_ϕ+kγ)^{-1}$ as $k\searrow 0$, where $γ$ is a self-adjoint operator anti-commuting with $ð_ϕ$ and whose square is the identity. This yields in particular a pseudodifferential characterization of the low energy limit of the resolvent of $ð_ϕ^2$, generalizing a result of Guillarmou and Sher about the low energy limit of the resolvent of the Hodge Laplacian of an asymptotically conical metric. As an application, we use our result to give …

Odd Pfaffian forms

On any odd-dimensional oriented Riemannian manifold we define a volume form, which we call the odd Pfaffian, through a certain invariant polynomial with integral coefficients in the curvature tensor. We prove an intrinsic Chern-Gauss-Bonnet formula for incomplete edge singularities in terms of the odd Pfaffian on the fibers of the boundary fibration. The formula holds for product-type model edge metrics where the degeneration is of conical type in each fiber, but also for general classes of perturbations of the model metrics. The same method produces a Chern- Gauss-Bonnet formula for complete,…

Determinant bundles, boundaries, and surgery

In this note we specialize and illustrate the ideas developed in the paper math.DG/0201112 of the first author ("Index theory, eta forms, and Deligne cohomology ") in the case of the determinant line bundle. We discuss the surgery formula in the adiabatic limit using the adiabatic decomposition formula of the zeta regularized determinant of the Dirac Laplacian obtained by the second author and K. Wojciechowski.

Boundary value problems for noncompact boundaries of Spin$^c$ manifolds and spectral estimates

We study boundary value problems for the Dirac operator on Riemannian Spin$^c$ manifolds of bounded geometry and with noncompact boundary. This generalizes a part of the theory of boundary value problems by C. Bär and W. Ballmann for complete manifolds with closed boundary. As an application, we derive the lower bound of Hijazi-Montiel-Zhang, involving the mean curvature of the boundary, for the spectrum of the Dirac operator on the noncompact boundary of a Spin$^c$ manifold. The limiting case is then studied and examples are then given.

Pseudodifferential operators on manifolds with foliated boundaries

Let X be a smooth compact manifold with boundary. For smooth foliations on the boundary of X admitting a `resolution' in terms of a fibration, we construct a pseudodifferential calculus generalizing the fibred cusp calculus of Mazzeo and Melrose. In particular, we introduce certain symbols leading to a simple description of the Fredholm operators inside the calculus. When the leaves of the fibration `resolving' the foliation are compact, we also obtain an index formula for Fredholm perturbations of Dirac-type operators. Along the way, we obtain a formula for the adiabatic limit of the eta inva…

平坦与球面背景下具有平均凸边界的流形的 Brown-York 质量正定性及刚性的紧致方法

Compact approach to the positivity of Brown-York mass and rigidity of manifolds with mean-convex boundaries in flat and spherical contexts

本文利用旋量证明与 ADM 质量正定性，为 Brown-York 质量正定性提供了紧致方法，并得出 Dirac 算子特征值下界及平坦与球面空间中平均凸流形的刚性结果。

Boundaries, eta invariant and the determinant bundle

Cobordism invariance shows that the index, in K-theory, of a family of pseudodifferential operators on the boundary of a fibration vanishes if the symbol family extends to be elliptic across the whole fibration. For Dirac operators with spectral boundary condition, Dai and Freed \cite{dai-freed1} gave an explicit version of this at the level of the determinant bundle. Their result, that the eta invariant of the interior family trivializes the determinant bundle of the boundary family, is extended here to the wider context of pseudodifferential families of cusp type.

第一边界 Dirac 特征值与边界容量势

First boundary Dirac eigenvalue and boundary capacity potential

本文研究非负标量曲率自旋渐近平坦流形中超曲面的第一 Dirac 特征值，利用边界容量势与容量建立新的几何下界，并通过奇异度量紧流形的特征值估计完成证明。

$\mathbf{Pin}^\pm$- 与 $\mathbf{Spin}^c$-流形上的正标量曲率

Positive scalar curvature on $\mathbf{Pin}^\pm$- and $\mathbf{Spin}^c$-manifolds

本文研究具有spin$^c$或pin$^\pm$结构的非旋量流形，证明狄拉克算子指标完全控制特殊子流形附近不变psc-度量的存在性，并将流形对解释为带纤维化奇点的流形。

从格点中捕捉阿蒂亚-帕蒂迪-辛格索引

Capturing the Atiyah-Patodi-Singer index from the lattice

本文通过格点规范理论构建狄拉克算子的阿蒂亚-帕蒂迪-辛格索引公式，利用域墙费米子狄拉克算子的谱流性质，证明在足够小的格点间距下，该方法能正确捕捉连续极限下的索引。