We prove a lower bound for the first eigenvalue of the Dirac operator on a compact Riemannian spin manifold depending on the scalar curvature as well as a chosen Codazzi tensor. The inequality generalizes the classical estimate from [2].
We prove the Reilly formula for a class of elliptic divergence differential operator $L_Au=div(A\nabla u)$, where $A$ is a (1,1)-Codazzi tensor field. Then we get some estimates for the first positive eigenvalue of the operator.
In this note, we prove lower and upper bounds for Dirac operators of submanifolds in certain ambient manifolds in terms of conformal and extrinsic quantities.
In two previous papers, we started a study of the first eigenvalue of the Dirac operator on compact spin symmetric spaces, providing, for symmetric spaces of "inner" type, a formula giving this first eigenvalue in terms of the algebraic data of the groups involved. We conclude here that study by giving the explicit expression of the first eigenvalue for "outer" compact spin symmetric spaces.
We re-visit the eigenvalue estimate of the Dirac operator on spin manifolds with boundary in terms of the first eigenvalues of conformal Laplace operator as well as the conformal mean curvature operator. These problems were studied earlier by Hijazi-Montiel-Zhang and Raulot and we re-prove them under weaker assumption that a boundary chirality operator exists. Moreover, on these spin manifolds with boundary, we show that any $C^{3,α}$ conformal compactification of some Poincare-Einstein metric must be the standard hemisphere when the first nonzero eigenvalue of the Dirac operator achieves its …
In this paper, we get estimates on the higher eigenvalues of the Dirac operator on locally reducible Riemannian manifolds, in terms of the eigenvalues of the Laplace-Beltrami operator and the scalar curvature. These estimates are sharp, in the sense that, for the first eigenvalue, they reduce to the result of Alexandrov.
Existence of Dirac Eigenvalues of higher Multiplicity
本文证明了:在任意m维同余0,6,7 mod 8的紧自旋流形上,存在一个度量,使得相应的Dirac算子至少有一个重数至少为2的本征值.我们证明了这一点,通过捕捉所需的度量在一个子空间的黎曼度量的循环,是不是同伦平凡。我们展示了如何可以做到这一点的领域与一个循环的度量引起的家庭的旋转。最后,我们通过推广有关自旋流形上手术理论的一些已知结果,将这个循环转移到任意流形(具有适当的维度)。
设M是一个具有固定拓扑自旋结构的至少为3维的闭自旋流形。对于任何黎曼度量,我们可以构造相应的狄拉克算子。这个狄拉克算子的谱当然取决于度规。在2005年,达尔提出M可以被给定一个度量,使得谱的有限部分由任意规定的任意(有限)重数的本征值组成。唯一的限制是零特征值的例外(由于Atiyah-Singer指数定理),在某些维度上,特征空间的四元数结构和谱的对称性。达尔还证明了他的猜想的情况下,所有的特征值有简单的多重性。这个问题,如果一个人可以规定任意的多重性,或者如果存在的本征值的更高的多重性可能会以某种方式拓扑阻碍,一直开放至今。在这篇论文中,我们证明了在任意m维同余0,6,7 mod 8的闭自旋流形上,存在至少一个特征值具有较高重数的度量。为了证明,我们引入了一种技术,它“捕捉”所需的度量与所有黎曼度量的空间中的一个循环。我们将在球面上构造这样一个环,并通过推广Bär和Dahl的一些经典的外科手术理论结果,将它转移到一般流形上。作为准备,我们将表明,狄拉克频谱可以描述的一个连续的家庭的空间上的黎曼度量的功能和旋量场丛的各种度量组装成一个连续丛的希尔伯特空间。这些结果本身可能是有用的。
In this note, we prove an optimal upper bound for the first Dirac eigenvalue of some hypersurfaces in Euclidean space by combining a positive mass theorem and the construction of quasi-spherical metrics. As a direct consequence of this estimate, we obtain an asymptotic expansion for the first eigenvalue of the Dirac operator on large spheres in three dimensional asymptotically flat manifolds. We also study this expansion for small geodesic spheres in a three dimensional Riemannian manifold. We finally discuss how this method can be adapted to yield similar results in the hyperbolic space.
We get optimal lower bounds for the eigenvalues of the submanifold Dirac operator on locally reducible Riemannian manifolds in terms of intrinsic and extrinsic expressions. The limiting-cases are also studied. As a corollary, one gets several known results in this direction.