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In this paper, we establish a new eigenvalue estimate for the Kohn-Dirac operator on a compact CR manifold. The equality case of this estimate is characterized by the existence of a CR twistor spinor. We then classify CR manifolds carrying…

Differential Geometry · Mathematics 2025-03-31 Georges Habib , Felipe Leitner

We present an introduction to boundary value problems for Dirac-type operators on complete Riemannian manifolds with compact boundary. We introduce a very general class of boundary conditions which contains local elliptic boundary…

Differential Geometry · Mathematics 2024-10-02 Christian Baer , Werner Ballmann

Let $M$ be a closed hypersurface in a noncompact rank-1 symmetric space $(\bar{\mathbb{M}}, ds^2)$ with $-4 \leq K_{\bar{\mathbb{M}}} \leq -1,$ or in a complete, simply connected Riemannian manifold $\mathbb{M}$ such that $0 \leq…

Differential Geometry · Mathematics 2013-01-08 Binoy , G. Santhanam

In this paper, we obtain geometric upper bounds for the first eigenvalue $\lambda_1(J)$ of the Jacobi operator for both closed and compact with boundary hypersurfaces having constant mean curvature (CMC). As an application, we derive new…

Differential Geometry · Mathematics 2026-02-09 Marcio Batista , Marcos P. Cavalcante , Luiz R. Melo

An integer valued topological index of a Dirac operator is introduced for a pair of a 4n+2 dimensional open Spin^c manifold and a section of the determinant line bundle satisfying some property. We show a relation between the index and an…

Differential Geometry · Mathematics 2014-01-22 Shin Hayashi

We study the behavior of the spectrum of the Dirac operator together with a symmetric $W^{1, \infty}$-potential on spin manifolds under a collapse of codimension one with bounded sectional curvature and diameter. If there is an induced spin…

Spectral Theory · Mathematics 2017-08-15 Saskia Roos

In this paper we study eigenvalues of the closed eigenvalue problem of the Witten-Laplacian on an $n$-dimensional compact Riemannian manifold. Estimates for eigenvalues are given. As applications, we give a sharp upper bound for the…

Differential Geometry · Mathematics 2017-01-08 Qing-Ming Cheng , Lingzhong Zeng

Consider a Dirac operator on an oriented compact surface endowed with a Riemannian metric and spin structure. Provided the area and the conformal class are fixed, how small can the $k$-th positive Dirac eigenvalue be? This problem mirrors…

Differential Geometry · Mathematics 2023-08-16 Mikhail Karpukhin , Antoine Métras , Iosif Polterovich

In this paper, we obtain lower bounds for the first eigenvalue to some kinds of the eigenvalue problems for Bi-drifted Laplacian operator on compact manifolds (also called a smooth metric measure space) with boundary and $m$-Bakry-Emery…

Differential Geometry · Mathematics 2021-11-23 Marcio Costa Araújo Filho

We consider the two-dimensional Dirac operator with infinite mass boundary conditions posed in a tubular neighborhood of a $C^4$-planar curve. Under generic assumptions on its curvature $\kappa$, we prove that in the thin-width regime the…

Spectral Theory · Mathematics 2022-07-19 William Borrelli , Nour Kerraoui , Thomas Ourmières-Bonafos

We give a new estimate on the lower bound for the first Dirichlet eigenvalue for a compact manifold with positive Ricci curvature in terms of the in-diameter and the lower bound of the Ricci curvature. The result improves the previous…

Differential Geometry · Mathematics 2007-05-23 Jun Ling

We study an eigenvalue problem for the biharmonic operator with Neumann boundary conditions on domains of Riemannian manifolds. We discuss the weak formulation and the classical boundary conditions, and we describe a few properties of the…

Spectral Theory · Mathematics 2019-07-05 Bruno Colbois , Luigi Provenzano

We generalize the well-known lower estimates for the first eigenvalue of the Dirac operator on a compact Riemannian spin manifold proved by Th. Friedrich (1980) and O. Hijazi (1986, 1992). The special solutions of the Einstein-Dirac…

Differential Geometry · Mathematics 2007-05-23 Thomas Friedrich , Eui Chul Kim

The aim of the present paper is to introduce the notion of first order (supersymmetric) Dirac operators on discrete and metric (``quantum'') graphs. In order to cover all self-adjoint boundary conditions for the associated metric graph…

Spectral Theory · Mathematics 2007-09-03 Olaf Post

In this paper, we analyze the lower bound property of the discrete eigenvalues by the rectangular Morley elements of the biharmonic operators in both two and three dimensions. The analysis relies on an identity for the errors of…

Numerical Analysis · Mathematics 2014-12-31 Jun Hu , Xueqin Yang

We give a new lower bound for the first gap $\lambda_2 - \lambda_1$ of the Dirichlet eigenvalues of the Schr{\"o}dinger operator on a bounded convex domain $\Omega$ in R$^n$ or S$^n$ and greatly sharpens the previous estimates. The new…

Differential Geometry · Mathematics 2007-05-23 Jun Ling

Let M be a closed spin manifold of dimension at least three with a fixed topological spin structure. For any Riemannian metric, we can construct the associated Dirac operator. The spectrum of this Dirac operator depends on the metric of…

Differential Geometry · Mathematics 2015-01-19 Nikolai Nowaczyk

We give lower bounds for the first Dirichilet eigenvalues for domains in submanifolds with locally bounded mean curvatures. These bounds depend on the injectivity radius, sectional curvature (upperbound) of the ambient space and on the mean…

Differential Geometry · Mathematics 2016-09-07 G. Pacelli Bessa , J. Fabio Montenegro

In this paper, we define the spectral Einstein functional associated with the sub-Dirac operator for manifolds with boundary. A proof of the Dabrowski-Sitarz-Zalecki type theorem for spectral Einstein functions associated with the sub-Dirac…

Differential Geometry · Mathematics 2024-04-02 Jin Hong , Yuchen Yang , Yong Wang

We consider the magnetic Dirac operator on a curved strip whose boundary carries the infinite mass boundary condition. When the magnetic field is large, we provide the reader with accurate estimates of the essential and discrete spectra. In…

Mathematical Physics · Physics 2025-01-20 Loïc Le Treust , Julien Royer , Nicolas Raymond
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