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We prove a generalization of Gromov's conjecture on scalar curvature rigidity of convex polytopes to arbitrary convex Riemannian polytope type domains via harmonic spinors on convex domians with boundary condition constructed by Brendle. In…

Differential Geometry · Mathematics 2024-10-29 Xuan Yao

We analyze the level sets of the norm of the Witten spinor in an asymptotically flat Riemannian spin manifold of positive scalar curvature. Level sets of small area are constructed. We prove curvature estimates which quantify that, if the…

Differential Geometry · Mathematics 2014-01-28 Felix Finster

We develop two connections between the quantitative framework of operator $K$-theory for geometric $C^*$-algebras and the problem of positive scalar curvature. First, we introduce a quantitative notion of higher index and use it to give a…

K-Theory and Homology · Mathematics 2024-09-02 Hao Guo , Zhizhang Xie , Guoliang Yu

New extrinsic lower bounds are given for the classical Dirac operator on the boundary of a compact domain of a spin manifold. The main tool is to solve some boundary problems for the Dirac operator of the domain under boundary conditions of…

Differential Geometry · Mathematics 2007-05-23 Oussama Hijazi , Sebastian Montiel , Xiao Zhang

This paper develops a weighted $L^2$-method for the (half) Dirac equation. For Dirac bundles over closed Riemann surfaces, we give a sufficient condition for the solvability of the (half) Dirac equation in terms of a curvature integral.…

Differential Geometry · Mathematics 2016-01-20 Qingchun Ji , Ke Zhu

We investigate the interaction between systolic geometry and positive scalar curvature through spinorial methods. Our main theorem establishes an upper bound for the two-dimensional stable systole on certain high-dimensional manifolds with…

Differential Geometry · Mathematics 2025-09-30 Shunichiro Orikasa

We prove a lower estimate for the first eigenvalue of the Dirac operator on a compact locally reducible Riemannian spin manifold with positive scalar curvature. We determine also the universal covers of the manifolds on which the smallest…

Differential Geometry · Mathematics 2007-05-23 Bogdan Alexandrov

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 derive a formula for the index of a Dirac operator on a compact, even-dimensional incomplete edge space satisfying a "geometric Witt condition". We accomplish this by cutting off to a smooth manifold with boundary, applying the…

Differential Geometry · Mathematics 2016-09-09 Pierre Albin , Jesse Gell-Redman

Let $(M_i, g_i)_{i \in \mathbb{N}}$ be a sequence of spin manifolds with uniform bounded curvature and diameter that converges to a lower dimensional Riemannian manifold $(B,h)$ in the Gromov-Hausdorff topology. Lott showed that the…

Spectral Theory · Mathematics 2019-05-08 Saskia Roos

Rigidity results for asymptotically locally hyperbolic manifolds with lower bounds on scalar curvature are proved using spinor methods related to the Witten proof of the positive mass theorem. The argument is based on a study of the Dirac…

dg-ga · Mathematics 2011-07-21 L. Andersson , M. Dahl

We give a lower bound for the eigenvalues of the Dirac operator on a compact domain of a Riemannian spin manifold under the $\MIT$ bag boundary condition. The limiting case is characterized by the existence of an imaginary Killing spinor.

Differential Geometry · Mathematics 2015-06-26 Simon Raulot

In this paper, we prove an upper bound on the $\widehat{A}$ genus of a smooth, closed, spin Riemannian manifold using its scalar curvature lower bound, Neumann isoperimetric constant, and volume. The proof of this result relies on spectral…

Differential Geometry · Mathematics 2024-10-14 Qiaochu Ma , Jinmin Wang , Guoliang Yu , Bo Zhu

We study the Dirac spectrum on compact Riemannian spin manifolds $M$ equipped with a metric connection $\nabla$ with skew torsion $T\in\Lambda^3 M$ in the situation where the tangent bundle splits under the holonomy of $\nabla$ and the…

Differential Geometry · Mathematics 2013-11-06 Ilka Agricola , Hwajeong Kim

In this paper, we consider a compact Riemannian manifold whose boundary is endowed with a Riemannian flow. Under a suitable curvature assumption depending on the O'Neill tensor of the flow, we prove that any solution of the basic Dirac…

Differential Geometry · Mathematics 2015-07-09 Fida El Chami , Nicolas Ginoux , Georges Habib , Roger Nakad

We give results about the L^2 kernel and the spectrum of the Dirac operator on a complete Riemannian manifold which is conformally equivalent to the interior of a Riemannian manifold with nonempty boundary.

Differential Geometry · Mathematics 2007-05-23 John Lott

We study the interplay between basic Dirac operator and transverse Killing and twistor spinors. In order to obtain results for general Riemannian foliations with bundle-like metric we consider transverse Killing spinors that appear as…

Mathematical Physics · Physics 2013-09-03 Adrian Mihai Ionescu , Vladimir Slesar , Mihai Visinescu , Gabriel-Eduard Vilcu

We prove lower Dirac eigenvalue bounds for closed surfaces with a spin structure whose Arf invariant equals 1. Besides the area only one geometric quantity enters in these estimates, the spin-cut-diameter which depends on the choice of spin…

Differential Geometry · Mathematics 2007-05-23 Bernd Ammann , Christian Baer

Given a Riemannian spin^c manifold whose boundary is endowed with a Riemannian flow, we show that any solution of the basic Dirac equation satisfies an integral inequality depending on geometric quantities, such as the mean curvature and…

Differential Geometry · Mathematics 2016-12-13 Fida Chami , Nicolas Ginoux , Georges Habib , Roger Nakad

We construct spectral triples and, in particular, Dirac operators, for the algebra of continuous functions on certain compact metric spaces. The triples are countable sums of triples where each summand is based on a curve in the space.…

Metric Geometry · Mathematics 2007-06-19 Erik Christensen , Cristina Ivan , Michel L. Lapidus