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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 relate a recently introduced non-local geometric invariant of compact strictly pseudoconvex Cauchy-Riemann (CR) manifolds of dimension 3 to various eta-invariants in CR geometry: on the one hand a renormalized eta-invariant appearing…

Differential Geometry · Mathematics 2007-05-23 Olivier Biquard , Marc Herzlich , Michel Rumin

In this paper, we introduce the spectral Einstein functional for perturbations of Dirac operators on manifolds with boundary. Furthermore, we provide the proof of the Dabrowski-Sitarz-Zalecki type theorems associated with the spectral…

Geometric Topology · Mathematics 2023-12-06 Sining Wei , Yong Wang

We use the Dirac operator technique to establish sharp distance estimates for compact spin manifolds under lower bounds on the scalar curvature in the interior and on the mean curvature of the boundary. In the situations we consider, we…

Differential Geometry · Mathematics 2024-05-22 Simone Cecchini , Rudolf Zeidler

We derive upper eigenvalue bounds for the Dirac operator of a closed hypersurface in a manifold with Killing spinors such as Euclidean space, spheres or hyperbolic space. The bounds involve the Willmore functional. Relations with the…

Differential Geometry · Mathematics 2007-05-23 Christian Baer

We show that the Dirac operator on a spin manifold does not admit $L^2$ eigenspinors provided the metric has a certain asymptotic behaviour and is a warped product near infinity. These conditions on the metric are fulfilled in particular if…

Differential Geometry · Mathematics 2019-01-08 Andrei Moroianu , Sergiu Moroianu

We give lower bounds for the eigenvalues of the submanifold Dirac operator in terms of intrinsic and extrinsic curvature expressions. We also show that the limiting cases give rise to a class generalizing that of Killing spinors. We…

Differential Geometry · Mathematics 2007-05-23 N. Ginoux , B. Morel

It is known that, for Dirac operators on Riemann surfaces twisted by line bundles with Hermitian-Einstein connections, it is possible to obtain estimates for the first eigenvalue in terms of the topology of the twisting bundle \cite{JL2}.…

Differential Geometry · Mathematics 2013-10-15 Rafael F. Leão

The spectral metric and Einstein functionals defined by two vector fields and Laplace-type operators over vector bundles, giving an interesting example of the spinor connection and square of the Dirac operator. Motivated by the spectral…

Differential Geometry · Mathematics 2025-06-09 Jian Wang , Yong Wang

In the setting of operators on Hilbert spaces, we prove that every quasinilpotent operator has a non-trivial closed invariant subspace if and only if every pair of idempotents with a quasinilpotent commutator has a non-trivial common closed…

Functional Analysis · Mathematics 2022-04-27 Neeru Bala , Nirupam Ghosh , Jaydeb Sarkar

In his book Mickelsson notices that the infinite-dimensional Grassmannian manifold of Segal and Wilson admits a Spin^c structure and after this he naturally considers the problem of defining a Dirac operator on it. Mickelsson gives a…

Representation Theory · Mathematics 2010-07-27 Vesa Tahtinen

We calculate the RT-invariants of all oriented Seifert manifolds directly from surgery presentations. We work in the general framework of an arbitrary modular category as in [V. G. Turaev, Quantum invariants of knots and 3--manifolds, de…

Geometric Topology · Mathematics 2014-10-01 Soren Kold Hansen

We present a new proof, as well as a ${\bf C/Q}$ extension, of the Riemann-Roch-Grothendieck theorem of Bismut-Lott for flat vector bundles. The main techniques used are the computations of the adiabatic limits of $\eta$-invariants…

Differential Geometry · Mathematics 2007-05-23 Xiaonan Ma , weiping Zhang

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

We introduce partial secondary invariants associated to complete Riemannian metrics which have uniformly positive scalar curvature outside a prescribed subset on a spin manifold. These can be used to distinguish such Riemannian metrics up…

K-Theory and Homology · Mathematics 2017-06-15 Rudolf Zeidler

In this article, we study a generalisation of the Seiberg-Witten equations, replacing the spinor representation with a hyperKahler manifold equipped with certain symmetries. Central to this is the construction of a (non-linear) Dirac…

Differential Geometry · Mathematics 2018-08-29 Varun Thakre

We study the Dirac spectrum on compact Riemannian spin manifolds $M$ equipped with a metric connection $\nabla$ with skew torsion $T\in\Lambda^3M$ by means of twistor theory. An optimal lower bound for the first eigenvalue of the Dirac…

Differential Geometry · Mathematics 2013-11-05 Ilka Agricola , Julia Becker-Bender , Hwajeong Kim

We study the deformations of an asymptotically cylindrical Cayley submanifold inside an asymptotically cylindrical Spin(7)-manifold. We prove an index formula for the operator of Dirac type that arises as the linearisation of the…

Differential Geometry · Mathematics 2015-06-02 Matthias Ohst

The purpose of this paper is to give a new proof of results of Moscovici and Stanton on the orbital integrals associated with eta invariants on compact locally symmetric spaces. Moscovici and Stanton used methods of harmonic analysis on…

Differential Geometry · Mathematics 2022-08-12 Jean-Michel Bismut

In this paper we give a new proof of Bismut-Freed's result on the local regularity of the eta invariant of a Dirac operator in odd dimension.

Differential Geometry · Mathematics 2015-06-26 Raphael Ponge