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We calculate the eta-invariant for the odd signature operator relative to a specific submersion metric on the Milnor fibration of a quasihomogeneous hypersurface singularity using certain global boundary conditions in terms of the data of…

Differential Geometry · Mathematics 2012-08-16 Andreas Klein

Consider the massless Dirac operator on a 3-torus equipped with Euclidean metric and standard spin structure. It is known that the eigenvalues can be calculated explicitly: the spectrum is symmetric about zero and zero itself is a double…

Spectral Theory · Mathematics 2013-11-12 Robert J. Downes , Michael Levitin , Dmitri Vassiliev

The Rarita-Schwinger operator is the twisted Dirac operator restricted to 3/2-spinors. Rarita-Schwinger fields are solutions of this operator which are in addition divergence-free. This is an overdetermined problem and solutions are rare;…

Differential Geometry · Mathematics 2021-05-24 Christian Baer , Rafe Mazzeo

An elliptic theory is constructed for operators acting in subspaces defined via odd pseudodifferential projections. Subspaces of this type arise as Calderon subspaces for first order elliptic differential operators on manifolds with…

Differential Geometry · Mathematics 2015-06-26 A. Yu. Savin , B. Yu. Sternin

In this paper, we consider the eigenvalue problem of Dirac operator on a compact Riemannian manifold isometrically immersed into Euclidean space and derive some extrinsic estimates for the sum of arbitrary consecutive $n$ eigenvalues of the…

Differential Geometry · Mathematics 2024-02-23 Lingzhong Zeng

We find and classify possible equivariant spin structures with Dirac operators on the noncommutative torus, proving that similarly as in the classical case the spectrum of the Dirac operator depends on the spin structure.

Quantum Algebra · Mathematics 2018-06-04 Mario Paschke , Andrzej Sitarz

In this paper, we describe the group SpinT (n) and give some properties of this group. We construct SpinT spinor bundle S by means of the spinor representation of the group SpinT (n) and define covariant derivative operator and Dirac…

Differential Geometry · Mathematics 2015-08-24 Senay Bulut , Ali Kemal Erkoca

In this expository paper, we explain a formula for the multiplicities of the index of an equivariant transversally elliptic operator on a $G$-manifold. The formula is a sum of integrals over blowups of the strata of the group action and…

Differential Geometry · Mathematics 2021-01-28 Jochen Brüning , Franz W. Kamber , Ken Richardson

We generalize the transgression formula for the eta form of Bismut, Cheeger and Berline, Getzler, Vergne for vertical Dirac operators on a fibre bundle with odd dimensional fibres where the Dirac operators have locally at most one…

Differential Geometry · Mathematics 2017-07-27 Anja Wittmann

The aim of the lectures is to introduce first-year Ph.D. students and research workers to the theory of the Dirac operator, spinor techniques, and their relevance for the theory of eigenvalues in Riemannian geometry. Topics: differential…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Giampiero Esposito

On a n-dimensional connected compact manifold with non-empty boundary equipped with a Riemannian metric, a spin structure and a chirality operator, we study some properties of a spin conformal invariant defined from the first eigenvalue of…

Differential Geometry · Mathematics 2009-03-10 Simon Raulot

We examine the metric and Einstein bilinear functionals of differential forms introduced in Adv.Math.,Vol.427,(2023)1091286, for Hodge-Dirac operator $d+\delta$ on an oriented even-dimensional Riemannian manifold. We show that they…

Differential Geometry · Mathematics 2024-08-22 Ludwik Dąbrowski , Paweł Zalecki , Andrzej Sitarz

We consider Dirac-like operators with piecewise constant mass terms on spin manifolds, and we study the behaviour of their spectra when the mass parameters become large. In several asymptotic regimes, effective operators appear: the…

Spectral Theory · Mathematics 2022-06-01 Brice Flamencourt

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

We show that the Atiyah-Patodi-Singer reduced $\eta$-invariant of the twisted Dirac operator on a closed $4m-1$ dimensional spin manifold, with the twisted bundle being the Witten bundle appearing in the theory of elliptic genus, is a…

Differential Geometry · Mathematics 2014-07-10 Fei Han , Weiping Zhang

We study the effects of having multiple Spin structures on the partition function of the spacetime fields in M-theory. This leads to a potential anomaly which appears in the eta-invariants upon variation of the Spin structure. The main…

High Energy Physics - Theory · Physics 2012-04-03 Hisham Sati

A version of Kirby calculus for spin and framed three-manifolds is given and is used to construct invariants of spin and framed three-manifolds in two situations. The first is ribbon *-categories which possess odd degenerate objects. This…

Quantum Algebra · Mathematics 2007-05-23 Stephen F. Sawin

We classify the twists of almost commutative spectral triples that keep the Hilbert space and the Dirac operator untouched. The involved twisting operator is shown to be the product of the grading of a manifold by a finite dimensional…

Mathematical Physics · Physics 2021-12-14 Manuele Filaci , Pierre Martinetti

We find sufficient conditions for the absence of harmonic $L^2$ spinors on spin manifolds constructed as cone bundles over a compact K\"ahler base. These conditions are fulfilled for certain perturbations of the Euclidean metric, and also…

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

We study the $\eta$-invariant of a Dirac operator on a manifold with boundary subject to local boundary conditions with the help of heat kernel methods. In even dimensions, we relate this invariant to $\eta$-invariants of a boundary Dirac…

High Energy Physics - Theory · Physics 2022-10-13 A. V. Ivanov , D. V. Vassilevich