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A locally-built, LLM-digested index of recent arXiv papers in quant finance, geometry/topology, and statistical ML — keyword search served straight from SQLite on this machine.

168,657 papers · 148 categories

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4896143191 · May 202619922001200920172026
48 results for spin-c Dirac operator

The study explores psc-metrics on non-spin manifolds with pin^\pm or spin^c structures.

problem Existence of psc-metrics on non-spin manifolds with specific structures.
method Analysis of Dirac operators and index theory on pin^\pm or spin^c manifolds.
result The index of a Dirac operator controls the existence of psc-metrics on certain manifolds.

We derive an inequality that relates nodal set and eigenvalues of a class of twisted Dirac operators on closed surfaces and point out how this inequality naturally arises as an eigenvalue estimate for the Spinc\rm Spin^c Dirac operator. This allows us to obtain eigenvalue estimates for the twisted Dirac operator appearing…

2016-01-28abs ↗pdf ↗

We extend to the eigenvalues of the hypersurface Spinc^c Dirac operator well known lower and upper bounds. Examples of limiting cases are then given. Futhermore, we prove a correspondence between the existence of a Spinc^c Killing spinor on homogeneous 3-dimensional manifolds E(κ,τ)\mathbb E^*(κ, τ) with 4-dimensional is…

2012-07-12abs ↗pdf ↗

Alternative proof and description of orientations for instanton moduli spaces.

problem Describing the relation between different orientations of GG-instanton moduli spaces.
method Using Witten localization of the index of a Dirac type operator.
result Alternative construction and proof of orientability of instanton moduli spaces.

We establish a vanishing result for indices of certain twisted Dirac operators on Spinc\text{Spin}^c-manifolds with non-abelian Lie-group actions. We apply this result to study non-abelian symmetries of quasitoric manifolds. We give upper bounds for the degree of symmetry of these manifolds.

2011-08-04abs ↗pdf ↗

We establish the factorization of Dirac operators on Riemannian submersions of compact spinc^c manifolds in unbounded KK-theory. More precisely, we show that the Dirac operator on the total space of such a submersion is unitarily equivalent to the tensor sum of a family of Dirac operators with the Dirac operator on th…

2016-10-10abs ↗pdf ↗

The Dirac operator for a manifold Q, and its chirality operator when Q is even dimensional, have a central role in noncommutative geometry. We systematically develop the theory of this operator when Q=G/H, where G and H are compact connected Lie groups and G is simple. An elementary discussion of the differential geome…

2002-10-30abs ↗pdf ↗

On SpincSpin^c manifolds, we study the Energy-Momentum tensor associated with a spinor field. First, we give a spinorial Gauss type formula for oriented hypersurfaces of a SpincSpin^c manifold. Using the notion of generalized cylinders, we derive the variationnal formula for the Dirac operator under metric deformation and po…

2010-11-01abs ↗pdf ↗

In this paper, we write down Seiberg-Witten equations on contact metric manifolds of dimension 5. Any contact metric manifold has a spin^c structure. For Dirac equation we use Dirac type operators associated to the generalized Tanaka-Webster connection on spin^c spinor bundle of a contact metric manifold. For curvature…

2013-06-05abs ↗pdf ↗

Let GG be a compact connected Lie group, and MM a compact Hamiltonian GG-space, with moment map JJ. For each GG-equivariant Hermitian vector bundle EE over MM, one has an associated twisted Spin-C Dirac operator, whose equivariant index is a symplectic invariant of EE. In the present paper, we study gluing prop…

1995-04-26abs ↗pdf ↗

In this paper, we extend the Hijazi type inequality, involving the Energy-Momentum tensor, to the eigenvalues of the Dirac operator on complete Riemannian Spinc^c manifolds without boundary and of finite volume. Under some additional assumptions, using the refined Kato inequality, we prove the Hijazi type inequality f…

2011-01-23abs ↗pdf ↗

The paper classifies hypersurfaces in Spinc^c manifolds that satisfy a specific inequality.

problem Classifying hypersurfaces in Spinc^c manifolds that satisfy a particular inequality.
method Using the Spinc^c Bär inequality and properties of real Killing spinors.
result Hypersurfaces satisfying the equality case in the Spinc^c Bär inequality are slices of cones over Riemannian Spinc^c manifolds.

Classifies manifolds with specific spinors and constructs parallel spinors.

problem Classifying manifolds with generalized Killing spinors.
method Explicitly constructs parallel spinors and considers modified Dirac currents.
result Classifies Riemannian spin^c manifolds with type I and II imaginary generalized Killing spinors.

We study two quantization schemes for compact symplectic manifolds with almost complex structures. The first of these is the Spin-c quantization. We prove the analog of Kodaira vanishing for the Spin-c Dirac operator, which shows that the index space of this operator provides an honest (not virtual) vector space semicl…

1996-08-17abs ↗pdf ↗

Paper extends variational formula for Bismut-Cheeger eta form, proving key theorems in K-theory.

problem Extending variational formula for Bismut-Cheeger eta form without kernel bundle assumption.
method Twisting spinc^c Dirac operators by isomorphic vector bundles, proving Z2\mathbb{Z}_2-graded additivity.
result Analytic index in differential K-theory is a well-defined group homomorphism, and Riemann-Roch-Grothendieck theorem in R/Z\mathbb{R}/\mathbb{Z} K-theory.

This paper explores conditions for positive scalar curvature on spin^c manifolds.

problem Conditions for the existence of metrics with positive scalar curvature on spin^c manifolds.
method Introduces a new scalar-valued function and uses it to study positivity conditions.
result Equivalence between positivity of the new scalar function and the old twisted scalar curvature.

Paradan and Vergne generalised the quantisation commutes with reduction principle of Guillemin and Sternberg from symplectic to Spinc^c-manifolds. We extend their result to noncompact groups and manifolds. This leads to a result for cocompact actions, and a result for non-cocompact actions for reduction at zero. The r…

2014-08-01abs ↗pdf ↗

Constructs small bundle gerbes and proves index theorems for manifolds.

problem Constructing and analyzing bundle gerbes on manifolds.
method Defines and constructs small bundle gerbes, uses pseudodifferential and semiclassical smoothing operators, proves index theorems.
result Proves the Atiyah-Singer type theorem for small bundle gerbes, showing their relation to twisted K-theory.

The study classifies spinc^c manifolds with positive generalized scalar curvature.

problem Classifying spinc^c manifolds with positive generalized scalar curvature.
method Using generalized scalar curvature, index of spinc^c Dirac operator, and surgery techniques.
result Positive generalized scalar curvature metrics exist if and only if a specific invariant vanishes.

In this note, we look at estimates for the scalar curvature k of a Riemannian manifold M which are related to spin^c Dirac operators: We show that one may not enlarge a Kaehler metric with positive Ricci curvature without making k smaller somewhere on M. We also give explicit upper bounds for min(k) for arbitrary Riema…

1999-05-14abs ↗pdf ↗

Researchers compute Floer homotopy types and eta invariants for Seifert 3-manifolds.

problem Computing Floer homotopy types and eta invariants for Seifert 3-manifolds.
method Floer homology, Seiberg-Witten Floer homotopy type, adiabatic connections, spin^c-Dirac operators, eta invariants, orbifold pin^c-connections.
result Floer homotopy types are suspensions of S^0, and Seifert 3-manifolds are L-spaces.

We develop the theory of Berezin-Toeplitz operator on any compact symplectic prequantizable manifold from scratch. Our main inspiration is the Boutet de Monvel-Guillemin theory, that we simplify in several ways to obtain a concise exposition. A comparison with the spin-c Dirac quantization is also included.

2014-09-30abs ↗pdf ↗

Constructs differential models for twisted Spin^c-bordism and its dual, defining a new anomaly map.

problem Modeling and understanding twisted Spin^c-bordism and its dual.
method Geometric construction using bundle gerbes, gerbe modules, and eta-invariants.
result Definition of a twisted anomaly map from differential twisted K-theory to differential Anderson dual of twisted Spin^c-bordism.

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 possible candidate for such an operator but unfortunately it proves out to be badly di…

2009-09-07abs ↗pdf ↗

We study general conditions under which the computations of the index of a perturbed Dirac operator Ds=D+sZD_{s}=D+sZ localize to the singular set of the bundle endomorphism ZZ in the semi-classical limit ss\to \infty . We show how to use Witten's method to compute the index of DD by doing a combinatorial computation inv…

2003-07-17abs ↗pdf ↗

Study Floer theory of hyperbolic three-manifolds using Dirac spectral flow.

problem Computing Floer theory of hyperbolic three-manifolds with non-trivial homology.
method Combining geometric data with Fourier analytic tools and odd Selberg trace formulas.
result First computations of monopole Floer chain complexes for hyperbolic three-manifolds.