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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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97194290387 · May 202619922001200920172026
48 results for spinor condition

Study of Killing spinor-valued forms and their integrability conditions.

problem Understanding Killing spinor-valued forms and their properties.
method Detailed treatment of prolongation and integrability conditions, relating to curvature of the manifold.
result New solutions found that are not from tensor products of Killing spinors and Killing-Yano forms.

Symmetry operators of twistor spinors and harmonic spinors can be constructed from conformal Killing-Yano forms. Transformation operators relating twistors to harmonic spinors are found in terms of potential forms. These constructions are generalized to gauged twistor spinors and gauged harmonic spinors. The operators …

2017-04-16abs ↗pdf ↗

Let (M,ω)(M,ω) be a symplectic manifold admitting a metaplectic structure (a symplectic analogue of the Riemannian spin structure) and a torsion-free symplectic connection .\nabla. Symplectic Killing spinor fields for this structure are sections of the symplectic spinor bundle satisfying a certain first order partial dif…

2010-04-25abs ↗pdf ↗

Generalization of twistor spinors to Kähler manifolds which are called Kählerian twistor spinors are considered. We find the differential equation satisfied by the bilinear forms of Kählerian twistor spinors. We show that the bilinear form equation reduces to Kählerian conformal Killing-Yano equation under special cond…

2018-11-26abs ↗pdf ↗

In this paper, we study the existence of a skew Killing spinor (see the definition below) on 2 and 3-dimensional Riemannian spin manifolds. We establish the integrability conditions and prove that these spinor fields correspond to twistor spinors in the two dimensional case while, up to a conformal change of the metric…

2011-10-10abs ↗pdf ↗

On a Lorentzian manifold the existence of a parallel null vector field implies certain constraint conditions on the induced Riemannian geometry of a space-like hypersurface. We will derive these constraint conditions and, conversely, show that every real analytic Riemannian manifold satisfying the constraint conditions…

2014-11-12abs ↗pdf ↗

We show stability of pairs of Ricci flat metrics and parallel spinor fields with respect to the spinor flow, i.e. we show that the spinor flow with initial conditions near such pairs converges to a critical point with exponential speed. Moreover, we show stability of certain volume constrained critical points of the sp…

2017-06-28abs ↗pdf ↗

In this note we compare the spinor bundle of a Riemannian manifold (M=M1×...×MN,g)(M=M_1\times...\times M_N,g) with the spinor bundles of the Riemannian factors (Mi,gi)(M_i,g_i). We show, that - without any holonomy conditions - the spinor bundle of (M,g)(M,g) for a special class of metrics is isomorphic to a bundle obtained by tensoring t…

2002-12-04abs ↗pdf ↗

In this text we introduce the torsion of spinor connections. In terms of the torsion we give conditions on a spinor connection to produce Killing vector fields. We relate the Bianchi type identities for the torsion of spinor connections with Jacobi identities for vector fields on supermanifolds. Furthermore, we discuss…

2006-11-09abs ↗pdf ↗

The paper finds exact solutions to a complex Einstein-Dirac-Maxwell system on 4D Sasakian spacetimes.

problem Finding exact solutions to an Einstein-Dirac-Maxwell system with Sasakian quasi-Killing spinors.
method Constructing a family of exact solutions on four-dimensional static Sasakian spacetimes using the Sasakian frame.
result Closed and open universe models are found with specific energy conditions.

We show that the first-order symmetry operators of twistor spinors can be constructed from conformal Killing-Yano forms in conformally-flat backgrounds. We express the conditions on conformal Killing-Yano forms to obtain mutually commuting symmetry operators of twistor spinors. Conformal superalgebras which consist of …

2016-05-11abs ↗pdf ↗

Study on harmonic spinors on specific Lie groups.

problem Existence of left-invariant harmonic spinors on 3D Lie groups.
method Revised spin Dirac operator formula for left-invariant spinors, identified constraints on Lie algebras, and classified metrics with harmonic spinors.
result Identified conditions and metrics for left-invariant harmonic spinors on 3D Lie groups.

The theory of spinors is developed for locally anisotropic (la) spaces, in brief la-spaces, which in general are modeled as vector bundles provided with nonlinear and distinguished connections and metric structures (such la-spaces contain as particular cases the Lagrange, Finsler and, for trivial nonlinear connections,…

1996-04-05abs ↗pdf ↗

We study twistor spinors (with torsion) on Riemannian spin manifolds (Mn,g,T)(M^{n}, g, T) carrying metric connections with totally skew-symmetric torsion. We consider the characteristic connection c=g+12T\nabla^{c}=\nabla^{g}+\frac{1}{2}T and under the condition cT=0\nabla^{c}T=0, we show that the twistor equation with torsion w.r…

2015-09-28abs ↗pdf ↗

This paper classifies 4D spin manifolds with skew Killing spinors.

problem Classifying 4D Riemannian spin manifolds with skew Killing spinors.
method Analyzing skew Killing spinors with skew-symmetric endomorphisms A, considering both degenerate and non-degenerate cases.
result In the degenerate case, the manifold is locally isometric to R x N with N having a skew Killing spinor.

Study of pure spinors on neutral manifolds with applications to supersymmetric solutions.

problem Characterizing pure spinors and their properties on neutral manifolds.
method Using the theory of real spinorial forms and differential systems, the square of pure spinors is analyzed.
result Non-pure spinors correspond to specific structures in signature (4,4), and parallel spinors are characterized by differential systems.

This text is dedicated to the real Killing equation on 3-dimensional Weyl manifolds. Any manifold admitting a real Killing spinor of weight 0 satisfies the conditions of a Gauduchon-Tod geometry. Conversely, any simply connected Gauduchon-Tod geometry has a 2-dimensional space of solutions of the real Killing equation …

1999-12-15abs ↗pdf ↗

The paper proves stability for Einstein metrics with special twisted spinors.

problem Stability of Einstein metrics with specific spinor conditions.
method Proves linear semi-stability for a class of Einstein metrics with non-positive scalar curvature.
result Linear semi-stability for Einstein metrics carrying a parallel twisted spinr^r spinor.

The paper studies parallel spinor flows on 3D Cauchy hypersurfaces and provides initial data characterizations.

problem Characterizing parallel spinors on Ricci flat Lorentzian four-manifolds.
method Evolution flow defined by parallel spinors, proving preservation of constraints, solving left-invariant flows.
result Initial data characterization of parallel spinors on Ricci flat Lorentzian four-manifolds.

We classify locally homogeneous quasi-Sasakian manifolds in dimension five that admit a parallel spinor ψψ of algebraic type Fψ=0F \cdot ψ= 0 with respect to the unique connection \nabla preserving the quasi-Sasakian structure and with totally skew-symmetric torsion. We introduce a certain conformal transformation of …

2001-11-12abs ↗pdf ↗

Study torsion parallel spinors on Lorentzian 4-manifolds and their evolution flows.

problem Investigate torsion parallel spinors on Lorentzian four-manifolds.
method Geometric study via spinorial polyforms and supersymmetric NS-NS system.
result Globally hyperbolic evolution flow determined by supersymmetric solutions.

Massless Majorana spinors cannot exist in Kerr spacetime under certain conditions.

problem Existence of massless Majorana spinors in Kerr spacetime.
method Analyzing Dirac equation and separating it into radial and angular equations; proving nonexistence under specific conditions.
result Massless Majorana spinors can only exist if angular momentum a=0a=0 and spacetime reduces to Schwarzschild spacetime.

Generic distributions on 5- and 6-manifolds give rise to conformal structures that were discovered by P. Nurowski resp. R. Bryant. We describe both as Fefferman-type constructions and show that for orientable distributions one obtains conformal spin structures. The resulting conformal spin geometries are then character…

2010-04-21abs ↗pdf ↗

Extends Killing superalgebras to higher dimensions and signatures.

problem Generalizing Killing superalgebras to higher dimensions and signatures.
method Definition of Killing superalgebras for connections on spinor bundles, sufficient conditions for existence, abstract study using Spencer cohomology.
result Existence of Killing superalgebras as filtered deformations of graded subalgebras of the Poincaré superalgebra.

We develop a spinorial description of CR structures of arbitrary codimension. More precisely, we characterize almost CR structures of arbitrary codimension on (Riemannian) manifolds by the existence of a Spinc,r^{c, r} structure carrying a partially pure spinor field. We study various integrability conditions of the alm…

2016-10-14abs ↗pdf ↗

We consider weighted parallel spinors in Lorentzian Weyl geometry in arbitrary dimensions, choosing the weight such that the integrability condition for the existence of such a spinor, implies the geometry to be Einstein-Weyl. We then use techniques developed for the classification of supersymmetric solutions to superg…

2011-07-05abs ↗pdf ↗

Investigates parallel spinors on Lorentzian four-manifolds using differential geometry.

problem Characterizing and classifying Lorentzian four-manifolds with parallel spinors.
method Formulated parallel spinor flow equations and used parabolic pairs theory.
result Characterized all parallel Cauchy pairs on simply connected Cauchy surfaces and classified compact three-manifolds.

Develops complex spinorial forms for all dimensions and signatures, proving Brinkmann waves in supergravity.

problem Study of constrained parallelicity conditions for irreducible complex spinors.
method Differential theory of complex spinorial forms, reformulating conditions as equivalent differential systems.
result Every quasi-supersymmetric solution of Freedman's gauged supergravity belongs to a family of Brinkmann waves.

We develop a new framework for the study of generalized Killing spinors, where generalized Killing spinor equations, possibly with constraints, can be formulated equivalently as systems of partial differential equations for a polyform satisfying algebraic relations in the Kähler-Atiyah bundle constructed by quantizing …

2019-11-20abs ↗pdf ↗

Modified construction for conformal structures with twistor spinors.

problem Geometric construction and characterization of conformal structures.
method Geometric construction and characterization of 2n2n-dimensional split-signature conformal structures.
result Explicit geometrically constructed Fefferman-Graham ambient metric with vanishing QQ-curvature.

Study of differential spinors on three-manifolds with skew-torsion.

problem Characterizing differential spinors on Lorentzian three-manifolds with skew-torsion.
method Developed spinorial polyforms and used them to study differential spinors, proving that every differential spinor is equivalent to an isotropic line preserved by a metric connection with skew-torsion.
result Obtained structural results about Lorentzian three-manifolds equipped with skew-torsion parallel spinors, which are necessarily Kundt and geodesically complete in the compact case.

Researchers prove an index formula for spinors on 3-manifolds branching along graphs.

problem Index formula for Dirac operators on 3-manifolds with branch points.
method Analyzes Dirac operator on two-valued spinors on a 3-manifold with a graph branch, with boundary conditions.
result Index formula vanishes when the branch is a smooth curve, extends to graphs with vertices.

Study proves positivity of quasi-local masses in general relativity using spinors.

problem Proving the positivity of quasi-local masses in general relativity.
method Using spinors and solving Dirac equation on compact Riemannian manifolds with boundary conditions.
result Gravitational mass bounded by a spacelike topological 2-sphere is non-negative, vanishing only in Minkowski space.

The paper constructs pseudo-Iwasawa solvmanifolds with Killing spinors.

problem Constructing Killing spinors on pseudo-Riemannian solvmanifolds.
method Using nilsolitons and pseudo-Iwasawa condition, the paper constructs families of pseudo-Iwasawa solvmanifolds with Killing spinors.
result All pseudo-Iwasawa solvmanifolds admitting a Killing spinor belong to a specific family.

In this paper, the Dirac, twistor and Killing equations on Weyl manifolds with CSpin structures are investigated. A conformal Schr"odinger-Lichnerowicz formula is presented and used to show integrability conditions for these equations. By introducing the Killing equation for spinors of arbitrary weight, the result of A…

1999-01-27abs ↗pdf ↗

Consider a Riemannian spin manifold (Mn,g)(M^{n}, g) (n3)(n\geq 3) endowed with a non-trivial 3-form TΛ3TMT\inΛ^{3}T^{*}M, such that cT=0\nabla^{c}T=0, where c:=g+12T\nabla^{c}:=\nabla^{g}+\frac{1}{2}T is the metric connection with skew-torsion TT. In this note we introduce a generalized 12\frac{1}{2}-Ricci type formula for the spinor…

2017-03-12abs ↗pdf ↗

The paper shows connections can be uniquely determined by their boundary data.

problem Determining unique connections from boundary measurements.
method Defined a Dirichlet-to-Neumann map for twisted Dirac Laplacians and showed its pseudodifferential properties.
result Equal Dirichlet-to-Neumann maps imply locally gauge equivalent connections.

Paper shows how Non-Abelian T-duality solves pure spinor equations in supersymmetric vacua.

problem Preserving N=1{\cal{N}} = 1 supersymmetry in Type II supergravity requires specific pure spinor equations.
method Demonstrates that Non-Abelian T-duality (NATD) is a solution generating transformation for these pure spinor equations, showing covariance under Pin(d,d)Pin(d,d) transformations.
result Non-Abelian T-duality (NATD) generates a flux that matches the geometric flux associated with the isometry group.

We study the twistor equation on pseudo-Riemannian SpincSpin^c-manifolds whose solutions we call charged conformal Killing spinors (CCKS). We derive several integrability conditions for the existence of CCKS and study their relations to spinor bilinears. A construction principle for Lorentzian manifolds admitting CCKS wit…

2014-03-10abs ↗pdf ↗