Maple Professionel
Maple Académique
Maple Edition Étudiant
Maple Personal Edition
Maple Player
Maple Player for iPad
MapleSim Professionel
MapleSim Académique
Maple T.A. - Suite d'examens de classement
Maple T.A. MAA Placement Test Suite
Möbius - Didacticiels de mathématiques en ligne
Machine Design / Industrial Automation
Aéronautique
Ingénierie des véhicules
Robotics
Energie
System Simulation and Analysis
Model development for HIL
Modélisation du procédé pour la conception de systèmes de contrôle
Robotics/Motion Control/Mechatronics
Other Application Areas
Enseignement des mathématiques
Enseignement de l’ingénierie
Enseignement secondaire et supérieur (CPGE, BTS)
Tests et évaluations
Etudiants
Modélisation financière
Recherche opérationnelle
Calcul haute performance
Physique
Webinaires en direct
Webinaires enregistrés
Agenda des évènements
Forum MaplePrimes
Blog Maplesoft
Membres Maplesoft
Maple Ambassador Program
MapleCloud
Livres blancs techniques
Bulletin électronique
Livres Maple
Math Matters
Portail des applications
Galerie de modèles MapleSim
Cas d'Etudes Utilisateur
Exploring Engineering Fundamentals
Concepts d’enseignement avec Maple
Centre d’accueil utilisateur Maplesoft
Centre de ressources pour enseignants
Centre d’assistance aux étudiants
Tensor[SpinConnection] - compute the spin connection defined by a solder form
Calling Sequences
SpinConnection(sigma)
Parameters
sigma - a solder form
Description
The DifferentialGeometry Tensor package supports general computations with connections on vector bundles (Connection, Example 3; CovariantDerivative, Example 3; DirectionalCovariantDerivative, Example 3; and CurvatureTensor, Example 3). This functionality naturally provides for covariant differentiation of spinors.
Given a solder form sigma, let g be the associated metric. There is a unique spin connection nabla such that nabla(sigma) = 0 and nabla(epsilon) = 0, where epsilon denotes either of the covariant epsilon spinors (EpsilonSpinor). In the definition of nabla(sigma) the tensorial argument or index is covariantly differentiated with respect to the Christoffel connection for g. It is this connection nabla which is computed by the command SpinConnection(sigma).
Note that a generic connection for the differentiation of spinors can be constructed using the Connection command.
This command is part of the DifferentialGeometry:-Tensor package, and so can be used in the form SpinConnection(...) only after executing the commands with(DifferentialGeometry); with(Tensor); in that order. It can always be used in the long form DifferentialGeometry:-Tensor:-SpinConnection.
Examples
Example 1.
First create a vector bundle over M with base coordinates [t, x, y, z] and fiber coordinates [z1, z2, w1, w2].
Define a spacetime metric g on M.
Define an orthonormal frame on M with respect to the metric g.
Calculate the solder form sigma from the frame F.
Calculate the spin-connection for the solder form sigma.
Example 2.
Define a rank 1 spinor phi. Calculate the covariant derivative of phi. Calculate the directional derivatives of phi.
Example 3.
Check that the covariant derivative of sigma vanishes. Because sigma is a spin-tensor, both connections are required. Calculate the Christoffel connection for the metric g.
Define an epsilon spinor and check that its covariant derivative vanishes.
Example 4.
Calculate the curvature spin-tensor for the spin-connection Gamma2.
The curvature tensor R for the Christoffel connection can be expressed in terms of the curvature spin-tensor SpinR, its complex conjugate barSpinR and the bivector solder forms S and barS by the identity
2*R^i_{jhk} = S^i_j_A^B*R^A_{Bhk} + S^i_j_A'^B'*R^A'_{B'hk} (*)
Let's check this formula for the Christoffel connection Gamma1 and the spin-connection Gamma2. First calculate the curvature tensor for Gamma1.
Calculate the complex conjugate of the spinor curvature SpinR.
Calculate the bivector soldering forms S and barS.
The first term on the right-hand side of (*) is
The second term on the right-hand side of (*) is
See Also
DifferentialGeometry, Tensor, BivectorSolderForm, Connection, Physics[Christoffel], CovariantDerivative, Physics[D_], DirectionalCovariantDerivative, CurvatureTensor, Physics[Riemann], EnergyMomentumTensor, EpsilonSpinor, MatterFieldEquations, SpacetimeConventions
Download Help Document