Journal of geometryand physics elsevier journal of geometry and physics 18 1996 1146 the graded algebra and the derivative z of spinor fields related to the twistor equation k. Some way must be found to pick out a single irreducible representation s from the reducible representation on rn. Spinor lie derivatives and fermion stressenergies proceedings of. These spinors generate the killing superalgebra, which is a useful invariant of the universe. Kosmann was able to define a lie derivative of a spinor field along a killing vector. A geometric construction of exceptional lie algebras. When a sequence of such small rotations is composed to form an overall final rotation, however, the. Pdf a geometric definition of lie derivative for spinor. Spinor representation of lie algebra for complete linear group. Alternatively, the covariant derivative is a way of introducing and working with a connection on a manifold by means of a differential operator, to be contrasted with the approach given by a principal connection on the frame bundle see affine connection. Pdf we show how the ad hoc prescriptions appeared in 2001 by ortin for the. Twistor spinors and extended conformal superalgebras.
Geometric significance of the spinor lie derivative i. In trying to get to grips with lie derivatives im completely lost, just completely lost. In mathematics, the covariant derivative is a way of specifying a derivative along tangent vectors of a manifold. Relying on the general theory of lie derivatives a new geometric definition of lie derivative for general spinor fields is given, more general than kosmanns one. In a series of very important papers yvette kosmann 9,10,11,12 introduced the notion of lie derivative for spinor fields on spin manifolds and the study of the. We already know how to make sense of a directional derivative of real valued functions on a manifold. Our aim is to introduce the reader to the modern language of advanced calculus, and in particular to the calculus of di erential. Kosmann computed equivalent quantities the lie derivatives of the dirac gammas.
The formulas for the lie covariant derivatives of spinors, adjoint spinors, and operators in spin space are deduced, and it is observed that the lie covariant derivative. To establish the claim reproduced in the above quote z, it is necessary that a certain hypothesis be satisfied, namely, that the covariant derivative v, or the lie derivative lx should commute with map a that enables one to define the tensorial equivalent of a spinor. Lie derivatives of tensor fields any lie derivative on vector. Like geometric vectors and more general tensors, spinors transform linearly when the euclidean space is subjected to a slight infinitesimal rotation. In a background with metric g, a conformal killing vector k preserves the metric up to conformal rescalings 5 l k g 2. Pdf twospinor tetrad and lie derivatives of einstein. Various generalizations of the lie derivative play an important role in differential geometry. Covariant derivative of a dirac spinor and kosmann lift. Is there anyone who could provide an example of calculating the lie derivative of the most basic function. Schulz department of mathematics and statistics, northern arizona university, flagsta. I delve into greater detail when i do topics that i have more trouble with, and i lightly pass over the things i understand clearly. On the concepts of lie and covariant derivatives of spinors. For the covariant spinor derivative we need to introduce a connection which can parallel transport a spinor. In a previous article, the writer explored the geometric foundation of the generally covariant spinor calculus.
Concept of lie derivative of spinor fields a geometric motivated. Relying on the general theory of lie derivatives a new. This book is meant to complement traditional textbooks by covering the mathematics used in theoretical physics beyond that typically covered in undergraduate math and physics courses. Chapter 11 di erential calculus on manifolds in this section we will apply what we have learned about vectors and tensors in linear algebra to vector and tensor elds in a general curvilinear coordinate system. On lie derivation of spinors against arbitrary tangent vector fields. A theorem about the lie covariant derivative of an operator in spin space that was stated in part i of this work is discussed. Geometric significance of the spinor lie derivative.
Covariant derivative for spinor fields stack exchange. Spinor lie derivatives and fermion stressenergies arxiv. Pdf lie derivative of symplectic spinor fields, metaplectic. The principle of equivalence may be used to constrain torsion, but in doing so one may only get torsion to be completely antisymmetric weyl theorem. A definition of lie differentiation of spinors along arbitrary vector fields was first proposed by kosmann 8. The lie derivative can be written as the covariant derivative of the connection which is a connection with torsion. Such a connection takes values in the lie algebra of the group the spinor transforms under. This lift extends to a prolongation gammastructure on p. Relying on the general theory of lie derivatives a new geometric definition of lie derivative for general spinor fields is given, more general than kosmanns. In contrast to lie derivatives of vector fields, the kosmann lie derivative of a spinor field depends on the metric, but otherwise satisfies all the properties of a lie derivative. Noether identities in einsteindirac theory and the lie. Pdf a geometric definition of lie derivative for spinor fields.
Pdf general theory of lie derivatives for lorentz tensors. A spinor visualized as a vector pointing along the mobius band, exhibiting a sign inversion when the circle the physical system is continuously rotated through a full turn of 360. A definition of lie differentiation of spinors along. The incompatibility of newtonian gravity with the relativity principle is not. Lie derivative the things in the numerator are numbers, so they can be compared at di erent points, unlike vectors which may be compared only on the same space. Haberrnann mathematisches institut, ruhruniversitiir bochum, 44780 bochum, germany received 10 july 1994. Lie derivative of symplectic spinor fields, metaplectic representation.
Vector algebras in this chapter, unless otherwise noted, we will limit our discussion to finitedimensional real vector spaces \v\mathbbrn\. Such a connection takes values in the liealgebra of the group the spinor transforms under. Spinor representation of lie algebra for complete linear group 1205 this space realizes representation of the dilatation subgroup. On the concepts of lie and covariant derivatives of. This means that there is no clear set of criteria for what the lie derivative of a spinor should be. We characterize the lie derivative of spinor fields from a variational point of view by resorting to the theory of the lie derivative of sections of gaugenatural bundles. Classical and quantum gravity letter to the editor related.
Our lie derivative, called the spinor lie derivative and denoted. Here, we see how a natural definition of the lie derivative of a spinor field may be given. To gain a better understanding of the longdebated concept of lie derivative of spinor fields see 9 and the original article, 10 where the definition of a lie derivative of spinor fields is placed in the more general framework of the theory of lie derivatives of sections of fiber bundles and the direct approach by y. How can i think of a lie derivative in an implementationindependent way, such that the concept may be a internalized and, in particular, b be categorified without effort read. Generalisations exist for spinor fields, fibre bundles with connection and vectorvalued. A geometric definition of lie derivative for spinor fields. Lie derivative of symplectic spinor fields, metaplectic representation, and quantization.
General theory of lie derivatives for lorentz tensors. Lie derivatives the lie derivative is a method of computing the directional derivative of a vector. The goal of this set of notes is to present, from the very beginning, my understanding of lie derivatives. Furthermore, an immediate interpretation of this lie derivative in the language of natural. Symmetry operators of massless dirac equation can be constructed from the lie derivative of spinor fields with respect to conformal killing vectors. In geometry and physics, spinors are elements of a vector space that can be associated with euclidean space. A definition for lie derivatives of spinors along generic spacetime vector fields, not necessarily killing ones, on a general pseudo riemannian manifold was already proposed in 1972 by yvette kosmann. Covariant derivative for spinor fields physics stack exchange.
The ideas are very close to those of kosmann, but the connection with the spacetime geometry of spinors is emphasized. It is useful to see formally the way in which any vector. That is, these are more like personal notes than they are like a textbook. Today we will apply this idea to a classical geometric situation. Conformal geometry of the supercotangent and spinor bundles. This geometric reasoning can be extended quite naturally to include the lie covariant differentiation of spinors. Nov 28, 2014 concept of lie derivative of spinor fields. The lie covariant derivative of the spinor connection is calculated, and is given a geometric meaning.
This change is coordinate invariant and therefore the lie derivative is defined on any differentiable manifold. This problem is a bit like the one faced in the borelweil approach to the representations of compact lie groups, where. The formulas for the lie covariant differentiation of spinors are deduced from an algebraic viewpoint. Classical and quantum gravity letter to the editor. These double covers are lie groups, called the spin groups spinn or spinp, q. Noether identities from the gaugenatural invariance of the first variational derivative of the einsteincartandirac lagrangian provide restrictions on the lie. It is the aim of this note to present this construction.
In the case of a hamiltonian vector field all spinor fields live over the same symplectic manifold and a definition of a lie derivative for symplectic spinor fields in. The geometric theory of lie derivatives of spinor fields is an old and intriguing issue that is relevant. Next, we give a new characterization as well as a generalization of the killing equation, and propose a geometric reinterpretation of penroses lie derivative of spinor fields. Action of diffeos1 and relation to lie derivatives.
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