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Rafael F. Leão

Publications and source records attributed to Rafael F. Leão.

3 recordsLinked to original sources

Concept of Lie Derivative of Spinor Fields. A Geometric Motivated Approach

In this paper using the Clifford bundle (Cl(M,g)) and spin-Clifford bundle (Cl_{Spin_{1,3}^{e}}(M,g)) formalism, which permit to give a meaningfull representative of a Dirac-Hestenes spinor field (even section of Cl_{Spin_{1,3}^{e}}(M,g)) in the Clifford bundle , we give a geometrical motivated definition for the Lie derivative of spinor fields in a Lorentzian structure (M,g) where M is a manifold such that dimM =4, g is Lorentzian of signature (1,3). Our Lie derivative, called the spinor Lie derivative (and denoted £_{ξ}) is given by nice formulas when applied to Clifford and spinor fields, and moreoverl £_{ξ}g=0 for any vector field ξ. We compare our definitions and results with the many others appearing in literature on the subject.

math-ph↗

(1,1)-forms acting on Spinors on Kähler Surfaces

It is known that, for Dirac operators on Riemann surfaces twisted by line bundles with Hermitian-Einstein connections, it is possible to obtain estimates for the first eigenvalue in terms of the topology of the twisting bundle \cite{JL2}. Attempts to generalize topological estimates for higher rank bundles or higher dimensional manifolds have been so far unsuccessful. In this work we construct a class of examples which indicates one problem that arises on such attempts to derive topological estimates.

math.DG↗