The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Roldao Da Rocha - One of the best experts on this subject based on the ideXlab platform.
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on the Spinor representation
European Physical Journal C, 2017Co-Authors: J Hoff M Da Silva, C Coronado H Villalobos, Roldao Da Rocha, R Bueno J RogerioAbstract:A systematic study of the Spinor representation by means of the fermionic physical space is accomplished and implemented. The Spinor representation space is shown to be constrained by the Fierz–Pauli–Kofink identities among the Spinor bilinear covariants. A robust geometric and topological structure can be manifested from the Spinor space, wherein the first and second homotopy groups play prominent roles on the underlying physical properties, associated to fermionic fields. The mapping that changes Spinor fields classes is then exemplified, in an Einstein–Dirac system that provides the spacetime generated by a fermion.
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questing mass dimension 1 Spinor fields
European Physical Journal C, 2015Co-Authors: C Coronado H Villalobos, J Hoff M Da Silva, Roldao Da RochaAbstract:This work deals with new classes of Spinors of mass dimension 1 in Minkowski spacetime. In order to accomplish it, Lounesto’s classification scheme and the inversion theorem are going to be used. The algebraic framework shall be revisited by explicating the central point performed by the Fierz aggregate. Then the Spinor classification is generalized in order to encompass the new mass dimension 1 Spinors. The Spinor operator is shown to play a prominent role to engender the new mass dimension 1 Spinors, accordingly.
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bilinear covariants and Spinor fields duality in quantum clifford algebras
Journal of Mathematical Physics, 2014Co-Authors: Rafal Ablamowicz, Icaro Goncalves, Roldao Da RochaAbstract:Classification of quantum Spinor fields according to quantum bilinear covariants is introduced in a context of quantum Clifford algebras on Minkowski spacetime. Once the bilinear covariants are expressed in terms of algebraic Spinor fields, the duality between Spinor and quantum Spinor fields can be discussed. Thus, by endowing the underlying spacetime with an arbitrary bilinear form with an antisymmetric part in addition to a symmetric spacetime metric, quantum algebraic Spinor fields and deformed bilinear covariants can be constructed. They are thus compared to the classical (non quantum) ones. Classes of quantum Spinor fields classes are introduced and compared with Lounesto's Spinor field classification. A physical interpretation of the deformed parts and the underlying Z-grading is proposed. The existence of an arbitrary bilinear form endowing the spacetime already has been explored in the literature in the context of quantum gravity [S. W. Hawking, “The unpredictability of quantum gravity,” Commun. ...
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flag dipole Spinor fields in esk gravities
Journal of Mathematical Physics, 2013Co-Authors: Roldao Da Rocha, Luca Fabbri, J Hoff M Da Silva, R T Cavalcanti, J A SilvanetoAbstract:We consider the Riemann-Cartan geometry as a basis for the Einstein-Sciama-Kibble theory coupled to Spinor fields: we focus on f(R) and conformal gravities, regarding the flag-dipole Spinor fields, type-(4) Spinor fields under the Lounesto classification. We study such theories in specific cases given, for instance, by cosmological scenarios: we find that in such background the Dirac equation admits solutions that are not Dirac Spinor fields, but in fact the aforementioned flag-dipoles ones. These solutions are important from a theoretical perspective, as they evince that Spinor fields are not necessarily determined by their dynamics, but also a discussion on their structural (algebraic) properties must be carried off. Furthermore, the phenomenological point of view is shown to be also relevant, since for isotropic Universes they circumvent the question whether Spinor fields do undergo the Cosmological Principle.
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unfolding physics from the algebraic classification of Spinor fields
Physics Letters B, 2013Co-Authors: J Hoff M Da Silva, Roldao Da RochaAbstract:After reviewing the Lounesto Spinor field classification, according to the bilinear covariants associated to a Spinor field, we call attention and unravel some prominent features involving unexpected properties about Spinor fields under such classification. In particular, we pithily focus on the new aspects — as well as current concrete possibilities. They mainly arise when we deal with some non-standard Spinor fields concerning, in particular, their applications in physics.
J Hoff M Da Silva - One of the best experts on this subject based on the ideXlab platform.
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on the Spinor representation
European Physical Journal C, 2017Co-Authors: J Hoff M Da Silva, C Coronado H Villalobos, Roldao Da Rocha, R Bueno J RogerioAbstract:A systematic study of the Spinor representation by means of the fermionic physical space is accomplished and implemented. The Spinor representation space is shown to be constrained by the Fierz–Pauli–Kofink identities among the Spinor bilinear covariants. A robust geometric and topological structure can be manifested from the Spinor space, wherein the first and second homotopy groups play prominent roles on the underlying physical properties, associated to fermionic fields. The mapping that changes Spinor fields classes is then exemplified, in an Einstein–Dirac system that provides the spacetime generated by a fermion.
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questing mass dimension 1 Spinor fields
European Physical Journal C, 2015Co-Authors: C Coronado H Villalobos, J Hoff M Da Silva, Roldao Da RochaAbstract:This work deals with new classes of Spinors of mass dimension 1 in Minkowski spacetime. In order to accomplish it, Lounesto’s classification scheme and the inversion theorem are going to be used. The algebraic framework shall be revisited by explicating the central point performed by the Fierz aggregate. Then the Spinor classification is generalized in order to encompass the new mass dimension 1 Spinors. The Spinor operator is shown to play a prominent role to engender the new mass dimension 1 Spinors, accordingly.
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flag dipole Spinor fields in esk gravities
Journal of Mathematical Physics, 2013Co-Authors: Roldao Da Rocha, Luca Fabbri, J Hoff M Da Silva, R T Cavalcanti, J A SilvanetoAbstract:We consider the Riemann-Cartan geometry as a basis for the Einstein-Sciama-Kibble theory coupled to Spinor fields: we focus on f(R) and conformal gravities, regarding the flag-dipole Spinor fields, type-(4) Spinor fields under the Lounesto classification. We study such theories in specific cases given, for instance, by cosmological scenarios: we find that in such background the Dirac equation admits solutions that are not Dirac Spinor fields, but in fact the aforementioned flag-dipoles ones. These solutions are important from a theoretical perspective, as they evince that Spinor fields are not necessarily determined by their dynamics, but also a discussion on their structural (algebraic) properties must be carried off. Furthermore, the phenomenological point of view is shown to be also relevant, since for isotropic Universes they circumvent the question whether Spinor fields do undergo the Cosmological Principle.
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unfolding physics from the algebraic classification of Spinor fields
Physics Letters B, 2013Co-Authors: J Hoff M Da Silva, Roldao Da RochaAbstract:After reviewing the Lounesto Spinor field classification, according to the bilinear covariants associated to a Spinor field, we call attention and unravel some prominent features involving unexpected properties about Spinor fields under such classification. In particular, we pithily focus on the new aspects — as well as current concrete possibilities. They mainly arise when we deal with some non-standard Spinor fields concerning, in particular, their applications in physics.
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exotic dark Spinor fields
Journal of High Energy Physics, 2011Co-Authors: Roldao Da Rocha, Alex E Bernardini, J Hoff M Da SilvaAbstract:Exotic dark Spinor fields are introduced and investigated in the context of inequivalent spin structures on arbitrary curved spacetimes, which induces an additional term on the associated Dirac operator, related to a Cech cohomology class. For the most kinds of Spinor fields, any exotic term in the Dirac operator can be absorbed and encoded as a shift of the electromagnetic vector potential representing an element of the cohomology group \( {H^1}\left( {M,{\mathbb{Z}_2}} \right) \). The possibility of concealing such an exotic term does not exist in case of dark (ELKO) Spinor fields, as they cannot carry electromagnetic charge, so that the full topological analysis must be evaluated. Since exotic dark Spinor fields also satisfy Klein-Gordon propagators, the dynamical constraints related to the exotic term in the Dirac equation can be explicitly calculated. It forthwith implies that the non-trivial topology associated to the spacetime can drastically engender — from the dynamics of dark Spinor fields — constraints in the spacetime metric structure. Meanwhile, such constraints may be alleviated, at the cost of constraining the exotic spacetime topology. Besides being prime candidates to the dark matter problem, dark Spinor fields are shown to be potential candidates to probe non-trivial topologies in spacetime, as well as probe the spacetime metric structure.
R Bueno J Rogerio - One of the best experts on this subject based on the ideXlab platform.
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on the Spinor representation
European Physical Journal C, 2017Co-Authors: J Hoff M Da Silva, C Coronado H Villalobos, Roldao Da Rocha, R Bueno J RogerioAbstract:A systematic study of the Spinor representation by means of the fermionic physical space is accomplished and implemented. The Spinor representation space is shown to be constrained by the Fierz–Pauli–Kofink identities among the Spinor bilinear covariants. A robust geometric and topological structure can be manifested from the Spinor space, wherein the first and second homotopy groups play prominent roles on the underlying physical properties, associated to fermionic fields. The mapping that changes Spinor fields classes is then exemplified, in an Einstein–Dirac system that provides the spacetime generated by a fermion.
C Coronado H Villalobos - One of the best experts on this subject based on the ideXlab platform.
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on the Spinor representation
European Physical Journal C, 2017Co-Authors: J Hoff M Da Silva, C Coronado H Villalobos, Roldao Da Rocha, R Bueno J RogerioAbstract:A systematic study of the Spinor representation by means of the fermionic physical space is accomplished and implemented. The Spinor representation space is shown to be constrained by the Fierz–Pauli–Kofink identities among the Spinor bilinear covariants. A robust geometric and topological structure can be manifested from the Spinor space, wherein the first and second homotopy groups play prominent roles on the underlying physical properties, associated to fermionic fields. The mapping that changes Spinor fields classes is then exemplified, in an Einstein–Dirac system that provides the spacetime generated by a fermion.
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questing mass dimension 1 Spinor fields
European Physical Journal C, 2015Co-Authors: C Coronado H Villalobos, J Hoff M Da Silva, Roldao Da RochaAbstract:This work deals with new classes of Spinors of mass dimension 1 in Minkowski spacetime. In order to accomplish it, Lounesto’s classification scheme and the inversion theorem are going to be used. The algebraic framework shall be revisited by explicating the central point performed by the Fierz aggregate. Then the Spinor classification is generalized in order to encompass the new mass dimension 1 Spinors. The Spinor operator is shown to play a prominent role to engender the new mass dimension 1 Spinors, accordingly.
Laura Carrea - One of the best experts on this subject based on the ideXlab platform.
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Geometric Polarimetry—Part I: Spinors and Wave States
IEEE Transactions on Geoscience and Remote Sensing, 2014Co-Authors: David Bebbington, Laura CarreaAbstract:A new formal approach for the representation of polarization states of coherent and partially coherent electromagnetic plane waves is presented. Its basis is a purely geometric construction for the normalized complex-analytic coherent wave as a generating line in the sphere of wave directions and whose Stokes vector is determined by the intersection with the conjugate generating line. The Poincaré sphere is now located in physical space, simply a coordination of the wave sphere, with its axis aligned with the wave vector. Algebraically, the generators representing coherent states are represented by Spinors, and this is made consistent with the Spinor-tensor representation of electromagnetic theory by means of an explicit reference Spinor that we call the phase flag. As a faithful unified geometric representation, the new model provides improved formal tools for resolving many of the geometric difficulties and ambiguities that arise in the traditional formalism.
