9,798 research outputs found
Non-Associativity in the Clifford Bundle on the Parallelizable Torsion 7-Sphere
In this paper we discuss generalized properties of non-associativity in
Clifford bundles on the 7-sphere S7. Novel and prominent properties inherited
from the non-associative structure of the Clifford bundle on S7 are
demonstrated. They naturally lead to general transformations of the spinor
fields on S7 and have dramatic consequences for the associated Kac-Moody
current algebras. All additional properties concerning the non-associative
structure in the Clifford bundle on S7 are considered. We further discuss and
explore their applications.Comment: 16 page
On Clifford Subalgebras, Spacetime Splittings and Applications
Z2-gradings of Clifford algebras are reviewed and we shall be concerned with
an alpha-grading based on the structure of inner automorphisms, which is
closely related to the spacetime splitting, if we consider the standard
conjugation map automorphism by an arbitrary, but fixed, splitting vector.
After briefly sketching the orthogonal and parallel components of products of
differential forms, where we introduce the parallel [orthogonal] part as the
space [time] component, we provide a detailed exposition of the Dirac operator
splitting and we show how the differential operator parallel and orthogonal
components are related to the Lie derivative along the splitting vector and the
angular momentum splitting bivector. We also introduce multivectorial-induced
alpha-gradings and present the Dirac equation in terms of the spacetime
splitting, where the Dirac spinor field is shown to be a direct sum of two
quaternions. We point out some possible physical applications of the formalism
developed.Comment: 22 pages, accepted for publication in International Journal of
Geometric Methods in Modern Physics 3 (8) (2006
Information-entropic analysis of Korteweg--de Vries solitons in the quark-gluon plasma
Solitary waves propagation of baryonic density perturbations, ruled by the
Korteweg--de Vries equation in a mean-field quark-gluon plasma model, are
investigated from the point of view of the theory of information. A recently
proposed continuous logarithmic measure of information, called configurational
entropy, is used to derive the soliton width, defining the pulse, for which the
informational content of the soliton spatial profile is more compressed, in the
Shannon's sense.Comment: 6 pages, 1 figur
Black string corrections in variable tension braneworld scenarios
Braneworld models with variable tension are investigated, and the corrections
on the black string horizon along the extra dimension are provided. Such
corrections are encrypted in additional terms involving the covariant
derivatives of the variable tension on the brane, providing profound
consequences concerning the black string horizon variation along the extra
dimension, near the brane. The black string horizon behavior is shown to be
drastically modified by the terms corrected by the brane variable tension. In
particular, a model motivated by the phenomenological interesting case
regarding Eotvos branes is investigated. It forthwith provides further physical
features regarding variable tension braneworld scenarios, heretofore concealed
in all previous analysis in the literature. All precedent analysis considered
uniquely the expansion of the metric up to the second order along the extra
dimension, what is able to evince solely the brane variable tension absolute
value. Notwithstanding, the expansion terms aftermath, further accomplished in
this paper from the third order on, elicits the successive covariant
derivatives of the brane variable tension, and their respective coupling with
the extrinsic curvature, the Weyl tensor, and the Riemann and Ricci tensors, as
well as the scalar curvature. Such additional terms are shown to provide sudden
modifications in the black string horizon in a variable tension braneworld
scenarioComment: 12 pages, 5 figures, accepted in PR
Dark Spinors Hawking Radiation in String Theory Black Holes
The Hawking radiation spectrum of Kerr-Sen axion-dilaton black holes is
derived, in the context of dark spinors tunnelling across the horizon. Since a
black hole has a well defined temperature, it should radiate in principle all
the standard model particles, similar to a black body at that temperature. We
investigate the tunnelling of mass dimension one spin-1/2 dark fermions, that
are beyond the standard model and are prime candidates to the dark matter.
Their interactions with the standard model matter and gauge fields are
suppressed by at least one power of unification scale, being restricted just to
the Higgs field and to the graviton likewise. The tunnelling method for the
emission and absorption of mass dimension one particles across the event
horizon of Kerr-Sen axion-dilaton black holes is shown here to provide further
evidence for the universality of black hole radiation, further encompassing
particles beyond the standard model.Comment: 11 pages, improved version, to appear in AHE
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