28,023 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
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
Holographic entanglement entropy under the minimal geometric deformation and extensions
The holographic entanglement entropy (HEE) of the minimal geometrical
deformation (MGD) procedure and extensions (EMGD), is scrutinized within the
membrane paradigm of AdS/CFT. The HEE corrections of the Schwarzschild and
Reissner--Nordstr\"om solutions, due to a finite fluid brane tension, are then
derived and discussed in the context of the MGD and the EMGD.Comment: 31 pages and 23 figure
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