392 research outputs found
Crossed product extensions of spectral triples
Given a spectral triple and a -dynamical system where is dense in and is a locally compact
group, we extend the triple to a triplet
on the crossed product which can be promoted to a
modular-type twisted spectral triple within a general procedure exemplified by
two cases: the -algebra of the affine group and the conformal group acting
on a complete Riemannian spin manifold.Comment: Version 3: version to appear in Journal of Noncommutative Geometr
Heat trace for Laplacian type operators with non-scalar symbols
For an elliptic selfadjoint operator acting on a fiber bundle over a
Riemannian manifold, where are -matrices, we develop a
method to compute the heat-trace coefficients which allows to get them by
a pure computational machinery. It is exemplified in dimension 4 by the value
of written both in terms of or diffeomorphic and gauge
invariants. We also answer to the question: when is it possible to get explicit
formulae for ?Comment: 37 pages. v2: misprints corrected, references added, section 5.4
adde
A Remark on the Spontaneous Symmetry Breaking Mechanism in the Standard Model
In this paper we consider the Spontaneous Symmetry Breaking Mechanism (SSBM)
in the Standard Model of particles in the unitary gauge. We show that the
computation usually presented of this mechanism can be conveniently performed
in a slightly different manner. As an outcome, the computation we present can
change the interpretation of the SSBM in the Standard Model, in that it
decouples the SU(2)-gauge symmetry in the final Lagrangian instead of breaking
it.Comment: 16 page
Nucleon spin decomposition and differential geometry
In the last few years, the so-called Chen et al. approach of the nucleon spin
decomposition has been widely discussed and elaborated on. In this letter we
propose a genuine differential geometric understanding of this approach. We
mainly highligth its relation to the "dressing field method" we advocated in
[C. Fournel, J. Fran\c{c}ois, S. Lazzarini, T. Masson, Int. J. Geom. Methods
Mod. Phys. 11, 1450016 (2014)]. We are led to the conclusion that the claimed
gauge-invariance of the Chen et al. decomposition is actually unreal.Comment: 9 pages. v3: minor corrections in the text, addition of a new
referenc
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