Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Second order differential realization of the Bargmann-Wigner framework
  for particles of any spin   The Bargmann-Wigner (BW) framework describes particles of spin-j in terms of
Dirac spinors of rank 2j, obtained as the local direct product of n Dirac
spinor copies, with n=2j. Such spinors are reducible, and contain also
(j,0)+(0,j)-pure spin representation spaces. The 2(2j+1) degrees of freedom of
the latter are identified by a projector given by the n-fold direct product of
the covariant parity projector within the Dirac spinor space. Considering
totally symmetric tensor spinors one is left with the expected number of
2(2j+1) independent degrees of freedom. The BW projector is of the order
$\partial ^{2j}$ in the derivatives, and so are the related spin-j wave
equations and associated Lagrangians. High order differential equations can not
be consistently gauged, and allow several unphysical aspects, such as
non-locality, acausality, ghosts and etc to enter the theory. In order to avoid
these difficulties we here suggest a strategy of replacing the high order of
the BW wave equations by the universal second order. To do so we replaced the
BW projector by one of zeroth order in the derivatives. We built it up from one
of the Casimir invariants of the Lorentz group when exclusively acting on
spaces of internal spin degrees of freedom. This projector allows one to
identify anyone of the irreducible sectors of the primordial rank-2j spinor, in
particular (j,0)+(0,j), and without any reference to the external space-time
and the four-momentum. The dynamics is then introduced by requiring the (j,0)+
(0,j) sector to satisfy the Klein-Gordon equation. The scheme allows for a
consistent minimal gauging.

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The categories of this paper are: cs
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The categories of this paper are: atom-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: gr-qc
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The categories of this paper are: supr-con
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The categories of this paper are: astro-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: acc-phys
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
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The categories of this paper are: adap-org
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-ex