Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On gravitational defects, particles and strings   We study the inclusion of point and string matter in the deSitter gauge
theory, or MacDowell-Mansouri formulation of four dimensional gravity. We
proceed by locally breaking the gauge symmetries of general relativity along
worldlines and worldsheets embedded in the spacetime manifold. Restoring full
gauge invariance introduces new dynamical fields which describe the dynamics of
spinning matter coupled to gravity. We discuss the physical interpretation of
the obtained formalism by studying the flat limit and the spinless case on
arbitrary backgrounds. It turns out that the worldline action describes a
massive spinning particle, while the worldsheet action contains the Nambu-Goto
string augmented with spinning contributions. Finally, we study the
gravity/matter variational problem and conclude by discussing potential
applications of the formalism to the inclusion of the Nambu-Goto string in
spinfoam models of four dimensional quantum gravity.

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The categories of this paper are: nucl-ex
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The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
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The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
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The categories of this paper are: solv-int
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The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
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The categories of this paper are: physics
4
The categories of this paper are: cond-mat
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The categories of this paper are: math-ph
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The categories of this paper are: nlin