Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A spin foam model for general Lorentzian 4-geometries   We derive simplicity constraints for the quantization of general Lorentzian
4-geometries. Our method is based on the correspondence between coherent states
and classical bivectors and the minimization of associated uncertainties. For
spacelike geometries, this scheme agrees with the master constraint method of
the model by Engle, Pereira, Rovelli and Livine (EPRL). When it is applied to
general Lorentzian geometries, we obtain new constraints that include the EPRL
constraints as a special case. They imply a discrete area spectrum for both
spacelike and timelike surfaces. We use these constraints to define a spin foam
model for general Lorentzian 4-geometries.

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The categories of this paper are: supr-con
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The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: quant-ph
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The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-th
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The categories of this paper are: stat
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The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: math-ph
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The categories of this paper are: physics
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci