Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Cosmological Sector in Loop Quantum Gravity   We use the method of embedding a subsystem (i.e. its observable algebra) into
a larger quantum system to extract a cosmological sector from full Loop Quantum
Gravity. The application of this method provides a setting for a systematic
study of the interplay between diffeomorphism invariance and symmetry
reduction. The non-triviality of this relation is shown by extracting a
cosmological system that has configurations variables that are very similar to
the ones of a super-selection sector of standard Loop Quantum Cosmology. The
full operator algebra however turns out to be different from standard Loop
Quantum Cosmology. The homogeneous isotropic sector of pure gravity turns out
to be quantum mechanics on a circle. The dynamics of our system seems
pathological at first sight, and we give both mathematical and physical reasons
for this behavior and we explain a strategy to cure these pathologies.

9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
12
The categories of this paper are: nucl-th
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an