Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Canonical LQG operators and kinematical states for plane gravitational
  waves   In a 1+1 dimensional model of plane gravitational waves the flux-holonomy
algebra of loop quantum gravity is modified in such a way that the new basic
operators satisfy canonical commutation relations. Thanks to this construction
it is possible to find kinematical solutions for unidirectional plane
gravitational waves with finite geometric expectation values and fluctuations,
which was problematic in a more conventional approach in a foregoing paper by
the author and coauthors.

27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math