Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superselection Sectors in Asymptotic Quantization of Gravity   Using the continuity of the scalar $\Psi_2$ (the mass aspect) at null
infinity through $i_o$ we show that the space of radiative solutions of general
relativity can be thought of a fibered space where the value of $\Psi_2$ at
$i_o$ plays the role of the base space. We also show that the restriction of
the available symplectic form to each ``fiber'' is degenerate. By finding the
orbit manifold of this degenerate direction we obtain the reduced phase space
for the radiation data. This reduced phase space posses a global structure,
i.e., it does not distinguishes between future or past null infinity. Thus, it
can be used as the space of quantum gravitons. Moreover, a Hilbert space can be
constructed on each ``fiber'' if an appropriate definition of scalar product is
provided. Since there is no natural correspondence between the Hilbert spaces
of different foliations they define superselection sectors on the space of
asymptotic quantum states.

21
The categories of this paper are: adap-org
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg