Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Microcausality and Quantum Cylindrical Gravitational Waves   We study several issues related to the different choices of time available
for the classical and quantum treatment of linearly polarized cylindrical
gravitational waves. We pay especial attention to the time evolution of
creation and annihilation operators and the definition of Fock spaces for the
different choices of time involved. We discuss also the issue of microcausality
and the use of field commutators to extract information about the causal
properties of quantum spacetime.

28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
18
The categories of this paper are: econ
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas