Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A relativistically covariant stochastic model for systems with a
  fluctuating number of particles   We construct a relativistically covariant stochastic model for systems of
non-interacting spinless particles whose number undergoes random fluctuations.
The model is compared with the canonical quantization of the free scalar field
in the limit of infinite volume.

11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys