Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Back reaction in the formation of a straight cosmic string   A simple model for the formation of a straight cosmic string, wiggly or
unperturbed is considered. The gravitational field of such string is computed
in the linear approximation. The vacuum expectation value of the stress tensor
of a massless scalar quantum field coupled to the string gravitational field is
computed to the one loop order. Finally, the back-reaction effect on the
gravitational field of the string is obtained by solving perturbatively the
semiclassical Einstein's equations.

34
The categories of this paper are: chem-ph
35
The categories of this paper are: mtrl-th
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph