Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Destruction of Fermion Zero Modes on Cosmic Strings   I examine the existence of zero energy fermion solutions (zero modes) on
cosmic strings in an SO(10) grand unified theory. The current carrying
capability of a cosmic string formed at one phase transition can be modified at
subsequent phase transitions. I show that the zero modes may be destroyed and
the conductivity of the string altered. I discuss the cosmological implications
of this, and show that it allows vorton bounds to be relaxed.

14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin