Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Noncommutativity in Space and Primordial Magnetic Field   In this paper we show that noncommutativity in spatial coordinates can
generate magnetic field in the early Universe on a horizon scale. The strength
of such a magnetic field depends on the number density of massive charged
particles present at a given moment. This allows us to trace back the
temperature dependence of the noncommutativity scale from the bounds on
primordial magnetic field coming from nucleosynthesis.

23
The categories of this paper are: solv-int
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math