Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Primordial magnetic fields in theories of gravity with non-minimal
  coupling between curvature and matter   The existence of magnetic fields in the universe is unmistakable. They are
observed at all scales from stars to galaxy clusters. However, the origin of
these fields remains enigmatic. It is believed that magnetic field seeds may
have emerged from inflation, under certain conditions. This possibility is
analised in the context of an alternative theory of gravity with non-minimal
coupling between curvature and matter. We find, through the solution of the
generalised Maxwell equations in the context of non-minimal models, that for
general slow-roll inflationary scenarios with low reheating temperatures,
$T_{RH}\simeq10^{10}$GeV, the generated magnetic fields can be made compatible
with observations at large scales, $\lambda \sim 1 Mpc$.

32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga