Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Magnetic fields from inflation?   We consider the possibility of generation of the seeds of primordial magnetic
field on inflation and show that the effect of the back reaction of this field
can be very important. Assuming that back reaction does not spoil inflation we
find a rather strong restriction on the amplitude of the primordial seeds which
could be generated on inflation. Namely, this amplitude recalculated to the
present epoch cannot exceed $10^{-32}G$ in $Mpc$ scales. This field seems to be
too small to be amplified to the observable values by galactic dynamo
mechanism.

36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
13
The categories of this paper are: quant-ph
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
18
The categories of this paper are: econ