Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Polarized backgrounds of relic gravitons   The polarizations of the tensor modes of the geometry evolving in
cosmological backgrounds are treated as the components of a bispinor whose
dynamics follows from an appropriate gauge-invariant action. This novel
framework bears a close analogy with the (optical) Jones calculus and leads to
a compact classification of the various interactions able to polarize the relic
gravitons.

4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio