Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonlinear absorption of high-intensity shortwave radiation in plasma
  within relativistic quantum theory   On the base of the quantum kinetic equation for density matrix in plasma at
the stimulated bremsstrahlung of electrons on ions, the nonlinear absorption
rate for high-intensity shortwave radiation in plasma has been obtained within
relativistic quantum theory. Both classical Maxwellian and degenerate quantum
plasma are considered for x-ray lasers of high intensities. Essentially
different dependences of nonlinear absorption rate on polarization of strong
laser radiation is stated.

22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con