Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum Theory of Generation of Coherent X-Ray in a Wiggler   In this paper we present the nonlinear quantum theory of X-Ray FEL in a
wiggler. We present the solution of the Dirac equation in a space periodic
strong magnetic field, which describes the quantum dynamics of a single
electron in a wiggler. With the help of obtained wave function of an electron
the self-consistent set of the Maxwell and relativistic quantum kinetic
equations is obtained. Then, the process of coherent X-ray radiation generation
in nonlinear quantum regime, when the photon energy is larger than resonance
widths due to energetic/angular spreads of an electron beam and resonance width
caused by finite interaction length, is investigated.

28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg