Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum theory of transition radiation and transition pair creation   Theory of the transition radiation and the transition pair creation is
developed in the frame of QED. The spectral-angular distributions of
probability of the transition radiation and of the transition pair creation are
found. The total energy losses of and the total probability of pair creation
are calculated and analyzed. Features of radiation and pair creation processes
in a superdence medium (typical for white dwarfs) are discussed.

33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph