Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Atomic Photoeffect in Non-relativistic QED   In this paper we present a mathematical analysis of the photoelectric effect
for one-electron atoms in the framework of non-relativistic QED. We treat
photo-ionization as a scattering process where in the remote past an atom in
its ground state is targeted by one or several photons, while in the distant
future the atom is ionized and the electron escapes to spacial infinity. Our
main result shows that the ionization probability, to leading order in the
fine-structure constant, $\alpha$, is correctly given by formal time-dependent
perturbation theory, and, moreover, that the dipole approximation produces an
error of only sub-leading order in $\alpha$. In this sense, the dipole
approximation is rigorously justified.

30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol