Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Angular Momentum in Non-Relativistic QED and Photon Contribution to Spin
  of Hydrogen Atom   We study angular momentum in non-relativistic quantum electrodynamics
(NRQED). We construct the effective total angular momentum operator by applying
Noether's theorem to the NRQED lagrangian. We calculate the NRQED matching for
the individual components of the QED angular momentum up to one loop. We
illustrate an application of our results by the first calculation of the
angular momentum of the ground state hydrogen atom carried in radiative
photons, $\alpha_{\rm em}^3/18\pi$, which might be measurable in future atomic
experiments.

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The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
2
The categories of this paper are: math
14
The categories of this paper are: math-ph