Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Going from Classical to Quantum Description of Bound Charged Particles
  Part 2: Implications for the light hydrogenic atoms   This paper continues the analysis of bound quantum systems started in (T.
Yarman, A.L. Kholmetskii and O.V. Missevitch. Going from classical to quantum
description of bound charged particles. Part 1: basic concepts and assertions),
based on a novel approach, involving the requirement of energy-momentum
conservation for the bound electromagnetic (EM) field, when the EM radiation is
forbidden. It has been shown that the modified expression for the energy levels
of hydrogenic atoms within such a pure bound field theory (PBFT) provides the
same gross and fine structure of energy levels, like in the standard theory. At
the scale of hyperfine interactions our approach, in general, evokes important
corrections to the energy levels. Part of such corrections, like the spin-spin
splitting in hydrogen, is less than the present theoretical uncertainty in the
evaluation of hyperfine contributions into the atomic levels. But the most
interesting result is the appearance of a number of significant corrections,
which improve the convergence between theory and experiment. In particular, the
corrected 1S-2S interval and 1S spin-spin splitting in positronium reduce the
existing up to date discrepancy between theoretical and experimental data. The
re-estimated classic 2S-2P Lamb shift in the hydrogen atom lead to the proton
charge radius rp=0.841(6) fm, which perfectly agrees with the latest estimation
of proton size via the measurement of 2S-2P Lamb shift in muonic hydrogen, i.e.
rp=0.84184(67) fm.

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The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
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The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci