Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A New Limit for the Non-Commutative Space-Time Parameter   We study space-time noncommutativity applied to the hydrogen atom and the
phenomenological aspects induced. We find that the noncommutative effects are
similar to those obtained by considering the extended charged nature of the
proton in the atom. To the first order in the noncommutative parameter, it is
equivalent to an electron in the fields of a Coulomb potential and an electric
dipole and this allows us to get a bound for the parameter. In a second step,
we compute noncommutative corrections of the energy levels and find that they
are at the second order in the parameter of noncommutativity. By comparing our
results to those obtained from experimental spectroscopy, we get another limit
for the parameter.

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The categories of this paper are: physics
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
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The categories of this paper are: astro-ph
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
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The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an