Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Resonances of the helium atom in a strong magnetic field   We present an investigation on the resonances of a doubly excited helium atom
in a strong magnetic field covering the regime B = 0-100 a.u. A
full-interaction approach which is based on an anisotropic Gaussian basis set
of one-particle functions being nonlinearly optimized for each field strength
is employed. Accurate results for a total of 17 resonances below the threshold
of consisting of He+ in the N=2 state are reported in this work. This includes
states with total magnetic quantum numbers M=0,-1,-2 and even z-parity. The
corresponding binding energies are compared to approximate energies of
two-particle configurations consisting of two hydrogen-like electrons in the
strong field regime, thereby providing an understanding of the behavior of the
energies of the resonances with varying field strength.

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The categories of this paper are: astro-ph
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: cmp-lg
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The categories of this paper are: stat
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The categories of this paper are: acc-phys