Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low-energy dipole excitation modes in ${}^{10}$Be   Low-energy dipole excitations in ${}^{10}$Be were investigated based on the
generator coordinate method with $\alpha + {}^6$He and $\alpha + \alpha + 2n$
cluster models. We obtained three $1^-$ states in $E_{x} < 15$~MeV, which show
different characters in the $E1$, compressive dipole, and toroidal dipole
transition strengths. We found the strong toroidal dipole transition in the
$1_1^-$ state, remarkable $E1$ strength in the $1^-_2$ state, and the strong
$E1$ and compressive dipole strength in the $1^-_3$ state. The $1^-_1$ is
described by the $\alpha + {}^6$He cluster structure, where as the $1^-_2$ and
$1^-_3$ states are understood by three-body excitations of the $\alpha + \alpha
+ 2n$ clustering.

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The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph