Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dineutron structure in $^{8}$He   The ground and excited states of $^{8}$He were investigated with a method of
antisymmetrized molecular dynamics(AMD). We adopted effective nuclear
interactions which systematically reproduce the binding energies of $^4$He,
$^6$He and $^8$He. The ground state of $^8$He has both the $j$-$j$ coupling
feature($p_{3/2}$ closure) and the $L$-$S$ coupling feature($^4$He$+2n+2n$)
with a slight tail of dineutron at the long distance region. The theoretical
results give an indication of the $0^+_2$ state with dineutron gas-like
structure. The dineutron structure, $^4$He+$2n$+$2n$, of this state is similar
to the $3\alpha$-cluster structure of the $^{12}$C($0^+_2$) state which has
been interpreted as an $\alpha$ condensate state. Since the $^8$He($0^+_2$)
state has a significant overlap with the dineutron condensate wave function
where two dineutrons are moving in $S$ wave around the $\alpha$ core with a
dilute density, we suggest that this theoretically predicted $0^+_2$ state is a
candidate of the dineutron condensate state.

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The categories of this paper are: math
28
The categories of this paper are: alg-geom
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin