Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhanced collectivity of gamma vibration in neutron-rich Dy isotopes
  with N=108 - 110   Background: The $\gamma$ vibrational mode of excitation is an acknowledged
collective mode in deformed nuclei. The collectivity depends on the details of
the shell structure around the Fermi levels, in particular the presence of the
orbitals that have the enhanced transition matrix elements of the non-axial
quadrupole excitation. Quite recently, a sudden decrease in the excitation
energy of the $\gamma$ vibration was observed at RIKEN RIBF for the
neutron-rich Dy isotopes at $N=106$. Purpose: In the present work, by studying
systematically the microscopic structure of the $\gamma$ vibration in the
neutron-rich Dy isotopes with $N=98-114$, we try to understand the mechanism of
the observed softening. Methods: The low-frequency modes of excitation in the
neutron-rich rare-earth nuclei are described based on nuclear
density-functional theory. We employ the Skyrme energy-density functionals
(EDF) in the Hartree-Fock-Bogoliubov calculation for the ground states and in
the Quasiparticle Random-Phase Approximation (QRPA) for the excitations.
Results: The lowering of the excitation energy around $N=106$ is reproduced
well by employing the SkM* and SLy4 functionals. We find the similar isotopic
dependence of the excitation energy in the neutron-rich Er and Yb isotopes as
well. Conclusions: The microscopic framework of the Skyrme-EDF based QRPA
describes well the isotopic dependence of the energy of the $\gamma$ vibration
in the well-deformed neutron-rich rare-earth nuclei. The strong collectivity at
$N=108-110$ is expected as the Fermi level of neutrons lies just among the
orbitals that play an important role in generating the collectivity around
$N=106$.

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The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs