1,501 research outputs found
B+ states with chain-like structures in N
I investigate B+ cluster states of N with a
B+ cluster model. Near the -decay threshold energy, I
obtain and rotational bands having
B()+ and B()+ components, respectively.
I assign the band-head state of the band to the experimental
at =13.19 MeV of N observed in scattering reactions by
B and show that the calculated -decay width is consistent with
the experimental data. I discuss an -cluster motion around the B
cluster and show that B+ cluster states contain significant
components of a linear-chain 3 configuration, in which an
cluster is localized in the longitudinal direction around the deformed B
cluster.Comment: 14 pages, 11 figures, 2 table
Molecular Structure with Exotic Clusters in light Neutron-rich Nuclei
The excited states of Be-12, Be-14 and B-15 have been studied with a method
of antisymmetrized molecular dynamics. In the predicted excited states we find
novel molecule-like structures with very exotic clusters such as 6He+8He in
Be-14 and 6He+9Li in B-15. The origin of the He-6 cluster development in the
very neutron-rich nuclei is understood by the new-type correlation among 4
neutrons and 2 protons. In this paper we also present our recent challenge to
study -shell nuclei. Shape coexistence problems in Ar-36 and Ca-40 are
discussed.Comment: 10 pages, 5 figures. The proceedings of Yukawa International Seminar
2001 on "Physics of Unstable Nuclei". To appear in Prog. Theor. Phy
Isovector and isoscalar dipole excitations in Be and Be studied with antisymmetrized molecular dynamics
Isovector and isoscalar dipole excitations in Be and Be are
investigated in the framework of antisymmetrized molecular dynamics, in which
angular-momentum and parity projections are performed. In the present method,
1p-1h excitations on the ground state and large amplitude -cluster mode
are incorporated. The isovector giant dipole resonance (GDR) in MeV
shows the two peak structure which is understood by the dipole excitation in
the 2 core part with the prolate deformation. Because of valence
neutron modes against the core, low-energy E1 resonances appear in
MeV exhausting about of the Thomas-Reiche-Kuhn sum rule and
of the calculated energy-weighted sum. The dipole resonance at MeV in Be can be interpreted as the parity partner of the ground
state having a He+ structure and has the remarkable E1 strength
because of coherent contribution of two valence neutrons. The ISD strength for
some low-energy resonances are significantly enhanced by the coupling with the
-cluster mode. The calculated E1 strength of Be reasonably
describes the global feature of experimental photonuclear cross sections
consisting of the low-energy strength in MeV.Comment: 17 pages, 8 figure
Isoscalar monopole and dipole excitations of cluster states and giant resonances in C
The isoscalar monopole(ISM) and dipole(ISD) excitations in C are
theoretically investigated with the shifted antisymmetrized molecular
dynamics(AMD) plus -cluster generator coordinate method(GCM). The
small amplitude vibration modes are described by coherent one-particle one-hole
excitations expressed by small shift of single-nucleon Gaussian wave functions
within the AMD framework, whereas the large amplitude cluster modes are
incorporated by superposing -cluster wave functions in the GCM. The
coupling of the excitations in the intrinsic frame with the rotation and parity
transformation is taken into account microscopically by the angular-momentum
and parity projections. The present calculation describes the ISM and ISD
excitations in a wide energy region covering cluster modes in the low-energy
region and the giant resonances in the high-energy region, though the
quantitative description of the high-energy part is not satisfactory. The
low-energy ISM and ISD strengths of the cluster modes are enhanced by the
radial motion of clusters, and they split into a couple of states
because of the angular motion of clusters. The low-energy ISM
strengths exhaust 26% of the EWSR, which is consistent with the experimental
data for the C(;7.65 MeV) and C(;10.3 MeV) measured
by , , and (Li,Li) scatterings. In the
calculated low-energy ISD strengths, two states (the and )
with the significant strengths are obtained in MeV. It is indicated
that the ISD excitations can be a good probe to experimentally search for new
cluster states such as the C() obtained in the present
calculation.Comment: 13 pages, 6 figures. arXiv admin note: text overlap with
arXiv:1511.0853
Entanglement entropy and Schmidt number as measures of delocalization of clusters in one-dimensional nuclear systems
We calculated the von Neumann entanglement entropy and the Schmidt number of
one dimentional (1D) cluster states and showed that these are useful measures
to estimate entanglement caused by delocalization of clusters. We analyze
system size dependence of these entanglement measures in the linear-chain
states given by Tohsaki-Horiuchi-Schuck-R\"opke wave functions for 1D
cluster gas states. We show that the Schmidt number is an almost equivalent
measures to the von Neumann entanglement entropy when the delocalization of
clusters occurs in the entire system but it shows different behaviors in a
partially delocalized state containing localized clusters and delocalized ones.
It means that the R\'enyi-2 entanglement entropy, which relates to the Schmidt
number, is found to be almost equivalent to the von Neumann entanglement
entropy for the full delocalized cluster system but it is less sensitive to the
partially delocalized cluster system than the von Neumann entanglement entropy.
We also propose a new entanglement measure which has a generalized form of the
Schmidt number. Sensitivity of these measures of entanglement to the
delocalization of clusters in low-density regions was discussed.Comment: 15 pages, 10 figure
Analysis of delocalization of clusters in linear-chain -cluster states with entanglement entropy
I investigate entanglement entropy of one dimension (1D) cluster states to
discuss the delocalization of clusters in linear-chain - and
-cluster states. In analysis of entanglement entropy of 1D
Tohsaki-Horiuchi-Schuck-R\"opke (THSR) and Brink-Bloch cluster wave functions,
I show clear differences in the entanglement entropy between localized cluster
wave functions and delocalized cluster wave functions. In order to clarify
spatial regions where the entanglement entropy is generated by the
delocalization of clusters, I analyze the spatial distribution of entanglement
entropy. In the linear-chain cluster state, the delocalization occurs
dominantly in a low-density tail region while it is relatively suppressed in an
inner region because of Pauli blocking effect between clusters. In the
linear-chain 4 state having a larger system size than the linear-chain
state, the delocalization occurs in the whole system. The
entanglement entropy is found to be a measure of the delocalization of clusters
in the 1D cluster systems.Comment: 19 pages, 9 figure
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