Related papers: Sum rule approach to a soft dipole mode in $\Lambd…
We discuss low-lying collective excitations of $\Lambda$ hypernuclei using the self-consistent mean-field approaches. We first discuss the deformation properties of $\Lambda$ hypernuclei in the $sd$-shell region. Based on the relativistic…
The "soft dipole" E1 strength function is calculated for the transition from the $^{6}$He $0^+$ ground state to the $1^-$ continuum $^{4}$He+$n$+$n$. The calculations were performed within the hyperspherical harmonics formalism. The…
The dynamical influence of $\Lambda$ hyperons on the excited-state properties of closed-shell multi-$\Lambda$ Ca, Ni, Sn and Pb hypernuclei is investigated using the self-consistent Hartree-Fock + Random Phase Approximation in coordinate…
We study the shape of $\Lambda$ hypernuclei in the full ($\beta,\gamma$) deformation plane, including both axially symmetric and triaxial quadrupole deformations. To this end, we use the constrained Skyrme Hartree-Fock+BCS method on the…
The $A$-dependence of the bond energy $\Delta B_{\Lambda\Lambda}$ of the ${\Lambda\Lambda}$ hypernuclear ground states is calculated in a three-body ${\Lambda + \Lambda + {^{A}Z}}$ model and in the Skyrme-Hartree-Fock approach. Various…
Within the unified model of Bohr and Mottelson we derive the following linear energy weighted sum rule for low energy orbital 1$^+$ excitations in even-even deformed nuclei $$S_{\rm LE}^{\rm lew} (M_1^{\rm orb}) \cong (6/5) \epsilon (B(E2;…
Using the Hartree-Fock plus random-phase-approximation (HF+RPA), we study the impurity effect of $\Lambda$ hyperon on the collective vibrational excitations of double-$\Lambda$ hypernuclei. To this end, we employ a Skyrme-type $\Lambda N$…
In neutron-rich $^8$He, we study the soft dipole resonance, which is regarded as a dipole oscillation of four valence neutrons against the $^4$He core, and its effect on the low-energy electric dipole strength with a $^4$He+$n$+$n$+$n$+$n$…
The behavior of collective oscillations of a trapped boson-fermion mixed condensate is studied in the sum rule approach. Mixing angle of bosonic and fermionic multipole operators is introduced so that the mixing characters of the low-lying…
Using the density-dependent Hartree-Fock approximation and Skyrme forces together with the scaling method and constrained Hartree-Fock calculations, we obtain the average energies of the isoscalar giant monopole resonance. The calculations…
Background: Magnetic dipole (M1) excitation is the leading mode of nuclear excitation by the magnetic field, which couples unnatural-parity states. Since the M1 excitation occurs mainly for open-shell nuclei, the nuclear pairing effect is…
Taking the ground state rotational band in $^{24}$Mg as an example, we investigate the impurity effect of $\Lambda$ hyperon on collective excitations of atomic nuclei in the framework of non-relativistic energy density functional theory. To…
The isoscalar and isovector collective multipole excitations in stable nuclei are studied in the framework of relativistic random-phase approximation with the vacuum polarization arising from the nucleon-antinucleon field. A fully…
A generalized M1 sum rule for orbital magnetic dipole strength from excited symmetric states to mixed-symmetry states is considered within the proton-neutron interacting boson model of even-even nuclei. Analytic expressions for the dominant…
Shell-model calculations of the electric dipole (E1) polarizability have been performed for the ground state of selected p- and sd-shell nuclei, substantially advancing previous knowledge. Our results are slightly larger compared with the…
The low-energy behavior of the strength function for the $1^-$ soft dipole excitation in $^{6}$He is studied theoretically. Use of very large basis sizes and well-grounded extrapolation procedures allows to move to energies as small as 1…
We investigate the role of two- and three-body $\Lambda$-nucleon forces by computing the ground state of a few $\Lambda$-hypernuclei with the Auxiliary Field Diffusion Monte Carlo algorithm. Calculations have been performed for masses up to…
Properties of the neutron rich $^{11}$Li nucleus are calculated in the framework of the cluster model $^{9}$Li $+n+n$. The formalism of the harmonic oscillator representation of the scattering theory is used for the description of bound and…
In order to study isovector dipole response of neutron-rich nuclei, we have applied a time-dependent method of antisymmetrized molecular dynamics. The dipole resonances in Be, B and C isotopes have been investigated. In $^{10}$Be, $^{15}$B,…
Systematic investigations of the electric dipole (E1) modes of excitation are performed using the canonical-basis time-dependent Hartree-Fock-Bogoliubov (Cb-TDHFB) theory. The Cb-TDHFB is able to describe dynamical pairing correlations in…