Time-dependent wave-packet approach for fusion reactions of halo nuclei

The fusion reaction of a halo nucleus 11Be on 208Pb is described by a three-body direct reaction model. A time-dependent wave packet approach is applied to a three-body reaction problem. The wave packet approach enables us to obtain scattering solutions without considering the three-body scattering boundary conditions. The time evolution of the wave packet also helps us to obtain intuitive understanding of the reaction dynamics. The calculations indicate a decrease of the fusion probability by the presence of the halo neutron.Comment: 7 pages, 3 figures, use espcrc1.sty, Talk at the International Symposium on "Physics of Unstable Nuclei (ISPUN02)", Halong Bay, Vietnam, November 20-25, 200

Fusion reaction of halo nuclei: A real-time wave-packet method for three-body tunneling dynamics

We investigate fusion cross section of a nucleus with a valence neutron, using the time-dependent wave-packet method. For a stable projectile, in which the valence neutron is tightly bound (e_n < -3 MeV), the neutron could enhance the fusion probability when the matching condition of orbital energies are satisfied. In contrast, for a halo nucleus, in which the binding energy of the neutron is very small (e_n>-1 MeV), the fusion probability is hindered by the presence of the weakly bound neutron.Comment: Talk at Internaitonal Conference on "Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier" (FUSION06), Venice, Italy, March 19-23, 200

Resonance and continuum states in weakly bound systems

Linear response theories in the continuum capable of describing continuum spectra and dynamical correlations are presented. Our formulation is essentially the same as the continuum random-phase approximation (RPA) but suitable for uniform grid representation in the three-dimensional (3D) Cartesian coordinate assuming no spatial symmetry. Effects of the continuum are taken into account either by solving equations iteratively with a retarded Green's function or by an absorbing boundary condition. The methods are applied to giant resonances in a deformed nucleus 12C.Comment: Talk at 7th Internaltional Spring Seminar on Nuclear Physics "Challenges of Nuclear Structure" at Maiori, Italy, May. 27-31, 2001. 7 pages, 2 ps figure

Strong Orientation Dependence of Multinucleon Transfer Processes in 238^{238}U+124^{124}Sn Reaction

We theoretically investigate multinucleon transfer (MNT) processes in $^{238}$U+$^{124}$Sn reaction at $E_\mathrm{lab}=5.7$ MeV/$A$ using the time-dependent Hartree-Fock (TDHF) theory. For this reaction, measurements of MNT processes have been reported, showing substantial MNT cross sections accompanying more than ten protons. From the calculation, we find that the amount of transferred nucleons depends much on the relative orientation between the deformation axis of $^{238}$U and the relative vector connecting centers of $^{238}$U and $^{124}$Sn nuclei. We find a formation of thick neck when the $^{238}$U collides from its tip with $^{124}$Sn. However, the neck formation is substantially suppressed when $^{238}$U collides from its side. We have found that a large number of protons are transferred in the tip collision. This is caused by the breaking of the neck and subsequent absorption of nucleons in the neck region. We thus conclude that the measured MNT processes involving about ten protons originate from the neck breaking dynamics in the tip collisions of a deformed $^{238}$U nucleus.Comment: 4 pages, 2 figures, Poster given at 2nd Conference of Advances in Radioactive Isotope Science (ARIS2014), June 1-6, 2014, Tokyo, Japa

Resonance and continuum states in weakly bound systems

Linear response theories in the continuum capable of describing continuum spectra and dynamical correlations are presented. Our formulation is essentially the same as the continuum random-phase approximation (RPA) but suitable for uniform grid representation in the three-dimensional (3D) Cartesian coordinate assuming no spatial symmetry. Effects of the continuum are taken into account either by solving equations iteratively with a retarded Green's function or by an absorbing boundary condition. The methods are applied to giant resonances in a deformed nucleus 12C.Comment: Talk at 7th Internaltional Spring Seminar on Nuclear Physics "Challenges of Nuclear Structure" at Maiori, Italy, May. 27-31, 2001. 7 pages, 2 ps figure

Energy transfer from intense laser pulse to dielectrics in time-dependent density functional theory

Energy transfer processes from a high-intensity ultrashort laser pulse to electrons in simple dielectrics, silicon, diamond, and $\alpha$-quartz are theoretically investigated by first-principles calculations based on time-dependent density functional theory (TDDFT). Dependences on frequency as well as intensity of the laser pulse are examined in detail, making a comparison with the Keldysh theory. Although the Keldysh theory reliably reproduces the main features of the TDDFT calculation, we find some deviations between results by the two theories. The origin of the differences is examined in detail

3D Real-Space Calculation of the Continuum Response

We present that a linear response theory in the continuum can be easily formulated with Absorbing Boundary Condition (ABC). The theory is capable of describing continuum spectra and dynamical correlations. Application of the ABC does not require the spherical symmetry and the method is suitable for mesh representation in the real coordinate space. Isovector giant dipole resonances in beryllium isotopes are studied with the time-dependent Hartree-Fock with the Skyrme force in a three-dimensional mesh space with the ABC.Comment: PTPTeX, 5 pages, 2 figures, talk at the Yukawa International Seminar 2001 on "Physics of Unstable Nuclei", Nov., 2001, Kyoto, Japa