A5028646014- Nuclear physics research studies
- Advanced Chemical Physics Studies
- Quantum, superfluid, helium dynamics
- Quantum Chromodynamics and Particle Interactions
- Atomic and Molecular Physics
- Nuclear Physics and Applications
- Advanced NMR Techniques and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum chaos and dynamical systems
- Astronomical and nuclear sciences
- Atomic and Subatomic Physics Research
- Nuclear reactor physics and engineering
- Rare-earth and actinide compounds
- Spectroscopy and Quantum Chemical Studies
- High-pressure geophysics and materials
- Pulsars and Gravitational Waves Research
- Astro and Planetary Science
- Cold Fusion and Nuclear Reactions
- High-Energy Particle Collisions Research
- Physics of Superconductivity and Magnetism
- Particle accelerators and beam dynamics
- Solid-state spectroscopy and crystallography
- Crystallography and Radiation Phenomena
- Biochemical effects in animals
- Superconducting Materials and Applications
University of Tsukuba
2015-2024
RIKEN Nishina Center
2014-2024
RIKEN
2017-2018
Niigata University
2007-2014
University of North Carolina at Chapel Hill
2014
Argonne National Laboratory
1996-2011
The University of Tokyo
2001-2011
Kyoto University
1992-2010
Tohoku University
2002-2004
RIKEN Advanced Science Institute
2000-2001
We present the basic concepts and recent developments in time-dependent density functional theory (TDDFT) for describing nuclear dynamics at low energy. The symmetry breaking is inherent energy functionals (EDFs), which provides a practical description of important correlations ground state. Properties elementary modes excitation are strongly influenced by can be studied with TDDFT. In particular, number linear response calculation have demonstrated their usefulness collective nuclei....
Abstract We review our methods to calculate optical response of molecules in the linear time‐dependent density‐functional theory. Three distinct formalisms which are implemented three‐dimensional grid representation explained detail. They real‐time method solving Kohn–Sham equation time domain, modified Sternheimer calculates an external field fixed frequency, and matrix eigenvalue approach. also illustrate treatments scattering boundary condition, needed accurately describe photoionization...
We present a first-principles calculation for an optical dielectric breakdown in diamond, which is induced by intense laser field. employ the time-dependent density-functional theory solving Kohn--Sham equation real time and space. For low intensities, ionization agrees well with Keldysh formula. The shows qualitative change of electron dynamics as intensity increases, from screening at intensities to above $7\ifmmode\times\else\texttimes\fi{}{10}^{14}\text{ }\text{W}/{\text{cm}}^{2}$....
We propose a practical method to solve the random-phase approximation (RPA) in self-consistent Hartree-Fock (HF) and density-functional theory. The is based on numerical evaluation of residual interactions utilizing finite amplitude single-particle wave functions. only requires calculations Hamiltonian constructed with independent bra ket states. Using present method, RPA calculation becomes possible little extension code static HF calculation. demonstrate usefulness accuracy performing test...
We present simple equations for a canonical-basis formulation of the time-dependent Hartree-Fock-Bogoliubov (TDHFB) theory. The are obtained from TDHFB theory with an approximation that pair potential is assumed to be diagonal in canonical basis. significantly reduces computational cost. apply method linear-response calculations even-even light nuclei and demonstrate its capability accuracy by comparing our results recent quasi-particle random-phase Skyrme functionals. show systematic...
We study the dark matter effects on nuclear parameters characterising equation of states super dense neutron-rich nucleonic-matter. The observables matter, i.e. incompressibility, symmetry energy and its higher-order derivatives in presence for symmetric asymmetric are analysed with help an extended relativistic mean-field model. calculations also to beta-stable explore properties neutron star. analyse pure star using NL3, G3 IOPB-I forces. binding per particle pressure calculated without...
The continuum random-phase approximation is extended to the one applicable deformed nuclei. We propose two different approaches. One based on use of three-dimensional (3D) Green's function, and other small-amplitude TDHF with absorbing boundary condition. Both methods are 3D Cartesian grid representation systems no symmetry nuclear shape. accuracy identity these examined BKN interaction. Using full Skyrme energy functional in approach, we study isovector giant dipole states for...
We present the finite amplitude method (FAM), originally proposed in Ref. [17], for superfluid systems. A Hartree-Fock-Bogoliubov code may be transformed into a of quasiparticle-random-phase approximation (QRPA) with simple modifications. This technique has advantages over conventional QRPA calculations, such as coding feasibility and computational cost. perform fully self-consistent linear-response calculation spherical neutron-rich nucleus ${}^{174}$Sn, modifying hfbrad code, to...
The pygmy dipole resonances (PDR) for even-even nuclei in $8\ensuremath{\leqslant}Z\ensuremath{\leqslant}40$ are studied performing a systematic calculation of the random-phase approximation with Skyrme functional SkM*. is fully self-consistent and does not assume any symmetry nuclear shape ground state. In every isotopic chain, PDR emerges by showing peak $E1$ strength at energies less than 10 MeV. strongly depends on position Fermi level shows clear correlation occupation orbits orbital...
A systematic investigation of even-even superheavy elements in the region proton numbers $100 \leq Z 130$ and neutron from proton-drip line up to number $N=196$ is presented. For this study we use five most up-to-date covariant energy density functionals different types, with a non-linear meson coupling, dependent couplings, density-dependent zero-range interactions. Pairing correlations are treated within relativistic Hartree-Bogoliubov (RHB) theory based on an effective separable...
The finite amplitude method (FAM), which we have recently proposed (T. Nakatsukasa, T. Inakura, and K. Yabana, Phys. Rev. C 76, 024318 (2007)), simplifies significantly the fully self-consistent RPA calculation. Employing FAM, are conducting systematic, response calculations for a wide mass region. This paper is intended to present computational scheme be used in systematic investigation show performance of FAM realistic Skyrme energy functional. We implemented mixed representation forward...
A systematic analysis is made on the total reaction cross sections for Ne, Mg, Si, and S isotopes. The high-energy nucleus-nucleus collision described based Glauber model. Using Skyrme-Hartree-Fock method in three-dimensional grid-space representation, we determine nuclear density distribution a wide range of nuclei self-consistently without assuming any spatial symmetry. calculated consistently agree with recent section data Ne${+}^{12}$C at 240 $A$MeV, which makes it possible to discuss...
On the basis of adiabatic self-consistent collective coordinate method, we develop an efficient microscopic method deriving five-dimensional quadrupole Hamiltonian and illustrate its usefulness by applying it to oblate-prolate shape coexistence/mixing phenomena in proton-rich $^{68,70,72}\mathrm{Se}$. In this vibrational rotational masses (inertial functions) are determined local normal modes built on constrained Hartree-Fock-Bogoliubov states. Numerical calculations carried out using...
We present an efficient method for calculating strength functions using the finite-amplitude (FAM) deformed superfluid heavy nuclei within framework of nuclear density functional theory. demonstrate that FAM reproduces obtained with fully self-consistent quasiparticle random-phase approximation (QRPA) at a fraction computational cost. As demonstration, we compute isoscalar and isovector monopole strengths strongly configurations in ${}^{100}$Zr ${}^{240}$Pu by considering huge QRPA spaces....
Photoabsorption cross sections of Nd and Sm isotopes from spherical to deformed even nuclei are systematically investigated by means the quasiparticle-random-phase approximation based on Hartree-Fock-Bogoliubov ground states (HFB+QRPA) using Skyrme energy density functional. The gradual onset deformation in as increasing neutron number leads characteristic features shape phase transition. calculation well reproduce isotopic dependence broadening emergence a double-peak structure without any...
Systematic investigations of the electric dipole (E1) modes excitation are performed using canonical-basis time-dependent Hartree-Fock-Bogoliubov (Cb-TDHFB) theory. The Cb-TDHFB is able to describe dynamical pairing correlations in excited states nuclear systems. We apply method real-time calculation linear response even-even nuclei with Skyrme functionals. Effects shell structure, neutron skin, deformation, and chemical potential (separation energy) studied a systematic way. This reveals...
Effects of the isospin-symmetry breaking (ISB) beyond mean-field Coulomb terms are systematically studied in nuclear masses near $N=Z$ line. The exchange contributions calculated exactly. We use extended Skyrme energy density functionals (EDFs) with proton-neutron-mixed densities, to which we add new isospin symmetry. Two parameters associated determined by fitting mirror and triplet displacement energies (MDEs TDEs) multiplets. EDFs reproduce MDEs for $T=\frac12$ doublets $T=1$ triplets,...
We present linear response theories in the continuum capable of describing photoionization spectra and dynamic polarizabilities finite systems with no spatial symmetry. Our formulations are based on time-dependent local density approximation uniform grid representation three-dimensional Cartesian coordinate. Effects taken into account either a Green’s function method or complex absorbing potential real-time method. The two methods applied to negatively charged cluster spherical jellium model...
An excited superdeformed band in ${}^{194}\mathrm{Hg}$, observed to decay directly both normal-deformed and yrast states, is proposed be a ${K}^{\ensuremath{\pi}}{\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2}^{\ensuremath{-}}$ octupole vibrational band, based on its excitation energies, spins, likely parity. The transition energies are identical those of the ${}^{192}\mathrm{Hg}$, but originate from levels with different spins parities. evolution spin suggests that cancellations...
Giant multipole resonances in Nd and Sm isotopes are studied by employing the quasiparticle-random-phase approximation on basis of Skyrme energy-density-functional method. Deformation effects giant investigated these isotopes, which manifest a typical nuclear shape change from spherical to prolate shapes. The peak energy, broadening, deformation splitting isoscalar monopole (ISGMR) quadrupole (ISGQR) agree well with measurements. magnitude fraction energy-weighted strength lower ISGMR...
A microscopic description of dynamical fusion threshold in heavy ion collisions is performed the framework time-dependent Hartree-Fock (TDHF) theory using Skyrme energy density functional (EDF). TDHF a better agreement with experimental barrier. We find that onset extra push lies at effective fissility 33, which consistent prediction Swiatecki's macroscopic model. The our simulation systematically smaller than important effects and way to fit parameter might be responsible for different results.
Large-amplitude collective dynamics of shape phase transition in the low-lying states ${}^{30\ensuremath{-}36}$Mg is investigated by solving five-dimensional (5D) quadrupole Schr\"odinger equation. The masses and potentials 5D Hamiltonian are microscopically derived with use constrained Hartree-Fock-Bogoliubov plus local quasiparticle random approximation method. Good agreement recent experimental data obtained for excited ${0}^{+}$ as well ground bands. For ${}^{30}$Mg, coexistence picture...
The self-consistent relativistic random-phase approximation (RPA) in the radial coordinate representation is established by using finite-amplitude method (FAM). Taking isoscalar giant monopole resonance spherical nuclei as example, feasibility of FAM for covariant density functionals demonstrated, and newly developed methods are verified conventional RPA calculations. In present calculations, effects Dirac sea can be automatically taken into account coordinate-space representation....