scholarly journals Microscopic description of large amplitude collective motion in the nuclear astrophysics context

2015 ◽  
Vol 24 (09) ◽  
pp. 1541005 ◽  
Author(s):  
Denis Lacroix ◽  
Yusuke Tanimura ◽  
Guillaume Scamps ◽  
Cédric Simenel
Keyword(s):  
Large Amplitude ◽  
Density Functional ◽  
Collective Motion ◽  
Three Dimensional ◽  
Nuclear Astrophysics ◽  
Giant Resonances ◽  
Unified Framework ◽  
Energy Density Functional ◽  
Effective Interactions ◽  
Fusion Transfer

In the last 10 years, we have observed an important increase of interest in the application of time-dependent energy density functional (TD-EDF) theory. This approach allows to treat nuclear structure and nuclear reaction from small to large amplitude dynamics in a unified framework. The possibility to perform unrestricted three-dimensional simulations using state-of-the-art effective interactions has opened new perspectives. In the present paper, an overview of applications where the predictive power of TD-EDF has been benchmarked is given. A special emphasize is made on processes that are of astrophysical interest. Illustrations discussed here include giant resonances, fission, binary and ternary collisions leading to fusion, transfer and deep inelastic processes.

scholarly journals Microscopic optical potentials within the weak density dependent nucleon-nucleon effective interactions

2017 ◽  
Vol 126 (1C) ◽  
pp. 17
Author(s):  
Nguyễn Như Lê ◽  
Trần Viết Nhân Hào
Keyword(s):  
Density Functional ◽  
Collective Motion ◽  
Nucleon Nucleon ◽  
Energy Density Functional ◽  
Effective Interactions ◽  
Density Dependent ◽  
Hartree Fock ◽  
Optical Potentials ◽  
Weak Density ◽  
Nucleon Nucleon Interaction

<p class="tomtat1">The microscopic optical potentials have been investigated in the framework of the nuclear structure approach based on the energy-density functional approaches. The effective phenomenological nucleon-nucleon interaction SLy5 is consistently used to obtain the Hartree-Fock single particle states, the collective motion at small amplitudes of the target, and the coupling between the particle and phonons. The role of the weak density dependent interaction is showed. </p>

COLLECTIVE MODES OF EXCITATION IN DEFORMED NEUTRON-RICH Mg ISOTOPES

2010 ◽  
Vol 25 (21n23) ◽  
pp. 1783-1786 ◽  
Author(s):  
KENICHI YOSHIDA
Keyword(s):  
Density Functional ◽  
Random Phase ◽  
Negative Parity ◽  
Giant Resonances ◽  
Energy Density Functional ◽  
Hartree Fock ◽  
Peak Structure ◽  
Dipole Resonance ◽  
Giant Monopole Resonance ◽  
Mg Isotopes

Giant resonances and the pygmy mode in neutron-rich Mg isotopes close to the drip line are investigated by means of the deformed Hartree-Fock-Bogoliubov and quasiparticle random-phase approximations using a Skyrme energy-density functional. It is found that the giant monopole resonance has a two-peak structure due to the deformation. The lower-energy resonance is generated associated with the mixing with the Kπ = 0+ component of the giant quadrupole resonance. We find for the negative-parity excitations that the pygmy dipole resonance appeared just above the threshold has a significant mixing effect among the isovector dipole, isoscalar octupole and compression dipole excitations.

RESPONSE FUNCTIONS IN THE CONTINUUM OF DEFORMED NUCLEI STUDIED WITH THE TIME-DEPENDENT DENSITY-FUNCTIONAL CALCULATIONS

2009 ◽  
Vol 18 (10) ◽  
pp. 2088-2092
Author(s):  
TSUNENORI INAKURA ◽  
TAKASHI NAKATSUKASA ◽  
KAZUHIRO YABANA
Keyword(s):  
Density Functional ◽  
Three Dimensional ◽  
High Energy ◽  
Finite Amplitude ◽  
Time Dependent ◽  
Response Functions ◽  
Giant Resonances ◽  
Self Consistent ◽  
Dipole Response ◽  
Dependent Density

Electric dipole response functions of even-even nuclei are calculated with the time-dependent density-functional theory in perturbative regime. For an easy implementation of the fully self-consistent calculation, the finite amplitude method which we have proposed recently is employed. This is the first fully self-consistent RPA calculation in the three-dimensional mesh representation, including high-energy regions of giant resonances.

scholarly journals KIDS Energy Density Functional and Mass–Radius Relation of Neutron Stars

2019 ◽  
Vol 26 ◽  
pp. 112
Author(s):  
G. Ahn ◽  
P. Papakonstantinou
Keyword(s):  
Equation Of State ◽  
Energy Density ◽  
Neutron Stars ◽  
Symmetry Energy ◽  
Density Functional ◽  
Nuclear Symmetry Energy ◽  
Unified Framework ◽  
Energy Density Functional ◽  
Nuclear Equation Of State ◽  
Derivatives Of

Many efforts are made to determine the nuclear equation of state which governs the properties and evolution of neutron stars. Especially important is to constrain the parameters of the nuclear symmetry energy. In those efforts, nuclear energy density functional (EDF) theory has been a very useful tool, as it provides a unified framework for the description both of nuclei, which can be studied on Earth, and of infinite matter and its nuclear equation of state, which is a necessary input in the modelling of neutron stars. In the present study, a new nuclear EDF, the KIDS functional, is explored with a focus on the nuclear symmetry energy. The form of the functional allows us to vary at will the poorly constrained high-order derivatives of the symmetry energy and examine how the maximum possible mass of a neutron star is affected. Some tentative constraints on the skewness are presented, which will help guide further refinements. It is noteworthy that the pressure of neutron-rich matter is found strongly affected by skewness variations, both at low and high densities.

scholarly journals Nuclear structure and the nucleon effective mass: explorations with the versatile KIDS functional

2019 ◽  
Vol 26 ◽  
pp. 104
Author(s):  
P. Papakonstantinou ◽  
H. Gil
Keyword(s):  
Equation Of State ◽  
Effective Mass ◽  
Density Functional ◽  
Compression Modulus ◽  
Dipole Polarizability ◽  
Heavy Nuclei ◽  
Giant Resonances ◽  
Energy Density Functional ◽  
Atomic Nuclei ◽  
Giant Monopole Resonance

The connection from the structure and dynamics of atomic nuclei (finite nuclear system) to the nuclear equation of state (thermodynamic limit) is primarily made through nuclear energy-density functional (EDF) theory. Failure to describe both entities simultaneously within existing EDF frameworks means that we have either seriously misjudged the scope of EDF or not fully taken advantage of it. Enter the versatile KIDS Ansatz, which is based on controlled, order-by-order extensions of the nuclear EDF with respect to the Fermi momentum and allows a direct mapping from a given, immutable equation of state to a convenient Skyrme pseudopotential for applications in finite nuclei. A recent proof-of-principle study of nuclear ground-states revealed the subversive role of the effective mass. Here we summarize the formalism and previous results and present further explorations related to giant resonances. As examples we consider the electric dipole polarizability of 68Ni and the giant monopole resonance (GMR) of heavy nuclei, particularly the fluffiness of 120Sn. We find that the choice of the effective mass parameters and that of the compression modulus affect the centroid energy of the GMR to comparable degrees.

scholarly journals Pygmy and giant resonances: connecting the nuclear structure to stellar astrophysics

2018 ◽  
Vol 194 ◽  
pp. 04001
Author(s):  
Nadia Tsoneva
Keyword(s):  
Cross Sections ◽  
Density Functional ◽  
Reaction Cross ◽  
Giant Resonances ◽  
Energy Density Functional ◽  
Theoretical Investigations ◽  
Dipole Response ◽  
The Impact ◽  
Reaction Cross Sections ◽  
Phonon Model

Systematic theoretical investigations of dipole response in neutron-rich nuclei of importance for day-one photonuclear experiments at ELI-NP are presented. The calculations are performed in advanced mi- croscopic theory based on energy-density functional and three-phonon quasiparticle-phonon model. The model basis accounts for a large range of nuclear excitations with different spin and parity. In the focus of the studies are electric and magnetic dipole modes with energies up to 25 MeV. Of special interest are pygmy dipole and giant dipole resonances. The impact of different low-energy excitations and in particular of the PDR on radia- tive neutron-capture reaction cross sections in nuclei of key importance for nucleosynthesis is investigated.The obtained results are compared to available experimental data.

Automatic Three Dimensional Grid Generation in Turbo Machine Blade Passages

2014 ◽  
Author(s):  
R. A. Zagitov ◽  
A. N. Dushko ◽  
Yu. N. Shmotin
Keyword(s):  
Cell Size ◽  
Density Functional ◽  
Three Dimensional ◽  
Grid Generation ◽  
Energy Density Functional ◽  
Blade Passage ◽  
Main Requirement ◽  
Axial Turbines ◽  
Universal Grid ◽  
Solid Bodies

Generation of the grid for blade passages with packaging using universal grid generators usually takes much time. The paper is devoted to grid generation in turbo machine blade passages with packaging in automatic mode. The main requirement to the approach is to obtain the grid with minimum engineer participant. In the developed procedure engineer must specify only general input data: number of nodes, cell size near solid bodies and geometrical data. Multiblock structured grids are considered. All grid blocks have node-to-node attachment between each other; periodicity is also specified from node to node. The grid in blade passage consists of two blocks: “O” grid around blade and “H” grid in blade passage. Additional blocks are used to describe different ZR-effects such us tip clearances, leakage seals and bleed air systems. A variational method of constructing three dimensional grids composed of hexahedral cells is applied. The combination of the energy density functional and cell size functional is used. The first functional lets us control the shapes and the second functional lets us control the sizes of grid cells. Grid untangling procedure is also developed. Developed approach was tested using the blades of axial and centrifugal compressors and axial turbines. Results of grid generation are presented.

scholarly journals Signature-dependent triaxiality for shape evolution from superdeformation in rapidly rotating 40Ca and 41Ca

2020 ◽  
Vol 2020 (6) ◽  
Author(s):  
Shinkuro Sakai ◽  
Kenichi Yoshida ◽  
Masayuki Matsuo
Keyword(s):  
Density Functional ◽  
Density Functional Method ◽  
Three Dimensional ◽  
Decisive Role ◽  
Functional Method ◽  
Space Representation ◽  
Coordinate Space ◽  
Shape Evolution ◽  
Energy Density Functional ◽  
Collective Rotation

Abstract We investigate the possible occurrence of highly elongated shapes near the yrast line in $^{40}$Ca and $^{41}$Ca at high spins on the basis of the nuclear energy-density functional method. Both the superdeformed (SD) yrast configuration and the yrare configurations on top of the SD band are described by solving the cranked Skyme–Kohn–Sham equation in the three-dimensional coordinate space representation. It is suggested that some of the excited SD bands undergo band crossings and develop to hyperdeformation (HD) beyond $J \simeq 25 \hbar$ in $^{40}$Ca. We find that the change of triaxiality in response to rotation plays a decisive role in the shape evolution towards HD, and that this is governed by the signature quantum number of the last occupied orbital at low spins. This mechanism can be verified in an experimental observation of the positive-parity SD yrast signature-partner bands in $^{41}$Ca, one of which ($\alpha=+1/2$) undergoes crossings with the HD band, while the other ($\alpha=-1/2$) shows smooth evolution from collective rotation at low spins to non-collective rotation with an oblate shape at termination.

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