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.

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.

scholarly journals Nuclear Equation of State in the Relativistic Point-Coupling Model Constrained by Excitations in Finite Nuclei

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 71
Author(s):  
Esra Yüksel ◽  
Tomohiro Oishi ◽  
Nils Paar
Keyword(s):  
Experimental Data ◽  
Equation Of State ◽  
Energy Density ◽  
Symmetry Energy ◽  
Ground State ◽  
Density Functional ◽  
Dipole Polarizability ◽  
Energy Density Functional ◽  
Nuclear Equation Of State ◽  
Ground State Properties

Nuclear equation of state is often described in the framework of energy density functional. However, the isovector channel in most functionals has been poorly constrained, mainly due to rather limited available experimental data to probe it. Only recently, the relativistic nuclear energy density functional with an effective point-coupling interaction was constrained by supplementing the ground-state properties of nuclei with the experimental data on dipole polarizability and isoscalar monopole resonance energy in 208Pb, resulting in DD-PCX parameterization. In this work, we pursue a complementary approach by introducing a family of 8 relativistic point-coupling functionals that reproduce the same nuclear ground-state properties, including binding energies and charge radii, but in addition have a constrained value of symmetry energy at saturation density in the range J = 29, 30, …, 36 MeV. In the next step, this family of functionals is employed in studies of excitation properties such as dipole polarizability and magnetic dipole transitions, and the respective experimental data are used to validate the optimal choice of functional as well as to assess reliable values of the symmetry energy and slope of the symmetry energy at saturation.

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.

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