Nuclear Theory·nucl-th

Friday·March 18, 2022

8 papers—3 primary·5 cross-listed

01
[Submitted on 17 Mar 2022]
Neutron star mass formula with nuclear saturation parameters
Hajime Sotani · Hajime Togashi
We derive the empirical formulas for the neutron star mass and gravitational redshift as a function of the central density and specific combination of the nuclear saturation parameters, which are applicable to the stellar models constructed with the central density up to threefold nuclear saturation density. Combining the both empirical formulas, one also estimates the neutron star radius. In practice, we find that the neutron star mass (radius) can be estimated within $\sim 10%$ (a few percent) accuracy by comparing the mass and radius evaluated with our empirical formulas to those determined with the specific equation of state. Since our empirical formulas directly connect the neutron star mass and radius to the nuclear saturation parameters, one can discuss the neutron star properties with the specific values of nuclear saturation parameters constrained via nuclear experiments.
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2203.09004 [pdf]
PRD(2022)·9 citations
02
[Submitted on 17 Mar 2022]
Core structures of vortices in Ginzburg-Landau theory for neutron $^{3} P_{2}$ superfluids
Michikazu Kobayashi🇯🇵 · Muneto Nitta🇯🇵
We investigate vortex solutions in the Ginzburg-Landau theory for neutron $^{3} P_{2}$ superfluids relevant for neutron star cores in which neutron pairs possess the total angular momentum $J = 2$ with spin-triplet and $P$ wave, in the presence of the magnetic field parallel to the angular momentum of vortices. The ground state is known to be in the uniaxial nematic (UN) phase in the absence of magnetic field, while it is in the $D_{2}$ ( $D_{4}$ ) biaxial nematic (BN) phase in the presence of the magnetic field below (above) the critical value. We find that a singly quantized vortex always splits into two half-quantized non-Abelian vortices connected by soliton(s) as a vortex molecule with any strength of the magnetic field. In the UN phase, two half-quantized vortices with ferromagnetic cores are connected by a linear soliton with the $D_{4}$ BN order. In the $D_{2}$ ( $D_{4}$ ) BN phase, two half-quantized vortices with cyclic cores are connected by three linear solitons with the $D_{4}$ ( $D_{2}$ ) BN order. The energy of the vortex molecule monotonically increases and the distance between the two half-quantized vortices decreases with the magnetic field increases, except for a discontinuously increasing jump of the distance at the critical magnetic field. We also construct an isolated half-quantized non-Abelian vortex in the $D_{4}$ BN phase.
Comments:
13 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas)
arXiv:
2203.09300 [pdf]
PRC(2022)·12 citations
03
[Submitted on 17 Mar 2022]
Study on nuclear $α$ -decay energy by an artificial neural network with pairing and shell effects
Hong-Qiang You · Zheng-Zhe Qu · Ren-Hang Wu · Hao-Ze Su · Xiao-Tao He
We build and train the artificial neural network model (ANN) based on the experimental $α$ -decay energy ( $Q_{α}$ ) data. Besides decays between the ground states of parent and daughter nuclei, decays from the ground state of parent nuclei to the excited state of daughter nuclei are also included. By this way, the number of samples are increased dramatically. The results calculated by ANN model reproduce the experimental data with a good accuracy. The root-mean-square (rms) relative to the experiment data is 0.105 MeV. The influence of different input is investigated. It is found that either the shell effect or the pairing effect results in an obvious improvement of the predictive power of ANN model, and the shell effect plays a more important role. The optimal result can be obtained as both the shell and pairing effects are considered simultaneously. Application of ANN model in prediction of the $α$ -decay energy shows the neutron magic number at $N = 184$ , and a possible sub-shell gap around $N = 174$ or 176 in the superheavy nuclei region.
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2203.09412 [pdf]
Symmetry(2022)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

Neutron star mass formula with nuclear saturation parameters

Core structures of vortices in Ginzburg-Landau theory for neutron 3P2​ superfluids

Study on nuclear α-decay energy by an artificial neural network with pairing and shell effects

Affiliations

Core structures of vortices in Ginzburg-Landau theory for neutron $^{3} P_{2}$ superfluids

Study on nuclear $α$ -decay energy by an artificial neural network with pairing and shell effects