Nuclear Theory·nucl-th

Thursday·September 19, 2024

6 papers—3 primary·3 cross-listed

01
Optimization of Nuclear Mass Models Using Algorithms and Neural Networks
Jin Li · Hang Yang
Taking into account nucleon-nucleon gravitational interaction, higher-order terms of symmetry energy, pairing interaction, and neural network corrections, a new BW4 mass model has been developed, which more accurately reflects the contributions of various terms to the binding energy. A novel hybrid algorithm and neural network correction method has been implemented to optimize the discrepancy between theoretical and experimental results, significantly improving the model's binding energy predictions (reduced to around 350 keV). At the same time, the theoretical accuracy near magic nuclei has been marginally enhanced, effectively capturing the special interaction effects around magic nuclei and showing good agreement with experimental data.
nucl-th0 citations
02
Quantum Magic and Multi-Partite Entanglement in the Structure of Nuclei
Florian Brökemeier🇩🇪 · S. Momme Hengstenberg🇩🇪 · James W. T. Keeble🇩🇪 · Caroline E. P. Robin🇩🇪 · Federico Rocco🇩🇪 · Martin J. Savage🇺🇸
Motivated by the Gottesman-Knill theorem, we present a detailed study of the quantum complexity of $p$ -shell and $s d$ -shell nuclei. Valence-space nuclear shell-model wavefunctions generated by the BIGSTICK code are mapped to qubit registers using the Jordan-Wigner mapping (12 qubits for the $p$ -shell and 24 qubits for the $s d$ -shell), from which measures of the many-body entanglement ( $n$ -tangles) and magic (non-stabilizerness) are determined. While exact evaluations of these measures are possible for nuclei with a modest number of active nucleons, Monte Carlo simulations are required for the more complex nuclei. The broadly-applicable Pauli-String $I Z$ exact (PSIZe-) MCMC technique is introduced to accelerate the evaluation of measures of magic in deformed nuclei (with hierarchical wavefunctions), by factors of $\sim 8$ for some nuclei. Significant multi-nucleon entanglement is found in the $s d$ -shell, dominated by proton-neutron configurations, along with significant measures of magic. This is evident not only for the deformed states, but also for nuclei on the path to instability via regions of shape coexistence and level inversion. These results indicate that quantum-computing resources will accelerate precision simulations of such nuclei and beyond.
nucl-thquant-phPRC(2025)·58 citations
03
Quark saturation in the QCD phase diagram
Marcus Bluhm🇫🇷 · Yuki Fujimoto🇺🇸 · Larry McLerran🇺🇸 · Marlene Nahrgang🇫🇷
We determine the onset of Quarkyonic Matter corresponding to values of temperature and baryon chemical potential at which the quark phase space density becomes one. At zero temperature for baryon chemical potentials below the mass of the Lambda baryon, only nucleons contribute to the quark density. This is different at finite temperature, where all baryons, mesons and their resonances can be excited and thus add quarks to the phase space. The probability density to find a quark inside a hadron is determined using the Yukawa ansatz of the IdylliQ model of Quarkyonic Matter. We estimate separately the magnitude of the various contributions of nucleons, Delta baryons, pions as well as further hadrons and resonances. The uncertainty in the parametrization of the probability density to find a quark inside a nucleon is spanned by assuming that at zero temperature the transition density to Quarkyonic Matter is between one and three times that of nuclear matter. Various predictions for a possible critical point associated with the chiral phase transition are found close to a triple point at which the line of the deconfinement transition and the curve associated with the transition to Quarkyonic Matter intersect. These considerations provide an estimate for the region in the QCD phase diagram where Quarkyonic Matter may be found.
nucl-thhep-phPRC(2025)·15 citations
04
Pion Boer-Mulders function using a contact interaction
Dan-Dan Cheng🇨🇳 · Zhu-Fang Cui🇨🇳 · Minghui Ding🇨🇳 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪
A symmetry preserving treatment of a vector $\otimes$ vector contact interaction (SCI) is used as the basis for calculations of the two pion transverse momentum dependent parton distribution functions (TMDs); namely, that for unpolarised valence degrees-of-freedom and the analogous Boer-Mulders (BM) function. Amongst other things, the analysis enables the following themes to be addressed: the quark current mass dependence of pion TMDs; the impact of the gauge link model on the positivity constraint that bounds the BM function relative to the unpolarised TMD; the equivalence of direct diagrammatic and light-front wave function TMD calculations; and the size of the BM shift. Interpreted astutely, these SCI results enable one to draw insightful pictures of pion TMDs.
↳ hep-phhep-exhep-latnucl-ex+1EPJC(2025)·11 citations
05
Photo-nuclear reaction rates of $^{157, 159}$ Ho and $^{163, 165}$ Tm and their impact in the $γ$ --process
Hao Cheng · Bao-Hua Sun · Li-Hua Zhu · Motohiko Kusakabe · Yudong Luo · Toshitaka Kajino · Chang-Jian Wang · Xing-Qun Yao · Chuang-Ye He · Fu-Long Liu · Bing Guo
Reliable photo-nuclear reaction rates at the stellar conditions are essential to understand the origin of the heavy stable neutron-deficient isotopes between $^{74}$ Se and $^{196}$ Hg-p-nuclei, however, many reaction rates of relevance still have to rely on the Hauser-Feshbach model due to rare experimental progress. One such case is in the mass range of 160 for Dy, Er, Ho and Tm isotopes. In this work we attempt to constrain the Hauser-Feshbach model in the TALYS package by reproducing the available experimental data of $^{160}$ Dy( $p, γ$ ) $^{161}$ Ho and $^{162}$ Er( $p, γ$ ) $^{163}$ Tm in the $A \sim 160$ mass region, and examine the effects of level density, gamma strength function and the optical model potential. The constrained model then allows us to calculate the reaction rates of $^{157, 159}$ Ho( $γ$ , $p$ ) and $^{163, 165}$ Tm( $γ$ , $p$ ) for the $γ$ -process nucleosynthesis in carbon-deflagration SNe Ia model. Our recommended rates differ from the JINA REACLIB by more than 1 order of magnitude in the temperature range of 2-3 GK. This results in the changes of final abundance of $p$ -nuclei in the $A \sim 160$ mass range by -5.5-3\% from those with JINA, which means that the ( $γ$ , $p$ ) reactions uncertainty is not predominant for the synthesis of these nuclei.
↳ astro-ph.SRnucl-exnucl-thApJ(2024)·1 citation
06
Far-from-equilibrium attractors with Full Relativistic Boltzmann approach in 3+1 D: moments of distribution function and anisotropic flows $v_{n}$
Vincenzo Nugara (1 and 2)🇮🇹 · Vincenzo Greco (1 and 2)🇮🇹 · Salvatore Plumari (1 and 2) ((1) Department of Physics and Astronomy, University of Catania, Catania, (2) INFN-Laboratori Nazionali del Sud, Catania, Italy)🇮🇹
We employ the Full Relativistic Boltzmann Transport approach for a conformal system in 3+1D to study the universal behaviour in moments of the distribution function and anisotropic flows. We investigate different transverse system sizes $R$ and interaction strength $η / s$ and identify universality classes based upon the interplay between $R$ and the mean free path; we show that each of this classes can be identified by a particular value of the opacity $γ^$ , which has been previously introduced in literature. Our results highlight that, at early times, the inverse Reynolds number and momentum moments of the distribution function display universal behaviour, converging to a 1D attractor driven by longitudinal expansion. This indicates that systems of different sizes and interaction strengths tend to approach equilibrium in a similar manner. We provide a detailed analysis of how the onset of transverse flow affects these moments at later times. Moreover, we investigate the system size and $η / s$ dependence for the harmonic flows $v_{2}$ , $v_{3}$ , $v_{4}$ and their response functions, along with the impact of the $η / s$ and the system transverse size on the dissipation of initial azimuthal correlations in momentum space. Finally, we introduce the normalised elliptic flow $v_{2} / v_{2, e q}$ , showing the emergence of attractor behaviour in the regime of large opacity. These results offer new insights into how different systems evolve towards equilibrium and the role that system size and interaction play in this process.
↳ hep-phnucl-thEPJC(2025)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE

Optimization of Nuclear Mass Models Using Algorithms and Neural Networks

Quantum Magic and Multi-Partite Entanglement in the Structure of Nuclei

Quark saturation in the QCD phase diagram

Pion Boer-Mulders function using a contact interaction

Photo-nuclear reaction rates of 157,159Ho and 163,165Tm and their impact in the γ--process

Far-from-equilibrium attractors with Full Relativistic Boltzmann approach in 3+1 D: moments of distribution function and anisotropic flows vn​

Affiliations

Photo-nuclear reaction rates of $^{157, 159}$ Ho and $^{163, 165}$ Tm and their impact in the $γ$ --process

Far-from-equilibrium attractors with Full Relativistic Boltzmann approach in 3+1 D: moments of distribution function and anisotropic flows $v_{n}$