Nuclear Theory·nucl-th

Wednesday·June 4, 2025

12 papers—7 primary·5 cross-listed

01
Kolmogorov-Arnold Wavefunctions
Paulo F. Bedaque · Jacob Cigliano · Hersh Kumar · Srijit Paul · Suryansh Rajawat
This work investigates Kolmogorov-Arnold network-based wavefunction ansatz as viable representations for quantum Monte Carlo simulations. Through systematic analysis of one-dimensional model systems, we evaluate their computational efficiency and representational power against established methods. Our numerical experiments suggest some efficient training methods and we explore how the computational cost scales with desired precision, particle number, and system parameters. Roughly speaking, KANs seem to be 10 times cheaper computationally than other neural network based ansatz. We also introduce a novel approach for handling strong short-range potentials-a persistent challenge for many numerical techniques-which generalizes efficiently to higher-dimensional, physically relevant systems with short-ranged strong potentials common in atomic and nuclear physics.
nucl-thcond-mat.dis-nnquant-phPRC(2025)·2 citations
02
New level density parameter beyond Egidy-Bucurescu's systematics
Junzhe Zhang · Yanan Zheng · Caixin Yuan · Yangyang Shen · Yingchen Mao
Extending beyond the Egidy-Bucurescu systematics, the nuclear level density parameters (LDPs) for the back-shifted Fermi gas model were compiled. Three forms of LDPs were fitted: the liquid-drop model (LDM), the droplet model (DM), and the power-law dependence on mass number A. Additionally, the root-mean-square deviations (RMSDs) of the new LDPs and existing literature values were calculated. The newly fitted global LDM-type parameters outperform the commonly used Toke-Swiatecki parameters in various statistical model calculations. In contrast, neither the global nor the combined DM-type parameters yielded satisfactory results. Among the tested parameter sets, the widely adopted Reisdorf parameters exhibited the best overall performance, as evidenced by the larger number of experimental data points falling within their narrower RMSD confidence intervals. For the power-law A-dependence, the new global parameters performed better than the existing homogeneous ones. The ground-state deformation and isospin correction factors had minimal overall impact on the LDP fits. However, the current results suggest that theoretical calculations for transitional nuclei should account for ground-state deformation effects.
nucl-th0 citations
03
Ab initio study of the radii of oxygen isotopes
Zhengxue Ren🇩🇪 · Serdar Elhatisari🇸🇦 · Ulf-G. Meißner🇩🇪
We present an {\em ab initio} study of the charge and matter radii of oxygen isotopes from $^{16}$ O to $^{20}$ O using nuclear lattice effective field theory (NLEFT) with high-fidelity N $^{3}$ LO chiral interactions. To efficiently address the Monte Carlo sign problem encountered in nuclear radius calculations, we introduce the {\em partial pinhole algorithm}, significantly reducing statistical uncertainties and extending the reach to more neutron-rich and proton-rich isotopes. Our computed charge radii for $^{16}$ O, $^{17}$ O, and $^{18}$ O closely match experimental data, and we predict a charge radius of $2.810 (32)$ fm for $^{20}$ O. The calculated matter radii show excellent agreement with values extracted from low-energy proton and electron elastic scattering data, but are inconsistent with those derived from interaction cross sections and charge-changing cross section measurements. These discrepancies highlight model-dependent ambiguities in the experimental extraction methods of matter radii and underscore the value of precise theoretical benchmarks from NLEFT calculations.
nucl-thhep-latnucl-exPRL(2025)·15 citations
04
Deformed magic numbers at $N =$ 178 and $Z =$ 120, 124 in the 112 $\leq N \leq$ 190 superheavy region from Skyrme mean-field calculations
W. Asous · Mastura Syamimi Abdullah · Meng-Hock Koh · Kok-Siong Khoo
Background: Various motivations for exploration of superheavy region revolve around the question on whether 126 is a spherical proton magic number, as is the case for neutrons. In exploring this region, identification of nuclei with relatively longer half-life as compared to its neighbours is crucial for experimental studies. Such information is provided from theoretical predictions, which are however, heavily dependent on the theoretical model used and observable quantities under investigation. Purpose: Limiting ourselves to the Skyrme Hartree-Fock-plus-Bardeen-Cooper-Schrieffer approach, we aimed to analyse the appearance of a nuclear region with relatively high stability associated with emergence of spherical and deformed magic numbers in the region of $170 \leq N \leq 190$ ( $112 \leq Z \leq 130$ ) based on various observables. Methods: Three Skyrme parametrizations namely the SkM* frequently employed for fission calculations, and the SLy5 and SLy4 commonly used for superheavy region, are considered to provide comparisons within the Skyrme mean-field approach. We evaluated the variation of electric quadrupole deformation ( $β_{20}$ ), binding energy per nucleon ( $B E / A$ ), two-nucleon separation energy differential ( $δ S 2_{q}$ ), alpha-decay energy ( $Q_{α}$ ) and alpha-decay half-lives ( $T_{1/2}$ ). Conclusion: Our analyses suggest that neutron number $N = 178$ is candidate for deformed magic number around proton number $114 \leq Z \leq 118$ . For protons, $Z = 120$ and $124$ appears to be a candidate for deformed magic number at around $N = 172 \sim 178$ . Both sets of deformed magic numbers appear at oblate ground-state deformation.
nucl-thIJMPE(2025)·0 citations
05
Testing Variational Perturbation Theory for Effective Actions Using the Gaudin-Yang Model
Pranav Sharma · R. J. Furnstahl
The background field formalism based on effective actions is a compelling framework for developing an effective field theory for nuclear density functional theory. Among the challenges in carrying out this development is handling both the particle-hole and pairing channels beyond the mean-field level, which includes how to incorporate collective degrees of freedom. Here we use the exactly solvable one-dimensional Gaudin-Yang model as a theoretical laboratory to explore candidate approaches. We compare Variational Perturbation Theory (VPT) to ordinary many-body perturbation theory and the inversion method, all to second order in their respective expansions, and verify issues with Hubbard-Stratonovich auxiliary fields. VPT outperforms the other approaches at this level over a wide range of densities. The next steps to extend this approach toward nuclei are outlined.
nucl-thcond-mat.otherhep-phPRC(2025)·1 citation
06
High-order anisotropic flow and nonlinear hydrodynamic responses
Owen Horecny🇺🇸 · Chun Shen🇺🇸
In this work, we study the charged hadron anisotropic flow coefficients $v_{n}$ (up to $n = 12$ ) using high-statistics event-by-event simulations of Pb+Pb collisions at $s_{NN} = 5.02$ and $5.36$ ~TeV, employing the IP-Glasma + MUSIC + UrQMD hybrid approach. The power spectra of anisotropic flow coefficients ( $v_{n} {2}$ vs. $n$ ) are compared with the ALICE measurements from central to 50% centrality. To understand the various sources contributing to the high-order $v_{n}$ coefficients, we analyze the nonlinear mode coefficients for high-order anisotropic flow coefficients using different approximations and make comparisons with available measurements.
nucl-thhep-phnucl-exPRC(2025)·1 citation
07
Covariant Energy Density Functionals for Neutron Star Matter Equation of State Modeling: Cross-Comparison Analysis Using \texttt{CompactObject}
João Cartaxo🇵🇹 · Chun Huang🇺🇸 · Tuhin Malik🇵🇹 · Shashwat Sourav🇺🇸 · Wen-Li Yuan🇨🇳 · Tianzhe Zhou🇨🇳 · Xuezhi Liu🇨🇳 · Constança Providência🇵🇹
This study analyzes and contrasts different phenomenological methods used to model the nuclear equation of state (EOS) for neutron star matter based on covariant energy density functionals (CEDF). Using two complementary methodologies, we seek to capture a comprehensive picture of the potential behaviors of ultra-dense nucleonic matter and identify the most plausible models based on current observational and experimental constraints. Observational data from radio pulsar timing, gravitational wave detection of GW170817, and X-ray timing provide critical benchmarks for testing the models. We have derived the EOS posteriors for various CEDF models within the \texttt{CompactObject} package, utilizing recent observational data on neutron stars, state-of-the-art theoretical constraints from chiral effective field theory ( $χ$ EFT) calculations for pure neutron matter at low densities, and pQCD-derived constraints. Our analysis has demonstrated that while all considered CEDF models broadly reproduce current astrophysical and theoretical constraints, subtle yet important differences persist among them, with each framework exhibiting distinct characteristics at supra-nuclear density. This is in particular true for the proton fraction inside neutron stars, but also supported by the models' behavior with respect to the pure neutron matter EOS and the density dependence of the speed of sound. Our study highlights the sensitivity of dense matter predictions to the underlying EOS parameterizations and the priors considered.
nucl-thastro-ph.HEgr-qcAstrophys.J.Suppl.(2026)·14 citations

Affiliations

first authorsco-authorsvia INSPIRE

Kolmogorov-Arnold Wavefunctions

New level density parameter beyond Egidy-Bucurescu's systematics

Ab initio study of the radii of oxygen isotopes

Deformed magic numbers at N=178 and Z=120, 124 in the 112 ≤N≤ 190 superheavy region from Skyrme mean-field calculations

Testing Variational Perturbation Theory for Effective Actions Using the Gaudin-Yang Model

High-order anisotropic flow and nonlinear hydrodynamic responses

Covariant Energy Density Functionals for Neutron Star Matter Equation of State Modeling: Cross-Comparison Analysis Using \texttt{CompactObject}

Affiliations

Deformed magic numbers at $N =$ 178 and $Z =$ 120, 124 in the 112 $\leq N \leq$ 190 superheavy region from Skyrme mean-field calculations