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Nuclear Theory·nucl-th

Monday·January 12, 2026

4 papers—2 primary·2 cross-listed

All4Primary2Cross-lists2
  1. 01

    Skyrme-Hartree-Fock-Bogoliubov mass models on a 3D mesh: V. The N2LO extension of the Skyrme EDF

    G. Grams🇧🇪 · W. Ryssens🇧🇪 · A. Sánchez-Fernández🇧🇪 · N. N. Shchechilin🇧🇪 · L. González-Miret Zaragoza🇧🇪 · P. Demol🇧🇪 · N. Chamel🇧🇪 · S. Goriely🇧🇪 · M. Bender🇫🇷

    We present BSkG5, the latest entry in the Brussels-Skyrme-on-a-Grid (BSkG) series and the first large-scale nuclear structure model based on next-to-next-to-leading order (N2LO) Skyrme energy density functional (EDF). By extending the traditional Skyrme EDF ansatz with central terms containing up to four gradients, we are able to combine an excellent global description of nuclear ground state properties with a stiff equation of state for pure neutron matter that is consistent with all astronomical observations of neutron stars. More precisely, the new model matches the accuracy of earlier BSkG models but with two parameters less: we achieve root-mean-square deviations of 0.649 MeV for 2457 atomic masses, 0.0267 fm for 810 charge radii, and 0.43 MeV for 45 primary fission barriers of actinide nuclei. We demonstrate that the complexities of N2LO EDFs are not insurmountable, even for demanding many-body calculations.

    nucl-thastro-ph.HEnucl-exPLB(2026)·6 citations
  2. 02

    Constraining Hamiltonians from chiral effective field theory with neutron-star data

    Cassandra L. Armstrong🇺🇸 · Brendan T. Reed🇺🇸 · Tate Plohr🇺🇸 · Henrik Rose🇩🇪 · Soumi De🇺🇸 · Rahul Somasundaram🇺🇸 · Ingo Tews🇺🇸

    Multi-messenger observations of neutron stars (NSs) and their mergers have placed strong constraints on the dense-matter equation of state (EOS). The EOS, in turn, depends on microscopic nuclear interactions that are described by nuclear Hamiltonians. These Hamiltonians are commonly derived within chiral effective field theory (EFT). Ideally, multi-messenger observations of NSs could be used to directly inform our understanding of EFT interactions, but such a direct inference necessitates millions of model evaluations. This is computationally prohibitive because each evaluation requires us to calculate the EOS from a Hamiltonian by solving the quantum many-body problem with methods such as auxiliary-field diffusion Monte Carlo (AFDMC), which provides very accurate and precise solutions but at a significant computational cost. Additionally, we need to solve the stellar structure equations for each EOS which further slows down each model evaluation by a few seconds. In this work, we combine emulators for AFDMC calculations of neutron matter, built using parametric matrix models, and for the stellar structure equations, built using multilayer perceptron neural networks, with the \texttt{PyCBC} data-analysis framework to enable a direct inference of coupling constants in an EFT Hamiltonian using multi-messenger observations of NSs. We find that astrophysical data can provide informative constraints on two-nucleon couplings despite the high densities probed in NS interiors.

    nucl-thastro-ph.HEPLB(2026)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE