Fig. 3: Predictions for charge radii of nuclei and for pure neutron-matter energy per neutron and symmetric nuclear-matter energy per nucleon.

a, Predictions for charge radii (R_ch) of nuclei up to A = 58 at N3LO in χEFT and comparison with experimental data. The symbols with a black border indicate nuclei with unequal numbers of protons and neutrons. b, Predictions for pure neutron-matter energy per neutron and symmetric nuclear-matter energy per nucleon as a function of density at N3LO in χEFT. For pure neutron matter, we use the number of neutrons from 14 to 80 and various box sizes from 6.58 fm to 13.2 fm. For symmetric nuclear matter, we use nucleon numbers from 12 to 160 and a periodic box of length 9.21 fm. For comparison, we show the results from variational calculations (APR)⁶⁵, auxiliary-field diffusion Monte Carlo simulations (GCR)⁶⁶, many-body perturbation theory using N3LO/NNLO (two-nucleon (2NF)/three-nucleon (3NF)) chiral interactions (EM 500 MeV, EGM 450/500 MeV and EGM 450/700 MeV)⁶⁷ and coupled cluster theory using NNLO chiral interactions with explicit delta degrees of freedom (ΔNNLO)⁶⁸. The empirical saturation point is labelled with a black rectangular box. E denotes energy, ρ is the nucleon density, and ρ₀ is the saturation density of symmetric nuclear matter. The error bars show standard deviations.