The Quark-Meson-Coupling (QMC) model self-consistently relates the dynamics of the internal quark structure of a hadron to the relativistic mean fields arising in nuclear matter. It offers a natural explanation to some open questions in nuclear theory, including the origin of many-body nuclear forces and their saturation, the spin-orbit interaction and properties of hadronic matter at a wide range of densities. The QMC energy density functionals QMC-I and QMCπ-I have been successfully applied to calculate ground state observables of finite nuclei in the Hartree-Fock + BCS approximation, as well as to predict properties of dense nuclear matter and cold non-rotating neutron stars. Here we report the latest development of the model, QMCπ-II, extended to include higher order self-interaction of the σ meson. A derivative-free optimization algorithm has been employed to determine a new set of the model parameters and their statistics, including errors and correlations. QMCπ-II predictions for a wide range of properties of even-even nuclei across the nuclear chart, with fewer adjustable parameters, are comparable with other models. Predictions of ground state binding energies of even-even isotopes of superheavy elements with Z>96 are particularly encouraging.

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The quark-meson coupling (QMC) model describes atomic nuclei on the basis of the quark structure of nucleons and their self-consistent change as they interact with each other in the nuclear medium. The model has been successfully applied to even-even nuclei across the entire nuclear chart and results were comparable to other existing models despite having fewer adjustable parameters. Nuclear matter properties derived from the model are also within the widely used range of values. In this paper, we explore the latest version of the model, QMCπ-II. We put some emphasis on QMC predictions for neutron skin thickness which will be the subject for experiments in the near future. QMCπ-II predicts a value of around 0.15 and 0.16 fm for 48Ca and 208Pb, respectively, with the slope of symmetry energy at around 40 MeV.