Abstract
How does nuclear binding emerge from first principles? Our current best understanding of nuclear forces is based on a systematic low-energy expansion called chiral effective field theory. However, recent ab initio calculations of nuclear structure have found that not all chiral effective field theory interactions give accurate predictions with increasing nuclear density. In this letter we address the reason for this problem and the first steps toward a solution. Using nuclear lattice simulations, we deduce the minimal nuclear interaction that can reproduce the ground state properties of light nuclei, medium-mass nuclei, and neutron matter simultaneously with no more than a few percent error in the energies and charge radii. We find that only four parameters are needed. With these four parameters one can accurately describe neutron matter up to saturation density and the ground state properties of nuclei up to calcium. Given the absence of sign oscillations in these lattice Monte Carlo simulations and the mild scaling of computational effort scaling with nucleon number, this work provides a pathway to high-quality simulations in the future with as many as one or two hundred nucleons.
Highlights
How does nuclear binding emerge from first principles? Our current best understanding of nuclear forces is based on a systematic low-energy expansion called chiral effective field theory
Chiral effective field theory is a first principles approach to nuclear forces where interactions are arranged as a lowenergy expansion in powers of momentum and pion mass [1, 2]
We examine the predictions for pure neutron matter (NM)
Summary
In order to see what the essential elements might be, we take a constructive reductionist approach and deduce the minimal nuclear interaction that can reproduce the ground state properties of light nuclei, medium-mass nuclei, and neutron matter simultaneously with no more than a few percent error in the energies and charge radii. We are using SU(4)-symmetric short-range interactions with local and nonlocal smearing and one-pion exchange as the starting point for improved calculations of light and medium-mass nuclei with chiral forces up to N3LO. This 10% correction at NLO might still seem too large since the agreement between the LO results in this work and the experimental binding energies are better than 10% This better-than-expected agreement can be explained by the additional fine-tuning we gain by adjusting the balance between local and nonlocal interactions to achieve accurate liquid drop properties.
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