From bare two-nucleon interaction to nuclear matter and finite nuclei in a relativistic framework

TL;DR

This paper develops a relativistic framework using chiral interactions to describe nuclear forces, nuclear matter, and finite nuclei, achieving good agreement with experimental data and addressing longstanding challenges in nuclear physics.

Contribution

It introduces a relativistic approach with leading-order chiral interactions for nuclear systems, avoiding three-nucleon forces and improving upon previous nonrelativistic models.

Findings

Reproduces empirical saturation of nuclear matter

Achieves reasonable agreement with experimental binding energies and radii

Reduces the Coester line discrepancy

Abstract

Understanding nuclear forces, infinite nuclear matter, and finite nuclei within a unified framework has remained a central challenge in nuclear physics for decades. While most \textit{ab initio} studies employ nonrelativistic Schr\"odinger-equation frameworks, this work offers a relativistic perspective. Using a leading-order (LO) relativistic chiral interaction, we describe two-nucleon scattering via the Thompson equation, symmetric nuclear matter, and medium-mass nuclei (Ca, Ni, Zr, Sn) via the relativistic Brueckner-Hartree-Fock theory. Systematic uncertainties from regulator cutoffs and interaction parameters are analyzed. The empirical saturation region of nuclear matter is reproduced, and the binding energies and charge radii of medium-mass nuclei agree reasonably well with experimental data, significantly improving the ``Coester line". These results highlight that the relativistic approach, employing a leading-order chiral force with only four low-energy constants and no three-nucleon forces, can capture the most important dynamics and offer a complementary pathway to address longstanding challenges in nuclear \textit{ab initio} studies.