Nuclear Force from String Theory

TL;DR

This paper uses a holographic string theory model to derive the nuclear force, revealing a repulsive core at short distances and a potential scaling as 1/r^2, aligning with experimental and lattice findings.

Contribution

It demonstrates how gauge/string duality can quantitatively derive the nucleon-nucleon potential, including the repulsive core, from a string theory framework.

Findings

Nucleon-nucleon potential scales as 1/r^2 in the model.

The model reproduces a strongly repulsive core consistent with experiments.

A tensor force and central force are derived from the holographic setup.

Abstract

We compute nuclear force in a holographic model of QCD on the basis of a D4-D8 brane configuration in type IIA string theory. Repulsive core of nucleons is quite important in nuclear physics, but its origin has not been well-understood in strongly-coupled QCD. We find that string theory via gauge/string duality deduces this repulsive core at short distance between nucleons. Since baryons in the model are realized as solitons given by Yang-Mills instanton configuration on flavor D8-branes, ADHM construction of two instantons probes well the nucleon interaction at short scale, which provides the nuclear force quantitatively. We obtain, as well as a tensor force, a central force which is strongly repulsive as suggested in experiments and lattice results. In particular, the nucleon-nucleon potential V(r) (as a function of the distance) scales as 1/r^2, which is peculiar to the holographic model. We compare our results with one-boson exchange model using the nucleon-nucleon-meson coupling obtained in our previous paper (arXiv:0806.3122).