Holographic cold nuclear matter as dilute instanton gas

TL;DR

This paper models cold nuclear matter using holographic gauge theory, representing baryons as instantons in a dilute gas approximation, revealing a first-order phase transition with specific baryon size behaviors.

Contribution

It introduces a holographic approach to cold nuclear matter with instantons as baryons, analyzing phase transitions and baryon size evolution in a dilute gas framework.

Findings

First-order phase transition from vacuum to nuclear matter at critical chemical potential.

Baryon size increases with baryon density after the transition.

Baryon charge density jumps from zero to finite at the transition.

Abstract

We study cold nuclear matter based on the holographic gauge theory, where baryons are introduced as the instantons in the probe D8/D8 branes according to the Sakai-Sugimoto model. Within a dilute gas approximation of instantons, we search for the stable states via the variational method and fix the instanton size. We find the first order phase transition from the vacuum to the nuclear matter phase as we increase the chemical potential. At the critical chemical potential, we could see a jump in the baryon density from zero to a finite definite value. While the size of the baryon in the nuclear matter is rather small compared to the nucleus near the transition point, where the charge density is also small, it increases with the baryon density. Those behaviors obtained here are discussed by relating them to the force between baryons.