Holographic Baryons and Instanton Crystals

TL;DR

This paper reviews how holographic models describe baryons as instantons, exploring their crystalline phases and properties in dense nuclear matter using the ADHM construction.

Contribution

It summarizes known results on the construction and phases of holographic baryon crystals, highlighting their crystalline nature in dense matter.

Findings

Holographic baryons are modeled as Yang-Mills instantons.

Crystalline phases of baryons are a natural outcome in dense regimes.

The ADHM construction aids in analyzing baryon properties.

Abstract

In a wide class of holographic models, like the one proposed by Sakai and Sugimoto, baryons can be approximated by instantons of non-abelian gauge fields that live on the world-volume of flavor D-branes. In the leading order, those are just the Yang-Mills instantons, whose solutions can be obtained from the celebrated ADHM construction. This fact can be used to study various properties of baryons in the holographic limit. In particular, one can attempt to construct a holographic description of the cold dense nuclear matter phase of baryons. It can be argued that holographic baryons in such a regime are necessarily in a solid crystalline phase. In this review we summarize the known results on the construction and phases of crystals of the holographic baryons.