Holographic QCD with Topologically Charged Domain-Wall/Membranes

TL;DR

This paper explores the phase structure of holographic QCD with topologically charged membranes, revealing stable baryonic current phases and a Hagedorn-like transition, supported by lattice QCD findings.

Contribution

It introduces a holographic model with D6-brane fluxes representing topologically charged membranes, uncovering new phase behaviors in QCD-like systems.

Findings

Discovery of a stable phase with finite baryonic current density.

Identification of a crossover with a limiting baryonic current and temperature.

Evidence supporting the existence of topologically charged membranes in lattice QCD.

Abstract

We study the thermodynamical phase structures of holographic QCD with nontrivial topologically charged domain-wall/membranes which are originally related to the multiple $\theta$-vacua in the large $N_c$ limit. We realize the topologically charged membranes as the holographic D6-brane fluxes in the Sakai-Sugimoto model. The D6-brane fluxes couple to the probe D8-anti-D8 via Chern-Simon term, and act as the source for the baryonic current density of QCD. We find rich phase structures of the dual meson system by varying asymptotic separation of D8 and anti-D8. Especially, there can be a thermodynamically favored and stable phase of finite baryonic current density. This provides the supporting evidence for the discovery of the topologically charged membranes found in the lattice QCD calculations. We also find a crossover phase with the limiting baryonic current density and temperature which suggest a Hagedorn-like phase transition of meson dissociation.