Dynamically flavored description of holographic QCD in the presence of a magnetic field

TL;DR

This paper constructs a magnetic-field-dependent holographic model of QCD using the Witten-Sakai-Sugimoto setup, analyzing its thermodynamics, phase transitions, and physical properties holographically, with results aligning qualitatively with lattice QCD.

Contribution

It introduces a backreacted gravitational solution of the Witten-Sakai-Sugimoto model with magnetic field, enabling detailed study of magnetic effects on confinement and chiral symmetry.

Findings

Holographic solutions depend on magnetic field strength.

Magnetic field inhibits confinement and chiral symmetry breaking.

Phase diagram matches qualitative lattice QCD results.

Abstract

We construct the gravitational solution of the Witten-Sakai-Sugimoto model by introducing a magnetic field on the flavor brane. With taking into account their backreaction, we re-solve the type IIA supergravity in the presence of the magnetic field. Our calculation shows the gravitational solutions are magnetic-dependent and analytic both in the bubble (confined) and black brane (deconfined) case. We study the dual field theory at the leading order in the ratio of the number of flavors and colors, also in the Veneziano limit. Some physical properties related to the hadronic physics in an external magnetic field are discussed by using our confined backreaction solution holographically. We also investigate the thermodynamics and holographic renormalization of this model in both phases by our solution. Since the backreaction of the magnetic field is considered in our gravitational solution, it allows us to study the Hawking-Page transition with flavors and colors of this model in the presence of the magnetic field. Finally we therefore obtain the holographic phase diagram with the contributions from the flavors and the magnetic field. Our holographic phase diagram is in agreement with lattice QCD result qualitatively, which thus can be interpreted as the inhibition of confinement or chirally broken symmetry by the magnetic field.