The chiral model of Sakai-Sugimoto at finite baryon density

Abstract

In the context of holographic QCD we analyze Sakai-Sugimoto's chiral model at finite baryon density and zero temperature. The baryon number density is introduced through compact D4 wrapping S-4 at the tip of D8-(D8) over bar. Each baryon acts as a chiral point-like source distributed uniformly over R-3, and leads a non-vanishing U(1)(V) potential on the brane. For fixed baryon charge density n(B) we analyze the energy density and pressure using the canonical formalism. The baryonic matter with point like sources is always in the spontaneously broken phase of chiral symmetry, whatever the density. The point-like nature of the sources and large N-c cause the matter to be repulsive as all baryon interactions are omega mediated. Through the induced DBI action on D8-(D8) over bar, we study the effects of the fixed baryon charge density nB on the pion and vector meson masses and couplings. Issues related to vector dominance in matter in the context of holographic QCD are also discussed.