Holographic Mean-Field Theory for Baryon Many-Body Systems
  We propose a mean-field approach to analyze many-body systems of fermions in the gauge/gravity duality. We introduce a non-vanishing classical fermionic field in the gravity dual, which we call the holographic mean field for fermions. The holographic mean field takes account of the many-body dynamics of the fermions in the bulk. The regularity condition of the holographic mean field fixes the relationship between the chemical potential and the density unambiguously. Our approach provides a new framework of gauge/gravity duality for finite-density systems of baryons in the confinement phase. 
Masayasu Harada, Shin Nakamura, Shinpei Takemoto
hep-th hep-ph nucl-th