Cold Nuclear Matter In Holographic QCD

Understand

We study the Sakai-Sugimoto model of holographic QCD at zero temperature and finite chemical potential.

• We find that as the baryon chemical potential is increased above a critical value, there is a phase transition to a nuclear matter phase characterized by a condensate of instantons on the probe D-branes in the string theory dual.
• As a result of electrostatic interactions between the instantons, this condensate expands towards the UV when the chemical potential is increased, giving a holographic version of the expansion of the Fermi surface.
• We argue based on properties of instantons that the nuclear matter phase is necessarily inhomogeneous to arbitrarily high density.