  We study the asymmetric nuclear matter using a holographic QCD model by
introducing a baryonic charge in the infrared boundary. We first show that, in
the normal hadron phase, the predicted values of the symmetry energy and it's
slope parameter are comparable with the empirical values. We find that the
phase transition from the normal phase to the pion condensation phase is
delayed compared with the pure mesonic matter: The critical chemical potential
is larger than the pion mass which is obtained for the pure mesonic matter. We
also show that, in the pion condensation phase, the pion contribution to the
isospin number density increases with the chemical potential, while the
baryonic contribution is almost constant. Furthermore, the value of chiral
condensation implies that the enhancement of the chiral symmetry breaking
occurs in the asymmetric nuclear matter as in the pure mesonic matter. We also
give a discussion on how to understand the delay in terms of the 4-dimensional
chiral Lagrangian including the rho and omega mesons based on the hidden local
symmetry.
