  Analogous to the quarkyonic matter at high baryon density in which the quark
Fermi seas and the baryonic excitations coexist, it is argued that a
"quarksonic matter" phase appears at high isospin density where the quark
(antiquark) Fermi seas and the mesonic excitations coexist. We explore this
phase in detail in both large $N_c$ and asymptotically free limits: In large
$N_c$ limit, we sketch a phase diagram for the quarksonic matter. In the
asymptotically free limit, we study the pion superfluidity and thermodynamics
of the quarksonic matter by using both perturbative calculations and effective
model.
