On the relation between the long-wave instability and the pion condensation in nuclear matter

Abstract

The solutions to the zero-sound frequency equation and pion dispersion equation are considered for the different values of the parameters of the effective particle-hole interaction. The branches of solutions, responsible for the long-wave instability [Pomeranchuk] of the nuclear matter ω_P(k) are presented for the both equations. It is shown that in the pion dispersion equation the solutions ω_P(k) result in the instability not only for values of the spin-isospin constant g&#39;\leq -1/2, violating stability criteria, but for all g&#39; < g&#39;_p (|g&#39;_p|\ll 1 and g&#39;_p < 0). At g&#39; > g&#39;_p the branches ω_P(k) turn into the solutions responsible for pion condensation.