Scalar quanta in Fermi liquids: zero sounds, instabilities, Bose condensation, and a metastable state in dilute nuclear matter

Kolomeitsev, Evgeni E., 1970- Scalar quanta in Fermi liquids: zero sounds, instabilities, Bose condensation, and a metastable state in dilute nuclear matter / E. E. Kolomeitsev, D. N. Voskresensky. -- The spectrum of bosonic scalar-mode excitations in a normal Fermi liquid with local scalar interaction is investigated for various values and momentum dependence of the scalar Landau parameter f(0) in the particle-hole channel. For f(0) > 0 the conditions are found when the phase velocity on the spectrum of zero sound acquires a minimum at non-zero momentum. For1 < f(0) < 0 there are only damped excitations, and for f(0) <1 the spectrum becomes unstable against the growth of scalar-mode excitations. An effective Lagrangian for the scalar excitation modes is derived after performing a bosonization procedure. We demonstrate that the instability may be tamed by the formation of a static Bose condensate of the scalar modes. The condensation may occur in a homogeneous or inhomogeneous state relying on the momentum dependence of the scalar Landau parameter. We show that in the isospin-symmetric nuclear matter there may appear a metastable state at subsaturation nuclear density owing to the condensate. Then we consider a possibility of the condensation of the zero-sound-like excitations in a state with a nonzero momentum in Fermi liquids moving with overcritical velocities, provided an appropriate momentum dependence of the Landau parameter f(0)( k) > 0. We also argue that in peripheral heavy-ion collisions the Pomeranchuk instability may occur already for f(0) >1.

In The European Physical Journal A : Hadrons and Nuclei. -- Berlin : Springer, 2016. -- ISSN 1434-6001. -- ISSN 1434-601X. -- Vol. 52, no. 12 (2016), pp. [1-18]

1. heavy ion collisions 2. equation of state 3. relativistic mean-field models 4. hydrodynamics

I. Voskresensky, Dmitri
II. The European Physical Journal A : Hadrons and Nuclei. -- Vol. 52, no. 12 (2016), pp. [1-18]

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