Vibrational Spectrum of a Liquid Drop in Phase-Separated 3He-4He with a Highly Mobile Interface

We study the oscillation spectrum of a liquid drop in the phase-separated fluid when the interfacial dynamics of phase conversion can be described in terms of the kinetic growth coefficient. For a readily mobile interface, i.e., as the growth coefficient becomes comparable with a reciprocal of the acoustic impedance, anomalous behavior is found in the oscillation spectrum of a drop. Compared with the known case of two immiscible fluids, the high interface mobility leads to an anomalous softening of the radial drop pulsations in a two-phase suspension. The anomalous behavior takes place for the drops with size not exceeding the mean free path of excitations.