Roton excitations in a condensed medium

Here, it has been shown that the homogeneous state of the medium can be unstable in melts near the melting curve, in multicomponent liquids, in dense gases, as well as in superfluid helium. Nanoclusters may be spontaneously formed in the medium; their metastability is associated with the increase in orientational entropy during spontaneous rotation of the nanoparticles. With a positive energy of formation of nanoparticles, their concentration is determined by the increase in entropy of the system configuration. Like vacancies in crystals, roton clusters are structural defects of the melt.