Low-frequency vibrational modes of realistic model of glasses.

Understanding the vibrational features of amorphous glassy systems is the key to rationalize their peculiar low-temperature properties. Theoretical considerations pointed out for quite some time that low-frequency vibrational modes in amorphous glassy systems at low temperature are expected to present a universal density of states which depends as the fourth power of the frequency. The verification of this law in computer simulations however occurred only recently, due to the fact that the modes which are expected to exhibit this universal scaling are quasi-localized modes that in large systems hybridize strongly with low-frequency delocalized elastic (Debye) extended modes. Quasi-localized modes have been disentangled in simplified models of glasses. However, how wide this class of systems is and whether it also pertains to more realistic models of glasses remains an open question. Here we aim to establish the validity of the universal law of the density of quasi-localized modes also in richer and more realistic model glasses, such as silica and high entropy metallic glasses.