ﻻ يوجد ملخص باللغة العربية
We show that the presented in Phys.Rev.B, v.101, 214312 (2020) theoretical expressions for longitudinal current spectral function $C^L(k,omega)$ and dispersion of collective excitations are not correct. Indeed, they are not compatible with the continuum limit and $C^L(k,omegato 0)$ contradicts the continuity equation.
We show, that the theoretical expression for the dispersion of collective excitations reported in [Phys. Rev. B {bf 103}, 099901 (2021)], at variance with what was claimed in the paper, does not account for the energy fluctuations and does not tend i
In a recent paper, S. Singh and K. Tankeshwar (ST), [Phys. Rev. E textbf{67}, 012201 (2003)], proposed a new interpretation of the collective dynamics in liquid metals, and, in particular, of the relaxation mechanisms ruling the density fluctuations
We discuss the validity of recent results in [Phys. Rev. Lett. 125, 125501 (2020)] on an universal relation between the heat capacity and dispersions of collective excitations in liquids.
We comment on three incorrect claims in the paper by Fomin et al (arXiv:1507.06094) concerning the generalized hydrodynamic methodology and positive sound dispersion in fluids.
Inelastic x-ray scattering (IXS) measurements of the dynamic structure factor in liquid Na57K43, sensitive to the atomic-scale coarse graining, reveal a sound velocity value exceeding the long wavelength, continuum value and indicate the coexistence