Comment On "Collective Modes And Gapped Momentum States In Liquid Ga: Experiment, Theory, And Simulation"

We show that the theoretical expressions presented in Khusnutdinoff et al. [Phys. Rev. B 101, 214312 (2020)] for the longitudinal current spectral function C-l(k, omega) and the dispersion of collective excitations are not correct. Indeed, they are not compatible with the continuum limit and C-L (k, omega -> 0) contradicts the continuity equation.