Pragmatic ways of including lifetime broadening of collective modes in the electron liquid are critically compared. Special focus lies on the impact of the damping parameter onto the dispersion. It is quantitatively exemplified for the two-dimensional case, for both, the charge (`sheet'-)plasmon and the spin-density plasmon. The predicted deviations fall within the resolution limits of advanced techniques.
@article{arxiv.1608.03432,
title = {Phenomenological plasmon broadening and relation to the dispersion},
author = {Raphael Hobbiger and Jürgen T. Drachta and Dominik Kreil and Helga M. Böhm},
journal= {arXiv preprint arXiv:1608.03432},
year = {2017}
}