  Collective charge density excitation spectra of both a spatially separated
two-component quasi-one dimensional (1D) quantum plasma, as existing in a
semiconductor double quantum wire structure, and a 1D homogeneous electron-hole
plasma, as appropriate for a photoexcited semiconductor quantum wire system,
are calculated within the two-component random-phase-approximation. We also
investigate the effect of impurity scattering on the collective mode dispersion
and damping, and calculate the collective mode spectral weight by obtaining the
dynamical structure factor. We find that both OP and AP modes are overdamped by
impurity scattering below some critical wave vector. We find that in the long
wavelength limit the spectral weight is carried mostly by the OP, but the
spectral weight of the undamped AP mode at finite (but not too large) wave
vectors is comparable with that of the OP mode, making it viable to observe the
AP mode in semiconductor quantum wire systems. The effect of the interwire
electron tunneling in a biwire system on the collective charge density
excitation spectra is also studied. We discuss the mode dispersion and damping
from an effective Luttinger liquid perspective as well and in some cases
include local field corrections in our calculations.
