  Experimentally observed grey solitons are analytically extracted from a
physically viable \GP equation.
  Associated Lieb and Bogoliubov modes are calculated for these class of
solitons. It is observed that, these nonlinear excitations have strong coupling
with the trap at low momenta and hence can be effectively isolated from the
Bogoliubov sound modes, which responds weakly to harmonic confinement. This
strong coupling with the trap also makes the grey soliton amenable for control
and manipulation through both trap modulation and temporal variation of the
two-body interaction.
