  We have studied the collective excitation of Bose-Einstein condensate of
short range weak interacting atoms with spin-orbit coupling (SOC) in two
dimension in liquid phase. In our study, we have included Rashba, Dresselhaus
SOC as well as Raman SOC. The study of Bogoliubov excitation shows that in
small interaction case only phonon modes are present and for higher
interactions roton modes start to appear. Energy spectra contain two roton
modes in the system relatively strong interacting atomic system.
