Quantum noise reduction using a cavity with a Bose-Einstein condensate

We study an opto-mechanical system in which the collective density excitations (Bogoliubov modes) of a Bose-Einstein condensate (BEC) is coupled to a cavity field. We show that the optical force changes the frequency and the damping constant of the collective density excitations of the BEC. We further analyse the occurrence of normal mode splitting (NMS) due to mixing of the fluctuations of the cavity field and the fluctuations of the condensate with finite atomic two-body interaction. The NMS is found to vanish for small values of the two-body interaction. We further show that the density excitations of the condensate can be used to squeeze the output quantum fluctuations of the light beam. This system may serve as an opto-mechanical control of quantum fluctuations using a BEC.