We prove feasibility of high-fidelity pulsed optomechanical interface based on all-optical presqueezing of non-Gaussian quantum states of light before they enter the optomechanical system. We demonstrate that feasible presqueezing of optical states effectively increases the low noise transfer of them to mechanical oscillator. It allows one to surpass the limit necessary to transfer highly nonclassical states with negative Wigner function. In particular, we verify that with this help single photon states of light can be efficiently turned to single phonon states of mechanical oscillator, keeping the negativity of the Wigner function. It opens the possibility to merge quantum optomechanics with the recent methods of quantum optics.Comment: 10 pages, 3 figures, published versio

Feasible setup for pulsed quantum non-demolition interaction between two distant mechanical oscillators through optical or microwave mediator is proposed. The proposal uses homodyne measurement of the mediator and feedforward control of the mechanical oscillators to reach the interaction. To verify quantum nature of the interaction, we investigate the Gaussian entanglement generated in the mechanical modes. We evaluate it under influence of mechanical bath and propagation loss for the mediator and propose ways to optimize the interaction. Finally, both currently available optomechanical and electromechanical platforms are numerically analyzed. The analysis shows that implementation is already feasible with current technology.Comment: 10 pages, 5 figure

Optical rigidity in aLIGO gravitational-wave detector, operated on dark port regime, is unstable. We show that the same interferometer with excluded symmetric mechanical mode but with unbalanced arms allows to get stable optical spring for antisymmetric mechanical mode. Arm detuning necessary to get stability is shown to be a small one -it corresponds to small power in signal port. We show that stable optical spring may be also obtained in Michelson-Sagnac interferometer with both power and signal recycling mirrors and unbalanced arms.

We propose an optomechanical setup allowing quantum mechanical correlation, entanglement and steering of two ultrashort optical pulses. The protocol exploits an indirect interaction between the pulses mediated optomechanically by letting both interact twice with a highly noisy mechanical system. We prove that significant entanglement can be reached in the bad cavity limit, where the optical decay rate exceeds all other damping rates of the optomechanical system. Moreover, we demonstrate that the protocol generates a quantum non-demolition interaction between the ultrashort pulses which is the basic gate for further applications.

We propose a setup allowing to entangle two directly non-interacting radiation modes applying four sequential pulsed quantum resonant interactions with a noisy vibrational mode of a mechanical oscillator which plays the role of the mediator. We analyze Gaussian entanglement of the radiation modes generated by the transducer and confirm that the noisy mechanical mode can mediate generation of entanglement. The entanglement, however, is limited if the interaction gains are not individually optimized. We prove the robustness of the transducer to optical losses and the influence of the mechanical bath and propose the ways to achieve maximal performance through the individual optimization.