We investigate a coupled array of N identical cavity optomechanical systems. By adiabatically eliminating the cavity fields, we derive an effective Hamiltonian of the N phonon modes coupled via XX form. We show further that the coupled mechanical oscillators can be used to transmit state and the single mode of the oscillator and the two-mode of neighbor oscillators can exhibit squeezing simultaneously. Under the suitable regime of parameters, the phonon blockade is exhibited.
We investigate a coupled array of N identical cavity optomechanical systems. By adiabatically eliminating the cavity fields, we derive an effective Hamiltonian of the N phonon modes coupled via XX form. We show further that the coupled mechanical oscillators can be used to transmit state and the single mode of the oscillator and the two-mode of neighbor oscillators can exhibit squeezing simultaneously. Under the suitable regime of parameters, the phonon blockade is exhibited.
This paper investigates a coupled cavity optomechanical system consisting of two Fabry-Perot cavities and the two cavities are coupled via an optical fiber.Every cavity is made of one fixed mirror and a movable mirror,and the movable mirror can be regarded as a mechanical oscillators.Meanwhile,the two cavity modes are driven by classical laser fields.So,the interaction is inevitable between cavities,cavity and moving mirror,cavity and classical field.Firstly,in order to eliminate the two cavity fields,an effective Hamiltonian of the two phonon modes is derived by means of picture transformation,adiabatic eliminating,and rotating wave approximation ignoring the high frequency items,etc.Secondly,if the two mechanical oscillators initially are in coherent states,the coupled mechanical oscillators can be used to transmit state.Finally,in order to verify the analytical result,the fidelity of quantum state is numevically simulated,the result shows that the quantum state can be transferred periodically between the two mechanical oscillators,which is the same as the analytical result.
We propose a scheme to realize the two-phonon blockade effect in a quadratically coupled optomechanical system. We consider the case that the optical cavity is simultaneously driven by a strong pumping field and a weak driving field. By strongly driving the optical cavity, the nonlinear interaction between the optical mode and the mechanical resonator can be significantly enhanced and an effective second-order nonlinearity between photons and phonons is induced. Based on this effectively strong nonlinearity, the two-phonon blockade effect can be achieved when a weak driving field is applied into the optical cavity. By contrast, we study the case of weakly driving the mechanical resonator. In this case, the single-phonon blockade is generated, while the two-phonon blockade cannot be observed. By numerically calculating the second-order and third-order correlation function, we investigate the statistical characteristics of phonons. In addition, we also study the influence of the thermal noise on the achieved two-phonon blockade effect. Our work provides an alternative approach for implementing multiphonon blockade and has potential applications in quantum information processing.
In the field of optomechanics, one typically studies the interaction of a single mechanical resonator and a single optical cavity mode. In this thesis, we investigate collective quantum effects in optomechanical systems with two or more optical and mechanical modes. First, we study the generation and destruction of entanglement between two mechanical resonators effected by optical cavity fields. We also describe how the optomechanical interaction can be employed to mediate strong coherent coupling and entanglement between a micromechanical membrane and a single atom. Secondly, we show that a configuration with two optical and a single mechanical mode can lead to enhanced nonlinear interactions, which can be exploited for quantum non-demolition measurements of the phonon and photon numbers. Finally, we explore the quantum many-body dynamics of optomechanical arrays. In particular, we research into the transition from a disordered state due to quantum noise to a state with phasecoherent mechanical oscillations. As an intermediate step towards this study, we also investigate the nonlinear classical dynamics of single- and multi-mode optomechanical setups and compare theoretical predictions to experimental data.
Here we show that quantum states of a mechanical oscillator can be generated in an optomechanical analog of the micromaser in the absence of any atomlike subsystem, thus exhibiting single-atom masing effects in a system composed solely of oscillator components. In the regime where the single-photon coupling strength is on the order of the cavity decay rate, a cavity mode with at most a single-excitation present gives rise to sub-Poissonian oscillator limit-cycles that generate quantum features in the steady state just above the renormalized cavity resonance frequency and mechanical sidebands. The merger of multiple stable limit-cycles markedly reduces these nonclassical signatures. Varying the cavity-resonator coupling strength, corresponding to the micromaser pump parameter, reveals transitions for the oscillator phonon number that are the hallmark of a micromaser. The connection to the micromaser allows for a physical understanding of how nonclassical states arise in this system and how best to maximize these signatures for experimental observation.
The nonlinear quantum regime is crucial for implementing interesting quantum effects, which have wide applications in modern quantum science. Here we propose an effective method to reach the nonlinear quantum regime in a modulated optomechanical system (OMS), which is originally in the weak-coupling regime. The mechanical spring constant and optomechanical interaction are modulated periodically. This leads to the result that the resonant optomechanical interaction can be effectively enhanced into the single-photon strong-coupling regime by the modulation-induced mechanical parametric amplification. Moreover, the amplified phonon noise can be suppressed completely by introducing a squeezed vacuum reservoir, which ultimately leads to the realization of photon blockade in a weakly coupled OMS. The reached nonlinear quantum regime also allows us to engineer the nonclassical states (e.g., Schr\"odinger cat states) of the cavity field, which are robust against the phonon noise. This work offers an alternative approach to enhance the quantum nonlinearity of an OMS, which should expand the applications of cavity optomechanics in the quantum realm.
The effective Hamiltonian of the optmechanical systems is similar to one that describes the interaction between a classical driving field and a single trapped cold ion. In this paper, by using this idea, generation and transfer of the entanglement state is investigated. In optomechanical systems with one and two membranes inside the cavity and in the Lamb-Dick approximation, with selecting mode the state transfer and the generation of two mode squeezed state between two membranes is considered. Also, the measure of entanglement in interaction to the thermal phonons and damping rate of cavity is computed.In this paper we try to describe our experimental or theoretical results. This abstract should be about 100 words.