Generation And Manipulation Of Quantum Steering And Entanglement Between Two Mechanical Modes In A Cavity Optomechanical System

By radiation pressure and optical resonator,the cavity optomechanical systems can realize quantum manipulation and study the quantum phenomena of macroscopic objects,which is of great significance for testing quantum mechanical basic assumptions and realizing quantum information processing and storage.The present domestic and international research of cavity optomechanical systems not only helps to reveal the physical nature from classics to quantum transition,but also has crucial applications in the domains of ultra-precision measurement and information processing.With the development of quantum information and quantum communication,people have been researching quantum effects such as quantum steering,quantum entanglement,cooling and squeezing of macroscopic objects by different physical mechanisms in cavity optomechanical systems.For example,adding nonlinear media in cavity optomechanical systems can make more interesting dynamic characteristics.Dissipation is regarded as a favorable factor under reservoir-engineered conditions to prepare stronger nonclassical states.Quantum entanglement has important applications in many quantum technologies,such as hybrid quantum networks and quantum metrology;Quantum steering is a special kind of quantum entanglement with nonlocality and natural asymmetry which provides new insights for quantum information nonlocality and has important practical applications in quantum information,such as the one-sided device-independent quantum key distribution and quantum teleportation.Basing on reservoir-engineered and introducing a parametric amplifier,in this paper,the enhancement and manipulation of mechanical entanglement and steering in a three-mode optomechanical system consisting of two oscillators and a cavity mode.The research content of this paper consists of two parts:On the one hand,quantum entanglement and quantum steering of two mechanical oscillators generate through reservoir-engineered.It is well known that entanglement between oscillators can be prepared by two Bogoliubov dissipation channels,which constructed by two lasers with different frequencies driving cavity fields.Here,the paper extend this mechanism to quantum steering.In addition,the paper propose two methods to generate one-way quantum steering of two mechanical modes,which are to adjust the damping rates and thermal noises of mechanical oscillators,respectively.An interesting phenomenon is found for?₁（29）?₂,the steerabilityG_2?1（29）G_1?2,however when the thermal noisen_{1,t h}（29）n_2,th is gives one-way steering in the opposite direction.On the other hand,the parametric amplifier is introduced to enhance quantum entanglement and quantum steering.By numerical analysis,the paper are discussed in detail effects of the parametric amplifier’s strength and phase about the mechanical entanglement and quantum steering.It is found that adding a parametric amplifier to the cavity can not only enhance the entanglement and steering between oscillators,but also can significantly increase the asymmetry of quantum steering and expand the region of the one-way steering.Meanwhile,the addition of the parametric amplifier can also strengthen the robustness of the quantum entanglement and quantum steering against the thermal noise.The enhancement and manipulation schemes for quantum steering presented here may be meaningful for quantum cryptography and quantum information processing.