We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)proc...We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.展开更多
Quantum entanglement between distant massive mechanical oscillators is an important resource in sensitive measurements and quantum information processing.We achieve the nonreciprocal mechanical entanglement in a compo...Quantum entanglement between distant massive mechanical oscillators is an important resource in sensitive measurements and quantum information processing.We achieve the nonreciprocal mechanical entanglement in a compound optomechanical device consisting of two mechanical oscillators and a spinning whispering-gallery mode(WGM)optical microresonator.It is found that obvious nonreciprocal mechanical entanglement emerges in this system in the presence of the Sagnac effect which is induced by the rotation of the WGM resonator,and the nonreciprocal region can be controlled by tuning the angular velocity of the rotation.The nonreciprocity originates from the breaking of the time-reversal symmetry of this multimode system due to the presence of the Sagnac effect.The optomechanical coupling and the mechanical interaction provide cooling channels for the first and second mechanical oscillators,respectively.Two mechanical oscillators can be cooled simultaneously.The simultaneous cooling and the mechanical coupling of two mechanical oscillators ensure the generation of mechanical entanglement.Furthermore,an optimal mechanical entanglement can be achieved when the moderate optical frequency detuning and the driving power are chosen.The thermal noise of the mechanical environment has a negative effect on mechanical entanglement.Our scheme provides promising opportunities for research of quantum information processing based on phonons and sensitive measurements.展开更多
基金Project supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202400624)the Natural Science Foundation of Chongqing CSTC(Grant No.CSTB2022NSCQBHX0020)+3 种基金the China Electronics Technology Group Corporation 44th Research Institute(Grant No.6310001-2)the Project Grant“Noninvasive Sensing Measurement based on Terahertz Technology”from Province and MOE Collaborative Innovation Centre for New Generation Information Networking and Terminalsthe Key Research Program of CQUPT on Interdisciplinary and Emerging Field(A2018-01)the Venture&Innovation Support program for Chongqing Overseas Returnees Year 2022。
文摘We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.
基金supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202400624)the Natural Science Foundation of Chongqing CSTC(Grant No.CSTB2022NSCQ-BHX0020).
文摘Quantum entanglement between distant massive mechanical oscillators is an important resource in sensitive measurements and quantum information processing.We achieve the nonreciprocal mechanical entanglement in a compound optomechanical device consisting of two mechanical oscillators and a spinning whispering-gallery mode(WGM)optical microresonator.It is found that obvious nonreciprocal mechanical entanglement emerges in this system in the presence of the Sagnac effect which is induced by the rotation of the WGM resonator,and the nonreciprocal region can be controlled by tuning the angular velocity of the rotation.The nonreciprocity originates from the breaking of the time-reversal symmetry of this multimode system due to the presence of the Sagnac effect.The optomechanical coupling and the mechanical interaction provide cooling channels for the first and second mechanical oscillators,respectively.Two mechanical oscillators can be cooled simultaneously.The simultaneous cooling and the mechanical coupling of two mechanical oscillators ensure the generation of mechanical entanglement.Furthermore,an optimal mechanical entanglement can be achieved when the moderate optical frequency detuning and the driving power are chosen.The thermal noise of the mechanical environment has a negative effect on mechanical entanglement.Our scheme provides promising opportunities for research of quantum information processing based on phonons and sensitive measurements.
