Quantum non-demolition(QND) measurement is an important tool in the fields of quantum information processing and quantum optics. The atom-light hybrid interferometer is of great interest due to its combination of an a...Quantum non-demolition(QND) measurement is an important tool in the fields of quantum information processing and quantum optics. The atom-light hybrid interferometer is of great interest due to its combination of an atomic spin wave and an optical wave, which can be utilized for photon number QND measurement via the AC-Stark effect. In this paper, we present an SU(1,1)-SU(2)-concatenated atom-light hybrid interferometer, and theoretically study QND measurement of the photon number. Compared to the traditional SU(2) interferometer,the signal-to-noise ratio in a balanced case is improved by a gain factor of the nonlinear Raman process(NRP)in this proposed interferometer. Furthermore, the condition of high-quality QND measurement is analyzed. In the presence of losses, the measurement quality is reduced. We can adjust the gain parameter of the NRP in the readout stage to reduce the impact due to losses. Moreover, this scheme is a multiarm interferometer, which has the potential of multiparameter estimation with many important applications in the detection of vector fields,quantum imaging, and so on.展开更多
Photon number-squeezed states are of significant value in fundamental quantum research and have a wide range of applications in quantum metrology.Most of their preparation mechanisms require precise control of quantum...Photon number-squeezed states are of significant value in fundamental quantum research and have a wide range of applications in quantum metrology.Most of their preparation mechanisms require precise control of quantum dynamics and are less tolerant to dissipation.We propose a mechanism that is not subject to these restraints.In contrast to common approaches,we exploit the self-balancing between two types of dissipation induced by positive-and negative-temperature reservoirs to generate steady states with sub-Poissonian statistical distributions of photon numbers.We also show how to implement this mechanism with cavity optomechanical systems.The quality of the prepared photon number-squeezed state is estimated by our theoretical model combined with realistic parameters for various typical optomechanical systems.展开更多
A phonon counting scheme based on the control of polaritons in an optomechanical system is proposed. This approach permits us to measure the number of phonons in a quantum non-demolition(QND) manner for arbitrary mode...A phonon counting scheme based on the control of polaritons in an optomechanical system is proposed. This approach permits us to measure the number of phonons in a quantum non-demolition(QND) manner for arbitrary modes not limited by the frequency matching condition as in usual photon-phonon scattering detections. The performance on phonon number transfer and quantum state transfer of the counter are analyzed and simulated numerically by taking into account all relevant sources of noise.展开更多
The accelerometer plays a crucial role in inertial navigation.The performance of conventional accelerometers such as lasers is usually limited by the sensing elements and shot noise limitation(SNL).Here,we propose an ...The accelerometer plays a crucial role in inertial navigation.The performance of conventional accelerometers such as lasers is usually limited by the sensing elements and shot noise limitation(SNL).Here,we propose an advanced development of an accelerometer based on atom–light quantum correlation,which is composed of a cold atomic ensemble,light beams,and an atomic vapor cell.The cold atomic ensemble,prepared in a magneto-optical trap and free-falling in a vacuum chamber,interacts with light beams to generate atom–light quantum correlation.The atomic vapor cell is used as both a memory element storing the correlated photons emitted from cold atoms and a bandwidth controller through the control of free evolution time.Instead of using a conventional sensing element,the proposed accelerometer employs interference between quantum-correlated atoms and light to measure acceleration.Sensitivity below SNL can be achieved due to atom–light quantum correlation,even in the presence of optical loss and atomic decoherence.Sensitivity can be achieved at the ng∕√Hz level,based on evaluation via practical experimental conditions.The present design has a number of significant advantages over conventional accelerometers such as SNL-broken sensitivity,broad bandwidth from a few hundred Hz to near MHz,and avoidance of the technical restrictions of conventional sensing elements.展开更多
基金National Key Research and Development Program of China(2016YFA0302001)National Natural Science Foundation of China(11974111,11874152,91536114,11574086,11974116,11654005)+4 种基金Shanghai Rising-Star Program(16QA1401600)Innovation Program of Shanghai Municipal Education Commission(202101070008E00099)Shanghai Talent ProgramChinese National Youth Talent Support ProgramFundamental Research Funds for the Central Universities。
文摘Quantum non-demolition(QND) measurement is an important tool in the fields of quantum information processing and quantum optics. The atom-light hybrid interferometer is of great interest due to its combination of an atomic spin wave and an optical wave, which can be utilized for photon number QND measurement via the AC-Stark effect. In this paper, we present an SU(1,1)-SU(2)-concatenated atom-light hybrid interferometer, and theoretically study QND measurement of the photon number. Compared to the traditional SU(2) interferometer,the signal-to-noise ratio in a balanced case is improved by a gain factor of the nonlinear Raman process(NRP)in this proposed interferometer. Furthermore, the condition of high-quality QND measurement is analyzed. In the presence of losses, the measurement quality is reduced. We can adjust the gain parameter of the NRP in the readout stage to reduce the impact due to losses. Moreover, this scheme is a multiarm interferometer, which has the potential of multiparameter estimation with many important applications in the detection of vector fields,quantum imaging, and so on.
基金Innovation Program for Quantum Science and Technology(2021ZD0303200)National Key Research and Development Program of China(2016YFA0302001)+4 种基金National Natural Science Foundation of China(11654005,11974116,12234014)Shanghai Municipal Science and Technology Major Project(2019SHZDZX01)Fundamental Research Funds for the Central UniversitiesChinese National Youth Talent Support ProgramShanghai Talent Program。
文摘Photon number-squeezed states are of significant value in fundamental quantum research and have a wide range of applications in quantum metrology.Most of their preparation mechanisms require precise control of quantum dynamics and are less tolerant to dissipation.We propose a mechanism that is not subject to these restraints.In contrast to common approaches,we exploit the self-balancing between two types of dissipation induced by positive-and negative-temperature reservoirs to generate steady states with sub-Poissonian statistical distributions of photon numbers.We also show how to implement this mechanism with cavity optomechanical systems.The quality of the prepared photon number-squeezed state is estimated by our theoretical model combined with realistic parameters for various typical optomechanical systems.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFA0302001)the National Natural Science Foundation of China(Grant Nos.11574086,91436211,11234003,and11654005)+1 种基金the Shanghai Rising-Star Program(Grant No.16QA1401600)the Science and Technology Commission of Shanghai Municipality(Grant No.16DZ2260200)
文摘A phonon counting scheme based on the control of polaritons in an optomechanical system is proposed. This approach permits us to measure the number of phonons in a quantum non-demolition(QND) manner for arbitrary modes not limited by the frequency matching condition as in usual photon-phonon scattering detections. The performance on phonon number transfer and quantum state transfer of the counter are analyzed and simulated numerically by taking into account all relevant sources of noise.
基金National Key Research and Development Program of China (2016YFA0302001)National Natural Science Foundation of China (11874152, 11974111,11654005, 11974116, 91536114)+4 种基金Shanghai Municipal Science and Technology Major Project (2019SHZDZX01)Innovation Program of Shanghai Municipal Education Commission (202101070008E00099)Shanghai Talent ProgramChinese National Youth Talent Support ProgramFundamental Research Funds for the Central Universities.
文摘The accelerometer plays a crucial role in inertial navigation.The performance of conventional accelerometers such as lasers is usually limited by the sensing elements and shot noise limitation(SNL).Here,we propose an advanced development of an accelerometer based on atom–light quantum correlation,which is composed of a cold atomic ensemble,light beams,and an atomic vapor cell.The cold atomic ensemble,prepared in a magneto-optical trap and free-falling in a vacuum chamber,interacts with light beams to generate atom–light quantum correlation.The atomic vapor cell is used as both a memory element storing the correlated photons emitted from cold atoms and a bandwidth controller through the control of free evolution time.Instead of using a conventional sensing element,the proposed accelerometer employs interference between quantum-correlated atoms and light to measure acceleration.Sensitivity below SNL can be achieved due to atom–light quantum correlation,even in the presence of optical loss and atomic decoherence.Sensitivity can be achieved at the ng∕√Hz level,based on evaluation via practical experimental conditions.The present design has a number of significant advantages over conventional accelerometers such as SNL-broken sensitivity,broad bandwidth from a few hundred Hz to near MHz,and avoidance of the technical restrictions of conventional sensing elements.
