Quantum entanglement plays a key role in both understanding the fundamental aspects of quantum physics and realizing various quantum devices for practical applications. Here we propose how to achieve a coherent switch...Quantum entanglement plays a key role in both understanding the fundamental aspects of quantum physics and realizing various quantum devices for practical applications. Here we propose how to achieve a coherent switch of optomechanical entanglement in an optical whispering-gallery-mode resonator, by tuning the phase difference of the driving lasers. We find that the optomechanical entanglement and the associated two-mode quantum squeezing can be well tuned in a highly asymmetric way,providing an efficient way to protect and enhance quantum entanglement against optical backscattering, in comparison with conventional symmetric devices. Our findings shed a new light on improving the performance of various quantum devices in the practical noisy environment, which is crucial in such a wide range of applications as noise-tolerant quantum processing and the backscattering-immune quantum metrology.展开更多
Einstein-Podolsky-Rosen(EPR) entanglement involving a pair of particles entangled in their positions and momenta is of special interest in the field of quantum information. Previously, EPR entanglement has been studie...Einstein-Podolsky-Rosen(EPR) entanglement involving a pair of particles entangled in their positions and momenta is of special interest in the field of quantum information. Previously, EPR entanglement has been studied in different physical systems but in fixed coordinate spaces. Here, we demonstrate an experiment of ghost imaging and ghost interference in rotated position-momentum spaces by using positionmomentum entangled photons generated from a hot atomic ensemble. By using different image objects,the measured position-momentum correlations exhibit intriguing dynamics, including gradual decrease and axis-independent EPR entanglement. The reported results on manipulating the EPR entanglement in rotating coordinate spaces hold promise in quantum communication and distant quantum image processing.展开更多
The generation and manipulation of strong entanglement and Einstein-Podolsky-Rosen(EPR)steering in macroscopic systems are outstanding challenges in modern physics.Especially,the observation of asymmetric EPR steering...The generation and manipulation of strong entanglement and Einstein-Podolsky-Rosen(EPR)steering in macroscopic systems are outstanding challenges in modern physics.Especially,the observation of asymmetric EPR steering is important for both its fundamental role in interpreting the nature of quantum mechanics and its application as resource for the tasks where the levels of trust at different parties are highly asymmetric.Here,we study the entanglement and EPR steering between two macroscopic magnons in a hybrid ferrimagnet—light system.In the absence of light,the two types of magnons on the two sublattices can be entangled,but no quantum steering occurs when they are damped with the same rates.In the presence of the cavity field,the entanglement can be significantly enhanced,and strong two-way asymmetric quantum steering appears between two magnons with equal dissipation.This is very different from the conventional protocols to produce asymmetric steering by imposing additional unbalanced losses or noises on the two parties at the cost of reducing steerability.The essential physics is well understood by the unbalanced population of acoustic and optical magnons under the cooling effect of cavity photons.Our finding may provide a novel platform to manipulate the quantum steering and the detection of bi-party steering provides a knob to probe the magnetic damping on each sublattice of a magnet.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11935006,11774086,12147156,12125402,1197502612064010)+3 种基金supported by the Science and Technology Innovation Program of Hunan Province(Grant No.2020RC4047)supported by the China Postdoctoral Science Foundation(Grant Nos.2021M701176,and 2022T150208)the Science and Technology Innovation Program of Hunan Province(Grant No.2021RC2078)supported by the Natural Science Foundation of Hunan Province(Grant No.2021JJ20036)。
文摘Quantum entanglement plays a key role in both understanding the fundamental aspects of quantum physics and realizing various quantum devices for practical applications. Here we propose how to achieve a coherent switch of optomechanical entanglement in an optical whispering-gallery-mode resonator, by tuning the phase difference of the driving lasers. We find that the optomechanical entanglement and the associated two-mode quantum squeezing can be well tuned in a highly asymmetric way,providing an efficient way to protect and enhance quantum entanglement against optical backscattering, in comparison with conventional symmetric devices. Our findings shed a new light on improving the performance of various quantum devices in the practical noisy environment, which is crucial in such a wide range of applications as noise-tolerant quantum processing and the backscattering-immune quantum metrology.
基金supported by the National Key R&D Program of China (2017YFA0304800)the National Natural Science Foundation of China (11934013, 61525504, 61722510, 61435011, and 11604322)+5 种基金the Innovation Fund from Chinese Academy of Sciences and Anhui Initiative in Quantum Information Technologies (AHY020200)the Youth Innovation Promotion Association of Chinese Academy of Sciences (2018490)Qiong-Yi He acknowledges the support of the National Key R&D Program of China(2016YFA0301302 and 2018YFB1107200)the National Natural Science Foundation of China (11622428 and 61675007)the Key R&D Program of Guangzhou Province (2018B030329001)Beijing Natural Science Foundation (Z190005).
文摘Einstein-Podolsky-Rosen(EPR) entanglement involving a pair of particles entangled in their positions and momenta is of special interest in the field of quantum information. Previously, EPR entanglement has been studied in different physical systems but in fixed coordinate spaces. Here, we demonstrate an experiment of ghost imaging and ghost interference in rotated position-momentum spaces by using positionmomentum entangled photons generated from a hot atomic ensemble. By using different image objects,the measured position-momentum correlations exhibit intriguing dynamics, including gradual decrease and axis-independent EPR entanglement. The reported results on manipulating the EPR entanglement in rotating coordinate spaces hold promise in quantum communication and distant quantum image processing.
基金supported by the National Natural Science Foundation of China(Grant Nos.11975026,61475007,and 61704071)the National Key Research and Development Program of China(Grant Nos.2018YFB1107200,and 2016YFA0301302)+1 种基金the Key Research and Development Program of Guangzhou Province(Grant No.2018B030329001)the Beijing Natural Science Foundation(Grant No.Z190005)。
文摘The generation and manipulation of strong entanglement and Einstein-Podolsky-Rosen(EPR)steering in macroscopic systems are outstanding challenges in modern physics.Especially,the observation of asymmetric EPR steering is important for both its fundamental role in interpreting the nature of quantum mechanics and its application as resource for the tasks where the levels of trust at different parties are highly asymmetric.Here,we study the entanglement and EPR steering between two macroscopic magnons in a hybrid ferrimagnet—light system.In the absence of light,the two types of magnons on the two sublattices can be entangled,but no quantum steering occurs when they are damped with the same rates.In the presence of the cavity field,the entanglement can be significantly enhanced,and strong two-way asymmetric quantum steering appears between two magnons with equal dissipation.This is very different from the conventional protocols to produce asymmetric steering by imposing additional unbalanced losses or noises on the two parties at the cost of reducing steerability.The essential physics is well understood by the unbalanced population of acoustic and optical magnons under the cooling effect of cavity photons.Our finding may provide a novel platform to manipulate the quantum steering and the detection of bi-party steering provides a knob to probe the magnetic damping on each sublattice of a magnet.