Monogamy and Sharability of Multipartite EPR Steering in Asymmetric Superconducting Quantum Networks

Xue Zhang, Ruinian Li, Jiahui Chen +2 more

C Xiao, Xiaomao Cheng, Junwei Lv +6 more

Abstract Einstein–Podolsky–Rosen (EPR) steering is different from quantum entanglement because of its unique asymmetry. Multipartite asymmetric EPR steering can break through one-to-one monogamy steering and achieve one to many one-way steering. That is to say, the state of one part can steer the other rest parts simultaneously, while the other parts cannot steer this part. Here, a scheme is proposed to generate one to many one-way steering by optical parametric amplification cascaded with a sum-frequency generation process. One to many non-monogamy EPR steering, such as one to two and one to three one-way steering are demonstrated based on the criterion for asymmetric EPR steering. It is also find that different kinds of asymmetric EPR steering can be obtained by choosing different nonlinear parameters. This non-monogamous one to many quantum control has potential application in constructing quantum networks and realizing one-way quantum computing.

Mengxin Zhang, Yumei Long, Shiqing Zhao +1 more

We achieve the controllable multipartite Einstein-Podolsky-Rosen (EPR) steering and its monogamy relations by means of the dynamical Casimir effect in the frame of superconducting quantum network. We employ the external driving flux of the superconducting quantum interference device as a switch. It is interesting that the system exhibits different types of the EPR steering and monogamy relations by tuning parameters. In the system, the one-way or two-way EPR steerings for different parties have been realized, and the direction of the one-way EPR steering is reversed by tuning coupling parameters. Remarkably, we can also obtain the EPR steering orderly sudden death for different modes. In addition, the system not only shows the type-I and type-II monogamy relations, but also converts steering parties to get monogamy relations' swapping and cycling. Finally, we discuss the influence of temperature. In the system, the higher the temperature is, the earlier sudden death for the EPR steering is. These results are important for quantum information and lay a foundation for us to better understand the important role of the multipartite EPR steering in secure quantum communication.

Hui Li, Ting Gao, Fengli Yan

Zhi-Xiang Jin, Shao-Ming Fei

Ze-Yan Hao, Kai Sun, Yan Wang +5 more

Einstein-Podolsky-Rosen (EPR) steering, a category of quantum nonlocal correlations describing the ability of one observer to influence another party's state via local measurements, is different from both entanglement and Bell nonlocality by possessing an asymmetric property. For multipartite EPR steering, the monogamous situation, where two observers cannot simultaneously steer the state of the third party, has been investigated rigorously both in theory and experiment. In contrast to the monogamous situation, the shareability of EPR steering in reduced subsystems allows the state of one party to be steered by two or more observers and thus reveals more configurations of multipartite EPR steering. However, the experimental implementation of such a kind of shareability has still been absent until now. Here, in an optical experiment, we provide a proof-of-principle demonstration of the shareability of EPR steering without the constraint of monogamy in a three-qubit system. Moreover, based on the reduced bipartite EPR steering detection results, we verify the genuine three-qubit entanglement results. This work provides a complementary viewpoint for understanding multipartite EPR steering and has potential applications in many quantum information protocols, such as multipartite entanglement detection, quantum cryptography, and the construction of quantum networks.