By means of composite quantum collision models,we study the entanglement dynamics of a bipartite system,i.e.,two qubits S1 and S2 interacting directly with an intermediate auxiliary qubit SA,while SA is in turn couple...By means of composite quantum collision models,we study the entanglement dynamics of a bipartite system,i.e.,two qubits S1 and S2 interacting directly with an intermediate auxiliary qubit SA,while SA is in turn coupled to a thermal reservoir.We are concerned with how the intracollisions of the reservoir qubits influence the entanglement dynamics.We show that even if the system is initially in the separated state,their entanglement can be generated due to the interaction between the qubits.In the long-time limit,the steady-state entanglement can be generated depending on the initial state of S1 and S2 and the environment temperature.We also study the dynamics of tripartite entanglement of the three qubits S1,S2,and SA when they are initially prepared in the GHZ state and separated state,respectively.For the GHZ initial state,the tripartite entanglement can be maintained for a long time when the collision strength between the environment qubits is sufficiently large.展开更多
By means of collision models(CMs)where the environment is simulated by a collection of ancillas consisting of two entangled qubits,we investigate the effects of entanglement in the environment on the non-Markovianity ...By means of collision models(CMs)where the environment is simulated by a collection of ancillas consisting of two entangled qubits,we investigate the effects of entanglement in the environment on the non-Markovianity of an open quantum system.Two CMs are considered in this study,in the first one the open quantum system S directly collides with the environment,while in the second one the system interacts with two intermediate qubits which,in turn,are coupled to the environment.We show that it is possible to enhance the non-Markovianity by environment entanglement in both models.In particular,in the second model,we show that the initial state of the auxiliary qubits can also affect the non-Markovianity of the system and there exists the optimal combination of the initial environmental state and the initial state of auxiliary qubits.In this case,the non-Markovianity can be greatly enhanced.展开更多
基金National Natural Science Foundation of China(Grant Nos.61675115 and 11974209)the Taishan Scholar Project of Shandong Province of China(Grant No.tsqn201812059)the Shandong Provincial Natural Science Foundation of China(Grant No.ZR2016JL005).
文摘By means of composite quantum collision models,we study the entanglement dynamics of a bipartite system,i.e.,two qubits S1 and S2 interacting directly with an intermediate auxiliary qubit SA,while SA is in turn coupled to a thermal reservoir.We are concerned with how the intracollisions of the reservoir qubits influence the entanglement dynamics.We show that even if the system is initially in the separated state,their entanglement can be generated due to the interaction between the qubits.In the long-time limit,the steady-state entanglement can be generated depending on the initial state of S1 and S2 and the environment temperature.We also study the dynamics of tripartite entanglement of the three qubits S1,S2,and SA when they are initially prepared in the GHZ state and separated state,respectively.For the GHZ initial state,the tripartite entanglement can be maintained for a long time when the collision strength between the environment qubits is sufficiently large.
基金supported by National Natural Science Foundation(China)under Grant No.61675115 and No.11974209Taishan Scholar Project of Shandong Province(China)under Grant No.tsqn201812059Shandong Provincial Natural Science Foundation(China)under Grant No.ZR2016JL005。
文摘By means of collision models(CMs)where the environment is simulated by a collection of ancillas consisting of two entangled qubits,we investigate the effects of entanglement in the environment on the non-Markovianity of an open quantum system.Two CMs are considered in this study,in the first one the open quantum system S directly collides with the environment,while in the second one the system interacts with two intermediate qubits which,in turn,are coupled to the environment.We show that it is possible to enhance the non-Markovianity by environment entanglement in both models.In particular,in the second model,we show that the initial state of the auxiliary qubits can also affect the non-Markovianity of the system and there exists the optimal combination of the initial environmental state and the initial state of auxiliary qubits.In this case,the non-Markovianity can be greatly enhanced.
