It has recently been realized that quantum strategies have a great advantage over classical ones in quantum games. However, quantum states are easily affected by the quantum noise, resulting in decoherence. In this pa...It has recently been realized that quantum strategies have a great advantage over classical ones in quantum games. However, quantum states are easily affected by the quantum noise, resulting in decoherence. In this paper, we investigate the effect of quantum noise on a multiplayer quantum game with a certain strategic space, with all players affected by the same quantum noise at the same time. Our results show that in a maximally entangled state, a special Nash equilibrium appears in the range of 0≤p≤0.622 （p is the quantum noise parameter）, and then disappears in the range of 0.622 〈 p≤ 1. Increasing the amount of quantum noise leads to the reduction of the quantum player＇s payoff.展开更多
We present an optical scheme to almost completely teleport a bipartite entangled coherent state using afour-partite cluster-type entangled coherent state as quantum channel.The scheme is based on optical elements such...We present an optical scheme to almost completely teleport a bipartite entangled coherent state using afour-partite cluster-type entangled coherent state as quantum channel.The scheme is based on optical elements suchas beam splitters,phase shifters,and photon detectors.We also obtain the average fidelity of the teleportation process.It is shown that the average fidelity is quite close to unity if the mean photon number of the coherent state is not toosmall.展开更多
In this article, we derive the explicit entanglement and fidelity expressions for a larger class of two-qubit states, namely, a seven-parameter family of so ca^led X-states. The ana/ytical expressions of the entanglem...In this article, we derive the explicit entanglement and fidelity expressions for a larger class of two-qubit states, namely, a seven-parameter family of so ca^led X-states. The ana/ytical expressions of the entanglement, the output entanglement and the average fidelity are obtained for this genera/model by using the concept of concurrence and average fidelity. We study the relations between quantum entanglement, the output entanglement, and the average fidelity for standard teleportation of one-qubit and partial teleportation of two-qubit state. We discover that the average fidelity and entanglement is not a simple dependence relation. The higher entangled system is helpful for teleportation.展开更多
We study the Bell's inequality and multipartite entanglement generation for initially maximally entangled states of free Dirac field in a non inertial frame and asymptotically flat Robertson–Walker space-time.For...We study the Bell's inequality and multipartite entanglement generation for initially maximally entangled states of free Dirac field in a non inertial frame and asymptotically flat Robertson–Walker space-time.For two qubit case,we show that the Bell's inequality always is violated as measured by the accelerated observers which are in the causally connected regions.On the other hand,for those observers in the causally disconnected regions inequality is not violated for any values of acceleration.The generated three qubit state from two qubit state due to acceleration of one parties has a zero 3-tangle.For a three qubit state,the inequality violated for measurements done by both causally connected and disconnected observers.Initially GHZ state with non zero 3-tangle,in accelerated frame,transformed to a four qubit state with vanishing 4-tangle value.On the other hand,for a W-state with zero 3-tangle,in non inertial frame,transformed to a four qubit state with a non-zero 4-tangle acceleration dependent.In an expanding space-time with asymptotically flat regions,for an initially maximally entangled state,the maximum value of violation of Bell's inequality in the far past decreased in the far future due to cosmological particle creation.For some initially maximally entangled states,the generated four qubit state due to expansion of space-time,has non vanishing 4-tangle.展开更多
In this paper, by employing Bogliubov backreaction method, we investigate quantum correction effects on dynamical phase transition in a single species bosonic Josephson junction induced by increasing nonlinear interac...In this paper, by employing Bogliubov backreaction method, we investigate quantum correction effects on dynamical phase transition in a single species bosonic Josephson junction induced by increasing nonlinear interaction. Compared with mean field theory results, we find that the transition point is shined. The dynamical phase transition is accompanied by a change of the entanglement entropy, which is found to reach a maximum at the transition point of the mean field theory.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10374025）.
文摘It has recently been realized that quantum strategies have a great advantage over classical ones in quantum games. However, quantum states are easily affected by the quantum noise, resulting in decoherence. In this paper, we investigate the effect of quantum noise on a multiplayer quantum game with a certain strategic space, with all players affected by the same quantum noise at the same time. Our results show that in a maximally entangled state, a special Nash equilibrium appears in the range of 0≤p≤0.622 （p is the quantum noise parameter）, and then disappears in the range of 0.622 〈 p≤ 1. Increasing the amount of quantum noise leads to the reduction of the quantum player＇s payoff.
基金Supported by the National Natural Science Foundation of China under Grant No.60708003the National Key Basic Research Program of China under Grant No.2006CB921604the Basic Key Program of Shanghai Municipality under Grant No.07JC14017
文摘We present an optical scheme to almost completely teleport a bipartite entangled coherent state using afour-partite cluster-type entangled coherent state as quantum channel.The scheme is based on optical elements suchas beam splitters,phase shifters,and photon detectors.We also obtain the average fidelity of the teleportation process.It is shown that the average fidelity is quite close to unity if the mean photon number of the coherent state is not toosmall.
基金Supported by the Youth Foundation of Institute of Science under Grant Nos. QN-SL-2010-01,QN-SL-2010-10Pre-Research Foundation of PLA University of Science and Technology under Grant Nos. 20110515 and 20110101
文摘In this article, we derive the explicit entanglement and fidelity expressions for a larger class of two-qubit states, namely, a seven-parameter family of so ca^led X-states. The ana/ytical expressions of the entanglement, the output entanglement and the average fidelity are obtained for this genera/model by using the concept of concurrence and average fidelity. We study the relations between quantum entanglement, the output entanglement, and the average fidelity for standard teleportation of one-qubit and partial teleportation of two-qubit state. We discover that the average fidelity and entanglement is not a simple dependence relation. The higher entangled system is helpful for teleportation.
基金Islamic Azad University,Khorram Branch,for Financial support
文摘We study the Bell's inequality and multipartite entanglement generation for initially maximally entangled states of free Dirac field in a non inertial frame and asymptotically flat Robertson–Walker space-time.For two qubit case,we show that the Bell's inequality always is violated as measured by the accelerated observers which are in the causally connected regions.On the other hand,for those observers in the causally disconnected regions inequality is not violated for any values of acceleration.The generated three qubit state from two qubit state due to acceleration of one parties has a zero 3-tangle.For a three qubit state,the inequality violated for measurements done by both causally connected and disconnected observers.Initially GHZ state with non zero 3-tangle,in accelerated frame,transformed to a four qubit state with vanishing 4-tangle value.On the other hand,for a W-state with zero 3-tangle,in non inertial frame,transformed to a four qubit state with a non-zero 4-tangle acceleration dependent.In an expanding space-time with asymptotically flat regions,for an initially maximally entangled state,the maximum value of violation of Bell's inequality in the far past decreased in the far future due to cosmological particle creation.For some initially maximally entangled states,the generated four qubit state due to expansion of space-time,has non vanishing 4-tangle.
基金Supported by the National Natural Science Foundation of China under Grant No.11104217the Science Plan Foundation Office of the Education Department of Shaanxi Province under Grant No.11JK0555the Youth Foundation of XUPT under Grant Nos.0001295 and 0001287
文摘In this paper, by employing Bogliubov backreaction method, we investigate quantum correction effects on dynamical phase transition in a single species bosonic Josephson junction induced by increasing nonlinear interaction. Compared with mean field theory results, we find that the transition point is shined. The dynamical phase transition is accompanied by a change of the entanglement entropy, which is found to reach a maximum at the transition point of the mean field theory.
