本文主要研究了在非马尔可夫环境下在时变磁场中具有各种参数的交互作用非常丰富的两个比特的海森堡XYZ模型的量子稠密编码的性质。通过量子态扩散方法Quantum State Diffusion Method(QSD)模拟了信道容量χ随时间的演化关系。经过数值...本文主要研究了在非马尔可夫环境下在时变磁场中具有各种参数的交互作用非常丰富的两个比特的海森堡XYZ模型的量子稠密编码的性质。通过量子态扩散方法Quantum State Diffusion Method(QSD)模拟了信道容量χ随时间的演化关系。经过数值模拟显示:量子稠密编码对环境关联系数γ、耦合系数J和Jz以及余弦磁场的强度B都有依赖。当环境关联系数γ变小时也就是非马尔科夫特性增加时,量子稠密编码的信道容量χ明显呈现上升趋势。在这里值得提出的是较小的耦合系数Jz、较大的耦合系数J、和较强的时变磁场强度B对于在本系统下进行有效的量子稠密编码是非常有用的,其中在非马尔科夫情形下非常明显,这对能够有效地进行信息传输非常的重要。展开更多
We investigate the sudden birth and sudden death of entanglement of two qubits interacting with uncorrelatedstructured reservoirs.The system is initially prepared in two-qubit extended Werner-like state.We workout the...We investigate the sudden birth and sudden death of entanglement of two qubits interacting with uncorrelatedstructured reservoirs.The system is initially prepared in two-qubit extended Werner-like state.We workout the dependence of the entanglement dynamics on both non-Markovian environments and the purity of initial state,and show that non-Markovian environments and the purity can control the time of the two-qubit entanglement suddendeath and the reservoirs' entanglement sudden birth.Furthermore,under the conditions of different purity and initialentanglement,the revival of qubits' entanglement can manifest before,simultaneously or even after the disentanglementof their corresponding reservoirs.展开更多
The non-Markovian dynamics of quantum entanglement is studied by the Shabani-Lidar master equation when one of entangled quantum systems is coupled to a local reservoir with memory effects.The completely positive redu...The non-Markovian dynamics of quantum entanglement is studied by the Shabani-Lidar master equation when one of entangled quantum systems is coupled to a local reservoir with memory effects.The completely positive reduced dynamical map can be constructed in the Kraus representation.Quantum entanglement decays more slowly in the non-Markovian environment.The decoherence time for quantum entanglement can be markedly increased with the change of the memory kernel.It is found out that the entanglement sudden death between quantum systems and entanglement sudden birth between the system and reservoir occur at different instants.展开更多
By using negativity as entanglement measure,we have investigated the effect of local decoherence from anon-Markovian environment on the time evolution of entanglement of three-qubit states including the GHZ state,the ...By using negativity as entanglement measure,we have investigated the effect of local decoherence from anon-Markovian environment on the time evolution of entanglement of three-qubit states including the GHZ state,the Wstate,and the Werner state.From the results,we find that the entanglement dynamics depends not only on the couplingstrengths but also on the specific states of concern.Specifically,the entanglement takes different behaviors under weakor strong coupling and it varies with the quantum states under study.The entanglement of the GHZ state and theWerner state can be destroyed completely by the local decoherence,while the entanglement of the W state can survivethrough the local decoherence partially.展开更多
文摘本文主要研究了在非马尔可夫环境下在时变磁场中具有各种参数的交互作用非常丰富的两个比特的海森堡XYZ模型的量子稠密编码的性质。通过量子态扩散方法Quantum State Diffusion Method(QSD)模拟了信道容量χ随时间的演化关系。经过数值模拟显示:量子稠密编码对环境关联系数γ、耦合系数J和Jz以及余弦磁场的强度B都有依赖。当环境关联系数γ变小时也就是非马尔科夫特性增加时,量子稠密编码的信道容量χ明显呈现上升趋势。在这里值得提出的是较小的耦合系数Jz、较大的耦合系数J、和较强的时变磁场强度B对于在本系统下进行有效的量子稠密编码是非常有用的,其中在非马尔科夫情形下非常明显,这对能够有效地进行信息传输非常的重要。
基金Supported by the National Natural Science Foundation of China under Grant No.10904033Natural Science Foundation of Hubei Province under Grant No.2009CDA145+1 种基金Educational Commission of Hubei Province under Grant No.D20092204the Postgraduate Programme of Hubei Normal University under Grant No.2007D20
文摘We investigate the sudden birth and sudden death of entanglement of two qubits interacting with uncorrelatedstructured reservoirs.The system is initially prepared in two-qubit extended Werner-like state.We workout the dependence of the entanglement dynamics on both non-Markovian environments and the purity of initial state,and show that non-Markovian environments and the purity can control the time of the two-qubit entanglement suddendeath and the reservoirs' entanglement sudden birth.Furthermore,under the conditions of different purity and initialentanglement,the revival of qubits' entanglement can manifest before,simultaneously or even after the disentanglementof their corresponding reservoirs.
基金Supported by the Project of Teaching Quality in SUST under Grant No. 2010JGB-27the National Natural Science Foundation under Grant No. 10774108
文摘The non-Markovian dynamics of quantum entanglement is studied by the Shabani-Lidar master equation when one of entangled quantum systems is coupled to a local reservoir with memory effects.The completely positive reduced dynamical map can be constructed in the Kraus representation.Quantum entanglement decays more slowly in the non-Markovian environment.The decoherence time for quantum entanglement can be markedly increased with the change of the memory kernel.It is found out that the entanglement sudden death between quantum systems and entanglement sudden birth between the system and reservoir occur at different instants.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10947115 and 10975152the Fund of Anhui Province for the Young Talented Teachers under Grant No.2010SQRL037ZD
文摘By using negativity as entanglement measure,we have investigated the effect of local decoherence from anon-Markovian environment on the time evolution of entanglement of three-qubit states including the GHZ state,the Wstate,and the Werner state.From the results,we find that the entanglement dynamics depends not only on the couplingstrengths but also on the specific states of concern.Specifically,the entanglement takes different behaviors under weakor strong coupling and it varies with the quantum states under study.The entanglement of the GHZ state and theWerner state can be destroyed completely by the local decoherence,while the entanglement of the W state can survivethrough the local decoherence partially.
基金Supported by the Research Program of Natural Science for Colleges and Universities in Jiangsu Province under Grant No.09KJB140009the National Natural Science Foundation under Grant No.10904104
