关键词: 比特翻转噪声/
相移噪声/
量子通道/
量子消相干
English Abstract
Evolutions of two-qubit entangled system in different noisy environments and channels
Cao Lian-Zhen,Liu Xia,
Zhao Jia-Qiang,
Yang Yang,
Li Ying-De,
Wang Xiao-Qin,
Lu Huai-Xin
1.Shandong Provincial Key Laboratory of Multi-Photon Entanglement and Manipulation, Department of Physics and Optoelectronic Engineering, Weifang University, Weifang 261061, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 11174224, 11404246, 11447225), the Natural Science Foundation of Shandong Province, China (Grant No. BS2015DX015), the Science and Technology Development Program of Shandong Province, China (Grant Nos. 2011YD01049, 2013YD01016), and the Higher School Science and Technology Program of Shandong Province, China (Grant Nos. J13LJ54, J15LJ54).Received Date:27 August 2015
Accepted Date:12 November 2015
Published Online:05 February 2016
Abstract:Quantum information technology is mainly based on quantum entanglement. As an important coherent superposition state, the coherence of quantum entanglement source is easily affected by environment and becomes fragile, which will lead to the failure of the quantum information processing. Thus, it is critical to reveal the evolutions of quantum entanglement source under different noisy environments and different noisy channels. Firstly, we experimentally prepare a high-fidelity two-bit entangled state by several technical methods. The fidelity observed for the state prepared in our experiment is 0.993 and the signal-to-noise ratio can reach up to 299. Then, we simulate the bit-flip noise and phase-shift noise (collective and non-collective) using the all-optical experimental setup. Finally, based on the entanglement qubit state, we experimentally study the evolutions of entanglement characteristic under different noisy environments and the single, double and mixed noisy channels. The experimental results show that for the same type of noise, the entanglement properties disappear fast when entangled qubit passes through dual channel noisy environment. The upper bounds of noise intensity to destroy the entanglement property are 0.25 and 0.26 for the single bit-flip noise and phase-shift noisy channels, respectively. The comparison between the two different kinds of noisy environments shows that the entanglement properties disappear fast when entangled bit passes through non-collective environment. The upper bounds of noise intensity are 0.08 and 0.14 for non-collective bit-flip and phase-shift noise to destroy the entanglement property, while the noise intensities are 0.14 and 0.23 for collective bit-flip and phase-shift noise, respectively. For different kinds of noises, the results show that bit-flip noise is more likely to destroy the entanglement properties than the phase-shift. Our results have great significance for the theoretical and experimental studies of entanglement decoherence and have important application value for quantum information processing technology based on the nonlinear optical system.
Keywords: bit-flip nosie/
phase-shift noise/
quantum channel/
decoherence
