退相干条件下两比特纠缠态的量子非局域关联检验

Testing quantum nonlocality of two-qubit entangled states under decoherence

量子纠缠态的量子非局域关联特性在当前量子信息和量子计算协议中起着重要的作用.然而,任何实际的物理系统都不可避免地与周围环境相互作用,使得在量子信道中的传输过程中,量子态会发生相干性退化,进而弱化量子态的量子非局域关联特性.本文利用一种基于Hardy-type佯谬的高概率量子非局域关联检验方案,分别研究了两比特偏振纠缠态在经过振幅阻尼信道(ADC)、相位阻尼信道(PDC)和退极化阻尼信道(DC)后的量子非局域关联检验情况.研究结果表明,DC传输信道对量子态的量子非局域关联检验特性影响较大,而PDC传输信道对量子态的量子非局域关联检验特性影响较小.最后,本文还给出了利用弱测量结合弱测量反转操作克服ADC退相干时,偏振纠缠态成功进行量子非局域关联检验的条件.结果表明,当弱测量的强度增大时,可有效地降低ADC退相干效应对偏振纠缠态成功进行量子非局域关联检验造成的影响.

The quantum nonlocal correlation of quantum states plays an important role in the quantum information and quantum computing protocols.However,during the transmission of entangled states in the quantum channel,they will inevitably interact with the environment,resulting in the degradation of the coherence and then weakening the quantum nonlocal correlation.Using a high probability quantum nonlocal correlation testing scheme based on Hardy-type paradox,in this paper we investigate the quantum nonlocal correlation testing of two-qubit polarization entangled states when they transmit through amplitude damping channel(ADC),phase damping channel(PDC)and depolarization damping channel(DC).The results show that DC has a great influence on the quantum nonlocal correlation testing,while PDC has little influence on the quantum nonlocal correlation testing of quantum states.Finally,this paper also gives condition for the successful quantum nonlocal correlation testing of ADC under weak measurement and quantum weak measurement reversal operation.The results show that when the intensity of weak measurement increases,the influence of ADC decoherence effect on quantum nonlocal correlation testing can be effectively reduced.