基于单边微腔量子点耦合系统的极化纠缠浓缩

Polarization entanglement concentration based on coupling system of single-sided micro-cavity and quantum dot

量子纠缠是实现量子信息处理任务的重要资源,一些在经典领域中无法实现的任务,可以借助量子纠缠来完成.然而,纠缠态在噪声的作用下会发生退相干,进而变成非最大纠缠态或混态,不再能完成预定任务.纠缠浓缩是从非最大纠缠态中提取最大纠缠态的过程.我们提出两个非最大纠缠Bell态纠缠浓缩方案,一个是未知系数非最大纠缠Bell态纠缠浓缩方案,另一个是已知系数非最大纠缠Bell态纠缠浓缩方案.方案中利用量子点微腔耦合系统来实现光子与光子之间的非线性相互作用,进而可以通过分级浓缩的方法提高浓缩方案的成功概率.两个方案都可以推广为多光子非最大纠缠GHZ态的纠缠浓缩.

Quantum entanglement is an important resource to realize quantum information processing tasks.Some tasks that cannot be realized in the classical world can be accomplished with the help of quantum entanglement.However,a pure entangled state will decoherence under the environment noise,and then becomes a non-maximum entangled state or a mixed state,which can no longer complete the desired task.Entanglement concentration is a process of extracting maximum entangled states from non-maximum entangled states.In this paper,we propose two entanglement concentration schemes for non-maximally entangled Bell state.One is the entanglement concentration scheme with unknown coefficients,and the other is the entanglement concentration scheme with known coefficients.In the schemes,the nonlinear interaction between photons is realized by the coupling system of quantum dot and single-sided micro-cavity,and then the success probability of the concentration scheme can be improved by hierarchical concentration.Both schemes can be generalized to the entanglement concentration of multi-photon non-maximum GHZ states.