基于高阶相互作用下的原子纠缠特性

Atomic Entanglement Properties Based on the Higher-Order Interaction

原子间纠缠态是量子信息和量子计算研究中重要的量子资源.目前此类量子态的制备主要依赖于二阶非线性相互作用动力学演化.以四阶非线性相互作用制备的量子态为研究对象,通过与二阶非线性相互作用制备的量子态进行对比,探究其纠缠特性.分别利用量子Fisher信息和压缩度量化其纠缠特性.在理想情况下,四阶非线性相互作用相比于二阶非线性相互作用可以更加快速地实现高度纠缠量子态的制备,发现其可达到海森堡极限.在演化初始时刻,四阶相互作用可以更加快速地制备出更好的压缩态,但二阶相互作用的最优压缩更好.考虑系统中噪声对非线性相互作用制备纠缠态的影响,弱相互作用区域内高阶非线性相互作用下的纠缠态具有更好的鲁棒性.

Atomic entangled states are crucial quantum resources in the study of quantum information and quantum computing.At present,the generation of such quantum states depends mainly on the second-order nonlinear interaction dynamic.In this paper,quantum states generated by the fourth-order nonlinear interaction are studied,and entanglement properties are investigated by contrast with quantum states produced by the second-order nonlinear interaction.Here we quantify their entanglement properties using quantum Fisher information and squeezing parameter respectively.Ideally,the fourth-order nonlinear interaction can generates highly entangled quantum states more quickly than the second-order nonlinear interaction,which is found to reach the Heisenberg limit.We also discover that in the initial moments of evolution,the four-order interaction can produce squeezed states more quickly,but the optimal squeezing of the second-order interaction is better.In addition,taking into account the noise effect on the entangled states produced by the second-order nonlinear interaction,we note that entangled states with the higher-order nonlinear interaction in weak interaction regions are more robust against decoherence.