超冷原子体系中多自由度量子纠缠的研究

The ultra-cold atomic system can be well used of the study of quantum experiments and quantum simulation experiments, it is the one of the few physical systems that can generate the multi-particle entanglement deterministically, it is the important platform for studying quantum precision measurement. In this program we make use of the stimulated Raman transition technique as a beam splitting tool which be used to explore how to generated the multi-degree-of-freedom entanglement in atomic systems and how to distincted the four Bell states, considering the specific experimental conditions, we analysize deeply the factors such as particle number loss and phase dissipation factors which caused by heating effects and interaction between atoms, and explore the influence of above various factors on particle entanglement. In this project we plans to solve the master equations containing dissipative solutions and solve the nonlinear Gross-Pitaevkii (GP) equations to analyze the effects of dissipative and nonlinear interactions on entanglement, and look for the best way to get the most entanglement. We hope the study in our program can significantly advance the field of particle multi-degree-of-freedom entanglement and can open a door to the realization of quantum information protocols ranging from intrinsically secure cryptography to teleportation.

超冷原子体系可以很好地用于量子计算和量子模拟的实验研究,是少有的几个能确定性的制备多粒子纠缠态的物理系统之一，是研究量子精密测量的重要平台。本项目基于受激拉曼跃迁技术，将其作为一种分束工具，探索利用此工具如何更好地研究原子体系中多自由度纠缠在原子系统中的产生以及对四个Bell态的完全区分，并考虑具体的实验条件，对其中可能存在加热效应所导致的粒子数损失与位相耗散因素以及原子间相互作用等因素进行深入地分析，探求各种因素对粒子纠缠产生的影响。本项目计划通过求解其量子动力学演化，即通过求解构建描述包含耗散的主方程，以及通过求解非线性 Gross-Pitaevkii（GP）方程，从而分析耗散和非线性相互作用对纠缠的影响，寻找获得产生最大纠缠的最佳方法。我们希望本项目所研究的理论模型，可以显著推进粒子多自由度纠缠领域的进步，并且可以为实现从固有安全密码学到远程传送的量子信息方案打开一扇大门。

本项目围绕“超冷原子体系中多自由度量子纠缠的研究”这一主题，对利用拉曼跃迁技术在冷原子中实现纠缠的产生及纠缠操控，尤其是多自由度的纠缠的问题展开积极探讨研究。研究发现拉曼技术可以实现3中不同的原子分束器，运用这几种分束器可以实现对两粒子纠缠态的识别，即Bell态分析，发表了相关论文。此外还发现在原子中可以实现量子逻辑门，如CONT门等，利用此逻辑门可以实现纠缠态的产生与复制以及一些其它应用，这在量子信息和量子模拟中具有非常重要的应用。这些新的探索为丰富冷原子、量子信息研究领域奠定了研究基础。