Symmetric Many-Body Correlations in Atomic Ensembles

多体关联位于微观层面的复杂系统的核心，在那里量子物理的奇怪规则占据主导地位。从基本粒子到原子、分子和固态材料，这样的系统在所有尺度上都是自然存在的。此外，这种量子复杂性现在被理解为一种资源，用于以一种在经典物理逻辑下运行的世界中不可能的方式处理信息。多体关联的这些双重方面--定义了自然界的丰富性，并为强大的新应用打开了大门--目前正在推动原子、分子和光学物理的许多探索。这个项目将推动这一前沿领域的发展。这项研究将使操纵和理解量子多体系统及其复杂动力学的新能力成为可能，并在量子信息处理和精密测量方面具有潜在的应用。该项目将为量子信息科学的知识基础做出贡献，并为这一高度交叉领域的未来科学家的培训做出贡献。学生将参与该项目的各个方面，包括教育、研究和成果的传播。该项目是美国国家科学基金会资助的量子信息和控制中心的组成部分。活动包括每周一次的小组会议、研究研讨会和一年一度的研究务虚会，以加强初级和高级成员之间的联系。多体复杂性问题的两个关键方面，即创建和检测对称关联，将被探索。具体目标是开发实现一般量子控制的协议，以最优和稳健地产生量子关联。项目人员将研究如何将测量与控制结合使用，以提取有关多体系统中存在的初始关联的信息。这是建立在该小组在连续测量断层扫描方面的专业知识的基础上的，该技术以前用于重建一体关联。他们将把这些想法扩展到研究二体关联的重建，甚至更远。项目人员还将探索多体系统连续测量中信息增益、动力学复杂性和量子反作用之间的复杂关系。

Many-body correlations lie at the heart of complex systems at the microscopic level where the strange rules of quantum physics hold sway. Such systems occur naturally at all scales, ranging from fundamental particles, to atoms, molecules, and solid-state materials. In addition, such quantum complexity is now understood to be a resource for processing information in ways that are not possible in a world operating under the logic of classical physics. These dual aspects of many-body correlations - defining the richness in the natural world and opening the door to powerful new applications - are currently driving many explorations in atomic, molecular, and optical physics. This project will push the boundaries of this frontier. The research will enable new capabilities in manipulating and understanding quantum many-body systems and their complex dynamics, with potential applications in quantum information processing and precision measurement. The project will contribute to the knowledge base of quantum information science, and to the training of future scientists in this highly interdisciplinary field. Students will be involved in all aspects of the project, including education, research, and the dissemination of results. The project is an integral part of the NSF-funded Center for Quantum Information and Control. Activities include weekly group meetings, research seminars, and an annual research retreat that strengthens the connections between junior and senior members. Two key aspects of the problem of many-body complexity; namely, creating and detecting symmetric correlations, will be explored. The specific goals are to develop protocols for implementing general quantum control to optimally and robustly generate quantum correlations. Project personnel will study how a measurement, in conjunction with control, can be used to extract information about the initial correlations present in a many-body system. This builds on the group's expertise in continuous measurement tomography, used previously to reconstruct one-body correlations. They will extended these ideas to study the reconstruction of two-body correlations, and beyond. Project personnel will also explore the intricate relation between information gain, complexity of dynamics, and quantum backaction in the continuous measurement of many-body systems.