Cooperative and Subradiant Phenomena in Quantum Optical Systems

量子光学系统由可通过激光或单光量子探测的原子集合组成，构成了量子技术的通用平台，具有广泛的潜在应用，从用于安全通信的长寿命量子存储器和健壮的量子网络到量子计算。该项目中由新模型产生的实现与原子钟或量子模拟和量子信息处理等应用相关，早在所谓的“通用量子计算机”的影响可以预期之前。从高中到博士水平的学生的教育可以从深入研究这些主题中受益：量子效应在一般情况下，特别是量子信息科学，对学生的学习和研究参与具有良好的吸引力。这一呼吁将专门用于吸引和留住代表性不足的群体参与量子技术的学术研究。此外，主要基于最新物理教育研究的新教学技术将在高等物理课堂上进行测试，以改善不是额外教学资源主要接受者的班级的学习成果。在基于集成的量子光学中，原子自发发射到环境的真空模式中，随后信息丢失到这些不需要的通道中，这设置了基本的性能限制。这种自发发射通常被认为是每个原子的独立过程。这个项目的目标是挑战这个假设；的确，要解释不同原子发出的光之间的干涉，必须把耗散联系起来。这种相关耗散的性质可以在不同几何形状和有序原子阵列的气体等系统中得到精确的控制和设计。例如，它可能导致整个受保护的流形——所谓的“子辐射”——随着系统规模的增加，其衰减率接近于零。或者，通过将自发发射与强、远程相互作用相结合来控制原子介质的响应，可以实现远距离原子间的集体或纠缠多体态。该项目将解决以下问题：(i)如何有效地描述这些状态，描述它们的各种几何形状，以及如何根据系统参数和纠缠程度修改计算？（ii）看看二维阵列的具体例子，如何在拓扑状态的背景下访问子辐射状态，以及如何将这些知识潜在地转移到（实验上更容易访问的）单层半导体状态？（iii）如何将本研究应用于控制和探测协同缩小的时钟状态，为量子信息处理创造资源状态，或利用协同效应进行分子冷却？该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Quantum optical systems, consisting of ensembles of atoms that can be probed by laser light or by single light quanta, constitute a versatile platform for quantum technologies, with broad potential applications ranging from long-lived quantum memories for secure communication and robust quantum networks to quantum computation. The implementations resulting from the novel models in this project are relevant for applications such as atomic clocks or quantum simulation and quantum information processing, long before an impact from so-called "universal quantum computers" can be expected. Education of students from high school through doctoral level can particularly benefit from delving into these topics: quantum effects in general and quantum information science in particular are well-proven magnets for student learning and research involvement. This appeal will specifically be used to attract and retain underrepresented groups into academic research on quantum technologies. In addition, new teaching techniques that are largely based on recent physics education research will be tested on advanced physics classes to improve learning outcomes for classes that are not primary recipients for additional teaching resources. In ensemble-based quantum optics, the spontaneous emission of atoms into the vacuum modes of the environment and the subsequent loss of information into these undesired channels sets a fundamental performance limit. Such spontaneous emission is typically assumed to be an independent process for each atom. The goal of this project is to challenge this assumption; indeed, dissipation must be correlated to account for the interference between light emitted by different atoms. The nature of this correlated dissipation can be exquisitely controlled and engineered in systems such as gases in different geometries and ordered atomic arrays. For instance, it could lead to entire manifolds of protected - so-called "subradiant" - states whose decay rates approach zero with increasing system size. Alternatively, controlling the response of the atomic medium by combining spontaneous emission with strong, long-range interactions could enable the realization of collective or entangled many-body states across distant atoms. This project will address the following questions: (i) How can one efficiently describe such states, characterize them for various geometries, and how can one modify the calculation depending on system parameters and degree of entanglement? (ii) Looking at the particular example of two-dimensional arrays, how can subradiant states be accessed, used in the context of topological states, and how can this knowledge be potentially transferred to (experimentally easier-to-access) single-layer semiconductor states? (iii) How can this research be applied in order to control and probe cooperatively narrowed clock states, to create resource states for quantum information processing, or to utilize cooperative effects for molecule cooling?This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.