RUI: Quantum Sensing and Simulation with Ultracold Atoms in Ring Lattices

随着设备和应用达到经典物理学设定的极限，量子技术将在本世纪塑造人类和社会进步方面发挥核心作用，并且不可避免地被推动到量子力学领域以维持持续的进步。由于所涉及的原则和限制根本不同，这种迁移将是选择性的，而不是全面的，而传感、模拟和计算领域是最有希望的。本项目侧重于前两个方面，因为它们即使在短期内也能带来可观的效益。量子效应已经被证明提供了对加速度的灵敏度的显著增强，而由于相关希尔伯特空间的巨大维度，量子系统是量子物理的最佳模拟器，设计系统用于模拟难以访问的感兴趣的场景。然而，在所有这些目标的背后，定义性的挑战仍然是量子态和量子效应在与经典世界交互时的脆弱性。因此，广泛的成功取决于找到合适的平台。该项目旨在研究和开发一种新的替代平台，该平台由限制在环形周期晶格中的超冷原子组成，这是一种鲁棒的系统，但包含了与应用相关的所有量子力学特征。闭环结构形成了一个紧凑的单元，减轻了边界效应，有利于持续流动，允许尺寸和多样性的容易缩放，并直接体现了非局域性的典型量子特征。可变晶格结构提供了一种通用的方法来操纵系统，同时为相关的可观测物提供了精确的尺度。对众多本科生进行物理研究方面的培训将是一个优先事项，在之前获得资助的基础上取得成功，利用这些经验引导学生进入STEM职业道路，包括许多来自代表性不足的人口统计数据。传感器发展的目标包括两个主要方向。一种是基于一种新的原理，利用发生在环形晶格中的局部化转变。在中性原子的情况下，该原理可以适用于旋转检测和测量。或者，使用带电介质，它可以类似地适应于感应磁场。第二方面的研究将寻求在环形晶格中产生循环模式的压缩态，以实现使用量子相关态来提高灵敏度的干涉仪，例如SU（1,1）干涉仪。作为一个量子模拟器，该系统将被用来探索超流体和相关的绝缘体态跃迁的物理，以及拓扑对量子态的影响，如量子霍尔效应。由于晶格耦合环中的循环模式，就像激光场耦合原子中的电子态一样，该系统也将发展成为量子光学模拟器。环晶格中的冷原子具有自然的周期边界，可以减轻一些有限尺寸的影响，可以成为研究非平衡物理的新平台，包括多体量子系统的热化和弛豫问题。原子间相互作用和晶格结构在环形构型中的相互作用将允许模拟各种非线性动力学效应。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 technologies will play a central role in shaping human and societal progress in this century, as devices and applications reach limits set by classical physics, and are inevitably impelled into the realms of quantum mechanics to sustain continued advancement. Owing to fundamentally different principles and constraints involved, such migration will be selective rather than comprehensive, and the arenas of sensing, simulation and computation are the most promising. This project focuses on the first two aspects as they can already deliver considerable benefits even in the near term. Quantum effects have been demonstrated to offer substantial enhancement of sensitivity to accelerations, while due to the enormous dimensions of relevant Hilbert spaces, quantum systems are the best simulators of quantum physics with a designer system serving to mimic hard-to-access scenarios of interest. Underlying all such goals, however, the defining challenge continues to be the fragility of quantum states and effects as they interface with the classical world. Therefore, broad success hinges on finding the right platform. This project aims to study and develop a novel alternate platform comprised of ultracold atoms confined to a ring-shaped periodic lattice, a system that is robust, yet encompasses all quantum-mechanical features relevant for applications. The closed loop structure makes for a compact unit that mitigates boundary effects, favors sustained flow, allows easy scaling of size and multiplicity, and directly manifests the quintessential quantum feature of non-locality. The variable lattice structure provides a versatile way to manipulate the system while providing a precise scale for relevant observables. Training of numerous undergraduate students in physics research will be a priority, building on success under prior grants to leverage the experience to channel students into STEM career paths, including many from under-represented demographics. The goals for sensor development comprise two primary directions. One is based on a new principle that utilizes a localization transition that occurs in ring-shaped lattices. In the context of neutral atoms, the principle can be adapted for rotation detection and measurement. Alternately, with a charged medium, it can be similarly adapted for sensing magnetic fields. The second line of research will seek to generate squeezed states of circulating modes in ring lattices to realize implementations of interferometers that use quantum correlated states to improve sensitivity, as exemplified by SU(1,1) interferometers. As a quantum simulator, the system will be utilized to explore the physics of superfluidity and associated transitions to insulator states, as well as the impact of topology on quantum states, such as defined by the quantum Hall effect. With the lattice coupling the circulating modes in a ring much like a laser field couples electronic states in an atom, the system will also be developed as a quantum-optics simulator. With natural periodic boundaries mitigating some finite size effects, cold atoms in ring lattices can be a new platform for studying non-equilibrium physics, including questions of thermalization and relaxation of many-body quantum systems. Interplay of inter-atomic interactions and of the lattice structure in a ring configuration will allow simulation of various nonlinear dynamical effects.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.