RUI: Quantum State Control for Ultracold Atoms

量子传感、通信和量子模拟的进步为技术提供了一条新的前进道路，超越了当今设备的限制。量子技术的真正优势——比如增强传感——只能在高度量子纠缠的系统中实现。纠缠是量子系统的一个基本特性，它使信息能够在空间分离的量子系统中存储。该项目旨在了解控制这些脆弱系统的新方法，从而使纠缠更加有用和健壮。该项目将通过从理论上探索各种物理系统中的新型测量模型（称为“弱测量”）来实现这一研究目标。该项目为基于量子多体物理的科学进步和新技术的发展做出了贡献，符合国家利益。该奖项将为来自圣何塞州立大学不同学生群体的几名本科生研究助理提供资源支持。本科生将参与研究目标，在原子、分子和光学系统理论、科学计算、分析建模和数据分析方面建立研究技能。创建高度纠缠系统的主要方法是隔离：消除所有环境干扰并尽可能地保护系统。这种方法虽然成功，但很难扩大规模。这个研究项目通过弱测量和反馈来操纵量子系统，以设计超冷原子的新量子态，超越脆弱的、高度孤立的系统，进入更强大的多体量子模拟器。弱测量使观察者能够提取有关量子系统的一些信息，而只对其进行部分干扰，但对于这一过程如何影响具有自身内部动力学的超冷原子系统，人们知之甚少。此外，反馈控制在多粒子环境中很少被实现。本提案从理论上研究了超冷原子的“量子态控制”协议，从旋量玻色-爱因斯坦凝聚（BEC）开始，扩展到平均场理论之外的系统。超冷原子是这项研究的理想平台，因为它们具有高度可控性，非常适合弱测量和反馈控制。将测量和反馈纳入超冷原子系统的量子控制理论工具箱将是AMO理论的一个变革性进步。该项目通过三个研究目标扩展了PI的理论工作：(1)证明在旋量bec中新磁现象的动态创造，(2)将量子反馈控制从平均场扩展到费米子晶格系统，以及(3)研究弱测量和反馈对纠缠产生的潜力。每个目标都聚焦于一个不同的一维物理系统，该系统由一个共同的理论框架联合起来，用于超冷原子系统的量子控制。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。

Advances in quantum sensing, communications, and quantum simulation offer a new way forward for technology, surpassing the limitations of present-day devices. The true advantages of quantum technologies - such as enhanced sensing - can only be realized in systems with a high degree of quantum entanglement. Entanglement is a fundamental property of quantum systems that enables information to be stored across spatially separated quantum systems. This project seeks to understand new ways of controlling these fragile systems, thus making entanglement more useful and robust. The project will achieve this research goal by theoretically exploring new types of measurement models, called ‘weak measurements’ in a variety of physical systems. The project serves the national interest by contributing to the progress of science and the development of new technologies based on quantum many-body physics. This award will provide resources to support several undergraduate research assistants from the diverse student body of San José State University. Undergraduate students will engage with the research aims, building research skills in the theory of atomic, molecular, and optical systems, scientific computing, analytical modeling and data analysis. The predominant approach toward creating highly entangled systems has been isolation: remove all environmental disturbances and protect the system as much as possible. Although successful, this approach is hard to scale up. This research program instead manipulates quantum systems via weak measurement and feedback to engineer new quantum states of ultracold atoms, moving beyond fragile, highly isolated systems to more robust many-body quantum simulators. Weak measurement enables an observer to extract some information about a quantum system while only partially disturbing it, but there is little understanding of how this process affects ultracold atomic systems with their own internal dynamics. Furthermore, feedback control has scarcely been implemented in the many-particle context. This proposal theoretically investigates ‘quantum state control’ protocols for ultracold atoms, starting with spinor Bose-Einstein condensates (BEC) and extending to systems beyond mean-field theory. Ultracold atoms are an ideal platform for this research because they are highly controllable and well suited to weak measurement and feedback control. Incorporating measurement and feedback into the quantum control theory toolbox for ultracold atomic systems would be a transformative advance forward in AMO theory. The project extends theoretical work by the PI via three research aims: (1) to demonstrate dynamical creation of new magnetic phenomena in spinor BECs, (2) to extend quantum feedback control beyond mean-field to fermionic lattice systems, and (3) to study the potential of weak measurement and feedback for entanglement generation. Each aim focuses on a different one-dimensional physical system united by a common theoretical framework for quantum control in ultracold atomic systems.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.