Single Spin Resolved Quantum Metrology in Optical Lattices

光晶格中的单自旋分辨量子计量

• 批准号: 404723259
• 负责人: Professor Dr. Christian Groß
• 金额: --
• 依托单位: Arbeitsbereich Atomphysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/404723259?language=en
• 关键词: Single; Spin; Resolved; Quantum; Metrology

This project aims at the realization of single spin resolved detection of ultracold atoms in two dimensional optical lattices and its application to quantum metrology. At the heart of the detection technique will be a quantum spin pump, providing robust (topologically protected) spatial separation of the two involved spin states. This will enable full local qubit readout in two-dimensional atomic arrays, a fundamental requirement for quantum simulation and quantum information, which has not yet been demonstrated so far. Importantly, the technique will be generally applicable to two-dimensional ultracold lattice systems including alkaline-earth like atoms. The latter is important in the wider context of this project proposal, which is accompanying a Heisenberg professorship proposal at the University of Tübingen. One of the ongoing research efforts at the Center for Quantum Science in Tübingen - in close collaboration with Japanese research partners - is the realization of a compact and continuous alkaline-earth atom based optical lattice clock. On longer time scale, the techniques developed within the proposed project will allow us to realize quantum enhanced measurements in this optical clock.Single spin resolved readout and, hence, the detection of the parity of the magnetization, is required to make use of maximally entangled states for quantum metrology, which promise ultimate measurement precision at the Heisenberg limit. One-axis twisting dynamics, producing spin squeezing on short evolution times, indeed results in maximally entangled NOON states at longer times. This time is half-way to the revival time of the global magnetization, i.e. the time set by the inverse interaction strength. In between complicated non-gaussian states are produced that are in general difficult to characterize. Here local single spin resolved detection promises new insight as it allows one to characterize the system not only by global observable but also by local multi-point correlations.We propose to use long-range interactions between ten to hundred atoms in a two-dimensional optical lattice to implement one-axis twisting like quantum dynamics. The interaction is induced by near-resonant laser coupling to Rydberg states (aka Rydberg dressing). With such a setting, we recently demonstrated coherence times as long as 100 inverse interaction times, while the time scale for spin squeezing in this system is one tenth of the inverse interaction time. Thus, fully coherent evolution even to the time to produce NOON states seems within reach. We will additionally explore feasible schemes to realize a Loschmidt echo sequence, based on which much more general entangled states can be used for quantum metrology.

本项目旨在实现二维光晶格中超冷原子的单自旋分辨探测及其在量子计量学中的应用。探测技术的核心将是量子自旋泵，为两个相关的自旋态提供鲁棒的（拓扑保护的）空间分离。这将使二维原子阵列中的完整局部量子比特读出成为可能，这是量子模拟和量子信息的基本要求，迄今为止尚未得到证明。重要的是，该技术将普遍适用于二维超冷晶格系统，包括碱土类原子。后者在这个项目提案的更广泛背景下很重要，该项目提案伴随着蒂宾根大学的海森堡教授职位提案。图宾根量子科学中心与日本研究伙伴密切合作，正在进行的研究工作之一是实现一个紧凑和连续的基于碱土原子的光学晶格时钟。在更长的时间尺度上，该项目中开发的技术将使我们能够在该光学时钟中实现量子增强测量。单自旋分辨读出，从而检测磁化的奇偶性，需要利用量子计量学的最大纠缠态，这保证了海森堡极限的最终测量精度。单轴扭转动力学在短时间内产生自旋压缩，在较长时间内确实会导致最大纠缠NOON态。该时间是全局磁化的恢复时间的一半，即由逆相互作用强度设置的时间。在这两者之间，产生了复杂的非高斯状态，这些状态通常难以表征。在这里，本地单自旋分辨检测承诺新的洞察力，因为它允许一个表征系统不仅通过全球可观察到的，但也通过本地多点correlations.We建议使用远程之间的相互作用10到100个原子在一个二维光学lattice实现单轴扭转像量子动力学。这种相互作用是由近共振激光耦合到里德堡态（又名里德堡敷料）引起的。在这样的设置下，我们最近证明了相干时间长达100个逆相互作用时间，而在这个系统中自旋压缩的时间尺度是逆相互作用时间的十分之一。因此，完全相干的进化甚至到产生NOON态的时间似乎是可以实现的。此外，我们将探索实现Loschillo回波序列的可行方案，基于此，更一般的纠缠态可以用于量子计量学。