Submerged-Shell Atoms Trapped in Noble Gas Solids for Quantum Information and Measurement

该项目将对被困在凝固惰性气体中的中性钍原子进行光学和红外光谱分析，这些惰性气体是化学惰性固体，有时称为低温晶体。被俘获的钍原子可以用激光激发，这允许测量原子能级之间的跃迁频率。选择钍是因为它不寻常的电子构型，其中包含在核附近的f-壳层的价电子。与其他被困在低温晶体中时能级大幅加宽的物种不同，钍的能级被分解为可分辨的成分。该项目将采用一套新的光谱技术来揭示被困在固体氩和氖中的铥原子的完整能级图，这为利用其独特的性质作为纳米尺度的局部环境探针或量子设备中的纠缠元素铺平了道路。该项目对量子信息科学和测量具有巨大的潜在影响，并将有助于学生在表面科学，低温学，光学和原子物理学方面的教育。该项目的动机特别是最近的观察，即在1140 nm处f壳层之间的磁偶极跃迁可以窄至1.5 GHz，即使在人口平均时。此外，没有迹象表明在GHz尺度下的人口不均匀性，这表明随着进一步冷却，可能会获得MHz的线宽。这是显着窄于，例如，在金刚石NV中心的不均匀性，这支持的概念，在气相光谱中看到的，淹没的f壳与周围环境的相互作用比s或p水平少得多。这为量子信息和测量提出了一个新的平台，其中频率分辨率允许详细的光学泵浦方案，即使原子在亚纳米尺度下保持在适当的位置，与测量目标共处，和/或通过需要单个步骤的通用兼容过程直接集成到量子硬件中：冷凝惰性气体固体与钍的共沉积。特别是，高密度与均匀性相结合的量子信息应用和观察相干效应，如超辐射是有前途的。为了研究这些可能性，将进行一系列实验，以确定固体氩和氖基质中铥的低温线宽，解决晶体场分裂引起的基态亚结构，提高最大光子循环速率，并试图感知玻璃基板附近的环境。该奖项反映了NSF的法定使命，并通过使用基金会的学术价值和更广泛的影响审查标准。

This project will perform optical and infrared spectroscopy of neutral thulium atoms trapped in solidified noble gases, which are chemically inert solids sometimes called cryocrystals. The trapped thulium atoms may be excited with a laser, which allows transition frequencies between the atomic energy levels to be measured. Thulium is chosen because of its unusual electron configuration, which contains valence electrons in the f-shell near the nucleus. Unlike other species whose energy levels are substantially broadened when trapped in a cryocrystal, thulium energy levels are split into resolvable components. This project will employ a new set of spectroscopy techniques to uncover the complete energy level diagram for thulium atoms trapped in solid argon and neon, which paves the way for using their unique properties as probes of the local environment at nanometer scale, or as entangled elements in a quantum device. The project has great potential for broader impacts to quantum information science and measurement, and will contribute to education of students in surface science, cryogenics, optics, and atomic physics.This project is motivated in particular from recent observations that the magnetic dipole transition between f shells at 1140 nm can be as narrow as 1.5 GHz, even when averaged over a population. Furthermore, there is no indication of population inhomogeneity at the GHz scale, suggesting that with further cooling, MHz linewidths might be obtained. This is significantly narrower than, for example, the inhomogeneity in diamond NV centers, which supports the notion, seen in gas phase spectroscopy, that submerged f shells interact much less with the surrounding environment than s or p levels. This suggests a novel platform for quantum information and measurement, where frequency resolution permits detailed optical pumping schemes, even as atoms are held in place at the sub-nanometer scale, co-located with measurement targets, and/or directly integrated into quantum hardware via a universally compatible process requiring a single step: condensing noble gas solids with co-deposition of thulium. In particular, the high density combined with homogeneity are promising for quantum information applications and for observing coherent effects such as superradiance. To investigate these possibilities, a series of experiments will be performed to determine the low-temperature linewidth of thulium in solid argon and neon hosts, to resolve ground state substructure coming from crystal field splitting, to increase the maximum photon cycling rate, and to attempt to sense the environment near a glass substrate.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.