Institut für Angewandte Physik, Universität Bonn, Wegelerstrasse 8, D-53115 Bonn, Germany.
Proc Natl Acad Sci U S A. 2012 Jun 19;109(25):9770-4. doi: 10.1073/pnas.1204285109. Epub 2012 Jun 4.
Engineering quantum particle systems, such as quantum simulators and quantum cellular automata, relies on full coherent control of quantum paths at the single particle level. Here we present an atom interferometer operating with single trapped atoms, where single particle wave packets are controlled through spin-dependent potentials. The interferometer is constructed from a sequence of discrete operations based on a set of elementary building blocks, which permit composing arbitrary interferometer geometries in a digital manner. We use this modularity to devise a space-time analogue of the well-known spin echo technique, yielding insight into decoherence mechanisms. We also demonstrate mesoscopic delocalization of single atoms with a separation-to-localization ratio exceeding 500; this result suggests their utilization beyond quantum logic applications as nano-resolution quantum probes in precision measurements, being able to measure potential gradients with precision 5 x 10(-4) in units of gravitational acceleration g.
工程量子粒子系统，如量子模拟器和量子细胞自动机，依赖于在单个粒子水平上对量子路径的完全相干控制。在这里，我们展示了一种使用单个囚禁原子的原子干涉仪，其中通过与自旋相关的势来控制单个粒子波包。该干涉仪由一系列基于一组基本构建块的离散操作构建而成，这些操作允许以数字方式组合任意干涉仪几何形状。我们利用这种模块化设计，设计了著名的自旋回波技术的时空模拟，从而深入了解退相干机制。我们还展示了单个原子的介观去局域化，其分离到局域化的比例超过 500；这一结果表明，它们可以超越量子逻辑应用，作为纳米分辨率的量子探针用于精密测量，能够以重力加速度 g 的 5 x 10(-4)的精度测量电势梯度。
