Controlling Rings of Trapped Ions for Quantum Information Applications

控制捕获离子环以实现量子信息应用

• 批准号: 1620838
• 负责人: Hartmut Haeffner
• 金额: $ 30万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1620838&HistoricalAwards=false
• 关键词: Controlling; Rings; Trapped; Ions; Quantum

Quantum computing promises to speed up computations by exploiting the unique properties of quantum physics that dictates that quantum systems can be in multiple states at the same time. This non-classical property, called "superposition", can be used to design new computer algorithms that process information faster, as, for example, in the factorization of large numbers on which many modern encryption schemes rely. The difficulty is that superposition states are so fragile that even small amounts of noise, for example from electric fields, can remove the quantum advantage. The goal of this project is to establish a novel ring configuration of trapped ions for quantum computing. To date quantum computational schemes that employ trapped ions as the logical bits have relied on a linear string of ions. This new ring architecture will reduce the influence of the dominant noise source, thereby increasing the accuracy of the quantum operations. In addition to quantum computation benefits, the ring shape also opens up opportunities to study aspects of the fundamental physics behind quantum mechanics, the theory that currently best describes the atomic world. Specifically, because the ion ring can freely rotate, it allows for the study of effects present in large rotating objects and symmetric systems. Thus, the project will explore unique avenues towards quantum information processing and provide novel insights into quantum mechanics as well as offering students new possibilities in this rapidly-developing field of technology.A symmetric ring of ions offers the opportunity to study a number of phenomena requiring translationally symmetric systems and ring topologies as well as to implement quantum gates that benefit specifically from the ring geometry. However, in order to realize any of these studies, a high degree of control over the quantum state of the ions and their collective motion is necessary. For this, the ring must not only be symmetric but also well cooled and have the rotational degree of freedom precisely controlled. Towards these goals, ions will be trapped with oscillating electric fields above a planar electrode configuration. The electrode configuration is carefully chosen to trap the ions in a compact ring far away from symmetry breaking imperfections of the substrate. To establish the degree of symmetry of the ring, cooling to temperatures in the low microkelvin range will be required. Hence, emphasis will be given to various cooling techniques including ground state cooling in an asymmetric configuration followed by adiabatic transformation into a symmetric ring. Of particular interest for quantum information applications is the rate with which the rotational (quantum) state changes. After this characterization phase, laser light will be used to initiate controlled rotation depending on the quantum information stored in individual ions. This interaction will be used to implement the key operation for any meaningful quantum computing, namely quantum operations of an individual (qu)bit conditioned on the state of another bit.

量子计算有望通过利用量子物理学的独特性质来加速计算，量子物理学的独特性质决定了量子系统可以同时处于多种状态。 这种称为“叠加”的非经典属性可用于设计更快地处理信息的新计算机算法，例如许多现代加密方案所依赖的大数分解。 困难在于叠加态非常脆弱，即使是少量的噪声（例如来自电场的噪声）也会消除量子优势。该项目的目标是建立一种用于量子计算的新型捕获离子环结构。 迄今为止，采用捕获离子作为逻辑位的量子计算方案依赖于线性离子串。 这种新的环结构将减少主要噪声源的影响，从而提高量子运算的准确性。除了量子计算的好处之外，环形还为研究量子力学背后的基础物理方面提供了机会，量子力学是目前最能描述原子世界的理论。具体来说，由于离子环可以自由旋转，因此可以研究大型旋转物体和对称系统中存在的效应。因此，该项目将探索量子信息处理的独特途径，提供对量子力学的新颖见解，并为学生在这个快速发展的技术领域提供新的可能性。对称的离子环提供了研究许多需要的现象的机会。平移对称系统和环形拓扑，以及实现特别受益于环形几何形状的量子门。然而，为了实现这些研究中的任何一项，必须对离子的量子态及其集体运动进行高度控制。为此，环不仅必须是对称的，而且必须良好冷却并具有精确控制的旋转自由度。为了实现这些目标，离子将被平面电极配置上方的振荡电场捕获。电极配置经过精心选择，以将离子捕获在远离基底对称性破坏缺陷的紧凑环中。为了确定环的对称程度，需要冷却到低微开尔文范围内的温度。因此，将重点关注各种冷却技术，包括非对称配置中的基态冷却，然后绝热转变为对称环。量子信息应用特别感兴趣的是旋转（量子）状态变化的速率。在此表征阶段之后，将使用激光根据单个离子中存储的量子信息来启动受控旋转。这种交互将用于实现任何有意义的量子计算的关键操作，即以另一个位的状态为条件的单个（qu）位的量子操作。