QnTM: Quantum Information Processing in Single Crystal Solids with NMR

在过去的十年里，量子计算和量子信息处理（QIP）吸引了人们的极大兴趣，因为它们有望提供更有效的算法来解决数据搜索和分解等经典难题。从国家安全的角度来看，后者尤其重要，因为许多数据加密方案都是基于分解大整数密钥的难度而保持安全的。目前，我们不知道如何建造一个足够大的量子计算机，以实现提高计算能力的承诺。在许多正在开发的用于量子处理器的物理系统中，核磁共振（NMR）是最先进的。核磁共振利用存在于“上”和“下”自旋状态的原子核。这些自旋态可以利用脉冲磁场来产生量子逻辑门和实现量子算法。迄今为止，几种类型的操作和算法已经证明了溶液中使用液态核磁共振自旋轴承分子。然而，在静态单晶固体中执行QIP有显著的好处。特别是，量子算法的速度可以通过利用固体中固有的更大的核自旋之间的相互作用而提高2-3个数量级。此外，单晶固体与低温兼容，这可以大大提高灵敏度，并解决状态初始化和可扩展性的基本问题。事实上，由于速度的提高，潜在的更大的处理器和更好的灵敏度，固态核磁共振已被用于下一代QIP。最近，我们的小组首次报道了使用同位素标记甘氨酸（H215N13CH213COOH）的静态单晶进行三量子位核磁共振量子信息处理器的实验(化学物理学报119（3),1643-1649(2003)）。根据这项研究计划，我们建议为下一代单晶固态核磁共振QIP开发新材料和新方法，寻求扩展量子处理器的尺寸和功率，并绘制出定义该技术的重要物理参数。在此过程中，一些研究生、博士后和本科生将接受化学和物理最新技术的培训，从而建立强大的技术基础，以支持工业和政府研究实验室的未来需求。

In the last decade, quantum computing and quantum information processing (QIP) have attracted significant interest due to the promise of more efficient algorithms for solving classically hard problems such as data searching and factorization. The latter is particularly relevant from the standpoint of national security as many data encryption schemes remain secure based on the difficulty of factoring large integer keys. Currently, we do not know how to build a quantum computer that is large enough that the promises of increased computational power can be realized. Of the many physical systems under development for potential use as quantum processors, nuclear magnetic resonance (NMR) is the furthest advanced. NMR exploits atomic nuclei that exist in spin states of "up" and "down". These spin states can be manipulated using pulsed magnetic fields to produce quantum logic gates and implement quantum algorithms. To date, several types of manipulations and algorithms have been demonstrated for spin bearing molecules in solution using liquid-state NMR. There are significant benefits, however, to performing QIP in static single crystal solids. In particular, the speed of a quantum algorithm can be increased by 2-3 orders of magnitude by taking advantage of interactions between nuclear spins that are inherently larger in solids. As well, single crystal solids are compatible with low temperatures, which can substantially increase sensitivity and address fundamental questions of state initialization and scalability. Indeed, because of increased speed, potentially larger processors, and better sensitivity, solid-state NMR has been tapped for next-generation QIP. Recently our group was the first to report experiments on a three-qubit NMR quantum information processor, using a static single-crystal of isotopically labeled glycine (H215N13CH213COOH) (Journal of Chemical Physics 119(3), 1643-1649 (2003)). Under this research program, we propose to develop new materials and methods for next-generation single crystal solid-state NMR QIP, seeking to extend the size and power of quantum processors and mapping out important physical parameters that define this technology. In the process, a number of graduate, postdoctoral, and undergraduate students will be trained in state-of-the techniques of both chemistry and physics, enabling a strong technological base to support the future needs of both industrial and government research laboratories.