QnTM: Quantum Information Processing with Quantum Random Walks

QnTM：使用量子随机游走的量子信息处理

• 批准号: 0523431
• 负责人: Robin Cote
• 金额: --
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-15 至 2009-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0523431&HistoricalAwards=false
• 关键词: QnTM; Quantum; Information; Processing; Random

Recent advances in our understanding of quantum information suggest that computational devices based on fundamental quantum principles, such as interference and entanglement, could perform certain computational tasks much more quickly than any classical computer. The potential ramifications of computing devices based on these principles have inspired a great deal of effort aimed at determining the information processing power of such devices and possible methods for physically realizing them. A particularly promising direction of research has focused on the development of the quantum random walk (QRW). This basic algorithmic building-block is an especially attractive candidate for physical realization, as it is significantly less complex than general-purpose quantum computation and still has interesting algorithmic applications.We shall study QRWs, focusing both on implementation and theoretical issues. We will explore realistic physical systems in which QRWs could be realized, such as ultracold Rydberg atoms, and pay special attention to explicit experimental issues, such as laser excitation sequences and redundant detection to allow error rejection. We will also develop theoretical models of decoherence, specifically focusing on the effect that decoherence has on the properties of QRWs that underly current algorithmic applications. In particular, we will study the effect of imperfect walk lattices (that is, the situation where the walk takes place on an imperfect combinatorial structure, like a grid with some nodes removed), the effect of unintentional partial measurement on QRWs, the effect of non-uniform site-site interaction on QRW, and the effect of multiple particles.Intellectual Merit: We describe how ensembles of ultracold atoms can be used to process quantum information, and describe a new scheme based on ultracold Rydberg atoms in optical lattices to implement a continuous-time QRW. The proposed research covers new avenues, such as models of decoherence in QRWs due to imperfect walk lattices or effect of unintentional partial measurements, and a novel form of conditional interaction (the van der Waals blockade) to prepare qubits and execute quantum gates. Broader Impact: The proposed activities will promote teaching and training at all levels. In addition, the vibrant collaborative efforts, at the national and international levels, will enhance the flow of ideas and information, as well as promote training via exchange of students and postdoctoral researchers. The multidisciplinary nature of the proposed activities (research, training, and outreach) will cross-fertilize numerous subfields including computer science, applied mathematics, electrical engineering, and physics. Finally, beyond the immediate impact of the proposed research in quantum information processing, a deeper understanding of many-body qubits will impact development of new schemes and studies to implement quantum information processing.

我们对量子信息理解的最新进展表明，基于基本量子原理的计算设备，如干涉和纠缠，可以比任何经典计算机更快地执行某些计算任务。基于这些原理的计算设备的潜在后果激发了大量的努力，旨在确定这些设备的信息处理能力以及物理实现它们的可能方法。一个特别有希望的研究方向是量子随机游走(QRW)的发展。这种基本的算法积木是一个特别有吸引力的物理实现候选，因为它比一般用途的量子计算复杂得多，并且仍然具有有趣的算法应用。我们将研究QRW，重点是实现和理论问题。我们将探索可以实现QRW的现实物理系统，例如超冷里德堡原子，并特别关注明确的实验问题，如激光激发序列和冗余检测，以允许错误抑制。我们还将开发退相干的理论模型，特别是关注退相干对当前算法应用不足的QRW特性的影响。特别是，我们将研究不完美行走晶格的影响(即行走发生在不完美的组合结构上的情况，比如移除了一些节点的网格)，无意的部分测量对QRW的影响，非均匀的位-位相互作用对QRW的影响，以及多粒子的影响。智力上的优点：我们描述了如何利用超冷原子的系综来处理量子信息，并描述了一种基于光学晶格中的超冷Rydberg原子来实现连续时间QRW的新方案。拟议的研究涵盖了新的途径，如由于不完美的行走晶格或无意部分测量的影响而导致的QRW中的退相干模型，以及一种新形式的条件相互作用(范德华封锁)来准备量子比特和执行量子门。更广泛的影响：拟议的活动将促进各级的教学和培训。此外，在国家和国际层面的积极合作努力将加强思想和信息的流动，并通过交换学生和博士后研究人员来促进培训。拟议活动的多学科性质(研究、培训和推广)将交叉培养许多子领域，包括计算机科学、应用数学、电气工程和物理。最后，除了拟议的量子信息处理研究的直接影响之外，对多体量子比特的深入理解将影响实现量子信息处理的新方案和研究的发展。