BioComp: Collaborative Research: Is Resilient Quantum Computing in Solid State Systems Possible?

BioComp：协作研究：固态系统中的弹性量子计算可能吗？

• 批准号: 0523603
• 负责人: Eduardo Mucciolo
• 金额: $ 20万
• 依托单位: The University of Central Florida Board of Trustees
• 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=0523603&HistoricalAwards=false
• 关键词: BioComp; Collaborative; Research; Resilient; Quantum

This grant supports theoretical research on fundamental issues relatedto the implementation of quantum computation in solid-statedevices. Since the discovery that certain tasks could be performedwith great efficiency by algorithms based on quantum mechanics, anintense effort has been made to find suitable quantumhardware. Although several proposed implementations, such as thosebased on nuclear magnetic resonance and atomic trapping, have passedthe proof-of-principle, few-qubit phase, the path to achieving areliable multi-qubit quantum computer is still undefined.In this proposal we investigate the physical limitations to resilientcomputation with solid-state quantum bits (qubits), such assemiconductor quantum dots and superconductor junctions. Whilesolid-state qubits seem easily scalable from the fabricationviewpoint, they also present high decoherence rates as compared toother implementations. One major concern is that such strong decoherence may lead to errors occurring at a rate too large to be controlled.However, differently from other nuclear, atomic, and optical qubits, the interaction of solid-state quantum devices with the environment can introduce strong memory effects. As a result, temporal correlations may appear during the operation of multi-qubit systems. Current quantum error correction codes are not designed to cope with this situation, which may then invalidate any error threshold estimate for solid-state qubits based on the efficiency of those codes.We will explore these issues in a comprehensive way. Starting from athorough study of the mechanisms of decoherence in single- anddouble-qubit systems, we will study a model of multi-qubit systems inthe presence of correlated noise in a variety of realisticconditions. Our results will help set up new strategies for theoperation of multi-qubit systems. They will also let us understandwhat are the constraints that error correction codes will need tosatisfy in order to achieve fault-tolerant quantum computation inlarge-scale solid state implementations. To achieve our goals, we haveput together a team of researchers with expertise in nanoscale physics and computer science. The final outcome of our project will be a muchbetter understanding of how a real solid-state quantum computer wouldbehave.

该基金支持与在固态器件中实现量子计算相关的基本问题的理论研究。自从发现某些任务可以通过基于量子力学的算法以极高的效率执行以来，人们一直在努力寻找合适的量子硬件。尽管一些基于核磁共振和原子俘获的实现方案已经通过了原理验证和少量子位阶段，但实现可靠的多量子位量子计算机的途径仍然不明确。在本提案中，我们研究了使用固态量子比特（量子位）进行弹性计算的物理限制，例如半导体量子点和超导体结。虽然从制造的角度来看，固态量子比特似乎很容易扩展，但与其他实现相比，它们也具有很高的退相干率。一个主要的担忧是，如此强的退相干可能导致错误以太大而无法控制的速率发生。然而，与其他核、原子和光量子比特不同，固态量子器件与环境的相互作用会引入强烈的记忆效应。因此，在多量子位系统的运行过程中可能会出现时间相关性。目前的量子纠错码并不是为了应对这种情况而设计的，这可能会使基于这些码的效率对固态量子比特的任何错误阈值估计无效。我们将全面探讨这些问题。从深入研究单量子比特和双量子比特系统的退相干机制开始，我们将在各种现实条件下研究存在相关噪声的多量子比特系统模型。我们的研究结果将有助于为多量子比特系统的运行建立新的策略。它们还将让我们了解为了在大规模固态实现中实现容错量子计算，纠错码需要满足的约束是什么。为了实现我们的目标，我们组建了一个具有纳米物理和计算机科学专业知识的研究团队。我们项目的最终结果将是更好地理解真正的固态量子计算机的行为方式。