Fast quantum logic gates using optically trapped neutral atom arrays

在过去的二十年里，受控量子动力学在计算问题中的应用是信息科学中最重要的发展之一。该项目研究使用光学捕获的中性Rb原子阵列来创建多量子比特量子信息处理器。聚焦的激光光束将被用来操纵原子的量子态。内部基态之间的单量子比特旋转将通过光受激拉曼跃迁来实现。两量子位条件逻辑运算将通过将原子耦合到高激发的里德堡态来执行。中性原子的里德堡态具有很强的偶极-偶极相互作用，这为高保真的快速条件逻辑门提供了一种机制。据预测，单量子比特门和两量子比特门的速度将超过1 MHz。里德堡相互作用用于单个原子的确定性负载，这将导致可扩展的多量子比特设备，也将在实验上进行研究。作为这项工作的一部分，将获得关于强相互作用里德堡原子动力学的新知识。该项目包括在高速里德堡态激发和低退相干光学陷阱方面的新技术进展，这将促进冷原子外态和内态的光学操纵的最新技术水平。这项工作的更广泛影响是双重的。首先，这项研究是朝着实现超越传统经典计算机能力的大规模量子处理器的梦想迈出的重要一步。这种装置的出现将对数值数学、信息安全以及与开发具有技术价值的新材料有关的量子系统模拟问题产生深远影响。其次，该研究计划将有助于培养学生和博士后研究人员从事科学和工程工作。来自不同背景的人将接受现代实验科学的教育和培训，以及架起物理学和信息科学之间界限的抽象概念的教育和培训。培训将通过丰富课程和直接参与我们以大学为基础的研究计划进行。我们也会向当地社会介绍物理学对信息技术的重要性，以及量子信息科学领域的新发展。将通过物理系的公众探访日、实验室参观和对当地学校的教职员工访问来促进与公众的接触。

The application of controlled quantum dynamics to computational problems has been one of the most important developments in information science in the last two decades. This project studies the use of optically trapped arrays of neutral Rb atoms for creating a multi-qubit quantum information processor. Focused laser beams will be used to manipulate the quantum states of the atoms. Single qubit rotations between internal ground states will be performed by optically stimulated Raman transitions. Two-qubit conditional logic operations will be performed by coupling the atoms to highly excited Rydberg states. The Rydberg states of neutral atoms have strong dipole-dipole interactions which provide a mechanism for fast conditional logic gates with high fidelity. It is projected that single and two-qubit gates will be possible at speeds greater than 1 MHz. The use of Rydberg interactions for deterministic loading of single atoms which will result in a scalable multi-qubit device will also be studied experimentally. As part of this work new knowledge will be gained on the dynamics of strongly interacting Rydberg atoms. The project includes new technical developments in high speed Rydberg state excitation and low-decoherence optical traps which will advance the state of the art for optical manipulation of the external and internal states of cold atoms. The broader impacts of this work are twofold. First, this research is an important step towards realizing the dream of a large scale quantum processor that exceeds the capabilities of conventional classical computers. The availability of such a device will have far reaching impact on numerical mathematics, information security, and problems in the simulation of quantum systems related to the development of new, technologically valuable materials. Second, the research program will contribute to the training of students and postdoctoral researchers for careers in science and engineering. People from diverse backgrounds will be educated and trained in modern experimental science, as well as in abstract concepts that bridge the boundary between physics and information science. Training will occur via curriculum enrichments, and through direct participation in our University based research program. We will also inform the local community about the importance of physics to information technology, and the new developments in the area of quantum information science. Outreach to the public will be facilitated by public visiting days at the Physics department, laboratory tours, and faculty visits to local schools.