Quantum Gates, Algorithms, and Error Correction with a Neutral Atom Qubit Array

量子门、算法和中性原子量子位阵列的纠错

• 批准号: 1720220
• 负责人: Mark Saffman
• 金额: $ 70万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1720220&HistoricalAwards=false
• 关键词: Quantum; Gates; Algorithms; Error; Correction

Quantum computing is attracting great interest due to its potential for solving practical problems that are intractable on classical computers. Areas of application include cryptography, database searching, pattern classification, solving large systems of coupled equations, and design of new functional materials or chemical compounds. A quantum computer is built from quantum bits, or qubits, that store quantum information which is processed using quantum logic gates. This project will continue the development of quantum computing using qubits encoded in the internal states of individual atoms. While the current state of the art involves experiments with 10-20 qubits, it is believed that computers with many thousands of qubits will be needed to realize the promise of quantum computation. In this respect the atom based approach being developed in this project is particularly attractive since a large number of neutral atoms can be held and controlled in close proximity without undesired interference with each other. The project seeks to advance the state of the art of several key performance metrics: the ability of qubits to preserve their quantum states for a long time, the fidelity of logic gate operations and qubit measurements, and the number of qubits that can be prepared in a single system. These advances will then be used to demonstrate a quantum algorithm for database searching. The project will contribute to scientific workforce development through training of students and postdoctoral researchers. The training will be interdisciplinary, drawing on methods and ideas from atomic and laser physics, electronic and computer based control systems, and quantum information theory. Research results will be incorporated into the University teaching curriculum. The experimental approach will use a two-dimensional array of cesium and rubidium atoms trapped in potential wells defined by light. The potential wells will be prepared by combining laser light of several different frequencies in a way that protects stored quantum information from decoherence. A movable optical tweezer system will be implemented to arrange trapped atoms for 100% occupancy of an array with up to 50 qubit sites. Quantum logic gates to create entanglement will be performed by exciting atoms to Rydberg states with laser pulses. Adiabatic pulses with shaped temporal profiles will be used to improve the fidelity of the entangling operations. Atomic states will be measured without crosstalk to other qubits or loss of atoms using a two-species approach whereby one species (cesium) will be used for memory and quantum logic, and a second species (rubidium) will be used for measurements. The quantum states to be measured will be transferred from cesium to rubidium atoms using an interspecies Rydberg gate. These capabilities will then be leveraged to demonstrate a multi-qubit quantum algorithm that provides quadratic speedup for database searching. The team will also implement quantum error correction to protect qubits against bit flip or phase flip errors.

量子计算引起了极大的兴趣，因为它可以解决古典计算机上棘手的实际问题。应用领域包括密码学，数据库搜索，模式分类，求解大型耦合方程式以及新功能材料或化合物的设计。量子计算机是用量子位或量子位构建的，该量子位存储使用量子逻辑门处理的量子信息。该项目将使用在单个原子的内部状态中编码的量子位继续开发量子计算。虽然当前的艺术状态涉及10-20吨位的实验，但据信，将需要数千个Qubits的计算机来实现量子计算的承诺。在这方面，该项目中开发的基于原子的方法特别有吸引力，因为可以在不相互干扰的情况下密切保持大量中性原子和控制。该项目旨在推进几种关键性能指标的艺术状态：量子位长期保存其量子状态的能力，逻辑门操作和量子测量值的保真度，以及可以在单个系统中准备的量子数量。然后，这些进步将用于演示用于搜索数据库的量子算法。该项目将通过培训学生和博士后研究人员来为科学劳动力发展做出贡献。该培训将是跨学科的，借鉴了原子和激光物理学，基于电子和计算机的控制系统以及量子信息理论的方法和思想。研究结果将纳入大学教学课程中。实验方法将使用二维会害在光定义的潜在井中的剖腹产和rubium原子。潜在的井将通过将几个不同频率的激光组合起来，以保护存储的量子信息免受折叠性的影响。将实施一个可移动的光学镊子系统，以安排被困的原子，以100％占用阵列，最多50个Qubit位点。量子逻辑门要创建纠缠，将通过激光脉冲的rydberg状态进行刺激性的纠缠。具有形状时间曲线的绝热脉冲将用于改善纠缠操作的忠诚度。原子状态将在不串扰其他量子位的情况下测量或使用两种物种方法的原子丢失，其中一种物种（剖宫产）将用于记忆和量子逻辑，第二种（Rubidium）将用于测量。待测量的量子状态将使用种类的rydberg栅极从剖宫产到rubidium原子。 然后，将利用这些功能来演示一种多量量子算法，该算法为数据库搜索提供了二次加速。团队还将实施量子误差校正，以保护量子位免受位翻转或相位翻转错误。

项目成果

A reconfigurable blue-detuned lattice for neutral atom quantum computing

用于中性原子量子计算的可重构蓝色失谐晶格

• 发表时间: 2019
• 期刊: DAMOP 2019
• 作者: GRAHAM, T.;POOLE, C;JIANG, X;MARRA, Z;GRINKEMEYER, B;HICKMAN, G;CHEREK, J;EBERT, M;SAFFMAN, M.
• 通讯作者: SAFFMAN, M.

Quantum information with Rydberg excited atoms1

里德伯激发原子的量子信息1

• 发表时间: 2019
• 期刊: DAMOP 2019
• 作者: Saffman, M.

Symmetric Rydberg controlled- Z gates with adiabatic pulses

• DOI: 10.1103/physreva.101.062309
• 发表时间: 2019-12
• 期刊: arXiv: Quantum Physics
• 作者: M. Saffman;I. Beterov;A. Dalal;E. Paez;B. Sanders

Photon-recoil and laser-focusing limits to Rydberg gate fidelity

• DOI: 10.1103/physreva.103.022424
• 发表时间: 2020-11
• 期刊: arXiv: Quantum Physics
• 作者: F. Robicheaux;T. Graham;M. Saffman

Dual species Rydberg and collisional interactions in an optical dipole trap

光学偶极子陷阱中的双物种里德伯和碰撞相互作用

• 发表时间: 2018
• 期刊: DAMOP 2018
• 作者: Ebert, Matthew;Hickman, Garrett;Marra, Alphonse;Jiang, Xiaoyu;Graham, Trent;Saffman, Mark
• 通讯作者: Saffman, Mark