Quantum Computing with Cs Atom Qubits

使用 Cs 原子量子位进行量子计算

• 批准号: 1520976
• 负责人: David Weiss
• 金额: $ 55万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1520976&HistoricalAwards=false
• 关键词: Quantum; Computing; Cs; Atom; Qubits

Entanglement is an essential feature of quantum mechanics. For instance, if two identical particles can each be in either state A or B, they can be in an entangled state AA+BB, which means that the particles are in a superposition of both being in A or both being in B, but never one in A and the other in B. These highly non-classical states are central to the working of quantum computers. To date, proto-quantum computers have been made with up to 14 quantum bits (qubits), but their outputs can be readily reproduced with classical computers. As entangled states become increasingly complex they can no longer be modeled on classical computers. A quantum computer with more than 50 qubits could solve certain kinds of problems that are otherwise unsolvable.Quantum computing is being pursued using several different types of qubits, including ions, superconducting Josephson junctions, quantum dots, photons, nitrogen vacancy centers in diamonds, and neutral atoms. Each candidate qubit has its strengths and weakness. Neutral atoms trapped in optical lattices can be well-isolated from their environment, so they have relatively long coherence times, an essential qubit feature. Trapping them with light presents a relatively straightforward path to scalability well beyond 50 qubits. Still, there has been less work on trapped neutral atoms than on most other qubit candidates. The work proposed here is directed toward developing neutral atoms for quantum computation.Experimental techniques needed for a neutral atom quantum computer will be developed. Previously atoms in a 5 micron spaced 3D optical lattice have been trapped and cooled, with an atom at half the sites. Using accurate site occupancy maps and the ability to address individual sites within a 5×5×5 site volume, a procedure to arbitrarily sort the atoms within that volume will be executed. For instance, perfectly occupied 3×3×3 cubes and 5×5 planes will be created. Since the atoms can be cooled to near their vibrational ground state after sorting, the sorting procedure can be checked and small errors corrected if need be, giving an ideal starting point for a quantum computation.A new technique for measuring the internal states of a neutral atom qubit without atom loss by coherently splitting atoms based on their internal states, and then locking them in place with a shorter length scale optical lattice will be demonstrated. They can then be reliably detected in this new lattice, where their location encodes their initial internal state. A new type of single qubit microwave gate where atoms do not need to leave their storage basis will be demonstrated, which promises exceptionally high fidelity. Also work will continue to demonstrate two-qubit Rydberg gates, taking advantage of the low temperature of the atoms and the associated excellent localization. After all these techniques are developed, the system will allow for the implementation of ~3000 gates on 25 atoms before any atom loss is expected. This would constitute a sufficient proof of principle of scalability in neutral atom systems to stimulate further work in error correction and scaling in these systems.

纠缠是量子力学的重要特征。例如，如果两个相同的粒子可以在状态A或B中分别处于纠缠状态AA+Bb，这意味着粒子在A中均处于A或两个位于B中的叠加位置，但在B中都不是A中的一个，但在B中都不是一个。这些高度不经典的状态是量子计算机工作的核心。迄今为止，原始计算机已使用多达14个量子位（Qubits）制成，但是它们的输出可以很容易地使用经典计算机复制。随着纠缠状态变得越来越复杂，它们无法再在古典计算机上进行建模。具有50多次数量的量子计算机可以解决某些类型的问题，而这些问题原本是无法解决的。Quantum Computing正在使用几种不同类型的数量进行追求，包括离子，超过Josephson连接，量子点，照片，照片，氮气中的氮空位中心和中性原子。每个候选人都有其优点和缺点。被困在光学晶格中的中性原子可以从其环境中得到充分分离，因此它们具有相对较长的连贯时间，这是一个必不可少的量子特征。用光将它们捕获为远远超过50码位的可扩展性的相对简单的路径。尽管如此，与大多数其他Qubit候选者相比，在被困中性原子上的工作少。此处提出的工作是针对开发中性原子进行量子计算的。将开发中性原子量子计算机所需的实验技术。以前在5微米间隔3D光学晶格中的原子已被困和冷却，在一半的位置上有原子。使用准确的站点占用图以及在5×5×5站点量内解决各个站点的能力，将执行任意对原子进行任意分类原子的过程。例如，将创建完美占据的3×3×3立方体和5×5平面。由于排序后可以将原子冷却至其振动基态近乎接近的基态状态，因此可以检查分类过程，如果需要，则可以纠正量子的理想起点，用于量子计算的理想起点。这是一种基于其内部状态，然后将其锁定在shortical spacial的情况下，用于衡量无原子损失的中性原子零件的内部状态，而无需共处。然后，可以在这个新晶格中可靠地检测到它们，其中其位置编码其最初的内部状态。将展示一种新型的单量子量子微波门，其中原子不需要离开存储基础，这有望异常高的保真度。还将利用原子的低温和相关的出色定位来表现出两分的Rydberg大门。在制定了所有这些技术之后，该系统将允许在预计任何原子损失之前在25个原子上实施约3000个门。这将构成中性原子系统可伸缩性原理的足够证明，以刺激这些系统中的误差校正和缩放方面的进一步工作。