Optical Preparation and Manipulation of Entangled Spin States in Quantum Dot Molecules

量子点分子中纠缠自旋态的光学制备和操纵

• 批准号: 1005525
• 负责人: Eric Stinaff
• 金额: $ 27万
• 依托单位: Ohio University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1005525&HistoricalAwards=false
• 关键词: Optical; Preparation; Manipulation; Entangled; Spin

****NON-TECHNICAL ABSTRACT****An electron possesses a property known as spin, behaving in many ways like a tiny magnet. However, unlike familiar bar magnets, when the electron's spin is measured it points in only one of two directions, sometimes referred to as 'up' or 'down' or like a computer bit "1" or "0". In addition to this binary nature, the spin can also be in a state where it is 'pointing' in both directions 'up' and 'down' at the same time. A set of spins in such a state would contain all possible combinations of a classical set of bits. The capacity for a set of quantum bits to hold such an enormous amount of information would provide an exponential increase in computing power. Therefore, the ability to measure and control these spin properties has the potential to lead to transformative new technologies such as spintronics and quantum information processing. The goal of the research is to prepare and measure spin states through optical methods in a special type of semiconductor nanostructures known as coupled quantum dots (CQD). The ability to produce a robust initial state for quantum information operations is difficult; however, the CQD system may naturally be in desirable states after relaxation and emission of a photon. This research will characterize and use the emission from the CQD itself as a trigger indicating the spins are in the necessary configuration. The research provides students with training in various aspects of optics, photonics, spectroscopy, and basic semiconductor processing and characterization while participating in timely and technologically relevant research. One of the important broader impacts of the proposal is to recruit undergraduate students to engage in advanced research providing hands-on involvement in the operation of the laboratory.****TECHNICAL ABSTRACT****Robust control of spin in nanostructures will have broad scientific impacts, from advances in technology to probing fundamental quantum mechanics. The goal of the research is to prepare and measure entangled spin states through optical excitation in coupled quantum dots. Implementing quantum information processing requires the ability to identify, manipulate, and measure coupled quantum states. This program will impact the field by pursuing the use of excited state properties in coupled quantum dots (CQD) for spin preparation and measurement. These results will provide a natural route to spin manipulation through the use of pulsed laser techniques. The research will specifically address the excited state spectra through the use of optical polarization signatures and photon correlation measurements. Polarization signatures can offer a clear identification of specific charge and spin states, yet, a study of these signatures in the field of CQDs is still lacking. Similarly, selective excitation into higher energy states may provide a pathway for the preparation and coherent manipulation of coupled spins. Combining these techniques with photon correlation measurements will provide a straightforward method to select and study prepared spin states in CQDs. The research provides students with training in various aspects of optics, photonics, spectroscopy, and basic semiconductor processing and characterization while participating in timely and technologically relevant research. One of the important broader impacts of the proposal is to recruit undergraduate students to engage in advanced research providing hands-on involvement in the operation of the laboratory.

****非技术摘要****电子拥有一种称为自旋的特性，在很多方面表现得像一块微小的磁铁。 然而，与熟悉的条形磁铁不同，当测量电子的自旋时，它仅指向两个方向之一，有时称为“向上”或“向下”，或者像计算机位“1”或“0”一样。 除了这种二元性质之外，自旋还可以处于同时“指向”“向上”和“向下”两个方向的状态。 这种状态下的一组自旋将包含一组经典位的所有可能组合。 一组量子比特保存如此大量信息的能力将使计算能力呈指数级增长。 因此，测量和控制这些自旋特性的能力有可能带来自旋电子学和量子信息处理等变革性新技术。 该研究的目标是通过光学方法在一种称为耦合量子点（CQD）的特殊类型半导体纳米结构中制备和测量自旋态。为量子信息运算产生稳健的初始状态的能力很困难；然而，CQD 系统在弛豫和发射光子后自然可以处于理想的状态。这项研究将表征并使用 CQD 本身的发射作为触发器，指示自旋处于必要的配置。 该研究为学生提供光学、光子学、光谱学以及基本半导体加工和表征等各个方面的培训，同时参与及时的技术相关研究。 该提案的重要更广泛影响之一是招募本科生从事高级研究，提供实验室操作的实践参与。****技术摘要****纳米结构中自旋的鲁棒控制将具有广泛的影响科学影响，从技术进步到探索基础量子力学。 该研究的目标是通过耦合量子点中的光激发来制备和测量纠缠自旋态。 实现量子信息处理需要具有识别、操纵和测量耦合量子态的能力。 该计划将通过利用耦合量子点 (CQD) 中的激发态特性进行自旋制备和测量来影响该领域。 这些结果将为通过使用脉冲激光技术进行自旋操纵提供一条自然途径。 该研究将通过使用光学偏振特征和光子相关测量来专门解决激发态光谱。 偏振特征可以提供特定电荷和自旋态的清晰识别，然而，CQD 领域对这些特征的研究仍然缺乏。 类似地，选择性激发到更高能态可以为耦合自旋的制备和相干操纵提供途径。 将这些技术与光子相关测量相结合将提供一种直接的方法来选择和研究 CQD 中准备好的自旋态。 该研究为学生提供光学、光子学、光谱学以及基本半导体加工和表征等各个方面的培训，同时参与及时的技术相关研究。 该提案的重要更广泛影响之一是招募本科生从事高级研究，让他们亲身参与实验室的运营。