EAGER: Enabling Quantum Leap: Driven Non-Equilibrium Room Temperature Quantum States

EAGER：实现量子飞跃：驱动非平衡室温量子态

• 批准号: 1838507
• 负责人: Mercouri Kanatzidis
• 金额: $ 30万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-15 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1838507&HistoricalAwards=false
• 关键词: EAGER; Enabling; Quantum; Leap; Driven

Nontechnical description: Quantum-information science promises to revolutionize computation and communication, as well as our fundamental understanding of complex quantum systems. Qubits, the fundamental units of quantum computation, are the quantum analogs of the binary states of classical computers. A fundamental requirement of qubits is that the time over which they retain the encoded information, known as lifetime, is long compared to the operations that manipulate them. Here, the research team proposes a method to dramatically increase qubit lifetimes in specialized two-dimensional semiconductor materials. The main mechanism by which information in a qubit is lost is through interactions of the system and its environment, much like a pendulum is slowed down by friction at its suspension point. A common approach to increasing qubit lifetime is to isolate the system, analogous to lubricating the point of suspension of the pendulum, but this is highly impractical for many quantum information applications. The approach proposed here is to periodically decouple the system from its environment using various external controls. In this way, qubit lifetime is extended even at room temperature, greatly expanding the range of materials that can be used for quantum information applications. These research aims are naturally integrated with an educational plan that seeks to advance undergraduate, graduate, and postdoctoral training. The mechanism of this program is the development of online tutorial courses and outreach work that promotes science learning to a broad audience.Technical description: A major challenge in quantum information sciences has been the prevalence of short-lived coherences between quantum states, which impede practical utilization of quantum phenomena. This is especially problematic at room temperature where the environment causes large energy fluctuations that greatly accelerate decoherence. Here, the research team proposes a method to dramatically increase electronic coherence times in quantum-confined two-dimensional (2D) semiconductors at room temperature. The approach is multi-faceted: 1) perform 'single' particle measurements to minimize heterogeneous broadening, 2) identify transient excitonic states that are well-below the bandgap of the materials, and 3) create unique decoherence-free subspaces by optical driving fields that decouple the excitons from strongly coupled phonons, thereby giving rise to long-lived coherences among electronic states of matter. The proposed platform based on highly tunable 2D organic-inorganic perovskite crystals is used to create robust quantum states far from thermal equilibrium for applications in quantum sensing, quantum transport, and quantum information processing. 2D perovskites are ideal materials for this purpose because they exhibit a large manifold of transient and strongly-coupled exciton states that can be used as qubits in quantum information processing and sensing. The approach combines ideas from magnetic resonance, quantum chemistry, coherent spectroscopy, and quantum optics in order to create long-lived coherences with orders-of-magnitude longer electronic coherence times than currently possible in condensed-phase molecular systems under ambient conditions. The work proposed here enables understanding of how structural and chemical changes to the system, as well as modifications of the bath through external perturbations, affect decoherence far from thermal equilibrium. This project incorporates an educational component that advances undergraduate and graduate training through the creation of online tutorial courses that disseminate the research findings and the scientific background necessary to understand them. These courses are made available to a wide audience of students and teachers at the K-12 levels.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述：量子信息科学有望彻底改变计算和通信，以及我们对复杂量子系统的基本理解。量子比特是量子计算的基本单位，是经典计算机二进制状态的量子类似物。量子位的一个基本要求是，它们保留编码信息的时间（称为生命期）要比操作它们的操作长。在这里，研究小组提出了一种在专门的二维半导体材料中大幅增加量子比特寿命的方法。量子比特中信息丢失的主要机制是通过系统和环境的相互作用，就像钟摆在悬挂点被摩擦减慢一样。增加量子比特寿命的一种常见方法是隔离系统，类似于润滑钟摆的悬挂点，但这对于许多量子信息应用来说是非常不切实际的。这里提出的方法是使用各种外部控制周期性地将系统与其环境解耦。这样，即使在室温下，量子比特的寿命也会延长，从而大大扩展了可用于量子信息应用的材料范围。这些研究目标自然与寻求推进本科、研究生和博士后培训的教育计划相结合。该计划的机制是开发在线辅导课程和推广工作，向广大受众推广科学学习。技术描述：量子信息科学的一个主要挑战是量子态之间普遍存在的短时间相干，这阻碍了量子现象的实际利用。这在室温下尤其成问题，因为室温环境会导致巨大的能量波动，从而大大加速退相干。在这里，研究小组提出了一种在室温下显著增加量子受限二维（2D）半导体电子相干时间的方法。该方法是多方面的：1)执行“单”粒子测量以最大限度地减少非均匀展宽，2)识别远低于材料带隙的瞬态激子状态，以及3)通过光驱动场将激子与强耦合声子解耦，从而产生物质电子状态之间的长寿命相干，从而创建独特的无退相干子空间。所提出的基于高度可调谐的二维有机-无机钙钛矿晶体的平台用于创建远离热平衡的鲁棒量子态，用于量子传感、量子输运和量子信息处理。二维钙钛矿是实现这一目的的理想材料，因为它们具有大量的瞬态和强耦合激子态，可以用作量子信息处理和传感中的量子比特。该方法结合了磁共振、量子化学、相干光谱学和量子光学的思想，以创造长寿命的相干，其电子相干时间比目前在环境条件下的凝聚相分子系统长几个数量级。这里提出的工作使人们能够理解系统的结构和化学变化，以及通过外部扰动对浴池的修改，如何影响远离热平衡的退相干。该项目包含一个教育组成部分，通过创建在线辅导课程，传播研究成果和理解研究成果所需的科学背景，促进本科生和研究生的培训。这些课程面向K-12年级的广大学生和教师。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Negative Pressure Engineering with Large Cage Cations in 2D Halide Perovskites Causes Lattice Softening

• DOI: 10.1021/jacs.0c03860
• 发表时间: 2020-07-01
• 期刊: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
• 影响因子: 15
• 作者: Li, Xiaotong;Fu, Yongping;Kanatzidis, Mercouri G.
• 通讯作者: Kanatzidis, Mercouri G.