Spin Bath of a Central Spin System in Diamond: Polarization and Coherent Control

金刚石中央自旋系统的旋转浴：偏振和相干控制

• 批准号: 1005926
• 负责人: Paola Cappellaro
• 金额: $ 30万
• 依托单位: Massachusetts Institute of Technology
• 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: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1005926&HistoricalAwards=false
• 关键词: Spin; Bath; Central; System; Diamond

****NON-TECHNICAL ABSTRACT****Controlling and manipulating nature at the quantum level is one of the greatest challenges facing both theoretical and experimental physics. The combination of quantum physics with information science has made possible the use of quantum systems to perform calculations and tasks of a complexity unattainable by systems that behave classically. The most important challenge facing quantum information science is to reliably control a scalable quantum system, which provides the ability to build quantum devices, while staving off decoherence (the process that leads to the loss of the quantum properties). The focus of this project is to study decoherence of a small quantum system interacting with a larger environment, whose characteristics are in part under control. The goal is to achieve a deeper physical understanding of decoherence. The ability to vary the environment's properties is critical to achieve a better understanding of decoherence, which is a complex many-body non-equilibrium quantum phenomenon. In turn, a better understanding may lead to techniques for mitigating decoherence and to improved quantum devices. The project will focus on a system, the Nitrogen-Vacancy color center in diamond, which has emerged as a highly promising quantum device for computation, magnetic sensing and bioimaging. This project will support the training of a postdoctoral fellow in an exciting and multidisciplinary research field. This research project receives support from the Division of Materials Research and the Physics Division.****TECHNICAL ABSTRACT****The goal of this project is to study decoherence of a central spin by a spin bath with varying and controllable characteristics. The project will focus on the electronic spin bath in diamond nano-crystals and its effects on the Nitrogen-Vacancy (NV) color center, to achieve a deeper physical understanding as well as to potentially lead to practical applications. Theoretical and experimental efforts towards a full understanding of decoherence mechanisms have been hindered by the very complexity of the dynamics. The ability to manipulate the mesoscopic bath will be exploited to perform a systematic study of the central-spin problem. Specifically, schemes for decoupling the environment from the central spin, for refocusing its internal evolution as well as for polarizing the environment spins will be developed and tested experimentally Potential applications of the control and polarization techniques range from precision measurement and bio-imaging to quantum communication and computation. For example, control and polarization of the bath would not only improve the sensitivity of recently proposed NV-based magnetic sensors, but also allow using the bath itself as a means to achieve sensitivity at the Heisenberg limit. The proposed research program will also provide interdisciplinary training of a postdoctoral fellow in condensed matter physics, nanoscience, optical imaging techniques and quantum information science, as well as in areas of potential applications, such as surface science and bioimaging. This research project receives support from the Division of Materials Research and the Physics Division.

****非技术摘要****在量子水平上控制和操纵自然是理论和实验物理学面临的最大挑战之一。 量子物理学与信息科学的结合使得使用量子系统来执行经典行为系统无法实现的复杂计算和任务成为可能。量子信息科学面临的最重要的挑战是可靠地控制可扩展的量子系统，该系统提供了构建量子设备的能力，同时避免退相干（导致量子特性丧失的过程）。 该项目的重点是研究与较大环境相互作用的小型量子系统的退相干，其特性部分受到控制。目标是获得对退相干更深入的物理理解。 改变环境特性的能力对于更好地理解退相干至关重要，退相干是一种复杂的多体非平衡量子现象。反过来，更好的理解可能会带来减轻退相干的技术和改进的量子设备。该项目将重点研究钻石中的氮空位色心系统，该系统已成为用于计算、磁传感和生物成像的非常有前途的量子设备。该项目将支持在令人兴奋的多学科研究领域培训博士后研究员。 该研究项目得到了材料研究部和物理部的支持。****技术摘要****该项目的目标是研究具有变化且可控特性的旋转浴对中心旋转的退相干。 该项目将重点研究金刚石纳米晶体中的电子旋转浴及其对氮空位（NV）色心的影响，以实现更深入的物理理解并有可能带来实际应用。动力学的复杂性阻碍了充分理解退相干机制的理论和实验努力。将利用操纵介观浴的能力来对中心自旋问题进行系统研究。具体来说，将开发和实验测试将环境与中心自旋解耦、重新聚焦其内部演化以及极化环境自旋的方案。控制和极化技术的潜在应用范围从精密测量和生物成像到量子通信和计算。例如，浴的控制和极化不仅可以提高最近提出的基于 NV 的磁传感器的灵敏度，而且还允许使用浴本身作为实现海森堡极限灵敏度的手段。 拟议的研究项目还将为博士后提供凝聚态物理、纳米科学、光学成像技术和量子信息科学以及表面科学和生物成像等潜在应用领域的跨学科培训。该研究项目得到了材料研究部和物理部的支持。