CAREER: Electron-phonon processes in gate-defined silicon quantum dots: measurement, control, and applications.

职业：门定义硅量子点中的电子声子过程：测量、控制和应用。

• 批准号: 2046428
• 负责人: Meenakshi Singh
• 金额: $ 68.56万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2046428&HistoricalAwards=false
• 关键词: CAREER; Electron; phonon; processes; gate

Non-technical abstract: Acting like electrically controllable ‘artificial atoms’, quantum dots are a useful system to study a wide range of condensed matter physics phenomena ranging from bond formation and magnetism to the fundamentals of quantum information. In this project, the research team will study the ubiquitous coupling between electrons and phonons. Of particular interest is the impact of the phonons on the spin of the electrons. Control over the phonon-spin interaction, achieved here via nano-structuring and applied strain, has crucial implications for a number of applications, such as quantum computing. In the course of this project, a new generation of undergraduate and graduate students are being trained with expertise in nanoscale fabrication, cryogenics, and microwave measurements. These skills are relevant to the nationwide calls for a quantum workforce. The research efforts are being integrated with the Microelectronics Processing course at Mines via development of illustrative quantum experiments. Finally, modules are being developed to be incorporated into outreach efforts to middle school children in the Rocky Mountain Camp for Dyslexic Children.Technical abstract: Electron-phonon coupling is ubiquitous in Condensed Matter systems. It plays a pivotal role in relaxation and decoherence (in case of multiple spins) of electronic spin states and is predicted to mediate many-body phenomena. An immense body of research on tailoring it in fields as varied as superconductivity and thermoelectrics exists. Insight from these fields has never been applied to experiments in few-spin systems. This is a new and impactful opportunity, since few-spin systems are the fundamental prototype for rationalizing spin dynamics in more complex systems, important for quantum information applications. This project bridges the gap via an experimental effort focused on control and measurement of electron-phonon processes in silicon gate-defined quantum dots. The phonon bath is engineered through nano-structuring and spin-orbit coupling is controlled via applied strain to investigate the theoretically predicted ‘protected’ states. Measurements of spin relaxation and decoherence time are performed. Controlling the coupling of spins to the phonon bath has profound implications. First, it can be used for the design of ‘hot’ qubits and spintronic devices. Second, it leads to an examination of hitherto untested theoretical predictions. Third, the novel protocols developed in the project for sensing nanoscale electron-phonon thermalization are foundational for future quantum thermodynamics studies on the quantum dot platform. Finally, this is a pioneering effort to apply insight from the vast field of nano-phononics to spin qubits and paves the way for future integration of the fields.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.

非技术摘要：量子点就像电可控的“人造原子”，是研究从键形成和磁性到量子信息基本原理的各种凝聚态物理现象的有用系统。在这个项目中，研究小组将研究电子和声子之间无处不在的耦合。特别令人感兴趣的是声子对电子自旋的影响。通过纳米结构和施加的应变来控制声子-自旋相互作用，对量子计算等许多应用具有重要意义。在这个项目的过程中，新一代的本科生和研究生正在接受纳米制造，低温和微波测量专业知识的培训。这些技能与全国范围内对量子劳动力的需求有关。研究工作正在通过开发说明性量子实验与矿山的微电子处理课程相结合。最后，模块正在开发中，以纳入外展工作，以中学生在落基山营的诵读困难儿童。技术摘要：电子-声子耦合是无处不在的凝聚态物质系统。它在电子自旋态的弛豫和退相干（在多自旋的情况下）中起着关键作用，并被预测为介导多体现象。在超导和热电等不同领域，存在着大量的研究。从这些领域的见解从来没有被应用到少自旋系统的实验。这是一个新的和有影响力的机会，因为少自旋系统是在更复杂的系统中合理化自旋动力学的基本原型，对量子信息应用很重要。这个项目通过实验努力弥合了差距，重点是控制和测量硅栅极定义的量子点中的电子-声子过程。声子浴是通过纳米结构和自旋轨道耦合的工程控制，通过施加应变调查理论预测的“保护”状态。测量了自旋弛豫和退相干时间。控制自旋与声子池的耦合具有深远的意义。首先，它可以用于“热”量子比特和自旋电子器件的设计。第二，它导致迄今未经检验的理论预测的检查。第三，在该项目中开发的用于感测纳米级电子-声子热化的新协议是量子点平台上未来量子热力学研究的基础。最后，这是一项开创性的努力，将纳米声子学的广阔领域的见解应用于自旋量子比特，并为未来的领域整合铺平了道路。该奖项反映了NSF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。