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

非技术摘要：量子点就像电可控的“人造原子”一样，是一个有用的系统，可以研究从键形成和磁性到量子信息基础的广泛的凝聚态物理现象。在这个项目中，研究小组将研究电子和声子之间普遍存在的耦合。特别令人感兴趣的是声子对电子自旋的影响。对声子-自旋相互作用的控制，在这里通过纳米结构和应用应变实现，对于一些应用具有重要的意义，例如量子计算。在这个项目的过程中，新一代本科生和研究生正在接受纳米制造、低温和微波测量方面的专业知识培训。这些技能与全国范围内对量子劳动力的呼吁相关。通过开发说明性的量子实验，这些研究工作正在与Mines的微电子处理课程相结合。最后，正在开发模块，以便将其纳入到落基山阅读障碍儿童夏令营对中学生的推广工作中。技术摘要：电子-声子耦合在凝聚态系统中普遍存在。它在电子自旋态的弛豫和退相干(在多个自旋的情况下)中起着关键作用，并被预测为调节多体现象。在超导和热电等不同领域，存在着大量关于定制它的研究。来自这些领域的洞察力从未被应用于少数自旋系统的实验。这是一个新的有影响力的机会，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，这对量子信息应用非常重要。该项目通过专注于控制和测量硅门定义量子点中的电子-声子过程的实验努力来弥合这一差距。声子浴是通过纳米结构设计的，自旋-轨道耦合是通过施加应变来控制的，以研究从理论上预测的‘保护态’。测量了自旋弛豫和退相干时间。控制自旋与声子浴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。其次，它导致了对迄今未经检验的理论预测的检验。第三，在该项目中开发的纳米尺度电声子热化传感的新协议是未来在量子点平台上进行量子热力学研究的基础。最后，这是一项开创性的努力，将纳米声子学广阔领域的洞察力应用于旋转量子比特，并为未来该领域的整合铺平了道路。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.