CAREER: Real-Time First-Principles Approach to Understanding Many-Body Effects on High Harmonic Generation in Solids

职业：实时第一性原理方法来理解固体高次谐波产生的多体效应

• 批准号: 2337987
• 负责人: Diana Qiu
• 金额: $ 67.5万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-03-01 至 2029-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2337987&HistoricalAwards=false
• 关键词: CAREER; Real; Time; First; Principles

Nontechnical SummaryThis award supports research, education, and outreach activities focused on understanding how interactions between electrons change the way that materials behave when exposed to very strong electromagnetic fields. Strong electromagnetic fields interact with materials in a highly nonlinear way. One phenomenon that arises in these high fields is high harmonic generation—a process where low-energy light is absorbed by a material and combined to produce light at energies that are integer multiples (or harmonics) of the incoming light. Such high harmonic generation is fundamental for the development of ultrafast light sources that can be used to probe the physics of electronic and atomic motion on very short timescales. Most existing sources of high harmonic generation rely on generation from gases of atoms and molecules, where the allowed energy levels of the electrons are discrete. Extending these processes from the gas phase to crystalline solids introduces greater flexibility in the energy ranges that can be accessed by the incoming and generated light. The generation of high harmonic light in solids can also potentially be used as a tool for characterizing the behavior of electrons in these solids. However, the interpretation of high harmonic spectra in solids is highly challenging due to the complicated interplay of electronic and atomic motion that contribute to the yield of outgoing light under different generation conditions. This project aims to develop, implement, and apply new theoretical and computational tools to aid in understanding the role of electron motion and interactions in high harmonic generation from solids. The developed methods will be applied to study high harmonic generation in low-dimensional solids where electron interactions are expected to be strong.This project supports a postdoctoral researcher and the education of a graduate student. Additionally, this project will integrate research, education, and mentoring with a scaffolded outreach program designed to broaden the participation of groups that are historically under-represented in science and engineering. The PI will develop a new undergraduate materials science curriculum and a summer materials science workshop and offer a yearly summer internship for students from the New Haven public school system. The proposed outreach includes a rigorous data collection component that will allow the impact of the program to be assessed.TECHNICAL SUMMARYThis award supports research, education, and outreach activities focused on understanding many-body effects in nonperturbative high harmonic generation. High harmonic generation in solids is foundational for the creation of new attosecond light sources across the extreme ultraviolet regime and holds promise as an all-optical probe of materials’ bandstructure and topology. However, theory that can describe nonperturbative high harmonic generation in real materials is still nascent, especially when it comes to a quantitative understanding of many-body effects. This project aims to develop and apply a new ab initio method based on the Keldysh formalism for nonequilibrium many-body states to understand many-body effects in high harmonic generation and other nonlinear spectroscopies beyond the perturbative regime. The method is built on the time-dependent adiabatic GW approach (here, G stands for the one-particle Green’s function and W is the screened Coulomb interaction), where the one-particle density matrix is coupled to an external field and propagated in time with the ab initio GW self-energy. The PI and her team will apply this approach to (1) to understand signatures of topology, spin, polarization textures, and exciton effects in high harmonic spectra by performing calculations on a testbed of two-dimensional materials, where complex factors like exciton binding energy, screening, and symmetry can be more easily isolated; and (2) understand the limits of our computational techniques and constituent approximations.This project supports a postdoctoral researcher and the education of a graduate student. Additionally, this project will integrate research, education, and mentoring with a scaffolded outreach program designed to broaden the participation of groups that are historically under-represented in science and engineering. The PI will develop a new undergraduate materials science curriculum and a summer materials science workshop and offer a yearly summer internship for students from the New Haven public school system. The proposed outreach includes a rigorous data collection component that will allow the impact of the program to be assessed.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.

非技术摘要该奖项支持研究、教育和推广活动，重点是了解强电磁场与材料以高度非线性方式相互作用时，电子之间的相互作用如何改变材料的行为方式。高场是高谐波产生——低能量光被材料吸收并组合产生能量为入射光整数倍（或谐波）的光的过程，这种高谐波产生是产生光的基础。超快光源的开发可用于在极短的时间尺度上探测电子和原子运动的物理现象，大多数现有的高次谐波产生源依赖于原子和分子气体的产生，其中电子的允许能级为将这些过程从气相扩展到结晶固体，可以使入射光和产生的光获得更大的灵活性，固体中高次谐波光的产生也可以用作表征行为的工具。然而，由于电子和原子运动的复杂相互作用导致了不同生成条件下的出射光的产生，因此固体中的高次谐波光谱的解释非常具有挑战性。并应用新的理论和计算工具来帮助理解电子运动和相互作用在固体高次谐波产生中的作用，所开发的方法将用于研究低维固体中的高次谐波产生，其中电子相互作用预计会很强。该项目资助一名博士后此外，该项目还将研究、教育和指导与支架式外展计划相结合，旨在扩大历史上在科学和工程领域代表性不足的群体的参与。本科材料科学课程和夏季材料科学研讨会，并为纽黑文公立学校系统的学生提供每年的夏季实习机会。拟议的外展活动包括严格的数据收集部分，以便评估该计划的影响。技术摘要该奖项。支持研究、教育和外展活动的重点是了解非微扰高次谐波产生中的多体效应固体中的高次谐波产生是在极紫外范围内创建新阿秒光源的基础，并有望成为材料能带结构和拓扑结构的全光学探针。然而，能够描述实际材料中非微扰高次谐波产生的理论仍处于萌芽阶段，特别是在定量理解多体效应方面。该项目旨在开发和应用一种新的从头算方法。基于非平衡多体态的凯尔迪什形式主义，以了解高次谐波产生中的多体效应和超出微扰范围的其他非线性光谱学。该方法建立在依赖于时间的绝热引力波方法（此处，G 代表一元）。粒子格林函数，W 是屏蔽库仑相互作用），其中单粒子密度矩阵耦合到外部场并以从头算起的 GW 及时传播PI 和她的团队将通过在二维材料测试台上进行计算（其中存在复杂因素），将这种方法应用于 (1)，以了解高次谐波光谱中的拓扑、自旋、偏振纹理和激子效应的特征。像激子结合能、筛选和对称性可以更容易地分离；（2）了解我们的计算技术和成分近似的局限性。该项目支持博士后研究员和研究生的教育。此外，该项目还将将研究、教育和指导与支架式外展计划相结合，旨在扩大历史上在科学和工程领域代表性不足的群体的参与。PI 将开发新的本科材料科学课程和夏季材料科学研讨会，并每年举办一次。拟议的外展活动包括严格的数据收集部分，以便评估该计划的影响。该奖项是 NSF 的法定使命，并通过使用基金会的评估被认为值得支持。智力价值和更广泛的影响审查标准。