Resonant many-electron dynamics on helium

非技术摘要：二维(2D)电子系统是现代物理学的中心兴趣。这些系统的参数可以以可控的方式变化，使得能够在可控的环境中探索各种各样的量子多体现象。了解这些系统仍然是进步的主要驱动力，不仅在基础物理学方面，而且在纳米技术和量子信息科学方面也是如此。液氦表面的电子是实验上发现的第一个二维电子系统，它们仍然是已知的最原始的二维系统。低温下的超流氦表面非常干净，没有几乎所有其他材料系统都无法避免的缺陷和缺陷。放置在超流体表面附近的电子与其结合，并漂浮在表面上方约10纳米的真空中。它们展示了多体量子动力学的丰富方面。最吸引人的方面之一是系统的灵活性和可调性。通过改变电子的密度和体系的几何构型，可以有效地改变电子间相互作用的影响。这项研究工作旨在利用现有的控制手段来研究凝聚态物理的基本问题。人们最感兴趣的是不同量子系统之间相互作用的相互作用，以及这种相互作用如何影响远离热平衡的电子动力学。这种动态背后的一般原则尚未确立。由于氦上的电子系统是如此原始，它是研究耦合量子系统的独特工具。这项工作将利用现代实验和理论物理的各种工具来揭示该系统的基本特征。氦上的电子系统也是整合到量子设备中并潜在地开发新的量子技术的理想候选者。在这方面特别令人感兴趣的是用于量子信息科学的设备。由于这些特点，氦上的电子也是培养学生对基础科学和QIS技术感兴趣的理想平台。技术摘要：这次联合实验和理论工作的目的是了解液氦上多电子系统的共振动力学。这些非平凡的动力学是电子系统与氦表面量子激发相互作用、强电子关联和相互作用的结果。这项研究将解决的问题是，如果系统偏离热平衡，这种相互作用将如何改变系统的行为。具体地说，实验和理论工作将(I)研究高频激发下的线性和非线性共振响应，目的是了解在强直流场驱动下Wigner晶体中强关联和多体极化子效应的相互作用，这种强DC场有效地加强了电子对氦激发的耦合；(Ii)利用能够计数经过晶体的单个电子的单电子晶体管，探索晶相中电子迁移率的巨大非线性的本质和量子涨落对结晶的影响；(Iii)利用压电声表面波研究这些波与电子系统的等离子体模之间的共振相互作用，并研究高频电子的迁移率；以及(Iv)研究多电子系统中的量子和经典涨落如何影响面内和面外运动的面内磁场中子带间电子吸收的频谱，使该系统模拟具有受控电子-声子耦合的色心的光学响应。该奖项反映了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，认为值得支持。

Non-Technical Abstract:Two-dimensional (2D) electron systems are of central interest for modern physics. The parameters of these systems can be varied in a controllable way, enabling the exploration of a wide variety of quantum many-body phenomena in a controlled setting. Understanding these systems continues to be a major driver for progress, not only in fundamental physics, but also in nanotechnology and quantum information science. Electrons on the surface of liquid helium were the first two-dimensional electron system discovered experimentally, and they still stand out as the most pristine known 2D system. Superfluid helium at low temperatures functions as a fantastically clean surface without defects and imperfections that are unavoidable in almost all other material systems. Electrons placed near this superfluid surface become bound to it and float in vacuum about 10 nanometers above the surface. They exhibit rich aspects of many-body quantum dynamics. One of the most attractive aspects is the flexibility and tunability of the system. The effects of the interaction between electrons can be effectively modified by changing their density and the geometry of the system. This research work aims to use the available controls to study fundamental problems of condensed-matter physics. Of central interest is the interplay of interactions between different quantum systems and how this interplay affects the electron dynamics away from thermal equilibrium. No general principles underlying such dynamics have been established. Because the system of electrons on helium is so pristine, it is a unique tool for the studies of coupled quantum systems. This work will use various tools of modern experimental and theoretical physics to reveal the basic features of the system. The system of electrons on helium is also an ideal candidate for incorporating into quantum devices and to potentially developing novel quantum technologies. Of particular interest in this respect are devices used in quantum information science. Because of these features electrons on helium are also an ideal platform for training students interested in fundamental science and QIS technologies.Technical Abstract:The goal of this joint experimental and theoretical effort is to understand the resonant dynamics of the many-electron system on liquid helium. These non-trivial dynamics result from the interplay the strong electron correlations and the interaction of the electron system with the quantum excitations of the helium surface. The research will address the question of how this interplay modifies the behavior of the system if it is driven away from thermal equilibrium. Specifically, the experimental and theoretical work will (i) study the linear and nonlinear resonant response to high-frequency excitation with the goal to understand the interplay of the strong correlations and the many-body polaronic effect in a Wigner crystal driven by a strong dc field which effectively strengthens the electron coupling to the helium excitations; (ii) explore the nature of the giant nonlinearity of the electron mobility in the crystalline phase and the effect of quantum fluctuations on the crystallization using a single-electron transistor able to count individual electrons as they move past it; (iii) utilize piezoelectric surface acoustic waves to investigate resonant interaction between these waves and plasmonic modes of the electron system and to study the high-frequency electron mobility; and (iv) investigate how quantum and classical fluctuations in the many-electron system affect the spectrum of the inter-subband electron absorption in an in-plane magnetic field that couples in-plane and out-of-plane motion, making the system mimic the optical response of color centers with controlled electron-phonon coupling.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.