Experiments on Fractional Quantum Hall Effect and Related Physics in New Regimes

在现代电子学中，几乎所有的设备功能都是由电子来完成的，这些电子被限制在薄膜中或沿着半导体的界面移动。这种所谓的二维（2D）电子系统，在正常环境下表现为二维粒子的普通气体，当它们受到低温（T1K）和高磁场（B1T）的极端条件时，就会发展成为物理学的新前沿。一些观测到的物理现象是早期理论预测的第一次实现（例如维格纳晶体和斯基米恩）；其他的，比如复合费米子，是最近才发现和发明的。所有这些都代表了超低能量物理，体现在量子力学原理中，这些原理支配着固态中大量强相互作用电子的行为。该项目将在低电子密度和超低温度（低于1 mK）的以前无法到达的物理制度下探索这种超低能量电子物理。旨在揭示这些制度下的新量子相并探索其量子相变的实验，也有望在两个具有社会重要性的领域产生更广泛的影响：一是教育和培训具有多学科知识和观点以及尖端技术技能的未来科技领袖。本研究具有多学科性质，旨在培养学生和博士后精通凝聚态物理、半导体材料科学和半导体器件加工技术。另一个领域是未来的量子计算机。目前对容错量子计算机的设想是使用非阿贝尔粒子。迄今为止，这种粒子在固体状态下的唯一已知实现是在二维电子介质中发现的成对复合费米子的奇异液体凝聚态的准粒子。在现代电子学中，几乎所有的设备功能都是由电子来完成的，这些电子可以在薄膜中或沿着半导体的界面在二维空间中自由移动。这种所谓的二维（2D）电子在正常环境下的行为就像由独立的二维粒子组成的普通气体。它们大量聚集在一起的行为只是单个粒子的总和，每个粒子都可以用经典物理定律充分描述。然而，当受到极低温度和高磁场的影响时，它们成为超低能量物理学的新前沿，令人惊讶的是，它们具有丰富的新相，这些新相体现了量子物理学的运作，这些量子物理学控制着固体中大量强相互作用电子的行为。该项目将在低电子密度和低温的以前无法到达的物理制度中探索超低能量电子物理。这将揭示电子的新量子相，在那里它们更适合被描绘成一种新的奇异液体或固体，并探测它们的转变。预计它还将对教育和培训具有多学科知识和观点以及尖端技术技能的未来科学和技术领导者产生更广泛的影响。本研究具有多学科性质，旨在培养学生和博士后精通凝聚态物理、半导体材料科学和半导体器件加工技术。

In modern day electronics, almost all device functions are performed by electrons that are confined to move in thin films, or along the interfaces, of semiconductors. Such so-called two-dimensional (2D) electron systems, which behave at normal ambient as an ordinary gas of 2D particles, evolve into a new frontier of physics when they are subjected to the extreme conditions of low temperatures (T1K) and high magnetic fields (B1T). Some of the observed physical phenomena are first realizations of early theoretical predictions (e.g. the Wigner crystal and the skyrmion); others, such as composite fermions, are more recent discoveries and inventions. All represent the ultra-low energy physics manifested in the quantum mechanical principles that govern the behavior of large numbers of strongly interacting electrons in the solid state. This project will explore such ultra-low energy electron physics in previously inaccessible physical regimes of low electron densities and ultra-low temperatures, to below 1 mK. The experiments, designed to uncover new quantum phases in these regimes and to probe into their quantum phase transitions, are also expected to have broader impacts in two areas of societal importance: One is in the education and training of future leaders in science and technology with multi-disciplinary knowledge and perspectives, as well as cutting edge technical skills. The research, being multi-disciplinary in nature, will educate students and post-docs involved to be fluent in condensed matter physics, the science of semiconductor materials, and the processing technology of semiconductor devices. The other area is on the future quantum computer. The current vision for a fault-tolerant quantum computer is the one that uses nonAbelian particles. To date, the only known realization of such particles in the solid state consists of the quasi-particles of the exotic liquid condensate of paired composite fermions found in 2D electron media.In modern day electronics, almost all device functions are performed by electrons that are free to move in two dimensions in thin films, or along the interfaces, of semiconductors. Such so-called two-dimensional (2D) electrons behave at normal ambient as an ordinary gas of independent 2D particles. The behavior of a large number of them together is simply that of the sum of the individual particles, each adequately described by the classical law of physics. However, when subjected to extremely low temperatures and high magnetic fields, they become a new frontier for ultra-low energy physics, surprisingly rich in novel phases that manifest the workings of quantum physics that govern the behavior of a large number of strongly interacting electrons in the solid. This project will explore ultra-low energy electron physics in previously inaccessible physical regimes of low electron densities and low temperatures. This should uncover new quantum phases of the electrons, where they are more appropriately pictured as a new kind of exotic liquid or solid, and to probe their transformations. It is also expected to have broader impacts in the education and training of future leaders in science and technology with multi-disciplinary knowledge and perspectives, as well as cutting edge technical skills. The research, being multi-disciplinary in nature, will educate students and post-docs involved to be fluent in condensed matter physics, the science of semiconductor materials, and the processing technology of semiconductor devices.