Quantal Heating in Electron Systems with Discrete Spectra

非技术摘要：电能到热的转换，所谓的焦耳加热，是影响现代经济的主要物理过程之一。由于焦耳加热，发电厂和用户之间的总电能损失在8%到15%之间。减少如此巨大的损失将对社会大有裨益。最近，主要的研究小组发现，物质的量子性质对焦耳加热有很大的影响，这导致能量损失的大幅减少。这个项目的主要目标之一是揭示量子电导体中电能耗散的机制。对焦耳加热时间演化的研究可能有助于实现这一目标。研究结果对利用物质的量子特性设计新型无能量损耗电导体具有重要意义。这项研究是通过纽约城市学院的学生直接参与完成的，该学院是联邦承认的少数族裔服务机构。这项活动对这些学生产生了很大的影响，提供了量子物理和材料科学等高级领域的培训和教育。技术摘要：焦耳加热是一种显著的物理现象，它将电能转化为热。最近的研究表明，物质的量子性质显著地影响了这种加热，导致了能量空间中电子分布的热分层(量子化)。这种被称为量子加热的效应在经典电子系统中是不存在的。与经典的焦耳加热不同，量子加热导致高迁移率的2D电子具有突出的非线性输运特性，使它们进入奇异的非线性状态，在这种状态下，电压与电流无关，反之亦然。本项目是对量子加热动力学和处于量子化磁场中的高迁移率2D电子系统中的奇异非线性态的首次研究。研究内容包括：光谱扩散、空间电子再分布和非弹性电子弛豫等非线性响应的基本机制，包括直流驱动的二维电子的奇异非线性态和量子霍尔效应。在半整数填充因子下的非线性电子输运的研究主要集中在寻找复合费米子的量子加热和非线性状态对直流偏压的响应。该项目揭示了量子效应在电能转化为热过程中的重要作用。这项研究是通过纽约城市学院的学生直接参与完成的，该学院是联邦承认的少数族裔服务机构。该活动对这些学生产生了很大的影响，提供了量子物理和材料科学先进领域的培训和教育。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，被认为值得支持。

NON-TECHNICAL ABSTRACT:Conversion of electrical energy into heat, so called Joule heating, is one of the major physical processes affecting the modern economy. Due to Joule heating the overall electrical energy losses between power plants and consumers is in the range between 8 and 15%. A reduction of such enormous losses would be highly beneficial for society. Recently the principal investigator team has discovered that quantum properties of matter substantially affect Joule heating, that leads to a strong reduction of the energy losses. One of the main goals of this project is to reveal the mechanisms of the electrical energy dissipation in quantum electrical conductors. The proposed study of the temporal evolution of Joule heating may help realize this goal. The research results are of paramount importance for the design of novel energy-lossless electrical conductors utilizing the quantum properties of matter. The research is accomplished via direct participation of students of the City College of New York, which is a federally recognized minority serving institution. The activity has great impact on these students, providing training and education in advanced areas of quantum physics and material science.TECHNICAL ABSTRACT:Joule heating is a remarkable physical phenomenon, which transforms electric energy into heat. Recently it was shown that the quantum properties of matter significantly affect this heating, giving rise to a thermal stratification (quantization) of the electron distribution in the energy space. This effect, called quantal heating, does not exist in classical electron systems. In contrast to classical Joule heating, quantal heating leads to outstanding nonlinear transport properties of highly mobile 2D electrons, driving them into exotic nonlinear states in which voltage does not depend on current and vice versa. This project is the original study of the dynamics of quantal heating and the exotic nonlinear states in highly mobile 2D electron systems placed in quantizing magnetic fields. The research includes investigations of fundamental mechanisms of the nonlinear response: spectral diffusion, spatial electron redistribution and inelastic electron relaxation in different regimes including the dc-driven exotic nonlinear states of 2D electrons and Quantum Hall Effect. Investigations of nonlinear electron transport at half-integer filling factors are focused on the search for quantal heating and nonlinear states of composite fermions in response to dc bias. The project reveals the important role of quantum effects in the transfer of electric energy into heat. The research is accomplished via direct participation of students of the City College of New York, which is a federally recognized minority serving institution. The activity has great impact on these students, providing training and education in advanced areas of quantum physics and material science.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.