Quantal Heating in Electron Systems with Discrete Spectra

摘要：电能转化为热能，即焦耳加热，是影响现代经济的主要物理过程之一。由于焦耳加热，发电厂和消费者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非常有益。最近，首席研究小组发现，物质的量子特性在很大程度上影响了焦耳加热，从而大大减少了能量损失。本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。提出的焦耳加热的时间演化研究可能有助于实现这一目标。研究结果对设计利用物质量子特性的新型无能量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，这是一个联邦政府认可的少数民族服务机构。该活动对这些学生产生了很大的影响，为量子物理和材料科学的先进领域提供了培训和教育。技术摘要：焦耳加热是将电能转化为热能的一种显著的物理现象。最近有研究表明，物质的量子特性显著影响这种加热，导致电子在能量空间分布的热分层（量子化）。这种效应被称为量子加热，在经典电子系统中并不存在。与经典焦耳加热相比，量子加热导致高移动二维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，其中电压不依赖于电流，反之亦然。本项目是对量子化磁场中高移动二维电子系统的量子加热动力学和奇异非线性态的原始研究。本文研究了二维电子在直流驱动的奇异非线性态和量子霍尔效应下的谱扩散、空间电子重分布和非弹性电子弛豫等非线性响应的基本机制。半整数填充因子下非线性电子输运的研究主要集中在寻找复合费米子在直流偏置下的量子加热和非线性态。该项目揭示了量子效应在电能转化为热能中的重要作用。这项研究是通过纽约城市学院的学生直接参与完成的，这是一个联邦政府认可的少数民族服务机构。该活动对这些学生产生了很大的影响，为量子物理和材料科学的先进领域提供了培训和教育。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.