Strongly Correlated Nonequilibrium Transport Simulation in Complex Quantum Dot and Bulk Systems

该奖项支持介观和纳米系统中量子非平衡效应的计算和理论研究和教育。基于PI？在最近的稳态非平衡输运的虚时公式中，复杂量子点系统将通过量子蒙特卡罗技术和其他数值多体工具通过Matsubara电压方法进行研究。PI将把这种形式应用于复杂量子模型的非线性输运问题，这些问题目前很难通过计算来研究。最近在几个分子结上的实验表明，在源-漏偏置处存在与近藤能量尺度相当的电导振荡，并伴有近藤零偏异常。这种振荡据推测是由分子振动引起的。PI将采用安德森-霍尔斯坦模型来研究非Jahn-Teller和Jahn-Teller电子-声子耦合的作用，以及现场库仑相互作用。PI将研究自旋电子器件中自旋注入的强相关效应。利用动力学平均场理论的两种不同实现，将非平衡理论扩展到体极限：费米晶格中的多重化学势效应和利用布洛赫振荡基础的带电粒子的电场驱动输运。PI积极参与与电气工程和机械工程系的跨学科研究，并与视觉研究部门合作，在物理思想的艺术表现方面进行拓展工作。该奖项支持研究介观系统和纳米结构的理论研究和教育，例如大分子或大分子相互连接的系统，这些系统由于电场的应用而与周围环境失去平衡，并且在量子力学中占主导地位。这项研究建立在PI开发的方法的基础上，这些方法将使他能够计算这些结构的导电性能并探索新的现象。在实验的激励下，PI将运用他的方法来确定电子之间的强相互作用，以及电子和声子之间的相互作用如何影响电子在结构中的传输。这项研究有助于对我们周围世界出现的现象进行广泛的基本理解。用于开发半导体器件的传统理论越来越不足以描述现在接近分子大小的器件，器件和材料的概念变得越来越模糊。这一努力为未来的技术奠定了知识基础，这些技术将利用分子和纳米级结构来构建电子设备，作为维持电子工业巨大增长的一种策略。摩尔?法律。?本研究项目有助于对开放系统耦合的中尺度和纳米尺度结构的量子力学非平衡行为的一般理解。量子信息如何通过耦合传输和丢失到环境中的一般问题影响着量子计算的新兴领域。PI积极参与与电气工程和机械工程系的跨学科研究，并与视觉研究部门合作，在物理思想的艺术表现方面进行拓展工作。

TECHNICAL SUMMARYThis award supports computational and theoretical research and education on quantum nonequilibrium effects in mesoscopic and nanosystems. Based on the PI?s recent imaginary-time formulation of steady-state nonequilibrium transport, complex quantum dot systems will be studied via quantum Monte Carlo technique and other numerical many-body tools through the Matsubara voltage method. The PI will apply this formalism to nonlinear transport problems of complex quantum models which are currently difficult to study through computation. Recent experiments on several molecular junctions show a Kondo zero-bias anomaly accompanied by conductance oscillations at the source-drain bias comparable to the Kondo energy scale. The oscillation has been speculated to be from molecular vibrations. The PI will pursue an Anderson-Holstein model to investigate the roles of non-Jahn-Teller and Jahn-Teller electron-phonon coupling, and the on-site Coulomb interaction. The PI will study strong correlation effects in spin-injection proposed for spintronics devices. The nonequilibrium theory will be extended to the bulk limit using two different implementations of the dynamical mean-field theory: effect of multiple-chemical potentials in Fermi lattice and electric field driven transport of charged particles using the Bloch oscillation basis.The PI is actively involved in interdisciplinary research with the Electric Engineering and Mechanical Engineering Departments, and also in outreach effort of artistic representation of physics ideas in collaboration with the department of visual studies.NONTECHNICAL SUMMARYThis award supports theoretical research and education to study mesoscopic systems and nanostructures, such as large molecules or interconnected systems of large molecules, that are out of balance with their surroundings due to, for example, the application of an electric field, and for which quantum mechanics dominates. This research builds on methods developed by the PI that will enable him to calculate how well these structures conduct electricity and to explore new phenomena. Motivated by experiments, the PI will apply his approach to determine how strong interactions among electrons, and electrons and phonons affect the transport of electrons through the structures. This research contributes to the broad fundamental understanding of the phenomena that arise in the world around us. Conventional theories used to develop semiconductor devices become increasingly inadequate to describe devices now approaching the size molecules where the notion of a device and material become increasingly blurred. This effort contributes to the intellectual foundations for future technologies that would utilize molecules and nanoscale structures to construct electronic devices as a strategy to sustain the tremendous growth of the electronics industry encapsulated in ?Moore?s Law.? This research project contributes to the general understanding of quantum mechanical nonequilibrium behavior of mesoscale and nanoscale structures coupled to open systems. The general problem of how quantum information is transported and lost through coupling to the environment has impact on the emerging area of quantum computing.The PI is actively involved in interdisciplinary research with the Electric Engineering and Mechanical Engineering Departments, and also in outreach effort of artistic representation of physics ideas in collaboration with the department of visual studies.