Quantum Monte Carlo Using Multicore Processors: Enabling Simulations in Inhomogeneous Environments

发展对强关联电子系统(SCES)的理解和预测能力是一个快速发展的领域，它严重依赖于更快的计算来继续取得进展。SCE构成了关键材料能力的基础，包括高温超导、核燃料、新型热电材料以及在冷原子气体中看到的奇异和有希望的行为。超临界流体是一种很难从理论上模拟的材料，因为它们的电子组分具有高度随时间变化的特性。一项重要的新兴技术是多核处理器，其中越来越多的CPU(“核”)并列在单个芯片上，因此耦合非常紧密。由此产生的(预期的)计算吞吐量加速包括一条有希望的途径，以绕过半导体技术中众所周知的摩尔定律的崩溃。该项目涉及开发用于研究SCES性质的先进计算物理方法，如量子蒙特卡罗和密度泛函理论。通过制定在新兴多核处理器上实施这些新方法的有效战略，这些新方法的能力将大大增强。这项工作跨越了凝聚态物理和原子物理学之间的智力界限，也跨越了物理学、应用数学和计算机科学之间的界限。这些应用将探索相互作用对由磁性、金属绝缘体和超导转变产生的物质的新量子态的影响。一个特别的项目重点将是空间不均匀(“缺陷”)对量子系统有序相的影响。除了推进计算物理和材料科学的研究，这项工作还对培训研究生和博士后研究人员使用跨学科研究工具产生了更广泛的影响。首席调查员在让本科生甚至高中生参与研究方面也做出了很大努力，他们将继续这一项目。

Developing an understanding of, and a predictive capability for, strongly correlated electron systems (SCES), is a rapidly evolving field that relies critically on faster computation for continued progress. SCES form the basis of crucial materials capabilities, including high temperature superconductivity, nuclear fuels, new classes of thermoelectrics, and the exotic and promising behavior seen in cold atomic gases. SCES are difficult materials to model theoretically because of the highly time-dependent fluctuations of their electronic constituents. An important emerging technology is the multicore processor, where an increasingly large number of CPUs ("cores") are juxtaposed on a single chip and thus are extremely closely coupled. The resulting (expected) speedup in computational throughput comprises a promising path to sidestep the well publicized breakdown of Moore's law in semiconductor technology.This project involves the development of advanced computational physics methods, "Quantum Monte Carlo" and "Density Functional Theory," for studying SCES properties. The capabilities of these new approaches will be greatly enhanced by the formulation of efficient strategies for their implementation on emerging multicore processors. This work crosses the intellectual boundary between condensed matter and atomic physics, and also between physics, applied mathematics, and computer science. The applications will explore effects of interactions on novel quantum states of matter which arise from magnetic, metal-insulator, and superconducting transitions. A particular project focus will be on the effect of spatial inhomogeneities ("defects") on ordered phases of quantum systems. In addition to advancing research in computational physics and materials science, this work has broader impacts to training graduate students and postdoctoral researchers in interdisciplinaryresearch tools. The Principal Investigators have also a substantial effort in involving undergraduate students and even high school students in research, which they will continue with this project.