Ab Initio Calculations in Correlated Electron Models and Materials

点击翻译按钮获取中文摘要

NON-TECHNICAL SUMMARYThis award supports computational and theoretical research and education activities to advance our understanding of and capabilities to compute materials properties. Accurate and predictive calculations in quantum systems composed of many particles are a grand challenge in science. In these systems the delicate balance of competing tendencies creates rich possibilities of new phases of matter and collective phenomena, which offer the potential for remarkable material properties of great technological importance. This very richness and complexity, however, also means that the usual tools for quantitative calculations will tend to break down. The combination of methodological developments and the advent of high performance computing present an unprecedented opportunity to make fundamental progress in this problem now. The research will build on recent advances in a quantum many-particle simulation approach to contribute a unique component for catalyzing this progress.This research aims to advance the study of materials with strong electron-electron interactions, establish accurate benchmark calculations, and enhance the capabilities of direct, many-particle parameter-free computations in condensed matter systems. The theoretical framework and techniques developed can also have cross-cutting impact in nuclear physics, ultracold atom physics, and quantum chemistry.The PI will continue to integrate research with education and outreach activities, by mentoring both undergraduate and graduate students in research, incorporating materials from this project into courses, reaching out to minority students, and fostering interdisciplinary collaboration in computational science education and research. In the larger scientific community, the PI will continue to play an active role in training students, post-docs, and senior researchers through schools and workshops, and develop software packages and tutorials for hands-on learning of new theoretical and computational approaches and the properties of strongly interacting electron systems.TECHNICAL SUMMARYThis award supports research and educational activities on the application and further development of the auxiliary-field quantum Monte Carlo and related methods for calculations in correlated electron systems. The long-term goal of this research program is the ability to perform many-body simulations to address questions on structural phase transitions, magnetic order, and superconductivity in a more accurate and predictive manner. Both materials-specific calculations on real materials and the study of simplified models will be conducted. New capabilities will be developed to extend the system sizes that can be treated, further improve accuracy, compute excited state and response properties, and treat spin-orbit coupling.The leading difficulty in computer simulations of interacting many-fermion systems is the sign or phase problem. The constrained path or phase-free auxiliary-field quantum Monte Carlo approach provides a general framework for both ab initio materials simulations (as an approach to go beyond standard density-functional calculations) and for calculations in lattice models of strongly correlated systems. Success in the development can be expected to impact beyond the specific systems being studied. The PI will continue to integrate research with education and outreach activities, by mentoring both undergraduate and graduate students in research, incorporating materials from this project into courses, reaching out to minority students, and fostering interdisciplinary collaboration in computational science education and research. In the larger scientific community, the PI will continue to play an active role in training students, post-docs, and senior researchers through schools and workshops, and develop software packages and tutorials for hands-on learning of new theoretical and computational approaches and the properties of strongly interacting electron systems.