This project will address a central algorithmic problem in computational physics, namely, reliable calculations for strongly interacting quantum mechanical systems that obey fermion statistics. Some examples of such systems include high-temperature superconductors, heavy-fermion metals, and magnetic materials. The challenge lies in the correct and accurate treatment of microscopic correlations, which is essential to understanding the properties of these systems and their theoretical and technological implications. The project will be based on a recently developed algorithm for treating correlated many-fermion systems on a lattice, the Constrained Path Monte Carlo (CPMC) Method. It consists of three separate but closely related parts: (1) The Ground-State Properties of Prototypical Lattice models for Electron Correlation; (2) Finite Temperature; (3) Continuum Systems. All of this will be done in the context of scaleable parallel computing algorithms, a critical aspect of the problem of studying lattice models of great relevance to high-temperature superconductors and heavy-fermion materials. A new version of the CPMC algorithms will be developed for finite temperature calculations. This will enable studies of thermodynamically properties and true phase transitions. This project will also extend the algorithm to the continuum, which will enable more realistic calculations of materials.
