Finite-temperature Calculations of Correlated Electron Systems ?

We describe a quantum Monte Carlo approach to study nite-temperature properties of correlated fermion systems. The algorithm retains advantages of the standard auxiliary-eld formalism, which is widely applied in areas spanning condensed-matter, high-energy, and nuclear physics, while eliminating the sign decay that is the signature of the fermion sign problem. It allows simulations at larger system sizes and lower temperatures. The sign decay is eliminated by imposition of an approximate boundary condition in auxiliary-eld space. We discuss the analytical origin of the boundary condition and illustrate its implementation by highlighting the similarities to a diiusion process with absorption.