Finite-Temperature Constrained Path Monte Carlo for Bose-Fermi Mixtures

Brenda Rubenstein, Columbia University

Rapid progress in the study of ultracold atomic gases has paved the way toward experimentally simulating many solid-state systems. Past success simulating the superfluid-Mott insulator transition in bose gases and Fermi pressure in fermi gases has stimulated interest in Bose-Fermi mixtures. Analytical work suggests that Bose-Fermi mixtures may possess a rich phase diagram, yet current computational techniques have only permitted the simulation of one-dimensional systems. In this work, we outline how mixed Bose-Fermi systems may be studied free of the sign and phase problems within the framework of the finite-temperature Constrained Path Monte Carlo method. One of our key results is the derivation of a single-particle bosonic Green’s function that permits simulation of bosonic systems in any dimension, at any physical value of the temperature and chemical potential. We demonstrate the utility of our method by characterizing the density and momentum distributions of "bose-fermi" molecules in key regions of the Bose-Fermi Hubbard Model phase diagram. Our method may also be applied to the study of electron-phonon coupling and high-temperature superconductivity.

Abstract Author(s): Brenda M. Rubenstein and David R. Reichman(Columbia University)Shiwei Zhang(The College of William and Mary)