Path integral simulations of quantized conductance in nanowires

Theoretical studies of spin and charge transport in nanostructure often include interactions perturbatively or at a mean-field level. In some cases it is desirable to have a fully quantum many-body method to describe the interacting system: such is the case when investigating spin ordering near the ``0.7-structure'' in quantum point contacts or for simulating systems with strong polaronic effects. We have developed a new path-integral quantum Monte Carlo (QMC) approach to transport. Previous QMC simulations have been valued for accurately treating electronic correlation in quantum dot spectroscopy---this work now opens up many new opportunities for simulating quantum transport. We show simulation data demonstrating how current-current correlation functions in the Kubo formalism lead to quantization of conductance in GaAs nanowires. This new, finite-temperature, many-body computation technique should have many uses in the study of quantum wires and molecular electronics.