Computation of the viscosity of liquid helium by the path integral molecular dynamics

Abstract

We simulate the cryogenic liquid helium to observe superfluid by the path integral molecular dynamics, which maps the quantum systems into the classical molecular dynamics. This method gives correspondence between the quantum systems and the classical systems, thus the classical simulation methods are applicable to a simulation of liquid helium. A uniform source-and-sink scheme is a method to compute the viscosity of classical fluids by momentum exchange of particles. By introducing the two-fluid model which reasonably describes the superfluid, this method is applicable to the viscosity calculation of the superfluid helium. The results show that the viscosity decreases below about 2K.