  Using a generalized Langevin equation of motion, quantum ballistic thermal
transport is obtained from classical molecular dynamics. This is possible
because the heat baths are represented by random noises obeying quantum
Bose-Einstein statistics. The numerical method gives asymptotically exact
results in both the low-temperature ballistic transport regime and
high-temperature strongly nonlinear classical regime. The method can be thought
of as a semi-classical approximation to the quantum transport problem. A
one-dimensional quartic on-site model is used to demonstrate the crossover from
ballistic to diffusive thermal transport.
