Self-consistent mode-coupling theory for self-diffusion in quantum liquids.

A closed, self-consistent equation for the velocity autocorrelation function of a quantum liquid within the framework of a quantum mode-coupling theory is derived. The solution of the quantum generalized Langevin equation requires static input which is generated by an appropriate path-integral Monte Carlo scheme. In order to assess the accuracy of our approach we have studied the self-diffusion process of liquid para-hydrogen at two thermodynamic state points. Quantitative agreement for the self-diffusion constant is obtained in comparison to experimental measurements and other theoretical predictions.