Abstract:
In the first part of the talk I will introduce the so-called fixed-node diffusion Monte Carlo method (DMC) --- a stochastic technique for calculation of (mainly) ground-state properties of interacting fermionic systems. Basic principles and features of the method will be discussed with emphasis on application to realistic electronic structure of solids. In this area, the DMC is quite different from alternative approaches in that it builds on explicit knowledge of correlated many-body wave function, which other methods designed to deal with systems containing large number of interacting particles usually avoid as much as possible.

The second part of the presentation will be devoted to study of equation of state of crystalline FeO and to investigation of structural phase transition that was experimentally observed in this material at elevated pressure, approximately in the range of 70--90 GPa. Besides the actual physics, this application demonstrates consistency and robustness of the quantum Monte Carlo as applied to solids with strongly correlated electrons.