The quantum Monte Carlo method

Quantum Monte Carlo is an important and complementary alternative to density functional theory when performing computational electronic structure calculations in which high accuracy is required. The method has many attractive features for probing the electronic structure of real atoms, molecules and solids. In particular, it is a genuine many-body theory with a natural and explicit description of electron correlation which gives consistent, highly-accurate results while at the same time exhibiting favourable (cubic or better) scaling of computational cost with system size. This article is intended to provide a brief and hopefully accessible review of some relevant aspects of quantum Monte Carlo together with an outline of our implementation of it in the Cambridge computer code ‘CASINO’ [1, 2].