A method for calculating the electronic structure of many-electron systems in quantum mechanics in which there is strong correlation between the electrons. Examples of such systems include solids in which there are atoms with unfilled subshells of d and f electrons. Such a system cannot be described by approximation techniques, in which electrons are described as independent particles, or by Hartree–Fock theory, in which the interaction between one electron and all the other electrons is described by a static, averaged-out mean field theory. In dynamical mean field theory a quantum-mechanical lattice problem is mapped onto a single-site problem, with the mean field theory being generalized to incorporate time-dependent dynamical processes. Dynamical mean field theory has been used with great success in describing the Mott transition.