Category:Constrained-random-phase approximation

The constrained random-phase approximation (CRPA) is a method that allows the calculation of the effective interaction parameter ${\displaystyle U}$, ${\displaystyle J}$, and ${\displaystyle J'}$ for model Hamiltonians. The main idea is to neglect the screening effects of specific target states in the screened Coulomb interaction ${\displaystyle W}$ of the GW method. The resulting partially screened Coulomb interaction is evaluated in a localized basis that spans the target space and is described by the model Hamiltonian. The target space is usually low-dimensional and therefore allows for the application of a higher-level theory, such as dynamical-mean-field theory (DMFT).

More information about CRPA is found on the following page:

Constrained–random-phase–approximation_formalism