Category:Constrained-random-phase approximation

The constrained random-phase approximation (cRPA) is a method that allows the calculation of the effective interaction parameter [math]\displaystyle{ U }[/math], [math]\displaystyle{ J }[/math], and [math]\displaystyle{ J' }[/math] for model Hamiltonians. The main idea is to neglect the screening effects of specific target states in the screened Coulomb interaction [math]\displaystyle{ W }[/math] 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