View source for Category:Constrained-random-phase approximation

The '''constrained random-phase approximation''' (CRPA) is a method that allows the calculation of the effective interaction parameter <math>U</math>, <math>J</math>, and <math>J'</math> for model Hamiltonians. 
The main idea is to neglect the screening effects of specific target states in the screened Coulomb interaction <math>W</math> of the [[The GW approximation of Hedin's equations|GW method]]. 
The resulting partially screened Coulomb interaction is evaluated in a [[Wannier functions|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]]

[[Category:VASP|ACFDT]][[Category:Many-body perturbation theory]]