Impurity Green's functions

The ED_GREENS_FUNCTIONS wraps the different Green's functions calculation methods available in the code in a single procedure. This is used in the ED_MAIN Fortran API.

Normal mode

This set of modules implements the calculations of impurity dynamical response functions, e.g. the Green's functions and different susceptibilities, assuming \(\vec{Q}=\left[\vec{N}_\uparrow,\vec{N}_\downarrow \right]\). Where \(\vec{N}_\sigma=N_\sigma\) if the total number of electrons with spin \(\sigma\) is conserved (ed_total_ud = T ) or \(\vec{N}_\sigma=[ N_{1\sigma},\dots,N_{N_{orb}\sigma} ]\) if the number of electrons in the orbital \(\alpha=1,\dots,N_{orb}\) and spin \(\sigma\) is conserved (ed_total_ud = F).

This case corresponds to the normal phase in presence of spin conservation, possibly reduced to \(U(1)\) in presence of long range magnetic order along \(z\) quantization axis of the spin operator.

Superconductive mode

This set of modules implements the calculations of impurity dynamical response functions, e.g. the Green's functions, assuming \(\vec{Q}\equiv S_z=N_\uparrow-N_\downarrow\).

This case corresponds to the superconductive phase with \(s-\) wave pairing.

Non-SU(2) mode

This set of modules implements the calculations of impurity dynamical response functions, e.g. the Green's functions, assuming \(\vec{Q}\equiv N_{tot}=N_\uparrow+N_\downarrow\).

This case corresponds to the normal phase in the absence of spin conservation, as for instance in presence of Spin-Orbit coupling.