Impurity observbales

The ed_observables provides a single interface to all the different observables and static correlation calculation procedures available in the code. This is used in the ed_main Fortran API.

• Impurity observables interface

Normal mode

This set of modules implements the evaluation of impurity observables and other static correlations 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.

• Observables

Superconductive mode

This set of modules implements the evaluation of impurity observables and other static correlations assuming \(\vec{Q}\equiv S_z=N_\uparrow-N_\downarrow\).

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

• Observables

Non-SU(2) mode

This set of modules implements the evaluation of impurity observables and other static correlations 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.

• Observables