gftool.siam.gf0_loc_ret_t

gftool.siam.gf0_loc_ret_t(tt, e_onsite, e_bath, hopping)

Noninteracting retarded local Green’s function for the impurity.

Parameters:

tt : (…) float np.ndarray

Time variable. Note that the retarded Green’s function is 0 for tt<0.

e_onsite : (…) float np.ndarray

On-site energy of the impurity site.

e_bath : (…, Nb) float np.ndarray

On-site energy of the bath sites.

hopping : (…, Nb) complex np.ndarray

Hopping matrix element between impurity and the bath sites.

Returns:

gf0_loc_ret_t : (…) complex np.ndarray

Retarded Green’s function of the impurity site.