triqs.gfs.semicirc.g_semicirc_w

triqs.gfs.semicirc.g_semicirc_w(w, D)

Retarded semi-circular Green’s function on the real-frequency axis.

\[\begin{split}G^R(\omega) = \frac{2}{D^2} \begin{cases} \omega - i\sqrt{D^2 - \omega^2}, & |\omega| < D \\ \omega - \mathrm{sign}(\omega)\sqrt{\omega^2 - D^2}, & |\omega| \ge D \end{cases}\end{split}\]

Parameters:

wfloat or array_like

Real frequencies.

Dfloat

Half-bandwidth.

Returns:

Gcomplex or ndarray

Value of the retarded Green’s function at the supplied frequencies.