Smin

The $S^-$ operator is defined as: $$\begin{equation} S^- = \sum_{\tau} a^{\dagger}_{\tau\downarrow}a^{\phantom{\dagger}}_{\tau\uparrow}. \end{equation}$$ The equivalent operator in Quanty is created by:

Example.Quanty

OppSmin = NewOperator("Smin", NF, IndexUp, IndexDn)