RealTransferSum

Base class: RealBaseSum

The TransferSum operator is parametrized by a sparse matrix $A(i,j)$ of size $L \times L$. Each entry $A(i,j)$ corresponds to the operator $A(i,j) f_i^\dagger f_j$. The TransferSum operator represents the sum $\sum_{i,j}A_{i,j}f_i^{\dagger}f_j$.