ffsim.s_minus_operator¶
- ffsim.s_minus_operator(norb)[source]¶
Spin lowering operator.
The spin lowering operator is defined as
\[S_- = \sum_{i=0}^{N-1} a^\dagger_{i\beta} a_{i\alpha}\]where \(N\) is the number of spatial orbitals.
- Parameters:
norb (
int) – The number of spatial orbitals.- Return type:
- Returns:
The spin lowering operator.