ffsim.s_x_operator¶
- ffsim.s_x_operator(norb)[source]¶
Spin X operator.
The spin X operator is defined as
\[S_x = \frac{1}{2}(S_+ + S_-) = \frac{1}{2} \sum_{i=0}^{N-1} \left( a^\dagger_{i\alpha} a_{i\beta} + a^\dagger_{i\beta} a_{i\alpha} \right)\]where \(N\) is the number of spatial orbitals.
- Parameters:
norb (
int) – The number of spatial orbitals.- Return type:
- Returns:
The spin X operator.