ffsim.s_y_operator

ffsim.s_y_operator(norb)[source]

Spin Y operator.

The spin Y operator is defined as

\[S_y = \frac{1}{2i}(S_+ - S_-) = \frac{1}{2i} \sum_{i=0}^{N-1} \left( a^\dagger_{i\alpha} a_{i\beta} - a^\dagger_{i\beta} a_{i\alpha} \right)\]

where \(N\) is the number of spatial orbitals.

Parameters:

norb (int) – The number of spatial orbitals.

Return type:

FermionOperator

Returns:

The spin Y operator.