Function apply_sector_shift 

pub fn apply_sector_shift<Source, Target>(
    source: &Source,
    target: &Target,
    terms: &[OperatorSpec],
    input: &[Complex64],
    output: &mut [Complex64],
) -> Result<()>
where
    Source: Basis,
    Target: Basis<State = Source::State>,

Apply parsed terms directly between sectors without materializing a matrix.