pub fn raw_quantum_fluctuation(
operator: &(impl LinearOperator + ?Sized),
state: &[Complex64],
) -> Result<Complex64>Expand description
Raw pure-state fluctuation
⟨ψ|A²|ψ⟩ - ⟨ψ|A|ψ⟩² without normalizing ψ.
This preserves array-oriented compatibility semantics, including the zero
vector, while quantum_fluctuation remains the strict normalized-state
variance API.