Function purity
Source pub fn purity(state: &QuantumState) -> Result<f64, QuantumInfoError>
Expand description
Calculate the purity of a quantum state.
Purity = Tr[ρ²]
For pure states: Purity = 1
For maximally mixed states: Purity = 1/d
§Arguments
state - Quantum state (state vector or density matrix)
§Returns
The purity ∈ [1/d, 1]