# qiskit.quantum_info.state_fidelity¶

state_fidelity(state1, state2, validate=True)[fuente]

Return the state fidelity between two quantum states.

The state fidelity $$F$$ for density matrix input states $$\rho_1, \rho_2$$ is given by

$F(\rho_1, \rho_2) = Tr[\sqrt{\sqrt{\rho_1}\rho_2\sqrt{\rho_1}}]^2.$

If one of the states is a pure state this simplifies to $$F(\rho_1, \rho_2) = \langle\psi_1|\rho_2|\psi_1\rangle$$, where $$\rho_1 = |\psi_1\rangle\!\langle\psi_1|$$.

Parámetros
Devuelve

The state fidelity $$F(\rho_1, \rho_2)$$.

Tipo del valor devuelto

float

Muestra

QiskitError – if validate=True and the inputs are invalid quantum states.