qiskit.quantum_info.Statevector.expectation_value¶ Statevector.expectation_value(oper, qargs=None)[ソース]¶ Compute the expectation value of an operator. パラメータ oper (Operator) – an operator to evaluate expval of. qargs (None or list) – subsystems to apply operator on. 戻り値 the expectation value. 戻り値の型 complex