PauliBasisChange.construct_cnot_chain

PauliBasisChange.construct_cnot_chain(diag_pauli_op1, diag_pauli_op2)

Construct a CircuitOp (or PauliOp if equal to the identity) which takes the eigenvectors of diag_pauli_op1 to the eigenvectors of diag_pauli_op2, assuming both are diagonal (or performing this operation on their diagonalized Paulis implicitly if not). This works by the insight that the eigenvalue of a diagonal Pauli’s eigenvector is equal to or -1 if the parity is 1 and 1 if the parity is 0, or 1 - (2 * parity). Therefore, using CNOTs, we can write the parity of diag_pauli_op1’s significant bits onto some qubit, and then write out that parity onto diag_pauli_op2’s significant bits.

Parameters

• diag_pauli_op1 (PauliOp) – The origin PauliOp.

• diag_pauli_op2 (PauliOp) – The destination PauliOp.

Return type

PrimitiveOp

Returns

The PrimitiveOp performs the mapping.