1
$\begingroup$

I was going through the qiskit textbook and in this chapter, i came across a statement under the topic "Kickback with the T-gate" related to the Controlled-Z gate that "the controlled-Z rotation gates are symmetrical in fashion (two controls instead of a control and a target). There is no clear control or target qubit for all cases." What does it imply exactly?

enter image description here

$\endgroup$
  • $\begingroup$ A releted answer. $\endgroup$ – Davit Khachatryan Aug 31 at 17:39
  • 2
    $\begingroup$ CZ(control=i,target=j)=CZ(control=j,target=i)...maybe a bit surprising at first...so you can pick either bit for control/target $\endgroup$ – unknown Aug 31 at 17:50
0
$\begingroup$

For the mathematical explanation, check here: Why is the action of controlled-Z unaltered by exchanging target control qubits?

Maybe it would help you to see CZ in a different (symmetric) notation, like its current representation in Qiskit:

from qiskit import *
circuit = QuantumCircuit(2)
circuit.cz(0,1)
circuit.draw('mpl')

a CZ gate represented as a symmetric gate

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.