The Interesting Phenomenon Of Phase Kickback

A lesson on a secret quantum trick that powers everything from Shor’s Algorithm to Quantum Machine Learning.

Image generated with Google ImageFX

We learned about the CNOT gate a few weeks ago.

If you missed this lesson, the following link would help you understand the CNOT gate from the basics.

An Easy-To-Follow Introduction To The CNOT Gate

The CNOT gate, also known as the Controlled-NOT gate, is a two-qubit gate.

It receives two inputs and gives out two outputs.

The first input is called the Control qubit, and the second one is called the Target qubit.

The CNOT gate flips the state of the target qubit only if the control qubit is in the state |1>. Otherwise, it does nothing to the target.

In other words, it acts as a NOT gate or Pauli X-gate when the control qubit is |1>.