How Do We Mark the Good Stuff?

The Oracle Of Grover's Algorithm

The goal of amplitude amplification is to increase the probability of favorable solutions. However, before we can do that, we first need to mark the corresponding quantum state. That is the job of the oracle.

Most tutorials on quantum computing do not devote much time and energy to the oracle. As a result, it remains shrouded in mystery. Perhaps that is why it got its name in the first place.

But there is really nothing mystical about the oracle. It is a technical artifact that we have to deal with in many quantum algorithms. Therefore, it is important to really understand what it is supposed to do and how it does it.

So, here is the comprehensive explanation of the quantum oracle.