From the course: Quantum Computing Fundamentals

Unlock the full course today

Join today to access over 24,700 courses taught by industry experts.

Toffoli gate

Toffoli gate

From the course: Quantum Computing Fundamentals

Start my 1-month free trial Buy for my team

Toffoli gate

“

- Now that we've learned about the controlled NOT gate which conditionally flips the state of a target qubit based on a single control bit, let's extend that concept from two qubits to three qubits with the controlled controlled NOT gate, also known as the Toffoli gate. The Toffoli gate uses two qubits as controls which are indicated on its circuit diagram with small dots. If and only if both of those control qubits are 1 the Toffoli gate will apply a POLYX operation to flip the state of the third target qubit, which is indicated with the circle and plus symbol. You'll often see this gate abbreviated as CCNOT or as CCX which stands for controlled controlled-X gate. If these two beach balls that I'm holding represent the control qubits- - And I'm holding the target qubit- - Then if my qubits are in any state other than 1-1, that could be 0-0, 0-1, or 1-0- - Then I don't do anything. - But if both control qubits are in the 1-1…

Contents