CNOTgate
CNOTgate, short for controlled-NOT gate, is a two-qubit quantum gate used to entangle qubits and implement conditional operations. It uses one qubit as the control and a second as the target. The gate flips the state of the target qubit if and only if the control qubit is in the state |1⟩; if the control is in |0⟩, the target remains unchanged.
In the computational basis ordered as |00⟩, |01⟩, |10⟩, |11⟩, the CNOTgate is represented by the unitary
Its action on basis states is: |00⟩ → |00⟩, |01⟩ → |01⟩, |10⟩ → |11⟩, |11⟩ → |10⟩. For general
In circuit diagrams, the CNOTgate is depicted with a solid dot on the control wire and a
CNOTgate is a unitary and Hermitian operation that satisfies CNOTgate squared equals the identity. It is a