Controlled-NOT Operator

The CNOT (Controlled-NOT) operator is a two-qubit quantum gate that flips the **target qubit** (applies an X gate) only if the **control qubit** is in the state (|1⟩). In matrix form, it leaves (|00⟩) and (|01⟩) unchanged, but swaps (|10⟩) and (|11⟩). It’s essential for creating entanglement between qubits.