Quantum gates are the quantum analog of classical logic gates. They operate on qubits through unitary transformations.

The Hadamard Gate (H)

The Hadamard gate creates superposition: H|0⟩ = (|0⟩ + |1⟩)/√2. Applying H to |0⟩ puts the qubit into an equal superposition of both states.

Pauli Gates

The Pauli-X gate is the quantum NOT gate, flipping |0⟩ to |1⟩ and vice versa. Pauli-Y and Pauli-Z introduce phase changes.

CNOT Gate

The Controlled-NOT gate is a two-qubit gate that flips the target qubit only when the control qubit is |1⟩. CNOT is essential for creating entanglement.

Building Circuits

By composing these gates, we build quantum circuits that can perform meaningful computations.