Gates & Interference

Amplitudes that cancel

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Gates transform amplitudes; H creates and undoes superpositions.
• $HH =$ identity: amplitudes interfere.
• Quantum algorithms arrange for wrong answers to cancel.

Steps

1. Quantum gates
2. Hadamard twice
3. Where did the randomness go?
4. Sandwich a gate
5. Phases that matter
6. Three Hadamards