Home Tracks — overview Track 1 — Quantum Basics Track 2 — Mathematics for Quantum Quantum Lab — overview Circuit simulator (fullscreen) Simulators — overview Demos: superposition, interference, entanglement About — overview Approach & philosophy How we teach Support — overview Donate (payments) Other ways to help Start Track 1 — Free →
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Interactive

Not animations.
Real simulators.

These run in your browser — no install, no signup. Each one is embedded directly in the lesson it belongs to. Here they are in one place.

It really is both at once. Until you look.

Drag the slider. The qubit's state shifts continuously between |0⟩ and |1⟩. At θ = 90° you hit perfect superposition — genuinely 50/50, not a metaphor. The Born rule: probability is the square of the amplitude, which is why both bars always sum to exactly 100%.

Full superposition lesson →
P(|0⟩) = 1.000  ·  P(|1⟩) = 0.000

Right answers get louder. Wrong ones vanish.

Quantum algorithms don't brute-force search — they engineer wrong answers to cancel (destructive) while right answers amplify (constructive). Push the phase to 180°. The combined wave vanishes completely. This cancellation is the secret behind every quantum speedup ever discovered.

Full interference lesson →
Constructive · Phase =

Two qubits. One fate. No communication required.

Entangled qubits share a single quantum state that can't be described separately. Measure one — the other instantly "knows" its answer. Not by sending a signal. Just by existing as one correlated whole. Measure again. Always perfectly correlated.

Full entanglement lesson →
Press to collapse both qubits simultaneously
Coming in future tracks

A simulator in every lesson.

Every lesson in every track ships with an interactive simulator. Here's a taste of what's coming.

🔲
Quantum Gate Composer
Drag gates onto qubits. Watch the Bloch sphere update in real time. Build Bell pairs, GHZ states, and QFT circuits. Track 3.
🔍
Grover's Oracle
Watch amplitude amplification in action. Mark a target state and see it grow with each Grover iteration until measurement is certain. Track 4.
🔑
BB84 Key Exchange
Simulate the BB84 quantum key distribution protocol step by step. Intercept Eve and watch her footprint appear in the error rate. Track 6.
🛡️
Surface Code Visualiser
Inject errors, run syndrome measurements, and watch the decoder correct them. The engineering reality of fault-tolerant quantum computing. Track 7.