Creative & games samples

Quon is a typed circuit language, but the concepts it teaches are also, at heart, fun: superposition is a fair coin, entanglement is a mind-reading trick, and interference draws patterns. The creative / games pack under samples/creative/ (issue #200) leans into that. Each sample is a small .qn circuit paired with a seeded Aer checker that doubles as the game referee — it runs the circuit many times and asserts the playable claim. No quantum-supremacy rhetoric: the point is that each concept is visible in statistics a beginner can run.

As with the application demos, the split is explicit: Quon prepares the state and measures; classical Python plays the game (distribution check, ASCII render).

The samples

Quantum dice — a fair 2ⁿ-sided die

A Hadamard on each of n qubits, placed in a single depth-1 parallel layer (for q in qubits(n) { H q }), measures to a uniformly random n-bit string — a face of a 2ⁿ-sided die. The randomness is genuine (the Born rule with equal amplitudes), not a pseudo-random seed. quantum_dice.qn

• quantum_dice.py, which asserts all 8 faces appear, each near 1/8 of the shots.

Concept: superposition + parallel composition + the Born rule. The many-qubit cousin of the single-qubit coin flip.

Entangled twins — predict Bob’s bits

Two Bell pairs with opposite correlations in one program: pair (q0, q1) is |Φ⁺⟩ — the bits always agree; pair (q2, q3) is |Ψ⁺⟩ — the bits always disagree. Alice holds q0 and q2 and announces Bob’s bits in full, correctly, every shot. The lesson: entanglement is not “the bits are the same” but “the bits are in a determined relation,” and whether that relation is same or opposite is set entirely by how the pair was prepared (an X on the CNOT target flips the correlation). entangled_twins.qn

• entangled_twins.py, which asserts b0==b1 and b2!=b3 on every shot.

Concept: entanglement, as a correlation locked in at preparation time.

Interference barcode — draw with phase

Each qubit gets H |> T |> H: a Hadamard makes |+⟩, the T gate adds a π/4 phase to |1⟩, and a second Hadamard interferes the paths back together. The phase is not 0 or π, so the paths no longer cancel symmetrically — P(0) ≈ 0.854, P(1) ≈ 0.146. Across three qubits the eight outcomes line up by Hamming weight into a descending fringe, which the checker renders as an ASCII barcode: a pattern drawn by phase, not by a lookup table. interference_barcode.qn

• interference_barcode.py, which renders the histogram and asserts it is monotone in Hamming weight.

Concept: interference — superposition alone is flat (the dice); a phase between the branches makes the randomness structured.

Reproducing

Build the compiler, then run any referee:

cargo build --release -p quonc
QUONC=target/release/quonc python test/verify/quantum_dice.py
QUONC=target/release/quonc python test/verify/entangled_twins.py
QUONC=target/release/quonc python test/verify/interference_barcode.py

Every ci: smoke catalog entry is also compiled with quonc in CI (the samples_catalog test); the Aer referees above are seeded for reproducibility.