Qniverse
QNIVERSE ARCADE
Rotate · Measure · Rally

QPong

CPU 0 first to 7 YOU 0

Pong with a qubit for a ball

Drag to move your paddle. When you hit the ball, where it strikes rotates its qubit — an off-center hit spins it into superposition.

At the center line the ball is measured and veers: |0⟩ → left, |1⟩ → right. A superposed ball forks unpredictably; a polarized one goes a known way.

Leave it superposed to fool your opponent — read the fork to defend. First to 7.

Touch: drag your half of the screen · Keys: P1 A / D, P2 ← →

Tap or press Space to serve
How it works
The dial (top-left) is the ball's qubit on a Bloch circle: |0⟩ at top, |1⟩ at bottom, sideways = superposition. The ball's color shows the same thing, and P(→) is its live chance of veering right.

Your paddle is a rotation gate. Hit dead-center and the qubit is unchanged; hit off-center and you spin it — a roughly half-paddle hit lands it sideways (a 50/50). Edge hits flip it.

Each time the ball crosses the center line it's measured: it collapses to |0⟩ or |1⟩ on those odds and veers accordingly, then travels as a definite state to the far paddle. So you set the odds on offense; you react to the collapse on defense.