Quantum Computing · Instrument 06 · Teleportation

Teleportation — move a qubit without moving it

You can't copy an unknown quantum state (no-cloning), and you can't read it without destroying it. Yet a shared entangled pair plus two ordinary classical bits can transfer it perfectly from Alice to Bob — the original vanishing as the copy appears. Step through it and watch the state leave one sphere and land on the other.

The journey — Alice's qubit becomes Bob's

Alice · sender

●╌╌╌●

shared Bell pair
(entanglement)

↓

2 classical bits
(not yet sent)

→

Bob · receiver

Did it arrive?

—

fidelity of Bob's qubit vs. Alice's original

What just happened — and what didn't

No cloningAlice's qubit is consumed: measuring it collapses it to a random bit. The state was moved, not copied — it only ever exists in one place.
No faster-than-lightUntil Alice's 2 classical bits reach Bob, his qubit is maximally mixed — pure noise. The bits travel no faster than light, so neither does the information.
Entanglement is fuelThe shared pair is used up: one entangled pair + two classical bits buys one teleported qubit. Teleport again, share a fresh pair.