Years 7–10 · Week 10 of 12
Quantum Teleportation
Learning goals
By the end, you can…
- Identify the unknown state, shared entangled pair and two classical bits in teleportation.
- Sequence the circuit's entanglement, gates, measurement and correction steps.
- Explain why classical communication is required.
- Explain why teleportation does not leave an independent perfect copy of the input state.
What you already know
Connect to a familiar idea
Entanglement creates joint correlations but cannot send a controllable message by itself. Teleportation combines a previously shared entangled pair with a local joint operation and two ordinary classical bits.
- H and CNOT can create entanglement.
- Measurement produces classical outcomes.
- X and Z are single-qubit correction gates.
Opening story
Start with something familiar
A laboratory wants a distant qubit to take on the state of an input qubit without physically sending that input carrier. One entangled pair was distributed earlier. A local measurement yields two bits; only after those bits arrive can the distant laboratory apply the correct operation.
Plain-English explanation
Build the idea carefully
Resources and circuit steps
Quantum teleportation transfers the quantum state of an input qubit to a distant qubit; it does not transport the input particle, a person or an object. The protocol consumes a previously shared entangled pair and requires a local CNOT, H, two measurements, two classical bits and a conditional correction.
What is—and is not—transferred
The two measurement results determine whether the receiver applies I, X, Z or both X and Z to recover the input state in the ideal protocol. The receiver cannot complete the recovery until the classical bits arrive, so teleportation cannot communicate faster than light. The sender's measurement changes the original joint state; the unknown input is not retained as an independent perfect copy, consistent with the no-cloning principle.
Try the model
Step-by-step teleportation animator
Choose an input preset, then play, pause or step through entanglement, local gates, measurement, classical-bit transfer and correction.
Qubit 0 is the least-significant state-vector bit. Displayed basis labels read q(n−1)…q0.
Ready. Adjust a control, then run the model.
What this model shows: An ideal circuit animation; wire spacing represents logical roles, not geographic scale.
Text alternative for this interactive
Teleportation step list Use previous and next buttons to read the state of each resource, the two measured bits and the required correction in a table.
Expected observation: Before the two classical bits arrive, the receiver does not have an independently usable copy of the input; the appropriate X/Z correction restores the state in the ideal model.
Guided activity
Correction lookup table
- Run one input preset and pause immediately after measurement.
- Record the two classical bits and the receiver's pre-correction state.
- Use the supplied table to select I, X, Z or XZ.
- Repeat until all four bit pairs have been examined.
Evidence to collect: A four-row measurement-to-correction table showing that classical bits select the operation needed to recover the input state.
Glossary
Words to know
- quantum teleportation
- A protocol transferring a quantum state using entanglement and classical communication.
- shared entanglement
- An entangled resource distributed between sender and receiver before the protocol.
- classical bit
- A two-state classical message symbol, 0 or 1.
- conditional correction
- An operation selected according to measurement results.
- no-cloning
- The principle that an arbitrary unknown quantum state cannot be perfectly copied.
- sender
- The station holding the input state and one half of the entangled pair.
- receiver
- The station whose qubit acquires the input state after correction.
Short recap
Keep these ideas
- Teleportation transfers a qubit state, not matter or a person.
- The protocol consumes shared entanglement and requires two classical bits.
- The original is not left as a perfect independent copy, and no faster-than-light communication occurs.
Knowledge check
6 clear questions
Choose an answer for immediate feedback. You may retry, and your best submitted score is kept.
Go Further Optional extension for Years 9–10
For Years 9–10, trace the four possible measurement branches for an input α|0⟩ + β|1⟩ symbolically. Focus on which X/Z correction is required rather than expanding every tensor product.
Try this
Match each branch's receiver state to I, X, Z or XZ, then explain why the same lookup works for every valid α and β.
Adult support Teacher and parent notes
Discuss
- Ask students to point to the physical carrier, state information and classical messages separately.
- Avoid science-fiction imagery that implies matter transmission.
Answer guidance
Complete explanations name shared entanglement, two measured bits, conditional correction, no cloning and the classical communication delay.
Offline activity
Use three labelled wire strips and correction cards to sequence the protocol; state explicitly that the cards are a circuit map, not a classical simulation of an unknown state.
Safety
No special hazards; do not present the activity as real quantum communication hardware.
Sources and further reading
Checked references for this lesson
These sources support the lesson’s main scientific claims. Links open on the source organisation’s site.
- Basics of Quantum Information IBM Quantum Learning · official course · checked 2026-08-02
- Entanglement and correlations Microsoft Learn · official documentation · checked 2026-08-02
- Quantum Computation and Quantum Information Cambridge University Press · textbook publisher page · checked 2026-08-02
Content review: Reviewed on 2026-08-02.