CNOT: from product state to Bell pair
Let CNOT turn a superposed control and a |0⟩ target into a correlated two-qubit state.
Back to learning pathMulti-qubit entanglementWhy this experiment matters
What you will do
Learn CNOT's conditional action and how it can create entanglement without copying an unknown qubit.
- 01
Prepare both qubits in |00⟩.
- 02
Rotate the control qubit with Rᵧ(θ), leaving the target in |0⟩.
- 03
Apply CNOT and measure fresh pairs in the Z basis.
04 · PREDICT
Predict before you measure
Choose one answer to unlock the measurement.
INTERACTIVE
Interactive model
Move the control, then run a measurement. This is a teaching simulation—not hardware output.
Make a prediction, then run the measurement to reveal the expected and sampled results.
Measurement results
What the result shows
At 0°, the output is |00⟩. At 90°, the ideal circuit prepares (|00⟩+|11⟩)/√2, so only 00 and 11 appear, about half each. Z results alone do not certify coherence.
GUIDED VIDEO
Watch the experiment
Follow the experiment with English narration and English subtitles.
Learn CNOT's conditional action and how it can create entanglement without copying an unknown qubit.
Full transcript5 · 1:00
- 01Overview
Learn CNOT's conditional action and how it can create entanglement without copying an unknown qubit.
- 02Experiment steps 1
Prepare both qubits in |00⟩.
- 03Experiment steps 2
Rotate the control qubit with Rᵧ(θ), leaving the target in |0⟩.
- 04Experiment steps 3
Apply CNOT and measure fresh pairs in the Z basis.
- 05What to observe
At 0°, the output is |00⟩. At 90°, the ideal circuit prepares (|00⟩+|11⟩)/√2, so only 00 and 11 appear, about half each. Z results alone do not certify coherence.
06 · CHECK
Check what you learned
Make a prediction, then run the measurement to reveal the expected and sampled results.