Gate order matters
Apply H and Z in opposite orders and reveal the difference in the X basis.
Back to learning pathPhase, bases, and gate orderWhy this experiment matters
What you will do
See that quantum gates are operations whose order can change the final state.
- 01
Prepare the qubit in |0⟩.
- 02
Choose H → Z or Z → H.
- 03
Measure in the X basis and compare + and −.
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.
Choose one answer to unlock the measurement.
Predict before you measureMake a prediction, then run the measurement to reveal the expected and sampled results.
Measurement results
What the result shows
H → Z produces |−⟩, while Z → H produces |+⟩. Both look 50/50 in the Z basis, but an X-basis measurement distinguishes them.
GUIDED VIDEO
Watch the experiment
Follow the experiment with English narration and English subtitles.
See that quantum gates are operations whose order can change the final state.
Full transcript5 · 1:00
- 01Overview
See that quantum gates are operations whose order can change the final state.
- 02Experiment steps 1
Prepare the qubit in |0⟩.
- 03Experiment steps 2
Choose H → Z or Z → H.
- 04Experiment steps 3
Measure in the X basis and compare + and −.
- 05What to observe
H → Z produces |−⟩, while Z → H produces |+⟩. Both look 50/50 in the Z basis, but an X-basis measurement distinguishes them.
06 · CHECK
Check what you learned
Make a prediction, then run the measurement to reveal the expected and sampled results.