All units

Level 1 · Geometry · Unit 3 of 4

Measuring casts a shadow

about 7 min · Free · No sign-in needed

Shine a light straight at each axis and the arrow casts a shadow on the 0-axis and on the 1-axis. A shadow's length is the amplitude; its square is the probability of that outcome. When you measure, you get one outcome, and the arrow jumps onto that axis.

  1. 1. Predict
  2. 2. Run
  3. 3. Rules
  4. 4. Redraw
  5. 5. Explain
  6. 6. Done

Prediction 1 of 2

Simulated

Predict first, then run it.

|0⟩|1⟩−|0⟩−|1⟩
60°
Measurement axes

Shadow on the 0 axis: 0.5 · Shadow on the 1 axis: 0.866

0: ??
1: ??
The arrow is at 60°. Its shadow on the 0-axis is 0.5 long. What is the probability of measuring 0?

Clears this unit's progress and drawing record on this device.