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Level 2 · Complex numbers & multiple qubits · Unit 2 of 2

More qubits, more slots

about 8 min · Free · No sign-in needed

One qubit has two slots for amplitudes, 0 and 1. Two qubits do not have 2 + 2 slots but 2 × 2 = 4: 00, 01, 10 and 11. If each qubit has its own arrow, each slot's amplitude is the product of the two matching amplitudes. But some four-slot states cannot be written that way at all. They are called entangled.

  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.

Amplitude in each slot

|00⟩1
|01⟩0
|10⟩0
|11⟩0

|00⟩ → H on the first qubit → CNOT (first controls second)

?

Start at 00. Apply H to the first qubit, then CNOT (flip the second qubit when the first is 1). Can the result be split into 'first qubit's arrow' times 'second qubit's arrow'?

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