Circuit Lab

Three qubits, six steps, four gates. Place gates on the wires and the bars show the chance of each measurement result. The circuit is saved in the address, so you can share it.

Examples

Choose a gate, then a slot on a wire. Choose a filled slot again to remove it.

q₀ |0⟩

q₁ |0⟩

q₂ |0⟩

Measurement probabilities

|ψ⟩ ≈ 0.71|000⟩ + 0.71|110⟩

|000⟩50.0%
|001⟩0.0%
|010⟩0.0%
|011⟩0.0%
|100⟩0.0%
|101⟩0.0%
|110⟩50.0%
|111⟩0.0%

How to read it

All qubits start in |0⟩. Time runs from left to right.
|011⟩ means q₀ reads 0, q₁ reads 1 and q₂ reads 1.
Try Bell pair: only |000⟩ and |110⟩ appear — the first two qubits always agree. That agreement is entanglement.
Try Interference: H, Z, H on one qubit sends it to |1⟩ with certainty. Phases you cannot see in the bars still change the result.

The simulator runs in your browser and is exact for three qubits. Real hardware adds noise — that is what our error-correction work is about.