|q⟩
Bad Qubits
Play
Quest
Questions
Learn
Playground
☕
← Question Bank
Multiple choice
A qubit in state
α
∣
0
⟩
+
β
∣
1
⟩
\alpha|0\rangle + \beta|1\rangle
α
∣0
⟩
+
β
∣1
⟩
is measured in the computational basis and yields outcome 0. Per this lesson, what is the qubit's state immediately afterward?
🔬 try it before you answer
Still
α
∣
0
⟩
+
β
∣
1
⟩
\alpha|0\rangle + \beta|1\rangle
α
∣0
⟩
+
β
∣1
⟩
, unchanged by the measurement
∣
0
⟩
|0\rangle
∣0
⟩
, with the original amplitudes
α
\alpha
α
and
β
\beta
β
gone
The maximally mixed state
I
/
2
I/2
I
/2
∣
1
⟩
|1\rangle
∣1
⟩
, the opposite of the observed outcome
Check answer