|q⟩
Bad Qubits
Play
Quest
Questions
Learn
Playground
☕
← Question Bank
Multiple choice
A single bit is protected by the 3-bit repetition code (
0
→
000
0 \to 000
0
→
000
,
1
→
111
1 \to 111
1
→
111
) and decoded by majority vote; each bit flips independently with probability
p
p
p
. What is the probability of a logical (majority) error?
🔬 try it before you answer
3
p
2
−
2
p
3
3p^2 - 2p^3
3
p
2
−
2
p
3
3
p
−
2
p
2
3p - 2p^2
3
p
−
2
p
2
p
p
p
, unchanged from a single unprotected bit
p
3
p^3
p
3
Check answer