Google shows a larger error-correcting code can make fewer errors

Why it matters

Error correction only helps if adding qubits to a code lowers the error rate; this experiment showed that trend on real hardware, although the improvement was small.

Related

• Google's Willow chip shows errors can shrink as qubits grow (Dec 9, 2024)

Sources (3)

• Nature Suppressing quantum errors by scaling a surface code logical qubit
  Primary sourceFeb 22, 2023

  “We find that our distance-5 surface code logical qubit modestly outperforms an ensemble of distance-3 logical qubits on average, in terms of both logical error probability over 25 cycles and logical error per cycle”

• Google Research Blog Suppressing quantum errors by scaling a surface code logical qubit
  Primary sourceFeb 22, 2023

  “To that end, we use a particular error-correcting code called a surface code and show for the first time that increasing the size of the code decreases the error rate of the logical qubit. A first-ever for any quantum computing platform, this was achieved by painstakingly mitigating many error sources as we scaled from 17 to 49 physical qubits.”

• The Register Google claims milestone in quantum error correction
  Independent coverageFeb 22, 2023

  “A team at Google Quantum AI said it has demonstrated that a method of quantum error correction called surface codes can exhibit lower error rates as larger surface codes are employed.”