Google reports milestone in reducing quantum computing errors

A team of physicists at Google’s Santa Barbara laboratory in California, USA have published a research paper in whicy they demonstrate that using more qubits can lower error rate of quantum calculations. The researchers have shown that they can lower the error rate of calculations by making the quantum code bigger.

Over the years, theoreticians have developed ‘quantum error correction’ schemes that rely on encoding a qubit of information in a collection of physical qubits rather than in a single one. Some of these physical qubits can then be used by the machine to check on the health of the logical qubit and correct any errors. Thus, the more physical qubits there are, the better they can supress an erros. But more physical qubits also mean more chances that two of them can be affected by an error at the same time. This is the issue that Google researchers have worked on addressing, by performing two versions of a quantum error-correction procedure. One, using 17 qubits, was able to recover from one error at a time. The second version used 49 qubits and could recover from two simultaneous errors, also showing a slightly better performance than the smaller version could achieve.