Google’s quantum department has announced that it has found a way to significantly reduce the number of errors made by quantum computers.
Quantum computing is valuable for its ability to perform calculations that traditional computers cannot usually do, and this leads to incredibly powerful machines. However, the high error rate, which makes many calculations unreliable, hinders serious use in this field.
Google says the error rate of quantum bits in its new third-generation Sycamore processor is typically between 1 in 10,000 and 1 in 100.
According to Hartmut Neven, Vice President of Engineering and Julian Kelly, Director of Quantum Hardware, quantum circuits need ratios of 1 in 10,000,000,000 to 1 in 10,000,000 to solve industrially relevant problems. So we are still far from these ratios.
The blog post explains: “Under the right conditions, the more physical qubits used to construct a logical qubit, the better the logical qubit becomes.” This is only true if the benefits of quantum error correction outweigh the additional errors from each additional physical qubit.
The Google Quantum Artificial Intelligence Team has achieved a first for any quantum computing platform and has produced an error-correcting code called surface code. The process involves repetition to eliminate errors that occur, such as inverted bits, in a method the researchers describe as majority vote.
This is just one part of the company’s six-step method that will eventually result in error-corrected quantum computing. The company has recently entered the second phase of its roadmap to produce a logical qubit prototype and hopes to make a long-lasting logical qubit beyond 2025.
Despite what the company sees as a major breakthrough, we are probably a few years (or even decades) away from error-free quantum computing, and it’s clear that we have a long journey ahead of us.