Three years ago, Google announced that it had achieved “quantum advantage,” meaning that it had achieved results on a quantum computer that would not have been possible with a classical supercomputer. However, since then, Google has been relatively quiet about its progress in the quantum computing space, with few updates on its achievements and ambitions. In contrast, many quantum start-ups have been announcing funding, executive appointments, new products, and technology innovations on a daily basis for the last two to three years.
Nevertheless, Google’s CEO Sundar Pichai announced this week that the company had achieved a major milestone in the field of error correction for quantum computers. For the first time, Google’s Quantum AI researchers have experimentally demonstrated that it’s possible to reduce errors by increasing the number of qubits. Qubits are the basic units of quantum information that can take on richer states beyond just 0 and 1. Google’s breakthrough represents a significant shift in how quantum computers operate.
Rather than working on the physical qubits on the quantum processor one by one, researchers are treating a group of them as one logical qubit. As a result, a logical qubit made from 49 physical qubits outperformed one made from 17 qubits. This is significant because the race to build viable quantum computers so far has largely been a race for more qubits to increase the potential computing power of quantum machines. However, the error rates of today’s quantum computers are not sufficient for the use cases that are developing for them.
Google’s latest contribution to the field of quantum error correction, outlined in Nature, is promising because it demonstrates the “scaling of logical qubits” that are needed to improve accuracy, in part by increasing the size of the quantum “surface code” used. Pichai explained that by encoding larger numbers of physical qubits on the quantum processor into one logical qubit, Google hopes to reduce the error rates to enable useful quantum algorithms.
Google’s latest breakthrough in quantum error correction is a significant milestone that could help bridge the gap between the current state of quantum computing and its potential. It demonstrates the potential for reducing errors in quantum computing by increasing the number of qubits and using a logical approach. While many other companies are also investing in quantum error correction, Google’s contribution is promising and could bring us closer to the development of useful quantum algorithms.