Google published an article in the prestigious scientific journal Nature which reveals the capabilities of its latest quantum chip called Willow. First of all, Google’s chip is equipped with an error correction system. Indeed, in the case of superconducting qubits, one of the biggest challenges is that they can lose their quantum properties due to interactions with the environment. Generally, the more qubits there are, the more errors there are. But in Willow’s case, the opposite seems to happen: “We tested increasingly larger arrays of physical qubits, going from a grid of 3×3 encoded qubits to a 5×5 grid, then to a 7×7 grid. At every step, thanks to our latest advances in quantum error correction, we have managed to reduce the error rate by half”announced Hartmut Neven, director of Google Quantum AI.
Another major advance: calculation speed. Google researchers used the testbed called random circuit sampling (RCS) to measure Willow’s performance. As a result, the chip, with 105 qubits, was able to carry out the calculation in less than five minutes, where current supercomputers would take 10 septillion (1025) years, more than the age of the universe. Now, the next step for Google is to demonstrate Willow’s performance for real-world applications.
