On December 10, Google made a groundbreaking announcement, unveiling its latest quantum chip, Willow, which features 105 physical qubits and delivers state-of-the-art performance across multiple metrics. Willow also marks two significant achievements in the field of quantum computing:
1. Breakthrough in Error Reduction: Willow’s innovation drastically reduces errors while scaling up the number of qubits, solving the quantum error correction challenge that has been a topic of research for nearly 30 years.
2. Unprecedented Speed: Willow completed a standard benchmark calculation in less than five minutes—something that the world’s fastest supercomputers would take 10^25 (10 quadrillion quadrillion) years to accomplish, a period far exceeding the age of the universe itself.
One of the biggest challenges in quantum computing has been dealing with errors, as qubits are prone to rapid interaction with their environment, making it difficult to preserve the information needed for computations. Typically, the more qubits used in a quantum system, the more errors occur, causing the system to behave like a classical system.
However, Google's experiments have shown that with the correct error-correction techniques, quantum computers can perform computations with increasingly higher accuracy as they scale, surpassing a critical threshold. According to research published by Google in Nature, the more qubits used in Willow, the fewer errors occur, leading to a more "quantum" system.
Google tested progressively larger arrays of physical qubits, starting from a 3x3 grid of encoded qubits, moving to a 5x5 grid, and finally a 7x7 grid. With the latest advancements in quantum error correction, each step halved the error rate, demonstrating an exponential reduction in errors.
Willow represents a monumental step forward, not only solving long-standing challenges in quantum computing but also pushing the boundaries of what is possible in the field.
