Willow: Google’s 105-Qubit Quantum Breakthrough

Google has unveiled its quantum chip, Willow—a device designed to significantly reduce computational errors and advance the development of next-generation quantum computers with quantum error correction capabilities.

During trials, Willow executed a Random Circuit Sampling (RCS) test in just five minutes. By comparison, a modern supercomputer would require a septillion years to complete the same task.

RCS is a test that evaluates a quantum computer’s ability to handle problems involving random quantum circuit processing. These circuits are specifically designed to simulate intricate processes that are nearly impossible to calculate accurately on classical computers due to the sheer volume of variations and interconnections. The essence of the test lies in the quantum computer’s ability to replicate a specified set of outcomes aligned with the mathematical probabilities embedded in the circuit.

The chip boasts 105 qubits—the quantum counterparts of bits used in classical computing. Unlike bits, qubits can exist in a state of “0” and “1” simultaneously, thanks to the phenomenon of superposition.

The research was conducted at Google’s quantum technology laboratory in Santa Barbara, purpose-built for such advancements. One of Willow’s standout features is its qubits’ ability to maintain an excited state (“1”) for nearly 100 microseconds—five times longer than previous Google chip models.

Despite these groundbreaking capabilities, the developers emphasize that Willow represents merely a step toward the creation of a universal quantum computer. At this stage, such devices surpass traditional systems only in a limited range of tasks, with classical technologies still proving more effective for the majority of commercial and scientific applications.

Hartmut Neven, the head of Google Quantum AI, noted in his blog that while the RCS test demonstrates significant advantages, it lacks direct real-world applications. Nonetheless, Willow has already been employed to simulate complex quantum systems, leading to new scientific insights. However, even these advancements remain within the reach of existing technologies for now.