Google Achieves Practical Computation with Quantum Algorithm

Researchers at Google Quantum AI have announced the achievement of 'verifiable quantum advantage' through the new Quantum Echoes algorithm, executed on the 105-qubit Willow processor.

This represents the first instance where a quantum device has solved a computational problem that is nearly impossible to simulate on classical supercomputers. The results can also be verified by another quantum system.

The new algorithm measures Out-of-Time-Order Correlators (OTOC), which describe how information spreads and becomes chaotic within a quantum system.

According to the researchers, the Quantum Echoes algorithm represents a new class of problems as it models a physical experiment, testing not only the complexity but also the accuracy of the final computations.

The technology employs 'forward' and 'reverse' evolution variables of the quantum system, rolling forward and slightly perturbing one qubit, then rolling back to observe the emergence of an 'echo.'

The interference-enhanced signal allows the study of fundamental properties of matter such as magnetic phases or spin network dynamics.

According to the Google team, this step paves the way for the first practical application of quantum computing. Potentially, the algorithm could be used to study molecular structures.

The company concluded that as they move closer to creating a fully functional quantum computer with error correction, they anticipate many more useful real-world applications. Currently, they are focused on achieving the third stage in their quantum hardware roadmap — creating a long-lived logical qubit.