China News Service, Beijing, February 23 (Reporter Sun Zifa) The internationally renowned academic journal "Nature" recently published a quantum computing paper. The researchers demonstrated quantum computing with an increase in the error correction scale. This research work means that A step closer to scalable quantum error correction to allow quantum computers to achieve error rates low enough to run usable quantum algorithms.

　　According to the paper, quantum computers, like classical computers, are prone to errors caused by the "noise" (or interference) of the physical system behind them; realizing their potential requires reducing the error rate.

One approach to quantum error correction is error-correcting codes, using a set of physical qubits (units of quantum information, the equivalent of bits in a classical computer) to form a logical qubit.

This system, called a surface-coded logic qubit, can detect and correct errors without affecting the information, but scaling up such a system means manipulating more qubits, which can introduce more logic errors.

For logic performance to improve as the code size increases, the overall error correction needs to outweigh the increased logic errors.

A photo of a fully assembled quantum system from Google's "Quantum AI" (Image credit: Google's "Quantum AI" team).

Photo courtesy of Springer Nature

　　In this study, Google's Quantum AI team demonstrated a logical qubit surface code that reduces error rates as the system scales up.

They built a 72-qubit superconducting quantum processor and tested it with two different surface codes: a so-called distance-5 logical qubit (based on 49 physical qubits) and a smaller distance- 3 logical qubits (based on 17 physical qubits).

Larger surface codes were shown to achieve better logical qubit performance (2.914% logic errors per cycle) than smaller surface codes (3.028% logic errors per cycle).

　　The research team concludes that more research is needed to achieve the logical error rates required for efficient computing, but their latest work demonstrates the basic requirements for the future development of quantum computing.

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