Explainer: How China's quantum leap is set to redefine future of computing

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(Xinhua) 08:49, March 05, 2025

Chinese quantum physicist Zhu Xiaobo (R) has a discussion with a student at a laboratory in Hefei, east China's Anhui Province, on March 3, 2025. Chinese scientists unveiled a superconducting quantum computer prototype named "Zuchongzhi 3.0" with 105 qubits on Monday (Beijing Time), marking a breakthrough in China's quantum computing advancements. (Photo by Dai Rui/Xinhua)

HEFEI, March 4 (Xinhua) -- A team of Chinese scientists on Monday unveiled Zuchongzhi 3.0, a 105-qubit superconducting quantum processor prototype with speed gains in the quadrillions over leading supercomputers for one specific task: quantum random circuit sampling.

The team's groundbreaking result has positioned China at the forefront of quantum supremacy amid rapid global tech progress.

But what does this leap mean, and how could it redefine the future of computing?

BEYOND SUPREMACY

The United States and China are both leading contributors to quantum innovation, advancing the field in parallel and driving breakthroughs that are redrawing computational frontiers.

In 2019, Google's Sycamore declared a quantum advantage over traditional supercomputers in solving a sampling task in 200 seconds, but Chinese scientists challenged that advantage in 2023, cutting the time to 17 seconds using classical chips and algorithms.

Meanwhile, China hit new quantum computing milestones with Zuchongzhi 2.0 and Jiuzhang 3.0. By 2024, Sycamore had again highlighted its quantum supremacy with expanded qubit counts.

But this week, Zuchongzhi 3.0 surpassed Sycamore's latest scores by six orders of magnitude, setting the highest benchmark for a superconducting system ever publicly reported.

Over the past 80 years, computing has reshaped our understanding of the world and daily life, but unlocking its next frontier hinges on overcoming the bottlenecks of processing power as the field approaches the physical limits of Moore's Law.

Quantum tech is broadly considered to be the front line of technology, poised to trigger a transformative breakthrough akin to that of fusion energy.

And scientists racing to embrace this future have laid out some critical milestones.

Zhu Xiaobo, the chief designer of Zuchongzhi 3.0, has outlined a three-stage roadmap for the development of practical quantum computers, the first of which has seen China and the United States showcase capabilities that surpass those of classical supercomputers, such as quantum random sampling carried out primarily through qubit scaling. But these advances remain niche demonstrations with minimal real-world impact.

In the second stage, researchers around the world are aiming to pinpoint a handful of practical quantum applications -- like quantum chemistry and drug discovery, now largely bolstered by supercomputers and AI algorithms -- within five years, translating quantum advantages into tangible productivity gains, according to Zhu.

The third stage will involve achieving universal fault-tolerant quantum computing, which requires suppressing qubit error rates to extreme lows. Given current physical qubit error rates and engineering hurdles, Zhu estimates this milestone remains about 15 years away.

Now, in early development of quantum computing, the front-runners and best technical approaches have not yet been consolidated, meaning "any country that is able to deploy quantum tech first will have a first-mover advantage," according to a report published by the Mercator Institute for China Studies last December.

LOWERING ERRORS

Zuchongzhi 3.0, a superconducting quantum processor with 105 readable qubits, has one of the highest qubit counts of any device that has demonstrated quantum supremacy.

Its world-leading fidelity metrics are its true distinction: its single-qubit gate (99.9 percent), its two-qubit gate (99.62 percent) and its readout (99.13 percent), which have earned peer recognition for what one journal reviewer referred to as "benchmarking a new superconducting quantum computer with state-of-the-art performance."

Zuchongzhi 3.0's ingenious architecture -- integrating frequency-tunable qubits, topological coupling and flip-chip bonding -- has achieved a decoherence performance surpassing that of Sycamore, in a critical advance to maintain quantum states in large-scale systems, according to Zhu.

Quantum coherence time is a measure of how long a quantum system can retain operational integrity, with a longer time enabling the execution of complex algorithms and relatively large-scale computations, Zhu said.

Despite the good performance of the existing Zuchongzhi system, Zhu recognizes that slashing quantum error rates remains a pivotal challenge to the viability of practical quantum computers. "To build a practical quantum computer, we must simultaneously scale qubit counts and reduce error rates."

Last December, Google unveiled a new quantum computer based on the Willow quantum chip that displays excellent error-correction ability.