The development of Zuchongzhi-3, a superconducting quantum computing prototype with 105 qubits and 182 couplers, represents a significant leap forward in the field of quantum computing. This groundbreaking achievement was spearheaded by a team of researchers from the University of Science and Technology of China (USTC) and marks a crucial advancement in random quantum circuit sampling, a critical area for demonstrating the power of quantum computers.
Quantum computing is poised to revolutionize the way we solve some of the most complex computational problems that classical computers struggle with. Zuchongzhi-3 exemplifies this potential by operating at a staggering speed—1015 times faster than the world’s fastest supercomputer and one million times faster than Google’s most recent results in the field. This feat not only follows the success of its predecessor, the Zuchongzhi-2, but also serves as a milestone in the quest to achieve practical quantum computational supremacy.
In 2019, Google made headlines by demonstrating its 53-qubit Sycamore processor, which completed a random circuit sampling task in just 200 seconds. This task was one that would have taken the world’s fastest supercomputer approximately 10,000 years to simulate. The achievement was hailed as the first demonstration of quantum supremacy, a term used to describe the point at which quantum computers can outperform classical computers on certain tasks.
However, this claim was challenged just a few years later in 2023, when USTC showcased the power of more advanced classical algorithms. By utilizing over 1,400 A100 GPUs, the team was able to complete the same task in just 14 seconds. With the help of the Frontier supercomputer, which boasts a significantly larger memory capacity, the same computation could be completed in just 1.6 seconds, overturning Google’s previous claim of quantum supremacy.
Building on this success, USTC researchers established a new benchmark for quantum computing by achieving rigorously proven quantum supremacy with the Jiuzhang photonic quantum computing prototype in 2020. Following this, in 2021, the Zuchongzhi-2 superconducting system achieved the same feat, further proving that quantum computers were capable of surpassing classical systems in real-world applications.
In 2023, USTC raised the bar once again with the 255-photon Jiuzhang-3, which demonstrated quantum supremacy by surpassing classical supercomputers by an astonishing 1016 times. Not to be outdone, in October 2024, Google’s Sycamore processor, now upgraded to 67 qubits, achieved quantum supremacy once again, outperforming classical systems by a factor of nine orders of magnitude.
However, the true breakthrough came with Zuchongzhi-3. Taking the lessons learned from its predecessor, the USTC research team significantly improved key performance metrics, resulting in a quantum processor with 105 qubits and 182 couplers. This upgrade allows for more complex operations and the potential for solving problems that were previously out of reach. The performance improvements are impressive: the quantum processor now boasts a coherence time of 72 μs, a parallel single-qubit gate fidelity of 99.90%, a parallel two-qubit gate fidelity of 99.62%, and a parallel readout fidelity of 99.13%.
These improvements in performance are vital for the operation of quantum computers. Coherence time refers to the amount of time a qubit can maintain its quantum state before decohering, and a longer coherence time allows for more complex computations. Gate fidelity measures the accuracy of quantum operations performed on qubits, and high fidelity is crucial for the reliable execution of quantum algorithms. The parallelization of qubit operations is another significant advancement, allowing for more efficient computations and greater scalability in quantum systems.
To test the capabilities of Zuchongzhi-3, the USTC team conducted an 83-qubit, 32-layer random circuit sampling task. In comparison to the best classical algorithms available, Zuchongzhi-3 demonstrated a speed that was 15 orders of magnitude faster than the world’s most powerful supercomputer, outperforming Google’s results by six orders of magnitude. This achievement establishes Zuchongzhi-3 as the strongest superconducting quantum computer to date, providing further evidence of the growing computational advantage of quantum systems over classical counterparts.
One of the most exciting aspects of the Zuchongzhi-3 development is its architecture. The team adopted a 2D grid qubit layout, which allows for more efficient qubit interconnections and faster data transfer rates. This layout is essential for scaling up quantum computers, as it facilitates the integration of more qubits while maintaining high performance. In addition, the team is actively pursuing research into quantum error correction, an area that is critical for improving the reliability and robustness of quantum systems.
Quantum error correction involves creating methods to detect and correct errors that may occur during quantum computation. These errors are a significant challenge for quantum computers due to the fragile nature of quantum states. The USTC team has integrated the surface code, a well-known quantum error correction method, into their research, and they are working to improve it with a distance-7 surface code. In the near future, they plan to increase the distance to 9 and 11, which will enable even larger-scale quantum operations.
The development of Zuchongzhi-3 and its associated advancements in quantum computing holds profound significance for the future of technology. Quantum computers have the potential to solve problems in fields such as cryptography, materials science, drug discovery, and artificial intelligence that are currently beyond the reach of classical computers. In particular, the ability to simulate quantum systems more efficiently could revolutionize our understanding of chemistry and physics, opening up new avenues for scientific discovery.
While Zuchongzhi-3 is a remarkable achievement, the team’s work is far from over. They continue to push the boundaries of quantum computing by advancing research in quantum entanglement, quantum simulation, and quantum chemistry. The improvements made in the Zuchongzhi-3 processor will serve as a foundation for even more powerful quantum systems in the future, and the team’s work in error correction will be critical to making these systems reliable and scalable.
The significance of these achievements has been widely recognized within the scientific community. One reviewer of the research described the work as “benchmarking a new superconducting quantum computer, which shows state-of-the-art performance,” noting that it represents “a significant upgrade from the previous 66-qubit device (Zuchongzhi-2).” The USTC team’s work has received widespread acclaim, not only for its technical achievements but also for its potential to transform the landscape of computational science.
The research team behind Zuchongzhi-3 includes prominent scientists such as Pan Jianwei, Zhu Xiaobo, and Peng Chengzhi. Their work has been supported by a number of institutions, including the Shanghai Research Center for Quantum Sciences, Henan Key Laboratory of Quantum Information and Cryptography, China National Institute of Metrology, Jinan Institute of Quantum Technology, School of Microelectronics at Xidian University, and the Institute of Theoretical Physics under the Chinese Academy of Sciences. The collaboration among these institutions highlights the global effort to push the boundaries of quantum computing and to establish quantum supremacy as a practical reality.
As quantum computing continues to evolve, Zuchongzhi-3 marks an important milestone in the race for quantum supremacy. Its speed and performance set a new benchmark for the field, demonstrating the growing capabilities of superconducting quantum computers. With ongoing advancements in quantum error correction, entanglement, and simulation, the future of quantum computing looks promising, and Zuchongzhi-3 may very well be just the beginning of a new era in computational science.
More information: Dongxin Gao et al, Establishing a New Benchmark in Quantum Computational Advantage with 105-qubit Zuchongzhi 3.0 Processor, Physical Review Letters (2025). DOI: 10.1103/PhysRevLett.134.090601. On arXiv: DOI: 10.48550/arxiv.2412.11924