by Researchers at the University of Science and Technology of China, the Henan Key Laboratory of Quantum Information and Cryptography, and the Hefei National Laboratory have successfully demonstrated the preparation of a logical magic state with fidelity beyond the distillation threshold on a superconducting quantum processor. This breakthrough could significantly contribute to the development of fault-tolerant quantum computing.
Quantum computers have shown promising potential in solving complex optimization problems, but they are also susceptible to noise and computational errors. To address this issue, engineers have been exploring fault-tolerant quantum computing approaches that can withstand noise and be scaled up more effectively. One such approach is the preparation of magic states, which introduce non-Clifford gates.
The recent research by Prof. Xiao-Bo Zhu and his colleagues focuses on the preparation of high-fidelity logical magic states, which are essential for realizing fault-tolerant quantum computing. Their objective is to achieve robust, fault-tolerant, universal quantum computing. The protocol they proposed involves injecting the state to be prepared into one of the qubits in the surface code and propagating the state information throughout the entire surface code. The choice of injection position and the initialization states of other qubits play a crucial role in the protocol’s success.
The research team successfully applied their protocol on a 66-qubit quantum processor called Zuchongzhi 2.1. This processor’s design allows for manipulation of the interaction between adjacent qubits, ensuring high-fidelity quantum gates despite a high degree of parallelism. The results were promising, with three logical magic states prepared non-destructively and achieving logical fidelities higher than the state distillation protocol threshold.
This achievement is a significant milestone in the development of fault-tolerant computing based on the surface code. It demonstrates that low-fidelity magic states can be fed into the magic state distillation circuit, undergo multiple distillations, and yield sufficiently high-fidelity magic states. These high-fidelity magic states can then be used to construct fault-tolerant non-Clifford logical gates.
Moving forward, the protocol developed by Prof. Zhu and his colleagues has the potential to be adopted by other research teams using different superconducting quantum processors. It could contribute to the realization of robust fault-tolerant quantum computing and the development of larger-scale quantum computers.
In the field of quantum error correction, Prof. Zhu highlighted two research directions. The first is to enhance the performance of logical qubits or error-corrected quantum memory by reducing the physical manipulation error rate and increasing the number of encoded qubits. This would help suppress the logical error rate to practical levels. The second direction is to conduct experimental research on error-corrected logical operations, such as lattice surgery, for future applications in fault-tolerant quantum computing.
Overall, the successful preparation of a logical magic state with fidelity beyond the distillation threshold is a significant advancement in the field of quantum computing. It brings us closer to realizing fault-tolerant quantum computing and paves the way for the development of more powerful quantum computers.
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1. Source: Coherent Market Insights, Public sources, Desk research
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