Quantum fault tolerance technology based on superconducting quantum systems

With the improvement of quantum control technology in superconducting systems, quantum error correction has seen rapid development. Recently, significant breakthroughs have been achieved on various platforms, even surpassing the break-even point of quantum error correction. However, to reach the final goal of fault tolerant quantum computation, it is crucial to further suppress the error through scaling up quantum systems. In this article we focus on superconducting quantum systems and present four approaches for implementing fault-tolerant error syndrome measurements. We then discuss the three key stages in achieving fault-tolerant quantum computation and the corresponding challenges at each stage. These challenges include surpassing the break-even point, reaching the fault-tolerant threshold, and implementing universal logical gates. To accomplish these goals, we classify three potential scaling-up schemes based on different forms of connectivity. We then summarize the experimental progress in quantum error correction and the exploration of connectivity. Finally, we address three key problems in this field.