Number-based High Fidelity Logical Qubit on the Surface Code FTQC

Seungju An, Byung-Soo Choi

http://doi.org/10.5626/JOK.2024.51.4.301

To achieve the quantum advantage, the quantum computing size should be increased. However, the quantum computational power cannot be easily increased because of the high error rates on qubits and gates. To overcome such problem, the surface code based on the fault-tolerant quantum computation model has been investigated a lot since it works with relatively higher error rates in theory. However, In practice, we need many improvements on the surface code such as the requirement of a large number of physical qubits. Therefore, in this work, we propose a logical qubit design method, which exploits the multiple lower level qubits unlike the conventional bigger-sized qubit design method. This method uses the concept of the block-code scheme. The analysis result shows that the proposed method achieves a lower error rate than the bigger-sized logical qubits with the same number of physical qubits. In conclusion, we believe this approach can improve the resource efficiency of the surface code FTQC.