Fig. 1: Comparison of space overhead of the proposed protocol with that for the surface code.
The figure plots the space overheads and logical error rates of the proposed protocol (▴) and the surface code (•). The logical error rate is calculated under a circuit-level depolarizing error model at a physical error rate 0.1%. The dash-dotted lines represent the logical error rate 10−10 and the corresponding space overhead, i.e., 162 physical qubits per logical qubit for our protocol. The dashed lines represent the logical error rate 10−24 and the corresponding space overhead, i.e., 373 physical qubits per logical qubit for our protocol. Our protocol reduces the space overhead to achieve the logical error rates 10−10 and 10−24 by more than 90% and 96%, respectively, compared to the protocol for the surface code.
