A processor architecture design method for improving reusability of special-purpose superconducting quantum processor

Abstract

Optimizing the architecture of superconducting quantum processors is crucial for improving the efficiency of executing quantum programs. Existing schemes either modify general-purpose architectures, which might lead to an increase in the probability of qubit frequency collisions, or customize special-purpose architectures based on the quantum programs to reduce the gate operations after qubit mapping, but the architectures lack support for the post-mapping gate operations’ optimization of multiple programs, which reduce their reusability. In this study, we propose a new processor architecture design method that reduces the average growth of the total post-mapping gate count on multiple quantum programs as well as to reduce the impact of processor architecture on frequency collisions, and thus improve the reusability of special-purpose processor. The main idea is to construct a new architecture by finding maximum common edge subgraph among multiple special-purpose processor architectures. To show the effectiveness of our method, we selected quantum programs with different functions covering 9 types of qubit numbers for comparison. Comprehensive simulation results show that the architecture schemes generated by using our method outperform two general-purpose architecture schemes based on the square lattice and the eff-5-freq’s special-purpose architecture schemes, respectively. Compared to the all 2-qubit bus and the eff-5-freq’s architecture schemes, after qubit mapping, the architecture schemes of our method have the smallest average growth of gate operations in multiple quantum programs (the largest average growth is 5.63%), which further supports the execution of different quantum programs. Meanwhile, the architecture schemes of our method also reduce the probability of frequency collisions by at least 4.48% compared to all other schemes. Furthermore, we compared our method with another special-purpose design method. In the schemes of different special-purpose architecture design methods, our method is able to generate architectures with better matching for multiple quantum programs. Therefore, our method can provide superconducting quantum processor architecture design with higher reusability for multiple quantum programs.