Strong quantum computational advantage using a superconducting quantum processor

TL;DR

This paper reports the development of a 66-qubit superconducting quantum processor, Zuchongzhi, demonstrating quantum advantage by performing sampling tasks infeasible for classical supercomputers within a reasonable time.

Contribution

The paper introduces a large-scale, high-precision superconducting quantum processor capable of achieving quantum advantage through complex sampling tasks.

Findings

Sampling task took 1.2 hours on Zuchongzhi, while classical supercomputers would need at least 8 years.

System characterized by random quantum circuits sampling up to 56 qubits and 20 cycles.

Classical simulation cost is 2-3 orders of magnitude higher than previous 53-qubit systems.

Abstract

Scaling up to a large number of qubits with high-precision control is essential in the demonstrations of quantum computational advantage to exponentially outpace the classical hardware and algorithmic improvements. Here, we develop a two-dimensional programmable superconducting quantum processor, \textit{Zuchongzhi}, which is composed of 66 functional qubits in a tunable coupling architecture. To characterize the performance of the whole system, we perform random quantum circuits sampling for benchmarking, up to a system size of 56 qubits and 20 cycles. The computational cost of the classical simulation of this task is estimated to be 2-3 orders of magnitude higher than the previous work on 53-qubit Sycamore processor [Nature \textbf{574}, 505 (2019)]. We estimate that the sampling task finished by \textit{Zuchongzhi} in about 1.2 hours will take the most powerful supercomputer at least 8 years. Our work establishes an unambiguous quantum computational advantage that is infeasible for classical computation in a reasonable amount of time. The high-precision and programmable quantum computing platform opens a new door to explore novel many-body phenomena and implement complex quantum algorithms.