High-quality two-qubit gate operations are crucial for scalable quantum information processing. Often, the gate fidelity is compromised when the system becomes more integrated. Therefore, a low-error-rate, easy-to-scale two-qubit gate scheme is highly desirable. Here, we experimentally demonstrate a new two-qubit gate scheme that exploits fixed-frequency qubits and a tunable coupler in a superconducting quantum circuit. The scheme requires less control lines, reduces crosstalk effect, simplifies calibration procedures, yet produces a controlled-Z gate in 30ns with a high fidelity of 99.5%, derived from the interleaved randomized benchmarking method. Error analysis shows that gate errors are mostly coherence limited. Our demonstration paves the way for large-scale implementation of high-fidelity quantum operations.
@article{arxiv.2006.11860,
title = {High-fidelity, high-scalability two-qubit gate scheme for superconducting qubits},
author = {Yuan Xu and Ji Chu and Jiahao Yuan and Jiawei Qiu and Yuxuan Zhou and Libo Zhang and Xinsheng Tan and Yang Yu and Song Liu and Jian Li and Fei Yan and Dapeng Yu},
journal= {arXiv preprint arXiv:2006.11860},
year = {2020}
}