For a frequency-tunable two-qubit system, a controlled-Z (CZ) gate can be realized by adiabatically driving the qubit system through an avoided level crossing between an auxiliary state and computational levels. Here, we theoretically propose a fast CZ gate using a shortcut-to-adiabaticity (STA). Experimentally, the STA CZ gate is implemented with a 52 ns control pulse for two coupled superconducting Xmon qubits. Measured fidelity of the STA CZ gate is higher than 96.0%, in both quantum process tomography and randomized benchmarking. The protocol allows a flexible design of the evolution time and control waveform. We suggest that this `fast adiabatic' CZ gate can be directly applied to other multi-qubit quantum systems.
@article{arxiv.1811.08096,
title = {Experimental realization of a fast controlled-Z gate via a shortcut-to-adiabaticity},
author = {Tenghui Wang and Zhenxing Zhang and Liang Xiang and Zhilong Jia and Peng Duan and Zhiwen Zong and Zhenhai Sun and Zhangjingzi Dong and Jianlan Wu and Yi Yin and Guoping Guo},
journal= {arXiv preprint arXiv:1811.08096},
year = {2019}
}