Experimental Realization of a Fast Controlled- Z Gate via a Shortcut to Adiabaticity
Tenghui Wang, Zhenxing Zhang, Liang Xiang, Zhi-Long Jia, Peng Duan, Zhiwen Zong, Zhenhai Sun, Zhangjingzi Dong, Jianlan Wu, Yi Yin, Guo‐Ping Guo · Physical Review Applied · 2019
In quantum information processing, the shortcut-to-adiabaticity (STA) protocol has been proposed to accelerate a system's adiabatic evolution by introducing an additional, counterdiabatic Hamiltonian. This protocol is particularly suitable for realizing the controlled-$Z$ ($C\phantom{\rule{0}{0ex}}Z$) gate, but a counterdiabatic Hamiltonian requires a variable, complex coupling of qubits. By introducing a representation transformation and a rescaling method, this work uses the STA protocol to obtain a high-fidelity $C\phantom{\rule{0}{0ex}}Z$ gate with two coupled transmon qubits. This method affords high flexibility in the evolution time and control waveform, and is expected to be directly useful in other quantum systems as well.