Demonstration of high-fidelity gates in a strongly anharmonic with long-coherence C-shunt flux qubit

S Silu Zhao (Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,) L Li Li W Weiping Yuan (Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,) X Xinhui Ruan (Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,) J Jinzhe Wang (Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,) B Bingjie Chen Y Yunhao Shi G Guihan Liang (Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,) S Shi Xiao J Jiacheng Song J Jinming Guo X Xiaohui Song K Kai Xu H Heng Fan Z Zhongcheng Xiang D Dongning Zheng

Abstract

We demonstrate high-fidelity single-qubit gates on a C-shunt flux qubit that simultaneously combines a large anharmonicity (A/2π=848  MHz) with long relaxation time (T1=23 μs). The large anharmonicity significantly suppresses leakage to higher energy levels, enabling fast and precise microwave control. Using derivative removal by adiabatic gate pulses and randomized benchmarking, the qubit achieves gate fidelities exceeding 99.9%, highlighting the capability of C-shunt flux qubits for robust and high-performance quantum operations. These results establish them as a promising platform for scalable quantum information processing.

Article Details

Volume / Issue Vol. 128, Issue 15
Published April 13, 2026
ISSN 0003-6951
Publisher American Institute of Physics

Journal Info

Applied Physics Letters

American Institute of Physics

ISSN: 0003-6951 Physical Sciences

Authors (16)

S

Silu Zhao

Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,

L

Li Li

W

Weiping Yuan

Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,

X

Xinhui Ruan

Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,

J

Jinzhe Wang

Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,

B

Bingjie Chen

Y

Yunhao Shi

G

Guihan Liang

Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences 1 , Beijing 100190,

S

Shi Xiao

J

Jiacheng Song

J

Jinming Guo

X

Xiaohui Song

K

Kai Xu

H

Heng Fan

Z

Zhongcheng Xiang

D

Dongning Zheng