Abstract

Superconducting fluxonium qubits provide a promising alternative to transmons on the path toward large-scale superconductor-based quantum computing due to their better coherence and larger anharmonicity. A major challenge for multi-qubit fluxonium devices is the experimental demonstration of a scalable crosstalk-free multi-qubit architecture with high-fidelity single-qubit and two-qubit gates, single-shot readout, and state initialization. Here, we present a two-qubit fluxonium-based quantum processor with a tunable coupler element. We experimentally demonstrate fSim-type and controlled-Z-gates with 99.55 and 99.23% fidelities, respectively. The residual ZZ interaction is suppressed down to the few kHz levels. Using a galvanically coupled flux control line, we implement high-fidelity single-qubit gates and ground state initialization with a single arbitrary waveform generator channel per qubit.

Details

Title
High fidelity two-qubit gates on fluxoniums using a tunable coupler
Author
Moskalenko, Ilya N. 1   VIAFID ORCID Logo  ; Simakov, Ilya A. 2   VIAFID ORCID Logo  ; Abramov, Nikolay N. 1 ; Grigorev, Alexander A. 3 ; Moskalev, Dmitry O. 4 ; Pishchimova, Anastasiya A. 4 ; Smirnov, Nikita S. 4 ; Zikiy, Evgeniy V. 4 ; Rodionov, Ilya A. 4   VIAFID ORCID Logo  ; Besedin, Ilya S. 5   VIAFID ORCID Logo 

 National University of Science and Technology ‘MISIS’, Moscow, Russia (GRID:grid.35043.31) (ISNI:0000 0001 0010 3972); Russian Quantum Center, Skolkovo, Russia (GRID:grid.452747.7) 
 National University of Science and Technology ‘MISIS’, Moscow, Russia (GRID:grid.35043.31) (ISNI:0000 0001 0010 3972); Russian Quantum Center, Skolkovo, Russia (GRID:grid.452747.7); Moscow Institute of Physics and Technology, Dolgoprudny, Russia (GRID:grid.18763.3b) (ISNI:0000000092721542) 
 National University of Science and Technology ‘MISIS’, Moscow, Russia (GRID:grid.35043.31) (ISNI:0000 0001 0010 3972) 
 Dukhov Research Institute of Automatics (VNIIA), Moscow, Russia (GRID:grid.472660.1) (ISNI:0000 0004 0544 1518); Bauman Moscow State Technical University, FMN Laboratory, Moscow, Russia (GRID:grid.61569.3d) (ISNI:0000 0001 0405 5955) 
 National University of Science and Technology ‘MISIS’, Moscow, Russia (GRID:grid.35043.31) (ISNI:0000 0001 0010 3972); Russian Quantum Center, Skolkovo, Russia (GRID:grid.452747.7); ETH Zurich, Department of Physics, Zurich, Switzerland (GRID:grid.5801.c) (ISNI:0000 0001 2156 2780) 
Publication year
2022
Publication date
2022
Publisher
Nature Publishing Group
e-ISSN
20566387
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2733868730
Copyright
© The Author(s) 2022. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.