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arXiv · 2005.02630

Fast parametric two-qubit gates with suppressed residual interaction using a parity-violated superconducting qubit

Atsushi Noguchi·Alto Osada·Shumpei Masuda·Shingo Kono·Kentaro Heya·Samuel Piotr Wolski·Hiroki Takahashi·Takanori Sugiyama·Dany Lachance-Quirion·Yasunobu Nakamura
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Abstract

We demonstrate fast two-qubit gates using a parity-violated superconducting qubit consisting of a capacitively-shunted asymmetric Josephson-junction loop under a finite magnetic flux bias. The second-order nonlinearity manifesting in the qubit enables the interaction with a neighboring single-junction transmon qubit via first-order inter-qubit sideband transitions with Rabi frequencies up to 30~MHz. Simultaneously, the unwanted static longitudinal~(ZZ) interaction is eliminated with ac Stark shifts induced by a continuous microwave drive near-resonant to the sideband transitions. The average fidelities of the two-qubit gates are evaluated with randomized benchmarking as 0.967, 0.951, 0.956 for CZ, iSWAP and SWAP gates, respectively.

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Atsushi Noguchi, Alto Osada, Shumpei Masuda, Shingo Kono, Kentaro Heya, Samuel Piotr Wolski, Hiroki Takahashi, Takanori Sugiyama, Dany Lachance-Quirion, Yasunobu Nakamura. 2020-05-06. Fast parametric two-qubit gates with suppressed residual interaction using a parity-violated superconducting qubit. https://doi.org/10.1103/physreva.102.062408

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