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arXiv · 2304.10401

The quartic Blochnium: an anharmonic quasicharge superconducting qubit

Luca Chirolli·Matteo Carrega·Francesco Giazotto
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Abstract

The quasicharge superconducting qubit realizes the dual of the transmon and shows strong robustness to flux and charge fluctuations thanks to a very large inductance closed on a Josephson junction. At the same time, a weak anharmonicity of the spectrum is inherited from the parent transmon, that introduces leakage errors and is prone to frequency crowding in multi-qubit setups. We propose a novel design that employs a quartic superinductor and confers a good degree of anharmonicity to the spectrum. The quartic regime is achieved through a properly designed chain of Josephson junction loops that shows minimal quantum fluctuations without introducing a severe dependence on the external fluxes.

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Luca Chirolli, Matteo Carrega, Francesco Giazotto. 2023-04-20. The quartic Blochnium: an anharmonic quasicharge superconducting qubit. https://doi.org/10.22331/q-2023-12-04-1193

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