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arXiv · 2103.08578

Millisecond coherence in a superconducting qubit

Aaron Somoroff·Quentin Ficheux·Raymond A. Mencia·Haonan Xiong·Roman V. Kuzmin·Vladimir E. Manucharyan
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Abstract

Increasing the degree of control over physical qubits is a crucial component of quantum computing research. We report a superconducting qubit of fluxonium type with the Ramsey coherence time reaching $T_2^*= 1.48 \pm 0.13 \mathrm{~ms}$, which exceeds the state of the art value by an order of magnitude. As a result, the average single-qubit gate fidelity grew above $0.9999$, surpassing, to our knowledge, any other solid-state quantum system. Furthermore, by measuring energy relaxation of the parity-forbidden transition to second excited state, we exclude the effect of out-of-equilibrium quasiparticles on coherence in our circuit. Combined with recent demonstrations of two-qubit gates on fluxoniums, our result paves the way for the next generation of quantum processors.

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Aaron Somoroff, Quentin Ficheux, Raymond A. Mencia, Haonan Xiong, Roman V. Kuzmin, Vladimir E. Manucharyan. 2021-03-15. Millisecond coherence in a superconducting qubit. https://arxiv.org/abs/2103.08578

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