The strong anharmonicity and high coherence times inherent to fluxonium superconducting circuits are beneficial for quantum information processing. In addition to requiring high-quality physical qubits, a quantum processor needs to be assembled in a manner that minimizes crosstalk and decoherence. In this paper, we report work on fluxonium qubits packaged in a flip-chip architecture, where a classical control and readout chip is bump-bonded to the quantum chip, forming a multi-chip module (MCM). The modular approach allows for improved connectivity between the qubits and control/readout elements, and separate fabrication processes. We characterize the coherence properties of the individual fluxonium qubits, demonstrate high fidelity single-qubit gates with 6 ns microwave pulses (without DRAG), and identify the main decoherence mechanisms to improve on the reported results.
@article{arxiv.2303.01481,
title = {Fluxonium Qubits in a Flip-Chip Package},
author = {Aaron Somoroff and Patrick Truitt and Adam Weis and Jacob Bernhardt and Daniel Yohannes and Jason Walter and Konstantin Kalashnikov and Mario Renzullo and Raymond A. Mencia and Maxim G. Vavilov and Vladimir E. Manucharyan and Igor V. Vernik and Oleg Mukhanov},
journal= {arXiv preprint arXiv:2303.01481},
year = {2023}
}