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arXiv · 2512.21213

3D cavity-based graphene superconducting quantum circuits in two-qubit architectures

Kuei-Lin Chiu·Avishma J. Lasrado·Cheng-Han Lo·Yen-Chih Chen·Shih-Po Shih·Yen-Hsiang Lin·Chung-Ting Ke
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Abstract

We construct a series of graphene-based superconducting quantum circuits and integrate them into 3D cavities. For a single-qubit device, we demonstrate flux-tunable qubit transition, with a measured $T_1$ $\approx$ 48 ns and a lower bound estimate of $T_2^\ast$ $\approx$ 17.63 ns. By coupling the device to cavities with different resonant frequencies, we access multiple qubit-cavity coupling regimes, enabling the observation of vacuum Rabi splitting and flux-dependent spectral linewidths. In a two-qubit device consisting of a SQUID and a single junction, power-dependent measurements reveal a two-stage dispersive shift. By flux-tuning the cavity frequency at different readout powers, we attribute the first shift to the fixed-qubit and the second to the SQUID-qubit, indicating successful coupling between the two circuits and a single cavity mode. Our study demonstrates the flexible coupling achievable between 2D-material-based superconducting circuits and 3D cavities, and paves the way toward constructing multi-qubit 3D transmon devices from 2D materials.

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Kuei-Lin Chiu, Avishma J. Lasrado, Cheng-Han Lo, Yen-Chih Chen, Shih-Po Shih, Yen-Hsiang Lin, Chung-Ting Ke. 2025-12-24. 3D cavity-based graphene superconducting quantum circuits in two-qubit architectures. https://arxiv.org/abs/2512.21213

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