We present a flip-chip architecture for an array of coupled superconducting qubits, in which circuit components reside inside individual microwave enclosures. In contrast to other flip-chip approaches, the qubit chips in our architecture are electrically floating, which guarantees a simple, fully modular assembly of capacitively coupled circuit components such as qubit, control, and coupling structures, as well as reduced crosstalk between the components. We validate the concept with a chain of three nearest neighbor coupled generalized flux qubits in which the center qubit acts as a frequency-tunable coupler. Using this coupler, we demonstrate a transverse coupling on/off ratio ≈ 50, zz-crosstalk ≈ 0.7 kHz between resonant qubits and isolation between the qubit enclosures > 60 dB.
@article{arxiv.2502.19927,
title = {Low crosstalk modular flip-chip architecture for coupled superconducting qubits},
author = {Soeren Ihssen and Simon Geisert and Gabriel Jauma and Patrick Winkel and Martin Spiecker and Nicolas Zapata and Nicolas Gosling and Patrick Paluch and Manuel Pino and Thomas Reisinger and Wolfgang Wernsdorfer and Juan Jose Garcia-Ripoll and Ioan M. Pop},
journal= {arXiv preprint arXiv:2502.19927},
year = {2025}
}