3D-integrated readout multiplexing of superconducting qubits

As superconducting circuits scale up towards large-scale fault-tolerant quantum computation, circuit designs that minimise complexity and resource overhead become increasingly attractive. Employing circuit designs with entirely off-chip signal wiring that can tile a 2D plane is a potentially scalable approach [1,2]. The resources required to operate large scale circuits can be reduced by employing signal multiplexing in which control or measurement signals for multiple qubits are carried on single transmission lines. In this talk I will present solutions to integrate off-chip 3D-integrated readout multiplexing with tileable superconducting circuits, including an approach based on re-entrant cavity filters [3].

[1] Rahamim et al., Applied Physics Letters 110, 222602 (2017)

[2] Spring et al., Science Advances 8, eabl6698 (2022)

[3] Bakr et al., Physical Review Applied 23, 054089 (2025)