Addressing infrastructure requirements for the coherent control of large superconducting quantum systems*

Superconducting-qubit systems are a promising platform for the implementation of error-corrected, fault-tolerant quantum computers, for which the surface code is a prominent approach. We consider an architecture where a repeatable tile of flux-tunable qubits, coupled through capacitive tunable couplers, is repeated to create lattices of qubits that can be controlled with minimal footprint and overhead, in a way amenable to the implementation of the surface code. Focusing on problems arising from the need to extend such platforms to relevant system sizes, while ensuring their coherent control, we propose various methods for the enhancement of control infrastructure required for 3D-integrated qubit designs. We do so at various levels of abstraction, from the qubit chip to the control software required for system calibration, including cryogenic package assemblies, signal delivery and room-temperature control electronics. Preliminary characterization of these will be presented.