34.2 A 28-nm Bulk-CMOS IC for Full Control of a Superconducting Quantum Processor Unit-Cell

While large-scale fault-tolerant quantum computers promise to enable the solution to certain classes of problems for which no other efficient approach is known, such a machine is believed to require over a million performant qubits. Scaling today's 0(100) qubit superconducting (SC) quantum computers to this extent while also improving performance carries many daunting challenges, including control of such a large quantum processor (QP). Integrating the control electronics at an intermediate temperature stage within the cryostat is an attractive option, e.g., due to the inherent thermal stability of the cryogenic environment and the feasibility of connecting to the QP via dense low-loss/high-thermal-isolation SC lines [1], [2]. Several cryo-CMOS quantum controllers have been reported, with examples used to control spin [3] and transmon [1], [2] qubits. To date, IC-based quantum control experiments have focused on resonant RF control, but baseband signals are often central to the execution of gates. Here, we report the design and system characterization of a cryo-CMOS IC for generating both the RF and baseband signals required for full control of a SC QP unit-cell, and show its ability to implement the components of a high-fidelity gate set that is universal for quantum computing.