Circuit Design for Large-Scale Quantum Controller SoC

The milestones of superconducting quantum processors predict an exponential growth in the number of physical qubits. However, there has been no clear answer to how to build the electronic system that can support such a scaling. Building the electronic system in the dilution refrigerator in a form of CMOS IC has emerged as a promising approach. While circuit design in cryo-CMOS has proven to bring few issues, the full integration of required electronics in an SoC is in starting phase and presents hard challenges to overcome. They include inevitable fidelity degradation by interactions among a huge number of different frequencies internally generated to drive qubits, a large memory system that should also be incorporated in the dilution refrigerator to handle program and data with interactive control of individual physical qubits, and unacceptable power consumption that exceeds allowable cooling capacity of a dilution refrigerator. This talk introduces considerations that should be addressed both in architecture and circuit design for the implementation of large-scale integrated systems. It will be also followed by some research works to tackle the issues mentioned above.