Driving a two-qubit gate between transmons using digitally reconfigurable cryogenic CMOS control electronics.

Control electronics composed of CMOS circuits are of growing interest for next generation quantum computing systems. Here we present experimental results on a two-qubit cross resonance gate generated from a CMOS control chip, that is thermalized to the 4K stage of a dilution refrigerator. This low power digitally reconfigurable arbitrary waveform generator (DRAWG) is fabricated on 14 nm FinFET technology and has an observed power dissipation of 23 mW per channel while control is active. It uses a single side band direct conversion topology to generate output frequencies between 4.5 and 5.5 GHz, and a maximum power output of -18 dBm. The cryo-DRAWG was used to generate the single and two-qubit control pulses necessary for calibrating and characterizing a cross-resonance gate between transmon qubits. Measurement results include Hamiltonian tomography, qubit lifetime and dephasing, as well as single-qubit and two-qubit randomized benchmarking (RB). We demonstrate an error-per-Clifford rate of ~5E-4 for 1Q RB and ~2E-2 for 2Q RB.