Direct Microwave Synthesis for Superconducting Qubit Control

Readout and control of superconducting qubits in the circuit QED architecture relies on microwave pulses whose frequencies are most commonly in the 4-8 GHz range. The electronics generating these signals typically rely on quadrature modulation, where baseband tones generated by \sim 1 GS/s digital-to-analog converters are mixed up with a CW carrier. We present an alternative approach to the generation of these signals that exploits recent advances in high-speed DACs capable of placing power in higher Nyquist zones above half the sampling rate.
This architecture can dramatically simplify control electronics for qubit applications, and we use it to demonstrate high-fidelity control and readout of a superconducting transmon qubit. We compare this approach to alternative systems, and discuss tradeoffs in the implementation
of direct synthesis control hardware.