Scalable Hardware-Efficient Qubit Control with Single Flux Quantum Pulse Sequences

Understand

The hardware overhead associated with microwave control is a major obstacle to scale-up of superconducting quantum computing.

• An alternative approach involves irradiation of the qubits with trains of Single Flux Quantum (SFQ) pulses, pulses of voltage whose time integral is precisely equal to the superconducting flux quantum.
• Here we describe the derivation and validation of compact SFQ pulse sequences in which classical bits are clocked to the qubit at a frequency that is roughly a factor 5 higher than the qubit oscillation frequency, allowing for variable pulse-to-pulse timing.
• The control sequences are constructed by repeated streaming of short subsequence registers that are designed to suppress leakage out of the computational manifold.