Effects of the integration of digital and quantum coherent superconducting electronics

Jonathan L. Habif, M. J. Feldman, Mark F. Bocko

Andrea M. Herr

Pavel Rott

Pascal Febvre

B. L. T. Plourde

Superconducting qubits based on Josephson junctions are one of the leading candidates for building a largescale quantum information processor. There have been significant advances in the performance of superconducting qubits over the past decade and there is currently rapid progress in the development of systems with up to tens of qubits. In order to build to yet larger systems, new techniques will need to be developed to address the overhead requirements for room-temperature electronics hardware and cryostat wiring for controlling and reading out large numbers of qubits. One approach to this challenge involves implementing more of the qubit control and readout in the low-temperature environment. I will describe our efforts on integrating superconducting classical digital circuitry with superconducting qubits for coherent control and readout.

Caleb Jordan, Aaron Somoroff, L. Palma +1 more

Current superconducting quantum computers (QC) rely on a brute-force scaling approach where quantum chips operating at the millikelvin stage inside dilution refrigerators are connected to room-temperature electronics via an ever-increasing number of signal wires. In order to drastically scale up such systems without facing refrigeration challenges, these quantum interface electronics need to be integrated at cryogenic temperatures, ideally at the same stage as qubits. In this paper, we show that, by employing energy-efficient digital superconducting microchips based on single flux quantum (SFQ) technology, all essential functions to operate a full stack quantum computer can be integrated at 10 mK. They include digital qubit charge control and magnetic flux control for single- and two-qubit gates, as well as digital qubit readout.