A cryogenic on-chip microwave pulse generator for large-scale superconducting quantum computing

TL;DR

This paper presents a cryogenic on-chip microwave pulse generator that enables scalable, high-fidelity control of superconducting qubits directly at millikelvin temperatures, reducing heat load and cost for large quantum processors.

Contribution

It introduces a monolithic, cryogenic microwave pulse generator compatible with superconducting circuits, facilitating large-scale quantum computing.

Findings

Successful high-fidelity qubit readout using the device

Small footprint with negligible heat load

Compatible with existing superconducting quantum circuits

Abstract

For superconducting quantum processors, microwave signals are delivered to each qubit from room-temperature electronics to the cryogenic environment through coaxial cables. Limited by the heat load of cabling and the massive cost of electronics, such an architecture is not viable for millions of qubits required for fault-tolerant quantum computing. Monolithic integration of the control electronics and the qubits provides a promising solution, which, however, requires a coherent cryogenic microwave pulse generator that is compatible with superconducting quantum circuits. Here, we report such a signal source driven by digital-like signals, generating pulsed microwave emission with well-controlled phase, intensity, and frequency directly at millikelvin temperatures. We showcase high-fidelity readout of superconducting qubits with the microwave pulse generator. The device demonstrated here has a small footprint, negligible heat load, great flexibility to operate, and is fully compatible with today's superconducting quantum circuits, thus providing an enabling technology for large-scale superconducting quantum computers.