CMOS-based cryogenic control of silicon quantum circuits

TL;DR

This paper demonstrates a cryogenic CMOS control chip operating at 3K that can coherently control silicon quantum bits at 20mK, enabling scalable, integrated quantum computing with high fidelity.

Contribution

The development and benchmarking of a cryogenic CMOS control chip that operates at 3K and controls silicon qubits at 20mK, matching the performance of commercial instruments.

Findings

Control chip achieves 99.99% fidelity with ideal qubits

Successfully controls silicon spin qubits coherently

Enables implementation of quantum algorithms like Deutsch-Josza

Abstract

The most promising quantum algorithms require quantum processors hosting millions of quantum bits when targeting practical applications. A major challenge towards large-scale quantum computation is the interconnect complexity. In current solid-state qubit implementations, a major bottleneck appears between the quantum chip in a dilution refrigerator and the room temperature electronics. Advanced lithography supports the fabrication of both CMOS control electronics and qubits in silicon. When the electronics are designed to operate at cryogenic temperatures, it can ultimately be integrated with the qubits on the same die or package, overcoming the wiring bottleneck. Here we report a cryogenic CMOS control chip operating at 3K, which outputs tailored microwave bursts to drive silicon quantum bits cooled to 20mK. We first benchmark the control chip and find electrical performance consistent with 99.99% fidelity qubit operations, assuming ideal qubits. Next, we use it to coherently control actual silicon spin qubits and find that the cryogenic control chip achieves the same fidelity as commercial instruments. Furthermore, we highlight the extensive capabilities of the control chip by programming a number of benchmarking protocols as well as the Deutsch-Josza algorithm on a two-qubit quantum processor. These results open up the path towards a fully integrated, scalable silicon-based quantum computer.