Broadband parametric amplification for multiplexed SiMOS quantum dot signals

TL;DR

This paper demonstrates broadband, multiplexed charge state readout of SiMOS quantum dots using a Josephson traveling-wave parametric amplifier, achieving high SNR, broad bandwidth, and magnetic field stability suitable for scalable quantum computing.

Contribution

It introduces a flux-insensitive JTWPA with broad tunable bandwidth for multiplexed quantum dot readout, enhancing signal quality without complex superconducting loops.

Findings

Achieved 3 GHz gate-based reflectometry readout of SiMOS quantum dots.

Enhanced SNR by over 10 dB using JTWPA, enabling multiplexed readout.

Demonstrated stable amplifier performance up to 1.2 Tesla magnetic field.

Abstract

Spins in semiconductor quantum dots hold great promise as building blocks of quantum processors. Trapping them in SiMOS transistor-like devices eases future industrial scale fabrication. Among the potentially scalable readout solutions, gate-based dispersive radiofrequency reflectometry only requires the already existing transistor gates to readout a quantum dot state, relieving the need for additional elements. In this effort towards scalability, traveling-wave superconducting parametric amplifiers significantly enhance the readout signal-to-noise ratio (SNR) by reducing the noise below typical cryogenic low-noise amplifiers, while offering a broad amplification band, essential to multiplex the readout of multiple resonators. In this work, we demonstrate a 3GHz gate-based reflectometry readout of electron charge states trapped in quantum dots formed in SiMOS multi-gate devices, with SNR enhanced thanks to a Josephson traveling-wave parametric amplifier (JTWPA). The broad, tunable 2GHz amplification bandwidth combined with more than 10dB ON/OFF SNR improvement of the JTWPA enables frequency and time division multiplexed readout of interdot transitions, and noise performance near the quantum limit. In addition, owing to a design without superconducting loops and with a metallic ground plane, the JTWPA is flux insensitive and shows stable performances up to a magnetic field of 1.2T at the quantum dot device, compatible with standard SiMOS spin qubit experiments.