Broadband parametric amplification for multiplexed SiMOS quantum dot signals

Spins in semiconductor quantum dots hold great promise as building blocks of quantum processors. Trapping them in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:mi>Si</a:mi> </a:math> MOS transistorlike devices eases future industrial-scale fabrication. Among the potentially scalable readout solutions, gate-based dispersive radio-frequency reflectometry only requires the already existing transistor gates to read a quantum dot state, which alleviates the need for additional elements. In this effort toward scalability, traveling-wave superconducting parametric amplifiers significantly enhance the readout signal-to-noise ratio (SNR) by reducing the noise below that of 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 3-GHz gate-based reflectometry readout of electron charge states trapped in quantum dots formed in <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:mi>Si</c:mi> </c:math> MOS multigate devices, with SNR enhanced due to a Josephson traveling-wave parametric amplifier (JTWPA). The broad tunable 2-GHz amplification bandwidth combined with more than 10-dB ON-OFF SNR improvement of the JTWPA enables frequency and time-division-multiplexed readout of interdot transitions, and noise performance consistent with JTWPA characteristics at higher frequencies. In addition, owing to a design without superconducting loops and with a metallic ground plane, the JTWPA is flux insensitive and shows stable performance up to a magnetic field of 1.1 T at the quantum dot device, compatible with standard <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mi>Si</e:mi> </e:math> MOS spin-qubit experiments.