On-chip Parametric Amplification in a Double Quantum Dots Circuit

TL;DR

This paper introduces a novel on-chip parametric amplifier using double quantum dots, achieving high gain and improved qubit readout, addressing key challenges in microwave quantum circuits.

Contribution

It demonstrates a reconfigurable quantum circuit with a DQD-based parametric amplifier, offering enhanced readout and new options for microwave quantum circuit amplification.

Findings

Achieved over 11 dB gain with the DQD-based amplifier.

Enhanced qubit readout with more than twofold SNR improvement.

Presented a versatile platform for quantum circuit readout enhancement.

Abstract

In microwave-based quantum circuits, including double quantum dots (DQDs), superconducting qubits and spin qubits, parametric amplifiers are indispensable in achieving high-fidelity qubit readouts. Despite its importance, the application of parametric amplifiers is hampered by several challenges, such as high insertion losses, constrained tunability, and a pronounced vulnerability to magnetic fields. Here, we demonstrate an on-site single-atom parametric amplifier (SAPA) within a reconfigurable quantum circuit, which consists of a superconducting microwave cavity and two GaAs gate-defined DQDs. Leveraging the inherent nonlinearity of the DQD, a parametric gain exceeding 11 dB is achieved. This gain contributes to enhance the qubit readout, as evidenced by exceeding two times improvement in the signal-to-noise ratio (SNR) when employing the DQD-based amplifier for reading out another DQD. Our work not only presents a versatile experimental platform with enhanced readout capabilities in quantum computing, but also introduces alternative choices of parametric amplifiers for a variety of microwave-based quantum circuits.