Qubit-assisted transduction for a detection of surface acoustic waves near the quantum limit

TL;DR

This paper presents a hybrid quantum system that enables ultra-sensitive detection of surface acoustic wave fluctuations near the quantum limit by leveraging qubit-assisted transduction and noise spectroscopy.

Contribution

It introduces a novel qubit-assisted transduction method for detecting surface acoustic waves with quantum-limited sensitivity.

Findings

Thermal fluctuations of the SAW resonator were observed near the quantum limit.

Parametric coupling enabled up-conversion of SAW excitations to microwave signals.

The system demonstrated ultra-sensitive measurement capabilities.

Abstract

We demonstrate ultra-sensitive measurement of fluctuations in a surface-acoustic-wave~(SAW) resonator using a hybrid quantum system consisting of the SAW resonator, a microwave (MW) resonator and a superconducting qubit. The nonlinearity of the driven qubit induces parametric coupling, which up-converts the excitation in the SAW resonator to that in the MW resonator. Thermal fluctuations of the SAW resonator near the quantum limit are observed in the noise spectroscopy in the MW domain.