Ultrawide-range photon number calibration using a hybrid system combining nano-electromechanics and superconducting circuit quantum electrodynamics

TL;DR

This paper introduces a hybrid system combining superconducting circuits and nano-electromechanics to calibrate photon numbers across nine orders of magnitude, demonstrating accurate measurement methods in both low and high power regimes.

Contribution

It presents a novel hybrid platform that integrates superconducting qubits and nanomechanical resonators for precise photon number calibration over a wide range.

Findings

Photon numbers calibrated up to nine orders of magnitude.

Quantitative agreement between two calibration methods.

Successful integration of superconducting circuits with nano-electromechanics.

Abstract

We present a hybrid system consisting of a superconducting coplanar waveguide resonator coupled to a nanomechanical string and a transmon qubit acting as nonlinear circuit element. We perform spectroscopy for both the transmon qubit and the nanomechanical string. Measuring the ac-Stark shift on the transmon qubit as well as the electromechanically induced absorption on the string allows us to determine the average photon number in the microwave resonator in both the low and high power regimes. In this way, we measure photon numbers that are up to nine orders of magnitude apart. We find a quantitative agreement between the calibration of photon numbers in the microwave resonator using the two methods. Our experiments demonstrate the successful combination of superconducting circuit quantum electrodynamics and nano-electromechanics on a single chip.