Noise thermometry and electron thermometry of a sample-on-cantilever system below 1 Kelvin

TL;DR

This study employs noise and electron thermometry to investigate thermal fluctuations in a microcantilever system below 1 Kelvin, demonstrating thermal equilibrium between macroscopic and microscopic degrees-of-freedom, which is promising for quantum experiments.

Contribution

It introduces combined noise and electron thermometry methods to measure and compare macroscopic and microscopic temperatures in a cantilever system at sub-Kelvin temperatures.

Findings

Thermal equilibrium maintained down to 300 mK

Both temperature measurements respond similarly to localized heating

Feasibility of using micromechanical devices for quantum experiments

Abstract

We have used two types of thermometry to study thermal fluctuations in a microcantilever-based system below 1 K. We measured the temperature of a cantilever's macroscopic degree-of-freedom (via the Brownian motion of its lowest flexural mode) and its microscopic degrees-of-freedom (via the electron temperature of a metal sample mounted on the cantilever). We also measured both temperatures' response to a localized heat source. We find it possible to maintain thermal equilibrium between these two temperatures and a refrigerator down to at least 300 mK. These results are promising for ongoing experiments to probe quantum effects using micromechanical devices.