Recently, solid-state mechanical resonators have become a platform for demonstrating non-classical behavior of systems involving a truly macroscopic number of particles. Here, we perform the most macroscopic quantum test in a mechanical resonator to date, which probes the validity of quantum mechanics at the microgram mass scale. This is done by a direct measurement of the Wigner function of a high-overtone bulk acoustic wave resonator mode, monitoring the gradual decay of negativities over tens of microseconds. While the obtained macroscopicity of μ=11.3 is on par with state-of-the-art atom interferometers, future improvements of mode geometry and coherence times could confirm the quantum superposition principle at unprecedented scales.
@article{arxiv.2209.06635,
title = {Macroscopic quantum test with bulk acoustic wave resonators},
author = {Björn Schrinski and Yu Yang and Uwe von Lüpke and Marius Bild and Yiwen Chu and Klaus Hornberger and Stefan Nimmrichter and Matteo Fadel},
journal= {arXiv preprint arXiv:2209.06635},
year = {2023}
}