Observation of decoherence in a carbon nanotube mechanical resonator

TL;DR

This paper reports the first observation of decoherence in a carbon nanotube mechanical resonator through ringdown measurements, revealing non-linear dephasing effects that impact the quality factor.

Contribution

It demonstrates the use of time-domain ringdown techniques to distinguish dephasing from dissipation in nanotube resonators, highlighting decoherence mechanisms at high amplitudes.

Findings

Spectral quality factor is four times smaller than ringdown quality factor.

Decoherence arises from non-linear dephasing at high driving amplitudes.

Time-domain techniques are crucial for understanding dissipation in nano-mechanical systems.

Abstract

In physical systems, decoherence can arise from both dissipative and dephasing processes. In mechanical resonators, the driven frequency response measures a combination of both, while time domain techniques such as ringdown measurements can separate the two. Here, we report the first observation of the mechanical ringdown of a carbon nanotube mechanical resonator. Comparing the mechanical quality factor obtained from frequency- and time-domain measurements, we find a spectral quality factor four times smaller than that measured in ringdown, demonstrating dephasing-induced decoherence of the nanomechanical motion. This decoherence is seen to arise at high driving amplitudes, pointing to a non-linear dephasing mechanism. Our results highlight the importance of time-domain techniques for understanding dissipation in nano-mechanical resonators, and the relevance of decoherence mechanisms in nanotube mechanics.