Classical decoherence in a nanomechanical resonator

TL;DR

This paper investigates classical decoherence in a nanomechanical resonator by experimentally controlling frequency fluctuations, providing insights into phase coherence loss and its implications for quantum and classical systems.

Contribution

It introduces a method to quantitatively model classical decoherence in mechanical resonators by separating pure dephasing from dissipation and demonstrates control over artificial dephasing.

Findings

Controlled frequency fluctuations induce measurable dephasing.

Silicon-nitride beams exhibit near-ideal properties.

Experimental and theoretical models align well.

Abstract

Decoherence is an essential mechanism that defines the boundary between classical and quantum behaviours, while imposing technological bounds for quantum devices. Little is known about quantum coherence of mechanical systems, as opposed to electromagnetic degrees of freedom. But decoherence can also be thought of in a purely classical context, as the loss of phase coherence in the classical phase space. Indeed the bridge between quantum and classical physics is under intense investigation, using in particular classical nanomechanical analogues of quantum phenomena. In the present work, by separating pure dephasing from dissipation, we quantitatively model the classical decoherence of a mechanical resonator: through the experimental control of frequency fluctuations, we engineer artificial dephasing. Building on the fruitful analogy introduced between spins/quantum bits and nanomechanical modes, we report on the methods available to define pure dephasing in these systems, while demonstrating the intrinsic almost-ideal properties of silicon-nitride beams. These experimental and theoretical results, at the boundary between classical nanomechanics and quantum information fields, are prerequisite in the understanding of decoherence processes in mechanical devices, both classical and quantum.