Generating Giant and Tunable Nonlinearity in a Macroscopic Mechanical Resonator from Chemical Bonding Force

TL;DR

This paper demonstrates a record-high nonlinear response in a macroscopic mechanical resonator by exploiting anharmonicity in a single chemical bond, enabling tunable nonlinearity and observation of vibrational bistate transitions at low temperature.

Contribution

The authors experimentally realize a giant, tunable nonlinearity in a macroscopic mechanical system through chemical bond anharmonicity, surpassing previous nonlinear response strengths.

Findings

Achieved a cubic elastic constant of 2×10^{18} N/m^3, much larger than prior reports.

Observed vibrational bistate transitions driven by thermal noise at 6 K.

Demonstrated tunability of nonlinearity via chemical bonding control.

Abstract

Nonlinearity in macroscopic mechanical system plays a crucial role in a wide variety of applications, including signal transduction and processing, synchronization, and building logical devices. However, it is difficult to generate nonlinearity due to the fact that macroscopic mechanical systems follow the Hooke's law and response linearly to external force, unless strong drive is used. Here we propose and experimentally realize a record-high nonlinear response in macroscopic mechanical system by exploring the anharmonicity in deforming a single chemical bond. We then demonstrate the tunability of nonlinear response by precisely controlling the chemical bonding interaction, and realize a cubic elastic constant of \mathversion{bold}$2 \times 10^{18}~{\rm N}/{\rm m^3}$, many orders of magnitude larger in strength than reported previously. This enables us to observe vibrational bistate transitions of the resonator driven by the weak Brownian thermal noise at 6~K. This method can be flexibly applied to a variety of mechanical systems to improve nonlinear responses, and can be used, with further improvements, to explore macroscopic quantum mechanics.