arXiv subjects

M. Seitner

Publications and source records attributed to M. Seitner.

3 recordsLinked to original sources

arXiv2022

Frequency comb from a single driven nonlinear nanomechanical mode

Phononic frequency combs have been attracting an increasing attention both as a qualitatively new type of nonlinear phenomena in vibrational systems and from the point of view of applications. It is commonly believed that at least two modes must be involved in generating a comb. In this paper we demonstrate that a comb can be generated by a single nanomechanical mode driven by a resonant monochromatic drive. The comb emerges where the drive is still weak, so that the anharmonic part of the mode potential energy remains small. We relate the effect to a negative nonlinear friction induced by the resonant drive, which makes the vibrations at the drive frequency unstable. We directly map the trajectories of the emerging oscillations in the rotating frame and show how these oscillations lead to the frequency comb in the laboratory frame. The results go beyond nanomechanics and suggest a qualitatively new approach to generating tunable frequency combs in single-mode vibrational systems.

cond-mat.mes-hall↗

arXiv2021

Resonant nonlinear response of a nanomechanical system with broken symmetry

We study the response of a weakly damped vibrational mode of a nanostring resonator to a moderately strong resonant driving force. Because of the geometry of the experiment, the studied flexural vibrations lack inversion symmetry. As we show, this leads to a nontrivial dependence of the vibration amplitude on the force parameters. For a comparatively weak force, the response has the familiar Duffing form, but for a somewhat stronger force, it becomes significantly different. Concurrently there emerge vibrations at twice the drive frequency, a signature of the broken symmetry. Their amplitude and phase allow us to establish the cubic nonlinearity of the potential of the mode as the mechanism responsible for both observations. The developed theory goes beyond the standard rotating-wave approximation. It quantitatively describes the experiment and allows us to determine the nonlinearity parameters.

cond-mat.mes-hall↗

arXiv2020

Amplification and spectral evidence of squeezing in the response of a strongly driven nanoresonator to a probe field

Because of their small decay rates, nanomechanical modes enable studying strongly nonlinear phenomena for a moderately strong resonant driving. Here we study the response of a driven resonator to an additional probe field. We experimentally demonstrate resonant amplification and resonant absorption of the probe field. The corresponding spectral peaks lie on the opposite sides of the strong-drive frequency. Even though the fluctuation-dissipation theorem does not apply, we show that the response to the probe field allows us to characterize the squeezing of fluctuations about the stable states of forced oscillations. Our two-tone experiment is done in the classical regime, but our findings should equally apply to quantum fluctuations as well. In quantum terms, the observed response is due to multiphoton processes. The squeezing parameter extracted from the spectra of the response is in excellent agreement with the calculated value with no free parameters.

cond-mat.mes-hall↗