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arXiv · 2606.30099

Anomalous Duffing mechanics of a suspended carbon nanotube quantum dot at ultrastrong coupling

Akong N. Loh·Furkan R. Özyiğit·Fabian Stadler·Katrin Burkert·Niklas Hüttner·Andreas K. Hüttel
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Abstract

At cryogenic temperatures, suspended single-wall carbon nanotube quantum dots act both as prototypical quantum dots as well as high-quality factor mechanical resonators. Single-electron tunneling enables reaching an ultrastrong electron-vibron coupling regime, where the coupling parameter exceeds the vibration frequency. Due to the high quality factors, a strongly nonlinear Duffing response is easily reached. Here, we quantitatively study the Duffing response parameters of such a device and their relation to Coulomb blockade oscillation. At the edges of single-electron tunneling regions, a local increase of the Duffing parameter corresponding to a stiffening spring is observed. Size and approximate scaling of the effect agree with single-electron tunneling phenomena, which however should lead to softening spring behaviour. Possible causes of these puzzling results are discussed.

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Akong N. Loh, Furkan R. Özyiğit, Fabian Stadler, Katrin Burkert, Niklas Hüttner, Andreas K. Hüttel. 2026-06-29. Anomalous Duffing mechanics of a suspended carbon nanotube quantum dot at ultrastrong coupling. https://arxiv.org/abs/2606.30099

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