Regensburg 2019 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 42: Nano- and Optomechanics
TT 42.1: Talk
Wednesday, April 3, 2019, 10:45–11:00, H7
Optomechanics of a suspended carbon nanotube quantum dot coupled to a coplanar microwave resonator, part 1: theory — Stefan Blien, Patrick Steger, Niklas Hüttner, Richard Graaf, and •Andreas K. Hüttel — Institute for Experimental and Applied Physics, Universität Regensburg, Regensburg, Germany
A clean, suspended single wall carbon nanotube is the ultimate limit of a nanomechanical beam resonator, where the fundamental transversal vibration mode reaches resonance frequencies on the order of 100MHz – 1 GHz and mechanical quality factors up to 106. Placing a nanotube next to a coplanar resonator at cryogenic temperatures results in a microwave optomechanical system with dispersive coupling. This system, however, has a fundamentally new property: the nanotube is also a quantum dot, and the interaction of motion and single electron tunneling dominates its behaviour.
We demonstrate how Coulomb blockade leads to an enhanced optomechanical coupling g that is also tuneable by the gate potential. The inherent electronic nonlinearity acts as amplifier, leading to values up to g≃ 10 kHz already at moderate cavity occupation. With the combined optomechanical system in the far resolved sideband limit, many interesting experiments become feasible.