Berlin 2018 – wissenschaftliches Programm

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SYSD: Symposium SKM Dissertation-Prize 2018

SYSD 1: SKM Dissertation-Prize 2018

SYSD 1.4: Hauptvortrag

Montag, 12. März 2018, 12:00–12:20, HE 101

Ground-state cooling of a mechanical oscillator in hybrid nano-conductors — •Pascal Stadler, Gianluca Rastelli, and Wolfgang Belzig — Universität Konstanz, Konstanz, Germany

Nanoelectromechanics paves the way to the formidable task of observing quantum effects in large mechanical systems formed by millions of atoms. To achieve this goal, a crucial requirement is cooling the mechanical resonator to very low temperatures. We show that ground-state cooling of a mechanical oscillator can be achieved via coupling of the resonator with the charge or the spin of a quantum dot inserted between (i) spin-polarized contacts [1] or (ii) a normal metal and a superconducting contact [2]. Such a system can be realized e.g. by a suspended carbon nanotube quantum dot with a suitable interaction between a vibrational mode and the charge or spin. We show that ground-state cooling of the mechanical oscillator can be achieved for many oscillator modes simultaneously [2] as well as selectively for single modes [1]. Furthermore, the nonequilibrium state of the oscillator can be detected in the current-voltage characteristics and the current noise. Our method allows a more sophisticated quantum manipulation of carbon nanotube oscillators like a coherent superposition of modes which might be used as quantum limited sensor of weight or motion.

[1] P. Stadler et. al., Phys. Rev. Lett. 113, 047201 (2014).

[2] P. Stadler et. al., Phys. Rev. Lett. 117, 197202 (2016).