Towards a Mechanical Qubit in a Carbon Nanotube

We present our efforts towards realizing the first ever mechanical qubit [1]. We employ a pristine [2], suspended carbon nanotube with exceptional cryogenic mechanical coherence [3] and seek to significantly tailor the energy potential of its mechanical vibrations by strongly coupling its motion to a localized double quantum dot. We present measurements which demonstrate operation in the ultra-strong electromechanical coupling regime generated by an electrostatic force between a biased gate electrode and a single charge quantum dot on a suspended carbon nanotube. We further present our efforts to extend these capabilities to a high frequency nanotube, suspended above 5 independently biased gates forming a double quantum dot [4]. The gates grant control of the interaction between the quantum dots, and their coupling to mechanical vibrations enable to tunable mechanical energy potential essential in the formation of the mechanical qubit.

[1] F. Pistolesi, A. N. Cleland, A. Bachtold, arXiv:2008.10524, (2020).
[2] W. Yang et al. PRL, 125, 187701 (2020)
[3] J. Moser et al., Nat. Nanotech. 9, 1007 (2014).
[4] I. Khivrich, A. A. Clerk and S. Ilani, Nat. Nanotech., 14, 161-167 (2019).