Towards a carbon nanotube-based hybrid quantum platform

Abstract

Hybrid quantum systems that integrate electronic, mechanical, and optical degrees of freedom hold promise as a versatile platform for quantum state preparation and manipulation. Yet, combining all three within a single device is notoriously difficult, and very few platforms in the world are able to do so. Among these, suspended carbon nanotubes (CNTs) stand out as ideal candidates for performing experiments in the quantum regime. The device we study consists of a pristine, suspended CNT, which is electrostatically controlled by an underlying array of five independent gates. We present an exhaustive study of the electronic degree of freedom of this device, fabricated using a stamping protocol. By precisely tuning the voltage on the gates, we can define high-quality single and double quantum dots in the nanotube. From their electronic transport characteristics, all electrostatic parameters of the device can be extracted. The double quantum dot is shown to be highly tunable, and it allows us to attain a regime where an electron delocalized over the two quantum dots can be used as an electronic two-level system. We will successfully demonstrate how previous double dot operation levels in the field can be matched, and a promising qubit outlook will finally be presented