Strongly-coupled nanotube electromechanical resonators

TL;DR

This paper reports the fabrication of two strongly-coupled, tunable nanotube electromechanical resonators that enable control of charge, spin states, and long-distance electron interactions, advancing quantum information applications.

Contribution

First demonstration of a micro-transfer technique creating strongly-coupled, electrically-tunable resonators on a single carbon nanotube with observed nonlocal modulation effects.

Findings

Strong coupling between electron charge and phonon modes.

Nonlocal conductance modulation by phonon modes.

Potential for phonon-mediated spin entanglement.

Abstract

Coupling an electromechanical resonator with carbon-nanotube quantum dots is a significant method to control both the electronic charge and the spin quantum states. By exploiting a novel micro-transfer technique, we fabricate two strongly-coupled and electrically-tunable mechanical resonators on a single carbon nanotube for the first time. The frequency of the two resonators can be individually tuned by the bottom gates, and strong coupling is observed between the electron charge and phonon modes of each resonator. Furthermore, the conductance of either resonator can be nonlocally modulated by the phonon modes in the other resonator. Strong coupling is observed between the phonon modes of the two resonators, which provides an effective long distance electron-electron interaction. The generation of phonon-mediated-spin entanglement is also theoretically analyzed for the two resonators. This strongly-coupled nanotube electromechanical resonator array provides an experimental platform for future studies of the coherent electron-phonon interaction, the phonon mediated long-distance electron interaction, and entanglement state generation.