Ultrastrong coupling between electron tunneling and mechanical motion

The ultrastrong coupling of single-electron tunneling and nanomechanical motion opens exciting opportunities to explore fundamental questions develop new platforms for quantum technologies. We have measured modeled this electromechanical in a fully suspended carbon nanotube device report ratio ${g}_{\text{m}}/{\ensuremath{\omega}}_{\mathrm{m}}=2.72\ifmmode\pm\else\textpm\fi{}0.14$, where ${g}_{\text{m}}/2\ensuremath{\pi}=0.80\ifmmode\pm\else\textpm\fi{}0.04\phantom{\rule{0.16em}{0ex}}\mathrm{GHz}$ is the strength ${\ensuremath{\omega}}_{\mathrm{m}}/2\ensuremath{\pi}=294.5\phantom{\rule{0.16em}{0ex}}\mathrm{MHz}$ mechanical resonance frequency. This well within regime highest among all other platforms. show that, although was present similar devices, it went unnoticed. Even higher ratios could be achieved with improvement on design.