Coupling a single spin to the motion of a carbon nanotube

The ability to couple a solitary spin to high-frequency motion would constitute a crucial advancement for a range of applications, including quantum sensing, intermediate and long-distance spin-spin coupling, and quantum information processing. While the possibility of such coupling has been explored theoretically more than a decade ago, experimental demonstrations have remained elusive. Here we report on the first observation of spin-mechanical coupling in a carbon nanotube device. We demonstrate this coupling in two different configurations: in one case the spin and mechanics are off-resonant and excited by two different tones, and in the other they are resonant and driven by a single tone. The coupling is evidenced as a shift and a broadening of the electric dipole spin resonance (EDSR), respectively. Moreover, both experimental plots are matched extremely well with our theoretical model, taking into account the tensor character of the coupling and the non-linearity of the motion. Our results propel spin-mechanical platforms to an uncharted regime. The revealed interaction provides the full toolbox for promising applications ranging from the demonstration of macroscopic superpositions and operation of fully quantum engines, to quantum simulators.