Frequency Control and Coherent Excitation Transfer in a Nanostring-resonator Network

A key ingredient for mechanical information processing with resonator networks is the possibility to tune the relevant mode frequencies independently and to operate the resonators in the strong coupling regime. We investigate a proof-of-principle realization of such a network based on two coupled highly tensile-stressed silicon nitride nanostring resonators. We demonstrate that the fundamental mode frequencies of both nanostrings can be tuned individually by a strong drive tone resonant with one of their higher-harmonic modes. Using this frequency tuning concept, we investigate the coherent dynamics of the two strongly coupled nanostring resonators acting as an effective classical two-level system. We show classical Rabi oscillations as well as Landau-Zener dynamics, enabling the controlled spacial transfer of mechanical excitation.