Selective Mode Suppression in a Levitated Diamagnetic Resonator Coupled to a Microwave Cavity

We present a new way to achieve selective mode dampening in levitated diamagnetic resonators through the control of eddy currents. We make use of a microwave cavity to obtain precise force and acceleration measurements of the levitated object. In vacuum conditions, the primary losses in diamagnetic oscillators are attributed to the generation of eddy currents within the levitated object.

To mitigate these losses, we have developed a composite material using graphene dust and resin, resulting in significantly reduced conductivity while retaining the high negative magnetic susceptibility for levitation. Using this material, we expect to increase the quality factor to nearly 10^6, enabling higher frequency oscillations to maintain coherence over an entire mechanical period at low temperatures. This coherence is imperative for numerous quantum electromechanical experiments and applications.

By applying a conductive layer such that only certain modes of oscillation generate substantial eddy currents one can target attenuation of those modes. Selective mode damping will be useful for preparing a system in a specific quantum state or for isolating the quantum behavior of a particular vibrational mode.