UC Merced

Levitating, controlling, and detecting the motion of mesoscopic objects is useful for inertial sensing and fundamental studies in quantum physics. We report the first experimental measurements of Meissner-effect levitation for a sequence of identical millimeter-scale neodymium magnets having varying strengths within a cm-scale superconducting aluminum coaxial quarter-wave stub cavity. We experimentally, theoretically, and analytically characterized Meissner-effect levitation within a 10 GHz superconducting aluminum coaxial quarter-wave stub cavity for a sequence of identically shaped millimeter-scale neodymium magnets having varying strengths (1.22-1.47 T). Magnet levitation within the cavity is accompanied by both gradual and abrupt shifts in the resonance frequency (with a height sensitivity as large as 400 MHz/mm) as well as changes in the total quality factor (8%-17%) as a function of temperature during the superconducting transition of the aluminum cavity. The experimental observation is confirmed with a cylindrical and spherical magnet. The controlled heating and cooling of the cavity show hysteresis in the frequency shift. Furthermore, the experimental observation has shown excellent agreement with finite element simulations, room temperature measurements, and a lumped element model.